COMBUSTOR HAVING DRIVER JETS FOR A GAS TURBINE ENGINE

Description

TECHNICAL FIELD

The present disclosure relates generally to a combustor having driver jets for a gas turbine engine.

BACKGROUND

Turbine engines, for example, for aircraft, generally include a fan and a turbo-engine section arranged in flow communication with one another. The turbo-engine includes, in serial flow relationship, a compressor section, a combustion section, and a turbine section. The combustion section includes a combustor where the compressed air is mixed with fuel and ignited to generate combustion gases.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages will be apparent from the following, more particular, description of various exemplary embodiments, as illustrated in the accompanying drawings, wherein like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements.

FIG. 1 is a schematic cross-sectional view of a turbine engine, according to an embodiment of the present disclosure.

FIG. 2 is a cross-sectional side view of a combustor of the turbine engine shown in FIG. 1, according to an embodiment of the present disclosure.

FIG. 3A is a schematic view sharing dimensions of a driver hole provided within a liner including a dome structure, an outer liner, and/or an inner liner, according to an embodiment of the present disclosure.

FIG. 3B is a schematic view showing dimensions of a driver hole provided within the liner including a dome structure, an outer liner, and/or an inner liner, according to another embodiment of the present disclosure.

FIG. 3C is a schematic view showing dimensions of a driver hole provided within a dome structure, an outer liner, and/or an inner liner, according to an embodiment of the present disclosure.

FIG. 4A is a plot of a discharge coefficient versus a ratio of curvature radius r of an inlet curvature to a diameter d (r/d) of the driver hole, according to the embodiment of the present disclosure.

FIG. 4B is a plot of the discharge coefficient versus a ratio of distance Lc of the inlet curvature to the diameter d (Lc/d) of the driver hole, according to the embodiment of the present disclosure.

FIG. 4C is a plot of the discharge coefficient versus a ratio of distance c of an inlet chamfer to the diameter d (c/d) of the driver hole, according to the embodiment of the present disclosure.

FIG. 5 is a schematic cross-sectional view of a liner defining a combustion chamber, the liner including a first segment and a second segment, according to an embodiment of the present disclosure.

FIG. 6A is a partial, schematic cross-sectional view showing details of the second segment and one or more driver holes in the second segment, according to an embodiment of the present disclosure.

FIG. 6B is a partial, schematic cross-sectional view showing details of the second segment and the one or more driver holes, according to another embodiment of the present disclosure.

FIGS. 7A and 7B are partial, schematic cross-sectional views showing details of the first segment and one or more driver holes, according to an embodiment of the present disclosure.

FIGS. 8A and 8B are partial, schematic cross-sectional views showing details of the second segment and the one or more driver holes, according to another embodiment of the present disclosure.

FIGS. 8C and 8D are partial, schematic cross-sectional views showing details of the second segment and the one or more driver holes, according to another embodiment of the present disclosure.

FIG. 9A is a partial, schematic cross-sectional view showing details of coupling the second segment having the one or more driver holes to the liner, according to an embodiment of the present disclosure.

FIG. 9B is a partial, schematic cross-sectional view showing details of coupling the second segment having the one or more driver holes to the liner, according to another embodiment of the present disclosure.

FIG. 9C is a top view of the second segment coupled to the liner using fasteners shown in FIG. 9B, according to an embodiment of the present disclosure.

FIG. 9D is a partial, schematic cross-sectional view showing details of coupling the second segment having the one or more driver holes to the liner, according to yet another embodiment of the present disclosure.

FIG. 10A is a partial, schematic cross-sectional view of the second segment having one or more driver holes integrally formed with the liner, according to an embodiment of the present disclosure.

FIG. 10B is a partial, schematic cross-sectional view of the second segment having one or more driver holes integrally formed with the liner, according to another embodiment of the present disclosure.

FIG. 11 is a schematic cross-sectional view of the liner of the combustor including the first segment and the second segment, according to an embodiment of the present disclosure.

FIG. 12 is a partial schematic cross-sectional view of a portion of the first segment having one or more driver vanes, according to an embodiment of the present disclosure.

FIG. 13 is a partial schematic cross-sectional view of a portion of the second segment having one or more driver vanes, according to an embodiment of the present disclosure.

FIG. 14 is a partial, schematic view of a geometric ramp of the first segment taken at line 14-14 shown in FIG. 11, according to an embodiment of the present disclosure.

FIG. 15 is a partial schematic view of a geometric ramp of the second segment taken at line 15-15 shown in FIG. 11, according to an embodiment of the present disclosure.

FIG. 16 is a partial, schematic cross-sectional enlarged view of a portion of the first segment having one or more driver holes, according to an embodiment of the present disclosure.

FIG. 17 is a partial, schematic cross-sectional view of a portion of the second segment having one or more driver holes, according to an embodiment of the present disclosure.

FIG. 18 is a partial, schematic view of a geometric ramp of the first segment taken at line 18-18 shown in FIG. 16, according to an embodiment of the present disclosure.

FIG. 19 is a partial, schematic view of a geometric ramp of the second segment taken at line 19-19 shown in FIG. 17, according to an embodiment of the present disclosure.

FIG. 20 is a schematic view of a driver hole with various dimensions, according to an embodiment of the present disclosure.

FIG. 21 is a schematic view of a driver hole with various dimensions, according to an embodiment of the present disclosure.

FIG. 22A shows schematic elevational views of example driver holes having a circular shape, according to an embodiment of the present disclosure.

FIG. 22B shows schematic elevational views of other example driver holes having a circular shape with different radii, according to another embodiment of the present disclosure.

FIG. 23A shows schematic elevational views of example driver holes having an oval shape, according to an embodiment of the present disclosure.

FIG. 23B shows schematic elevational views of example driver holes having an egg shape, according to another embodiment of the present disclosure.

FIG. 24A shows schematic elevational views of example driver slots having an “I” shape, according to an embodiment of the present disclosure.

FIG. 24B shows schematic elevational views of example driver slots having a wavy shape, according to another embodiment of the present disclosure.

FIG. 25A is a cutaway longitudinal cross-sectional view of an example driver hole having a conical shape, according to an embodiment of the present disclosure.

FIG. 25B is a top transverse view of the driver hole shown in FIG. 5A, according to an embodiment of the present disclosure.

FIG. 26A is a cutaway longitudinal cross-sectional view of an example driver hole having a fluted shape, according to another embodiment of the present disclosure.

FIG. 26B is a top transverse view of the driver hole shown in FIG. 6A, according to another embodiment of the present disclosure.

FIG. 27A is a cutaway longitudinal cross-sectional view of an example driver hole having a rifled shape, according to another embodiment of the present disclosure.

FIG. 27B is a top transverse view of the driver hole shown in FIG. 7A, according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

Features, advantages, and embodiments of the present disclosure are set forth or apparent from a consideration of the following detailed description, drawings, and claims. Moreover, the following detailed description is exemplary and intended to provide further explanation without limiting the scope of the disclosure as claimed.

Various embodiments of the present disclosure are discussed in detail below. While specific embodiments are discussed, this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without departing from the present disclosure.

As used herein, the terms “first” and “second” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.

The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows.

The terms “forward” and “aft” refer to relative positions within a turbine engine or vehicle, and refer to the normal operational attitude of the turbine engine or vehicle. For example, with regard to a turbine engine, forward refers to a position on the turbine engine that is closer to the propeller or the fan and aft refers to a position on the turbine engine that is further away from the propeller or the fan.

As used herein, the term “axial” refers to directions and orientations that extend substantially parallel to a centerline of the turbine engine. As used herein, the term “radial” refers to directions and orientations that extend substantially perpendicular to the centerline of the turbine engine. In addition, as used herein, the terms “circumferential” and “circumferentially” refer to directions and orientations that extend arcuately about the centerline of the turbine engine.

As used herein, “top” refers to a highest or uppermost point, portion, or surface of a component in the orientations shown in the figures.

As used herein, the terms “low,” “mid” (or “mid-level”), and “high,” or their respective comparative degrees (e.g., “lower” and “higher”, where applicable), when used with compressor, combustor, turbine, shaft, fan, or turbine engine components, each refers to relative pressures, relative speeds, relative temperatures, or relative power outputs within an engine unless otherwise specified. For example, a “low-power” setting defines the engine or the combustor configured to operate at a power output lower than a “high-power” setting of the engine or the combustor, and a “mid-level power” setting defines the engine or the combustor configured to operate at a power output higher than a “low-power” setting and lower than a “high-power” setting. The terms “low,” “mid” (or “mid-level”) or “high” in such aforementioned terms may additionally, or alternatively, be understood as relative to minimum allowable speeds, pressures, or temperatures, or minimum or maximum allowable speeds, pressures, or temperatures relative to normal, desired, steady state, etc., operation of the engine. A mission cycle for a turbine engine includes, for example, a low-power operation, a mid-level power operation, and a high-power operation. Low-power operation includes, for example, engine start, idle, taxiing, and approach. Mid-level power operation includes, for example, cruise. High-power operation includes, for example, takeoff and climb.

The various power levels of the turbofan engine are defined as a percentage of a sea level static (SLS) maximum engine rated thrust. Low power operation includes, for example, less than thirty percent (30%) of the SLS maximum engine rated thrust of the turbofan engine. Mid-level power operation includes, for example, thirty percent (30%) to eighty-five percent (85%) of the SLS maximum engine rated thrust of the turbofan engine. High power operation includes, for example, greater than eighty-five percent (85%) of the SLS maximum engine rated thrust of the turbofan engine. The values of the thrust for each of the low power operation, the mid-level power operation, and the high power operation of the turbofan engine are exemplary only, and other values of the thrust can be used to define the low power operation, the mid-level power operation, and the high power operation.

The terms “coupled,” “fixed,” “attached,” “connected,” and the like, refer to both direct coupling, fixing, attaching, or connecting, as well as indirect coupling, fixing, attaching, or connecting through one or more intermediate components or features, unless otherwise specified herein.

The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.

As used herein, a “turbo-engine” includes a compressor section, a combustion section, and a turbine section.

As used herein, a “turbofan engine” includes a turbo-engine and a fan that directs air into the turbo-engine, and rated for use in a regional aircraft, narrow body aircraft, or wide body aircraft. A turbofan engine rated for use on a regional aircraft will have a maximum takeoff thrust in a range of ten thousand pound-force to twenty thousand pound-force (10,000 lbf to 20,000 lbf). A turbofan engine rated for use on a narrow body aircraft will have a maximum takeoff thrust in a range of fifteen thousand pound-force to thirty thousand pound-force (15,000 lbf to 30,000 lbf). A turbofan engine rated for use on a wide body aircraft will have a maximum takeoff thrust in a range of forty thousand pound-force to one hundred ten thousand pound-force (40,000 lbf to 110,000 lbf).

As used herein, the term “ducted engine” means a turbofan engine with a fan casing or nacelle that circumferentially surrounds the fan.

Hereafter, the term “turbofan engine” will refer to either a “ducted engine” or an “open fan engine.”

As used herein, a Mach number is a ratio of the speed of the turbofan engine (of the aircraft) to the speed of sound in the surrounding airflow.

Approximating language, as used herein throughout the specification and claims, is applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” “generally,” and “substantially” is not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value, or the precision of the methods or the machines for constructing the components and/or the systems or manufacturing the components and/or the systems. For example, the approximating language may refer to being within a one, two, four, ten, fifteen, or twenty percent margin in either individual values, range(s) of values and/or endpoints defining range(s) of values.

Providing gas turbine engines with reduced length and weight while maintaining or improving combustion efficiency is a significant challenge due to the high level of maturity. Reducing length or combustion volume typically leads to lower efficiency and incomplete combustion in the combustor of the turbine engine.

The use of vortex combustors allows for reducing combustor length and volume while maintaining or improving combustion efficiency. For example, conventional trapped vortex combustors have a reduced length or volume while maintaining, or even improving, combustion efficiency. However, conventional trapped vortex combustors have a limitation. The trap in a trapped vortex combustor becomes less effective at small combustor sizes. Alternatively, an un-trapped or partially trapped vortex combustor can be implemented. However, maintaining a stable toroidal vortex without a trap may be difficult to accomplish.

The present disclosure uses driver airflow jets to both provide stability of an untrapped vortex as well as to reduce pattern factor. As used herein, “stability of a vortex” means that the flow structure of the vortex is such that the vortex is maintained across all power conditions low to high and recirculates some portion of combustion gases from aft to forward within the combustor in a circular type motion. The term “pattern factor” is used herein to refer to a maximum circumferential temperature variation at the exit of the combustor. The pattern factor (PTF) is defined as a two-dimensional (2D) curve of maximum combustor exit temperature for each radial span (T4max,r−T3) divided by bulk average combustor exit temperature (T4avg) versus radial span, i.e., PTF=(T4max,r−T3)/T4avg, where r ranges from 0% to 100% of combustor exit height. High pattern factor can damage downstream turbine hardware. In typical gas turbine combustors maintaining a low pattern factor is difficult due to the primary zone stabilization through many individual circumferentially adjacent swirlers each with flow swirling about their own respective axis. In a vortex combustor the primary zone has a single vortex with a central axis stretching circumferentially around the combustor encouraging fuel and air to move and mix circumferentially helping to reduce hot streaks and high pattern factor compared to current individual swirl stabilized combustors of current art. By implementing shaped driver holes or circumferential slots in the combustor, vortex stabilization can be improved while also reducing circumferential variation, essentially optimizing the vortex combustor performance.

Further stabilization can be achieved by locally increasing the thickness of the liner either by using a separate piece or integral to the liner of the combustor to increase L/D of the driver holes or slots, where L represents a length of the driver hole and D represents a diameter of the driver hole. Thin liners with cross flow on the inlet side result in the driver jet(s) leaning more aft. The term “driver jet” is used herein throughout to describe an airflow jet that is directed to drive a vortex inside the combustion chamber of the combustor. Greater L/D can better align the jet normal to the liner improving jet penetration to close of the vortex. Greater L/D also reduces sensitivity of jet direction to the inlet cross flow.

Increased L/D also enables use of vanes instead of holes. As a result, more vanes can be used than holes, and the vanes can be shaped to further optimize the vortex and adjacent flow field. Whether using a hole or using a vane, a tangential component can be added that is not possible with thin liners. The tangential component can then impart a bulk swirler vortex that increases residence time and allows for the same or greater combustion efficiency in a shorter combustor with less volume. Bulk swirl also allows greater circumferential mixing and reduction in pattern factor.

In an embodiment, driver holes or driver slots can be used to induce a toroidal vortex in a combustor. The driver holes and the driver slots can be of varying size and shape to optimize balance between driving vortex and minimizing pattern factor, where the driver holes or the driver slots are drilled, machined, or grown into the liner of constant or near constant thickness. The L/D ratio for driver holes can be from about 0.05 to about 0.70.

In another embodiment, driver holes or slots in which the driver holes or driver slots are in a thicker section of the liner that is welded or otherwise attached to the liners or integral to liners. The driver holes and the driver slots can have an L/D ratio of 0.20 to 5.0 or greater. Driver slots can also include a tangential component such air coming out of the driver slots to generate a tangential air flow component to impart bulk swirl in the combustor. Near continuous slots can also be used to create a driver sheet of air to reduce pattern factor. For example, by utilizing long circumferential slots a more continuous sheet of air is provided than when using a series of driver holes, leading to fewer gaps between slots than holes for rich streaks of fuel to pass through to secondary zone. Improved air/fuel mixing and fewer or weaker rich streaks reduces max peak temperature at exit of combustor which translates to lower pattern factor.

In another embodiment, vanes can be used in a thicker segment of the liner instead of the driver slots or the driver holes. The vanes may have a different leading edge than a trailing edge angle compared to combustor radial line. In addition, the vanes can have a different angle from axial forward to axial aft. The vanes can impart smaller wakes for greater turbulence levels and also produce an air sheet similar to a continuous driver slot. However, vanes provide structural connection between forward and aft sections of the liner without having large gap like holes or slots further reducing magnitude of rich streaks of fuel/air. Local vane spacing (effective area) can be circumferentially varied with relation to fuel injection to further reduce any rich streaks of fuel/air for even greater reduction in pattern factor or thermal NO_x.

A shorter combustor with less volume allows for a shorter and a lighter weight combustor and combustor case, which may provide fuel savings. Reducing the length of the combustor has additional benefits such as reducing the length of the engine shaft between the fan/compressor and the LPT/HPT turbine, resulting in reduced shaft dynamics, and may also allow increased aircraft volume and weight to be used for carrying capacity.

In addition, improving the pattern factor provides the added benefit of reducing necessary cooling for the turbine, leading to less parasitic loss and higher specific fuel consumption (SFC).

Referring now to the drawings, FIG. 1 is a schematic cross-sectional view of a turbine engine 10, taken along a longitudinal centerline axis 12 of the turbine engine 10, according to an embodiment of the present disclosure. As shown in FIG. 1, the turbine engine 10 defines an axial direction A (extending parallel to the longitudinal centerline axis 12 provided for reference) and a radial direction R that is normal to the axial direction A. In general, the turbine engine 10 includes a fan section 14 and a turbo-engine 16 disposed downstream from the fan section 14.

The turbo-engine 16 includes, in serial flow relationship, a compressor section 21, a combustion section 26, and a turbine section 27. The turbo-engine 16 is substantially enclosed within an outer casing 18 that is substantially tubular and defines a turbo-engine inlet 20 that is annular about the longitudinal centerline axis 12. As schematically shown in FIG. 1, the compressor section 21 includes a booster or a low pressure (LP) compressor 22 followed downstream by a high pressure (HP) compressor 24. The combustion section 26 is downstream of the compressor section 21. The turbine section 27 is downstream of the combustion section 26 and includes a high pressure (HP) turbine 28 followed downstream by a low pressure (LP) turbine 30. The turbo-engine 16 further includes a jet exhaust nozzle section 32 that is downstream of the turbine section 27, a high-pressure (HP) shaft 34 or a spool, and a low-pressure (LP) shaft 36. The HP shaft 34 drivingly connects the HP turbine 28 to the HP compressor 24. The HP turbine 28 and the HP compressor 24 rotate in unison through the HP shaft 34. The LP shaft 36 drivingly connects the LP turbine 30 to the LP compressor 22. The LP turbine 30 and the LP compressor 22 rotate in unison through the LP shaft 36. The compressor section 21, the combustion section 26, the turbine section 27, and the jet exhaust nozzle section 32 together define a turbo-engine air flow path.

For the embodiment depicted in FIG. 1, the fan section 14 includes a fan 38 (e.g., a variable pitch fan) having a plurality of fan blades 40 coupled to a disk 42 in a spaced apart manner. As depicted in FIG. 1, the fan blades 40 extend outwardly from the disk 42 generally along the radial direction R. In the case of a variable pitch fan, the plurality of fan blades 40 are rotatable relative to the disk 42 about a pitch axis P by virtue of the fan blades 40 being operatively coupled to an actuation member 44 configured to collectively vary the pitch of the fan blades 40 in unison. The fan blades 40, the disk 42, and the actuation member 44 are together rotatable about the longitudinal centerline axis 12 via a fan shaft 45 that is powered by the LP shaft 36 across a power gearbox, also referred to as a gearbox assembly 46. In this way, the fan 38 is drivingly coupled to, and powered by, the turbo-engine 16, and the turbine engine 10 is an indirect drive engine. The gearbox assembly 46 is shown schematically in FIG. 1. The gearbox assembly 46 is a reduction gearbox assembly for adjusting the rotational speed of the fan shaft 45 and, thus, the fan 38 relative to the LP shaft 36 when power is transferred from the LP shaft 36 to the fan shaft 45.

Referring still to the exemplary embodiment of FIG. 1, the disk 42 is covered by a fan hub 48 that is aerodynamically contoured to promote an airflow through the plurality of fan blades 40. In addition, the fan section 14 includes an annular fan casing or a nacelle 50 that circumferentially surrounds the fan 38 and at least a portion of the turbo-engine 16. The nacelle 50 is supported relative to the turbo-engine 16 by a plurality of outlet guide vanes 52 that are circumferentially spaced about the nacelle 50 and the turbo-engine 16. Moreover, a downstream section 54 of the nacelle 50 extends over an outer portion of the turbo-engine 16, and, with the outer casing 18, defines a bypass airflow passage 56 therebetween.

During operation of the turbine engine 10, a volume of air 58 enters the turbine engine 10 through an inlet 60 of the nacelle 50 or the fan section 14. As the volume of air 58 passes across the fan blades 40, a first portion of air, also referred to as bypass air 62 is routed into the bypass airflow passage 56, and a second portion of air, also referred to as turbo-engine air 64, is routed into the upstream section of the turbo-engine air flow path through the turbo-engine inlet 20 of the LP compressor 22. The pressure of the turbo-engine air 64 is then increased, generating compressed air 65. The compressed air 65 is routed through the HP compressor 24 and into the combustion section 26, where the compressed air 65 is mixed with fuel and ignited to generate combustion gases 66.

The combustion gases 66 are routed into the HP turbine 28 and expanded through the HP turbine 28 where a portion of thermal energy or kinetic energy from the combustion gases 66 is extracted via one or more stages of HP turbine stator vanes 68 and HP turbine rotor blades 70 that are coupled to the HP shaft 34. This causes the HP shaft 34 to rotate, thereby supporting operation of the HP compressor 24 (self-sustaining cycle). In this way, the combustion gases 66 do work on the HP turbine 28. The combustion gases 66 are then routed into the LP turbine 30 and expanded through the LP turbine 30. Here, a second portion of the thermal energy or the kinetic energy is extracted from the combustion gases 66 via one or more stages of LP turbine stator vanes 72 and LP turbine rotor blades 74 that are coupled to the LP shaft 36. This causes the LP shaft 36 to rotate, thereby supporting operation of the LP compressor 22 (self-sustaining cycle) and rotation of the fan 38 via the gearbox assembly 46. In this way, the combustion gases 66 do work on the LP turbine 30.

The combustion gases 66 are subsequently routed through the jet exhaust nozzle section 32 of the turbo-engine 16 to provide propulsive thrust. Simultaneously, the bypass air 62 is routed through the bypass airflow passage 56 before being exhausted from a fan nozzle exhaust section 76 of the turbine engine 10, also providing propulsive thrust. The HP turbine 28, the LP turbine 30, and the jet exhaust nozzle section 32 at least partially define a hot gas path 78 for routing the combustion gases 66 through the turbo-engine 16.

A controller 100 is in communication with the turbine engine 10 for controlling aspects of the turbine engine 10. For example, the controller 100 is in two-way communication with the turbine engine 10 for receiving signals from various sensors and control systems of the turbine engine 10, and for controlling components of the turbine engine 10, as detailed further below. The controller 100, or components thereof, may be located onboard the turbine engine 10, onboard the aircraft, or can be located remote from each of the turbine engine 10 and the aircraft. The controller 100 can be a Full Authority Digital Engine Control (FADEC) that controls aspects of the turbine engine 10.

The controller 100 may be a standalone controller or may be part of an engine controller to operate various systems of the turbine engine 10. In this embodiment, the controller 100 is a computing device having one or more processors and a memory. The one or more processors can be any suitable processing device, including, but not limited to, a microprocessor, a microcontroller, an integrated circuit, a logic device, a programmable logic controller (PLC), an application specific integrated circuit (ASIC), or a Field Programmable Gate Array (FPGA). The memory can include one or more computer-readable media, including, but not limited to, non-transitory computer-readable media, a computer readable non-volatile medium (e.g., a flash memory), a RAM, a ROM, hard drives, flash drives, or other memory devices.

The memory can store information accessible by the one or more processors, including computer-readable instructions that can be executed by the one or more processors. The instructions can be any set of instructions or a sequence of instructions that, when executed by the one or more processors, cause the one or more processors and the controller 100 to perform operations. The controller 100 and, more specifically, the one or more processors are programmed or configured to perform these operations, such as the operations discussed further below. In some embodiments, the instructions can be executed by the one or more processors to cause the one or more processors to complete any of the operations and functions for which the controller 100 is configured, as will be described further below. The instructions can be software written in any suitable programming language or can be implemented in hardware. Additionally, or alternatively, the instructions can be executed in logically or virtually separate threads on the processors. The memory can further store data that can be accessed by the one or more processors.

The technology discussed herein makes reference to computer-based systems and actions taken by, and information sent to and from, computer-based systems. One of ordinary skill in the art will recognize that the inherent flexibility of computer-based systems allows for a great variety of possible configurations, combinations, and divisions of tasks and functionality between and among components. For instance, processes discussed herein can be implemented using a single computing device or multiple computing devices working in combination. Databases, memory, instructions, and applications can be implemented on a single system or distributed across multiple systems. Distributed components can operate sequentially or in parallel.

The turbine engine 10 depicted in FIG. 1 is by way of example only. In other exemplary embodiments, the turbine engine 10 may have any other suitable configuration. For example, in other exemplary embodiments, the fan 38 may be configured in any other suitable manner (e.g., as a fixed pitch fan) and further may be supported using any other suitable fan frame configuration. The turbine engine 10 may also be a direct drive engine, which does not have a power gearbox. The fan speed is the same as the LP shaft speed for a direct drive engine. Moreover, in other exemplary embodiments, any other suitable number or configuration of compressors, turbines, shafts, or a combination thereof may be provided. In still other exemplary embodiments, aspects of the present disclosure may be incorporated into any other suitable turbine engine, such as, for example, turbofan engines, propfan engines, turbojet engines, turboprop, turboshaft engines, or aeroderivative ground based engines.

FIG. 2 is a cross-sectional side view of a combustor 206 in the combustion section 26 of the turbo-engine 16 shown in FIG. 1, according to an embodiment of the present disclosure. FIG. 2 depicts a longitudinal combustor centerline axis 112 that may generally correspond to the longitudinal centerline axis 12 (FIG. 1). The combustor 206, shown in FIG. 2, defines a combustor longitudinal direction (L) corresponding to the longitudinal combustor centerline axis 112, a combustor radial direction (R) extending outward from the longitudinal combustor centerline axis 112, and a combustor circumferential direction (C) extending circumferentially about the longitudinal combustor centerline axis 112. The combustor 206 extends from an upstream end 253 of the combustor 206 to a downstream end 255 of the combustor 206. The upstream end 253 of the combustor 206 may be in airflow communication with a diffuser 257 that is in airflow communication with the HP compressor 24 (shown in FIG. 1). The diffuser 257, in one aspect, may be arranged between an upstream end 263 of an outer casing 264 of the combustor 206 and an upstream end 265 of an inner casing 266 of the combustor 206. The downstream end 255 of the combustor 206 is in airflow communication with a turbine nozzle 272 that is in airflow communication with the HP turbine 28 (shown in FIG. 1). The outer casing 264 may extend circumferentially about the longitudinal combustor centerline axis 112 and may extend longitudinally from the upstream end 253 of the combustor 206 to the downstream end 255 of the combustor 206. The inner casing 266 may also extend circumferentially about the longitudinal combustor centerline axis 112 and may extend longitudinally from the upstream end 253 of the combustor 206 to the downstream end 255 of the combustor 206.

The combustor 206 further includes a dome structure 256 that may include an inner dome portion 258 and an outer dome portion 260. Together, the inner dome portion 258 and the outer dome portion 260 define a turn portion 262 that may be generally a convex-shaped curve that forms a flow path for directing the flow of combustion products within the combustor 206. In addition, the convex-shaped curve of the dome structure 256 may assist in guiding a portion of compressed airflow 282A to flow to an outer flow passage 288, and assist in guiding another portion of the compressed airflow 282B to flow to an inner flow passage 290. The convex-shaped curve of the dome structure 256 may therefore help to reduce pressure losses in the flow of compressed air 282 that may otherwise occur when a more blunt-shaped dome structure is implemented.

An outer liner 252 may extend downstream from an outer end 261 of the dome structure 256, and an inner liner 254 may extend downstream from an inner end 259 of the dome structure 256. The outer liner 252 and the inner liner 254 may be formed integral with the dome structure 256 (e.g., formed of a continuous structural material, such as a formed ceramic matrix composite (CMC) structure, additively manufactured, or forged/casted single piece), or may be joined to the dome structure 256 via, for example, a mechanical connection (e.g., a bolted connection), or bonded via, for example, welding or brazing. The inner liner 254, the outer liner 252, and the dome structure 256 form a liner 269 and define a combustion chamber 267. The inner liner 254 and the outer liner 252 extend longitudinally along the longitudinal combustor centerline axis 112 and circumferentially around the longitudinal combustor centerline axis 112. The inner liner 254 and the outer liner 252 are radially spaced apart from each other to define therebetween the combustion chamber 267. The outer liner 252 is spaced apart from the outer casing 264 to define therebetween the outer flow passage 288. The inner liner 254 is spaced apart from the inner casing 266 to define therebetween the inner flow passage 290.

As used herein, CMC refers to a class of materials with reinforcing fibers in a ceramic matrix. Generally, the reinforcing fibers provide structural integrity to the ceramic matrix. Some examples of reinforcing fibers can include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), non-oxide carbon-based materials (e.g., carbon), oxide ceramics (e.g., silicon oxycarbides, silicon oxynitrides, aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), aluminosilicates such as mullite, or mixtures thereof), or mixtures thereof.

Some examples of ceramic matrix materials can include, but are not limited to, non-oxide silicon-based materials (e.g., silicon carbide, silicon nitride, or mixtures thereof), oxide ceramics (e.g., silicon oxycarbides, silicon oxynitrides, aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), aluminosilicates, or mixtures thereof), or mixtures thereof. Optionally, ceramic particles (e.g., oxides of Si, Al, Zr, Y, and combinations thereof) and inorganic fillers (e.g., pyrophyllite, wollastonite, mica, talc, kyanite, and montmorillonite) can also be included within the ceramic matrix.

Generally, particular CMCs can be referred to as their combination of type of fiber/type of matrix. For example, C/SiC for carbon-fiber-reinforced silicon carbide, SiC/SiC for silicon carbide-fiber-reinforced silicon carbide, SiC/SiN for silicon carbide fiber-reinforced silicon nitride, SiC/SiC—SiN for silicon carbide fiber-reinforced silicon carbide/silicon nitride matrix mixture, etc. In other examples, the CMCs can be comprised of a matrix and reinforcing fibers comprising oxide-based materials such as aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), aluminosilicates, and mixtures thereof. Aluminosilicates can include crystalline materials such as mullite (3Al₂O₃·2SiO₂), as well as glassy aluminosilicates.

In certain non-limiting examples, the reinforcing fibers may be bundled (e.g., form fiber tows) and/or coated prior to inclusion within the matrix. The bundles of fibers may be impregnated with a slurry composition prior to forming the preform or after formation of the preform. The preform may then undergo thermal processing, and subsequent chemical processing to arrive at a component formed of a CMC material having a desired chemical composition. For example, the preform may undergo a cure or a burn-out to yield a high char residue in the preform, and subsequent melt-infiltration with silicon, or a cure or a pyrolysis to yield a silicon carbide matrix in the preform, and subsequent chemical vapor infiltration with silicon carbide. Additional steps may be taken to improve densification of the preform, either before or after chemical vapor infiltration, by injecting the preform with a liquid resin or a polymer followed by a thermal processing step to fill the voids with the silicon carbide. A CMC material as used herein may be formed using any known or hereafter developed methods including, but not limited to, melt infiltration, chemical vapor infiltration, polymer impregnation pyrolysis (PIP), or any combination thereof.

A fuel nozzle assembly 274 may be connected to the outer casing 264, and may extend through the outer casing 264 and through the outer liner 252 to provide a flow of fuel 275 to the combustion chamber 267. The compressed air 82 enters the combustor 206 via the diffuser 257 as an inlet airflow. A portion of the compressed air 282, shown schematically as compressed airflow 282A, flows into the outer flow passage 288, while another portion of the compressed air 282, shown schematically as compressed airflow 282B, flows into the inner flow passage 290. In an embodiment, the compressed airflow 282A in the outer flow passage 288 passes through openings 256A (e.g., holes, slots, or vanes) in the dome structure 256 and the outer liner 252 into the combustion chamber 267. The compressed airflow 282B in the inner flow passage 290 passes through openings (e.g., holes, slots, or vanes) in the dome structure 256 and the inner liner 254 into the combustion chamber 267 to generate a vortex 295 with the compressed airflow 282A and to mix with the fuel 275. In addition, the compressed airflow 282A in the outer flow passage 288 passes through openings (e.g., holes, slots, or vanes) in the dome structure 256 and the outer liner 252 into the combustion chamber 267. The compressed airflow 282B in the inner flow passage 290 passes through openings (e.g., holes, slots, or vanes) in the dome structure 256 and the inner liner 254 into the combustion chamber 267 to generate the vortex 295 and a vortex 297 with the compressed airflow 282A and to mix with the fuel 275. In an embodiment, as will be explained further in detail in the following paragraphs, the holes, slots and/or vanes in the dome structure 256, the outer liner 252, and/or in the inner liner 254 can be configured to orient a direction of flow of the compressed airflow 282A and a direction of flow of the compressed airflow 282B so as to create the vortex 295 and/or the vortex 297.

FIG. 3A is a schematic view showing dimensions of a driver hole 300 provided within the liner 269 including the dome structure 256 (FIG. 2), the outer liner 252 (FIG. 2), and/or the inner liner 254 (FIG. 2), according to an embodiment of the present disclosure. The compressed airflow 282A is introduced through the driver hole 300 in the liner 269 including the dome structure 256, the outer liner 252, and/or the inner liner 254 with an upstream pressure Pup to form a jet of air flow at a pressure P_jet to enter a combustion chamber 267 at a downstream pressure P_down. As shown in FIG. 3A, the driver hole 300 has a thickness or a length Li and a diameter D.

FIG. 3B is a schematic view showing dimensions of a driver hole 302 provided within the liner 269 including the dome structure 256 (FIG. 2), the outer liner 252 (FIG. 2), and the inner liner 254 (FIG. 2), according to another embodiment of the present disclosure. The compressed airflow 282A is introduced through the driver hole 302 in the liner 269 including the dome structure 256, the outer liner 252, and/or the inner liner 254 with an upstream pressure Pup to form a jet of air flow at a pressure P_jet to enter a combustion chamber 267 at a downstream pressure P_down. As shown in FIG. 3B, the driver hole 302 has a thickness or length l₂ and diameter D. As shown in FIGS. 3A and 3B, the length l₂ of the driver hole 302 is greater than the length 11 of the driver hole 300. The driver hole 302 and the driver hole 300 have approximately the same diameter D.

Conventional liners have lesser length to diameter (L/D) ratios, for example, less than 0.5. However, in driver holes, such as driver hole 300, having relatively lesser length to diameter (L/D) ratios, air flow detachment F, as indicated by converging contour lines indicating flow detachment from sidewalls of the driver hole, occurs leading to lower effective area and potential injection of hot gas, as shown in FIG. 3A. By increasing the length (thickness) of a driver hole and thus the length to diameter (L/D) ratio, the air flow within the hole reattaches and more air pressure (P_jet) is recovered at the exit of the driver hole 302, shown in FIG. 3B. As shown in FIG. 3A, with a relatively smaller L/D ratio, the Vena Contracta (the narrowest waist of the airflow) occurs within the combustion chamber 267, leading to lower effective area and potential injection of hot gas. On the other hand, as shown in FIG. 3B, with a relatively larger L/D ratio, the Vena Contracta (the narrowest waist of the airflow) occurs within the driver hole, leading to a more homogenous airflow at the exit of the driver jet, hence, leading to an improved discharge coefficient, as shown in FIG. 3B.

FIG. 3C is a schematic view showing dimensions of a driver hole 304 provided within the liner 269 including the dome structure 256 (FIG. 2), the outer liner 252 (FIG. 2), and the inner liner 254 (FIG. 2), according to an embodiment of the present disclosure. As shown in FIG. 3C, the driver hole 304 has a thickness or a length L_T and a diameter D. In an embodiment, the driver hole 304 may include an inlet chamfer 304A or an inlet curvature 304B with a radius R. The inlet chamfer 304A forms an angle θ relative to a wall 306 from a depth c or the depth L_c of the wall 306 of the driver hole 304. The sum of the depth c and the depth L_c is equal to the length L_T. The inlet curvature 304B can also form an arc having the radius R from the depth L_c of the wall 306 of the driver hole 304. The inlet chamfer 304A and/or the inlet curvature 304B can improve pressure recovery. However, the deeper the inlet chamfer 304A or the greater the radius R of the inlet curvature 304B, the lesser the ratio of the depth L_c to the diameter d. As a result, a discharge coefficient Cd of the airflow jet can be sensitive to manufacturing tolerance. Changes in the discharge coefficient Cd can increase pattern factor by increasing flow variation from driver hole to driver hole. Increasing the length (thickness) of a driver hole and thus the length to diameter ratio L/D provides for an improved discharge coefficient, thus leading to a more consistent flow.

FIG. 4A is a plot of the discharge coefficient, versus a ratio of curvature radius R of the inlet curvature 304B (FIG. 3C) to the diameter D (R/D) of the driver hole 304 (FIG. 3C), according to an embodiment of the present disclosure. The x-axis represents the ratio of curvature radius R of the inlet curvature 304B to the diameter D (R/D) of the driver hole 304. The y-axis represents the discharge coefficient C_d. As shown in FIG. 4A, the discharge coefficient Cd increases at a lower R/D ratio and then tapers off to a generally a constant level for a relatively greater r/d ratio.

FIG. 4B is a plot of the discharge coefficient, versus a ratio of distance L_c of the inlet curvature 304B to the diameter D (L_c/D) of the driver hole 304, according to an embodiment of the present disclosure. The x-axis represents the ratio of distance L_c of the inlet curvature 304B to the diameter D (L_c/D) of the driver hole 304. The y-axis represents the discharge coefficient Cd. As shown in FIG. 4B, the discharge coefficient Cd increases at lower L_c/D ratio and then decreases at a constant rate at a relatively greater L_c/D ratio. The driver hole 304 operates at a relatively smaller L_c/D ratio at around a higher level of the discharge coefficient Cd, at box 404. Whereas, conventional driver holes operate at a lesser L_c/D ratio and at a lesser discharge coefficient Cd, at box 406. A greater L_c/D has a higher and more stable Cd, meaning that the effective area of the driver hole 304 is less sensitive to manufacturing tolerance of hole diameter and length. The longer L_c/D also makes the exit angle of the driver hole 304 less sensitive to changes in passage cross flow on inlet side of driver hole 304. Less variation in Cd due to manufacturing and less change in exit angle due to cross flow both mean more consistent flow from hole-to-hole resulting in reduced rich or lean streaks downstream of the driver holes reducing pattern factor and thermal NO_x.

FIG. 4C is a plot of the discharge coefficient, versus a ratio of distance c of the inlet chamfer 304A (FIG. 3C) to the diameter D (c/D) of the driver hole 304, according to an embodiment of the present disclosure. The x-axis represents the ratio of distance c of the inlet chamfer 304A to the diameter D (c/D) of the driver hole 304. The y-axis represents the discharge coefficient C_d. As shown in FIG. 4C, the discharge coefficient C_d increases at lower c/D ratio and then tapers off to a constant level for a relatively greater c/D ratio. However, it is noted that increasing the angle θ of the inlet chamfer 304A decreases the discharge coefficient C_d and decreasing the angle θ of the inlet chamfer 304A increases the discharge coefficient C_d. Conventional driver holes operate at a relatively wide range of c/D ratios in a constant regime of the discharge coefficient, at box 400. Alternatively, the driver hole 304 can have a larger L/D allowing a smaller hole size allowing operation at mid c/D ratio in regime of constant discharge coefficient C_d versus c/D where discharge coefficient of the driver hole 304 is less sensitive to variations in chamfer depth due to manufacturing tolerance, at box 402. Less variation in C_d due to manufacturing means more consistent flow from hole-to-hole resulting in richer or leaner streaks at the combustor exit which helps lower pattern factor and thermal NO_x.

FIG. 5 is a schematic cross-sectional view of a liner 269 defining combustion chamber 267, the liner 269 including a first segment 502 and a second segment 504, according to an embodiment of the present disclosure. The first segment 502 is coupled to the outer liner 252 and the second segment 504 is coupled to the inner liner 254. Although, two segments are depicted in FIG. 5, one or more segments can be used. In general, a plurality of segments can be spatially distributed throughout a surface of the liner 269. The first segment 502 and the second segment 504 are provided to increase a thickness of the liner 269 at locations of driver holes 502A and 504A, respectively, to improve the discharge coefficient C_d and, also bring the discharge coefficient C_d to a more stable region, as shown, for example, at box 404 in FIG. 4B and at box 402 in FIG. 4C to reduce flow variation from driver hole to driver hole. The increase in thickness of the liner 269 (e.g., the outer liner 252 and/or the inner liner 254, shown in FIG. 2) at the location of the driver holes 502A and 504A includes an increase of the length of the driver holes 502A and 504A and thus an overall increase in the length to diameter (L/D) ratio of the driver holes 502A and 504A. The term “driver hole” is used herein to mean one or more driver holes. For example, the first segment 502 can include one or more driver holes 502A and the second segment 504 can include one or more driver holes 504A. The increase in the discharge coefficient Cd can reduce the overall pressure differential ΔP and/or can improve airflow jet exit pressure. Increasing the length to diameter ratio (L/D) of the driver holes 502A and 504A can also ensure that a velocity of the airflow jet exiting the driver holes 502A and 504A within the combustion chamber 267 is at an increased angle (for example, between 30° and 150°) relative to a surface of the liner 269 (e.g., a surface of the outer liner 252 and/or a surface of the inner liner 254) compared to driver holes with legacy L/D ratios to drive a vortex 506 and/or a vortex 508, regardless of upstream crossflow (e.g., compressed airflow 282A and compressed airflow 282B, shown in FIG. 2). In conventional combustor liners, the length to diameter (LID) ratio of driver holes is relatively lesser than the L/D ratio of the driver holes 502A and 504A. In conventional combustor liners, the upstream crossflow adds a significant component velocity parallel to the upstream crossflow. As a result, the airflow jet leans over tangentially to the liner 269 to generate a less effective vortex 506 and/or vortex 508.

FIG. 6A is a partial, schematic cross-sectional view showing details of the second segment 504 and the one or more driver holes 504A, according to an embodiment of the present disclosure. As shown in FIG. 6A, the second segment 504 includes a geometric ramp 600 that is coupled to the liner 269. An upstream crossflow 602 flows substantially tangentially to the liner 269 and is represented by an arrow. The upstream crossflow 602 has a pressure Pup. An airflow portion 604 of the upstream crossflow 602 goes through the driver hole 504A provided with the geometric ramp 600 of the second segment 504. The driver hole 504A traverses the entire thickness of the geometric ramp 600. The airflow portion 604 is guided by the driver hole 504A to generate an airflow jet 606 within the combustion chamber 267 (shown in FIG. 5). The combustion chamber 267 is at a pressure P_down. The airflow jet 606 makes an angle θjet relative to a flat interior surface 600A of the geometric ramp 600 of the second segment 504 facing the combustion chamber 269 (shown in FIG. 5). The airflow jet 606 also makes an angle θjet relative to a surface of the liner 269. The airflow jet 606 enters the combustion chamber 267 with a pressure Piet. The airflow jet penetration is proportional to fixed chute nozzle (FCN), according to the following expression (1) which can be converted to expression (2).

? ( 1 ) ? ( 2 ) ? indicates text missing or illegible when filed

As shown in expression (1), FCN is a function that depends on diameter D of the driver hole 504A, the pressure P_je and the square of the velocity u_jet², and the angle θ_jet that the airflow jet makes with respect to the relatively flat interior surface 600A of the geometric ramp 600 of the second segment 504. As expressed by expression (2), FCN is a function that depends on diameter D of the driver hole 504A, the angle θ_jet that the airflow jet makes with respect to the flat interior surface 600A of the geometric ramp 600 of the second segment 504, and two times the difference in pressure (2ΔP). ΔP represents the difference in pressure or pressure differential. U_∞ represents a free stream across flow velocity on the downstream side of the liner 269.

In general, increased length to diameter (L/D) ratio of the driver hole 504A reduces sensitivity of the driver jet angle θ_jet to the back side velocity u_jet. In an embodiment, a driver hole with L/D ratio greater than or equal to one may be preferred for purpose of limiting backside velocity impacts. This provides improved stability and increased jet angle θ_jet. The resulting increased jet penetration crossing over more than half the radial span of the combustor supports closure of the vortex on the downstream side by limiting the amount of flow that passes out of the vortex zone without being circulated. As a result, the overall stability of the vortex is improved.

In an embodiment, as shown in FIG. 6A, the geometric ramp 600 has a trapezoid shape. In an embodiment, the geometric ramp 600 has grooves 600B for coupling with the liner 269. As shown in FIG. 6A, the geometric ramp 600 has a relatively flat interior surface 600A facing the combustion chamber 267 (shown in FIG. 5) and has a protrusion or bump 600C opposite the relatively flat interior surface 600A. The protrusion or the bump 600C provides the ability to increase a thickness or a length of the driver hole 504A provided within the geometric ramp 600.

FIG. 6B is a partial, schematic cross-sectional view showing details of the second segment 504 and the one or more driver holes 504A, according to another embodiment of the present disclosure. As shown in FIG. 6B, the second segment 504 includes a geometric ramp 601 that is coupled to the liner 269. Similar to the embodiment depicted FIG. 6A, the upstream crossflow 602 flows substantially tangentially to the liner 269 and is represented by an arrow. The upstream crossflow 602 has a pressure Pup. The airflow portion 604 of the upstream crossflow 602 goes through the driver hole 504A in the geometric ramp 601 of the second segment 504. The airflow portion 604 is guided by the driver hole 504A to generate an airflow jet 606 within combustion chamber 267 (shown in FIG. 5). The combustion chamber 267 is at a pressure P_down. The airflow jet 606 makes an angle θ_jet relative to an interior surface 601A of the geometric ramp 601 of the second segment 504 facing the combustion chamber 269 (shown in FIG. 5). The airflow jet 606 enters the combustion chamber 267 with a pressure P_jet.

In an embodiment, as shown in FIG. 6B, the geometric ramp 601 has a diamond shape. In an embodiment, the geometric ramp 601 has grooves and/or edges 601B for coupling with the liner 269. As shown in FIG. 6B, contrary to the geometric ramp 600 of FIG. 6A, the geometric ramp 601 has an interior surface 601A facing the combustion chamber 267 (shown in FIG. 5) that has a curved shape and also has a protrusion or bump 601C opposite the interior surface 601A. The interior surface 601A together with the protrusion or bump 601C further increase a thickness or a length of the driver hole 504A provided within the geometric ramp 601.

Geometric ramps (e.g., geometric ramp 600 or geometric ramp 601) can be added to the liner 269 to provide both cooling of the liner 269 and free stream airflow to align with airflow jet angle to further reinforce vortex stability. Geometric ramp 600 and 601 can be flush to the downstream side of the liner 269 while still having the interior surface 601A that is curved at the upstream side for increasing L/D of the driver holes. As shown in FIG. 6B, the interior surface 601A that is curved at the upstream side can act to help turn the liner cooling flow and the near wall combustion gases upward in direction more parallel to the airflow jet 606 (driver jet), further assisting in increase of penetration of the airflow jet 606 (driver jet) and creating proper vortex. Ramp configuration may be driven from various requirements such pitch angle of the combustor, adjacent liner shape, durability requirements, etc.

FIGS. 7A and 7B are partial, schematic cross-sectional views showing details of the first segment 502 and the one or more driver holes 502A, according to an embodiment of the present disclosure. The perspective views shown in FIGS. 7A and 7B are shown at different perspective angles. As shown in FIGS. 7A and 7B, the first segment 502 includes a geometric ramp 700 that is coupled to the liner 269. The geometric ramp 700 includes a fuel conduit 702 for causing fuel to flow into the combustion chamber 267 (shown in FIG. 5). The fuel conduit 702 is provided within a body 700A (air-fuel block) of the geometric ramp 700. The fuel conduit 702 is shown having a rectangular shape. However, the fuel conduit 702 can have any desired shape (circular, oval, polygonal, etc.). The fuel conduit 702 is configured to communicate through a fuel channel 702A with the combustion chamber 267 to generate a fuel jet to exit through a nozzle 702B of the fuel channel 702A. The fuel jet exiting through the nozzle 702B mixes with an airflow vortex 701. The geometric ramp 700 includes one or more first driver holes 704 and one or more second driver holes 706 corresponding to the one or more driver holes 502A (shown in FIG. 5). The one or more first driver holes 704 communicate with an airflow path 704A provided within the body 700A of the geometric ramp 700 to guide a first airflow jet 704B into the combustion chamber 267. The one or more second driver holes 706 traverse the entire thickness of portion 706A of the body 700A of the geometric ramp 700 to guide an airflow jet 706B into the combustion chamber 267 (shown in FIG. 5).

The geometric ramp 700 further includes a hood 708 coupled to the body 700A of the geometric ramp 700 via a link portion 708A (shown more distinctly in FIG. 7B). The link portion 708A extends from the hood 708 to the body 700A of the geometric ramp 700. The hood 708 is spaced apart from the body 700A by the link portion 708A to define an airflow channel 708B. The hood 708 curves slightly to form an upstream curved portion 708C. The upstream curved portion 708C is spaced apart from the body 700A of the geometric ramp 700 and follows the contours of the body 700A of the geometric ramp 700 to define an inlet 708D. The hood 708 is configured to guide a portion of an upstream crossflow 710 having a pressure Pup through the airflow channel 708B. The portion of the upstream crossflow 710 is captured by the upstream curved portion 708C, enters through the inlet 708D, and is guided through the airflow channel 708B.

The hood 708 also curves slightly to form a downstream curved portion 708E. The downstream curved portion 708E is spaced apart from the body 700A of the geometric ramp 700 and follows the contours of the body 700A of the geometric ramp 700 at an interface of the geometric ramp 700 with the liner 269 to define an outlet 708F. The portion of the upstream crossflow 710 that entered through the inlet 708D and is guided through the airflow channel 708B splits into a first airflow portion and a second airflow portion. The first airflow portion enters through the one or more second driver holes 706 and is converted into airflow jet 706B (driver jet). The second airflow portion exits the airflow channel 708B through the outlet 708F. The ratio of the first airflow portion that is converted into airflow jet 706B to the second airflow portion that exits through the outlet 708F can be selected so as to provide an airflow jet 706B that is conducive to driving the vortex 701 that increasing the stability of the vortex 701.

FIGS. 8A and 8B are partial, schematic cross-sectional views showing details of the second segment 504 and the one or more driver holes 504A, according to another embodiment of the present disclosure. The views shown in FIGS. 8A and 8B are shown at different perspective angles. As shown in FIGS. 8A and 8B, the second segment 504 includes a geometric ramp 800 that is coupled to the liner 269. The geometric ramp 800 includes one or more driver holes 804 corresponding to the one or more driver holes 504A (shown in FIG. 5). The one or more driver holes 804 traverse the entire thickness of portion 800A of a body 800B of the geometric ramp 800 to guide an airflow jet 806 into the combustion chamber 267 (shown in FIG. 5). The body 800B of the geometric ramp 800 is shown having a trapezoid cross-sectional shape and the one or more driver holes 804 are provided in a thicker portion of the trapezoid cross-sectional shape. However, the body 800B of the geometric ramp 800 can have any shape, including a rounded shape or other polygonal shape. In an embodiment, the body 800B of the geometric ramp 800 is provided with grooves 800C that are arranged for coupling with the liner 269.

The geometric ramp 800 further includes one or more scoops 808. In an embodiment, as shown in FIGS. 8A and 8B, the geometric ramp 800 includes a plurality of scoops 808, for example. Each of the one or more scoops 808 is provided in communication with the one or more driver holes 804. The one or more scoops are located near each of the one or more driver holes 804. Hence, one scoop in the one or more scoops 808 is associated with a driver hole in the one or more driver holes 804. The one or more scoops 808 extend from the body 800B of the geometric ramp 800 at the location of the one or more driver holes 804. In an embodiment, the one or more scoops 808 are configured to intercept a first portion of an upstream crossflow 810 to guide the first portion through the one or more driver holes 804 to generate the airflow jet 806. The airflow jet 806 can be a plurality of spaced apart airflow jets (driver jets) generated using a plurality of driver holes 804. Each airflow jet of the plurality of airflow jets 806 is generated by a corresponding driver hole of the plurality of driver holes 804. A second portion of the upstream crossflow 810 is not intercepted by the one or more scoops 808 and instead, passes between or over the one or more scoops 808. In an embodiment, the one or more scoops 808 are configured to convert more of a total pressure of the upstream crossflow 810 instead of static pressure to increase pressure supply to the one or more airflow jets 806 to increase momentum of the one or more airflow jet 806. Increasing momentum of the one or more airflow jets 806 provides the ability to drive the vortex (not shown in FIGS. 8A and 8B) while increasing the penetration of the one or more airflow jets 806 to close the vortex and thus increase vortex stability.

FIGS. 8C and 8D are partial, schematic cross-sectional views showing details of the second segment 504 and the one or more driver holes, according to another embodiment of the present disclosure. The views shown in FIGS. 8C and 8D are also shown at different perspective angles. The embodiment shown in FIGS. 8C and 8D are similar in many aspects to the embodiments shown in FIGS. 8A and 8B. Therefore, a description of similar features will not be repeated, and similar features are referred to herein using the same reference numerals. The main difference between the embodiment shown in FIGS. 8A and 8B and the embodiment shown in FIGS. 8C and 8D is that, instead of providing a plurality of scoops 808 (FIGS. 8A and 8B), a single scoop 818 is used that forms a single ridge extending 360° around a circumference of the inner liner 254 (shown in FIG. 2). The one or more driver holes 804 (corresponding to the driver holes 504A) end near the single scoop 818. In this embodiment, the single scoop 818 is not localized to each of the one or more driver holes 804. Instead, the single scoop 818 is associated with the entirety of the one or more driver holes 804. In an embodiment, the single scoop 818 is configured to intercept a first portion of the upstream crossflow 810 to guide the first portion of the upstream crossflow 810 through the one or more driver holes 804 to generate the airflow jet 806. The airflow jet 806 can be a plurality of spaced apart airflow jets generated using a plurality of driver holes 804. A second portion of the upstream crossflow 810 is not intercepted by the single scoop 818 and instead passes over the single scoop 818. One benefit of providing the single scoop 818 instead of a plurality of scoops 808 may be to facilitate manufacture. However, this may be at the expense of reduced control of the airflow jets 806.

FIG. 9A is a partial, schematic cross-sectional view showing details of coupling the second segment 504 having the one or more driver holes to the liner 269, according to an embodiment of the present disclosure. As shown in FIG. 9A, the second segment 504 includes a geometric ramp 900 that is coupled to the liner 269. The geometric ramp 900 includes one or more driver holes 904 corresponding to the one or more driver holes 504A (shown in FIG. 5). The one or more driver holes 904 traverse the entire thickness of a portion 900A of a body 900B of the geometric ramp 900. The body 900B of the geometric ramp 900 is shown having a trapezoid cross-sectional shape. However, the body 900B of the geometric ramp 900 can have any shape, including a rounded shape or other polygonal shape. As shown in FIG. 9A, the body 900B of the geometric ramp 900 is provided with grooves 900C that are provided at opposite ends of the body 900B and are configured for coupling the body 900B with the liner 269. In embodiment, the body 900B of the geometric ramp 900 is further welded or brazed to the liner 269 (e.g., the inner liner 254, shown in FIG. 2) at the grooves 900C.

FIG. 9B is a partial, schematic cross-sectional view showing details of coupling the second segment 504 having the one or more driver holes to the liner 269, according to another embodiment of the present disclosure. The embodiment shown in FIG. 9B is similar in many aspects to the embodiment shown in FIG. 9A. In the embodiment shown in FIG. 9B, instead of, or in addition to brazing or welding at the grooves 900C, fasteners 909 (e.g., pins) can be used to attach or to mount the body 900B of the geometric ramp 900 to the liner 269 (e.g., inner liner 254 shown in FIG. 2) at an interface of the liner 269 with the grooves 900C.

FIG. 9C is a top view of the second segment 504 coupled to the liner 269 using fasteners 909 shown in FIG. 9B, according to an embodiment of the present disclosure. As shown in FIG. 9C, the fasteners 909 can be distributed on each end of the body 900B of the geometric ramp 900 along the annular circumference direction.

FIG. 9D is a partial, schematic cross-sectional view showing details of coupling the second segment 504 having the one or more driver holes 504A to the liner 269, according to yet another embodiment of the present disclosure. The embodiment shown in FIG. 9D is similar in many aspects to the embodiments shown in FIG. 9A and FIG. 9B. In the embodiment shown in FIG. 9D, the body 900B of the geometric ramp 900 includes a plurality of flanges 900D. In an embodiment, as shown in FIG. 9D, the plurality of flanges 900D are provided at an angle of about 90° relative to the body of the geometric ramp 900. The plurality of flanges 900D of the body 900B of the geometric ramp 900 are coupled to a plurality of arm extensions 910 of the liner 269. The plurality of arm extensions 910 are provided at an angle of about ninety degrees relative to the liner 269 to match the angle of the flanges 900D. A plurality of fasteners 912 (e.g., screws with bolts or pins, etc.) can be used to attach the plurality of flanges 900D of the body 900B of the geometric ramp 900 to the plurality of arm extensions 910 of the liner 269 (e.g., inner liner 254, shown in FIG. 2).

FIG. 10A is a partial, schematic cross-sectional view of the second segment 504 having one or more driver holes integrally formed with the liner 269, according to an embodiment of the present disclosure. In an embodiment, the second segment 504 includes the geometric ramp 900 that is coupled to the liner 269. The geometric ramp 900 includes the one or more driver holes 904 corresponding to the one or more driver holes 504A (shown in FIG. 5). The body 900B of the geometric ramp 900 is integrally formed as one piece with the liner 269, and from the same material as that of the liner 269. In an embodiment, the body 900B of the geometric ramp 900 can be cast, forged, machined, or additively grown.

FIG. 10B is a partial, schematic cross-sectional view of the second segment 504 having one or more driver holes integrally formed with the liner 269, according to another embodiment of the present disclosure. In this embodiment, the body 900B of the geometric ramp 900 is also integrally formed from the same material as that of the liner 269. In this embodiment, as shown in FIG. 10B, the body 900B of the geometric ramp 900 includes voids 914. The voids 914 are provided to reduce weight of the body 900B of the geometric ramp 900 and thus to reduce the overall weight of the combustor 206 (shown in FIG. 2). In an embodiment, the body 900B of the geometric ramp 900 having the voids 914 can be additively grown. The voids 914 can also provide reduced thermal gradients in the combustor liner 269 around the driver jets 904 which result in reduced material stresses especially in regions of thickness transition, compared to locally thickened liner with no voids.

FIG. 11 is a schematic cross-sectional view of the liner 269 of the combustor 206 including the first segment 502 and the second segment 504, according to an embodiment of the present disclosure. This embodiment is similar in many aspects to the embodiment shown in FIG. 5. In this embodiment, the first segment 502 has driver vanes 1002 instead of driver holes 502A (shown in FIG. 5). In this embodiment, the second segment 504 has driver vanes 1004 instead of driver holes 504A (shown in FIG. 5). The driver vanes 1002 and the driver vanes 1004 will be described in detail in the following paragraphs.

FIG. 12 is a partial, schematic cross-sectional view of a portion of the first segment 502 having one or more driver vanes 1002, according to an embodiment of the present disclosure. In this embodiment, the first segment 502 includes a geometric ramp 1202. The geometric ramp 1202 includes a body 1202B having the one or more driver vanes 1002. In the embodiment shown in FIG. 12, the body 1202B of the geometric ramp 1202 is shown having a plurality of driver vanes 1002. The plurality of driver vanes 1002 are similar in certain aspects to the driver holes described in the above paragraphs. Compared to one or more driver holes, the one or more driver vanes 1002 provide the additional benefit of packing more openings in a small area, thus allowing more airflow to penetrate through the openings of the one or more driver vanes 1002 and to spread the airflow more evenly to create a near-continuous sheet of airflow. The near-continuous sheet of airflow drives the formation and the stability of the vortex (or vortices) inside the combustion chamber 267. As shown in FIG. 12, the plurality of driver vanes 1002 are distributed circumferentially within the body 1202B of the geometric ramp 1202 around the liner 269. As shown in FIG. 12, the plurality of driver vanes 1002 define a plurality of openings 1202C between the plurality of driver vanes 1002. The plurality of openings 1202C have a center axis 1204 that forms an angle α with respect to a local tangent 1205 to a surface of the liner 269. The term “local tangent” is used to mean a tangent taken at a location of an opening of the plurality of openings 1202C. In an embodiment, the angle α can vary from 30° to 150°. The angle α can be swept to vary between the aft direction and the forward direction.

FIG. 13 is a partial, schematic cross-sectional view of a portion of the second segment 504 having one or more driver vanes 1004, according to an embodiment of the present disclosure. In this embodiment, the second segment 504 includes a geometric ramp 1302. The geometric ramp 1302 includes a body 1302B having one or more driver vanes 1002. In the embodiment shown in FIG. 13, the body 1302B of the geometric ramp 1302 is shown having a plurality of driver vanes 1004. The plurality of driver vanes 1004 are similar in certain aspects to the driver holes described in the above paragraphs. Compared to one or more driver holes, the one or more driver vanes 1004, similar to the one or more driver vanes 1002 (FIG. 12), provide the additional benefit of compacting more openings in a small area, thus allowing more airflow to penetrate through the openings between the one or more driver vanes 1004 and to create a near-continuous sheet of airflow to spread the airflow more evenly to drive the formation and the stability of the vortex (or vortices) inside the combustion chamber 267. As shown in FIG. 13, the plurality of driver vanes 1004 are distributed circumferentially within the body 1302B of the geometric ramp 1202 around the liner 269. As shown in FIG. 13, the plurality of driver vanes 1004 define a plurality of openings 1302C between the plurality of driver vanes 1004. The plurality of openings 1302C have a center axis 1304 that forms an angle ϕ with respect to a local tangent 1305 to the surface of the liner 269. The term “local tangent” is used to mean a tangent taken at a location of an opening of the plurality of openings 1302C. In an embodiment, the angle ϕ can vary from 30° to 150°. The angle ϕ can be swept to vary between the aft direction and the forward direction.

FIG. 14 is a partial, schematic cross-sectional view of a geometric ramp of the first segment 502 taken at line 14-14 shown in FIG. 11, according to an embodiment of the present disclosure. As discussed in the paragraph above, the body 1202B of the geometric ramp 1202 has one or more driver vanes 1002. For example, as shown in FIG. 12 and FIG. 14, the body 1202B of the geometric ramp 1202 has a plurality of driver vanes 1002. The plurality of driver vanes 1202A are distributed circumferentially within the body 1202B of the geometric ramp 1202 around the liner 269 (FIG. 12). The plurality of driver vanes 1002 define the plurality of openings 1202C between the plurality of driver vanes 1002. As shown in FIG. 14, the plurality of driver vanes 1002 have a first lateral axis 1404A that forms a first angle β_L with respect to a radial line 1405 of the combustor 206 (shown in FIG. 2) and a second lateral axis 1404B that forms a second angle β_T with respect to the radial line 1405 of the combustor 206 (shown in FIG. 2). The plurality of driver vanes 1002 have two lateral axes (the first lateral axis 1404A and the second lateral axis 1404B) because the plurality of driver vanes 1002 curve relative to the radial line 1405. As a result, the plurality of openings 1202C also curve similarly to the plurality of vanes 1002. In an embodiment, the angles β_L and β_T can vary from −60° to +60°. The plurality of driver vanes 1002 can have different leading-edge angle β_L to exit angle β_T to improve inlet feed in crossflow. The plurality of driver vanes 1002 can be swept to have different vane angle β_L and/or β_T radially.

FIG. 15 is a partial, schematic cross-sectional view of a geometric ramp of the second segment 504 taken at line 15-15 shown in FIG. 11, according to an embodiment of the present disclosure. As discussed in the paragraph above, the body 1302B of the geometric ramp 1302 has one or more driver vanes 1004. For example, as shown in FIGS. 13 and 15, the body 1302B of the geometric ramp 1302 has a plurality of driver vanes 1004. The plurality of the driver vanes 1004 are distributed circumferentially within the body 1302B of the geometric ramp 1302 around the liner 269. The plurality of the driver vanes 1004 define the plurality of openings 1302C between the plurality of the driver vanes 1004. As shown in FIG. 15, the plurality of driver vanes 1004 have a first lateral axis 1504A that forms a first angle ψ_L with respect to a radial line 1505 of the combustor 206 (shown in FIG. 2) and a second lateral axis 1504B that forms a first angle ψ_T with respect to the radial line 1505 of the combustor 206 (shown in FIG. 2). The plurality of driver vanes 1004 have two lateral axes (the first lateral axis 1504A and the second lateral axis 1504B) because the plurality of driver vanes 1004 curve relative to the radial line 1505. As a result, the plurality of openings 1302C also curve similarly to the plurality of vanes 1004. In an embodiment, the angles ψ_L and ψ_T can vary from −60° to +60°. The plurality of driver vanes 1004 can have different leading-edge angle ψ_L to exit angle ψ_T to improve inlet feed in crossflow. The plurality of driver vanes 1004 can be swept to have different vane angle ψ_L and/or ψ_T radially.

FIG. 16 is a partial, schematic cross-sectional enlarged view of a portion of the first segment 502 having one or more driver holes, according to an embodiment of the present disclosure. In this embodiment, the first segment 502 includes a geometric ramp 1602. The geometric ramp 1602 includes a body 1602B having one or more driver holes 1602A. In the embodiment shown in FIG. 16, the body 1602B of the geometric ramp 1602 is shown having a plurality of driver holes 1602A. The plurality of driver holes 1602A are similar in certain aspects to the driver holes described in the above paragraphs. The plurality of driver holes 1602A can have the same or different diameters. By providing a plurality of driver holes 1602A with different diameters (e.g., smaller and larger diameters), a dynamic of the airflow jet can be tailored to increase formation and driving of a vortex or vortices. In addition, the ratio L/D of a driving hole can be increased to improve C_d magnitude and C_d consistency for improved pattern factor. An increased ratio L/D also makes driver airflow jet angle insensitive to inlet crossflow and thus potentially leading to an increase in airflow jet penetration to improve performance for driving the vortex or vortices, increased ratio L/D also provides the flexibility of giving a tangential component to the airflow jets to drive bulk swirl to increase residence time to improve combustion efficiency. As shown in FIG. 16, the plurality of driver holes 1602A are distributed circumferentially within the body 1602B of the geometric ramp 1602 around the liner 269. As shown in FIG. 16, the plurality of driver holes 1602A have a center axis 1604 that forms an angle α with respect to a local tangent 1605 to a surface of the liner 269. Similar to the embodiment shown in FIG. 12, the term “local tangent” is used to mean a tangent taken at a location of an opening of the plurality of driver holes 1602A. In an embodiment, the angle α can vary from 30° to 150°.

FIG. 17 is a partial, schematic cross-sectional enlarged view of a portion of the second segment 504 having one or more driver holes, according to an embodiment of the present disclosure. In this embodiment, the second segment 504 includes a geometric ramp 1702. The geometric ramp 1702 includes a body 1702B having one or more driver holes 1702A. In the embodiment shown in FIG. 17, the body 1702B of the geometric ramp 1702 is shown having a plurality of driver holes 1702A. The plurality of driver holes 1702A are similar in certain aspects to the driver holes described in the above paragraphs. The plurality of driver holes 1702A can have the same or different diameters. For example, by providing a plurality of driver holes 1702A with different diameters (e.g., smaller and larger diameters), a dynamic of the airflow jet can be tailored to increase formation and driving of a vortex or vortices. In addition, the ratio L/D of a driving hole can be increased to improve C_d magnitude and C_d consistency for improved pattern factor, increased ratio L/D also makes driver jet angle insensitive to inlet crossflow and thus potentially leading to an increase in airflow jet penetration to improve performance for driving the vortex or vortices. An increased ratio L/D also provides the flexibility of giving a tangential component to the airflow jets to drive bulk swirl to increase residence time to improve combustion efficiency. As shown in FIG. 17, the plurality of driver holes 1702A are distributed circumferentially within the body 1702B of the geometric ramp 1702 around the liner 269. The plurality of driver holes 1702A have a center axis 1704 that forms an angle ϕ with respect to a local tangent 1705 to the surface of the liner 269. Similar to the embodiment shown in FIG. 13, the term “local tangent” is used to mean a tangent taken at a location of an opening of the plurality of driver holes 1702A. In an embodiment, the angle ϕ can vary from 30° to 150°.

FIG. 18 is a partial, schematic cross-sectional view of a geometric ramp of the first segment 502 taken at line 18-18 shown in FIG. 16, according to an embodiment of the present disclosure. As discussed in the paragraph above, the body 1602B of the geometric ramp 1602 has one or more driver holes 1602A. For example, as shown in FIGS. 16 and 18, the body 1602B of the geometric ramp 1602 has a plurality of driver holes 1602A. The plurality of driver holes 1602A are distributed circumferentially within the body 1602B of the geometric ramp 1602 around the liner 269. As shown in FIG. 18, the plurality of driver holes 1602A have a lateral axis 1804 that forms an angle β with respect to a radial line 1805 of the combustor 206 (shown in FIG. 2). In an embodiment, the angle β can vary from −60° to +60°. The plurality of driver holes 1602A can have different angles β to improve inlet feed in crossflow.

FIG. 19 is a partial, schematic cross-sectional view of a geometric ramp of the second segment 504 taken at line 19-19 shown in FIG. 17, according to an embodiment of the present disclosure. As discussed in the paragraph above, the body 1702B of the geometric ramp 1702 has one or more driver holes 1702A. For example, as shown in FIG. 17, the body 1702B of the geometric ramp 1702 has a plurality of driver holes 1702A. The plurality of driver holes 1702A are distributed circumferentially within the body 1702B of the geometric ramp 1702 around the liner 269. As shown in FIG. 19, the plurality of driver holes 1702A have a lateral axis 1904 that forms an angle ψ with respect to a tangent line 1905. In an embodiment, the angle ψ can vary from 30° to 150°.

FIG. 20 is a schematic view of a driver hole 1602A with various dimensions, according to an embodiment of the present disclosure. As shown in FIG. 20, the driver hole 1602A has diameter D_h and a thickness or length L_h. The driver hole 1602A can have a funnel shape with a conical end. The conical end may have thickness x and may diverge or open at an angle γ relative to a surface 2000 of the body 1602B of the geometric ramp 1602. The angle γ can be from 10° to 90°. A ratio of the thickness x to the length L_h (x/L_h) can be from 0.04 to 0.80 and the ratio of diameter D_h to the length L_h (D_h/L_h) can be from 0.20 to 6.0.

FIG. 21 is a schematic view of a driver hole 1702A with various dimensions, according to an embodiment of the present disclosure. As shown in FIG. 21, the driver hole 1702A has a diameter D_h and a thickness or length L_h. The driver hole 1702A can also have a funnel shape with a round end. The round end may have a radius r_i. A ratio of the radius r_i to the length L_h (r_i/L_h) can be from 0.04 to 0.70 and the ratio of the diameter of the driver hole D_h to the length L_h of the driver hole (D_h/L_h) can be from 0.20 to 6.0.

FIG. 22A shows schematic elevational views of example driver holes having a circular or round shape, according to an embodiment of the present disclosure. FIG. 22B shows schematic elevational views of example driver holes having a circular or round shape with different radii, according to another embodiment of the present disclosure. As shown in FIGS. 22A and 22B, a plurality of driver holes 2200 or a plurality of driver holes 2202 can be provided within the geometric ramps of the first segment and/or the second segments described in the above paragraphs. The plurality of driver holes can have a circular shape. The plurality of driver holes can have the same diameter or different diameters (or radii), as shown in FIG. 22A. For example, the plurality of driver holes 2200 have a same diameter (or radius). The plurality of driver holes 2202 have a different diameter (or radius), as shown in FIG. 22B. For example, in the plurality of driver holes 2202, some driver holes have a radius R₁ and other driver holes have a radius R₂ different from the radius R₁. In an embodiment, a ratio of radius R₂ to radius R₁ (R₂/R₁) can be from 0.2 to 5.0. In an embodiment, the driver holes can be distributed around a circumference of the combustor to optimize pattern factor. In an embodiment, as shown in FIG. 22B, one or more driver holes 2202 having the radius R₂ is/are positioned between the driver holes 2202 having the radius R₁.

FIG. 23A shows schematic elevational views of example driver holes having an oval shape, according to an embodiment of the present disclosure. FIG. 23B shows schematic elevational views of example driver holes having an egg shape, according to another embodiment of the present disclosure. In addition to or alternatively to selecting the radius of the driver holes, as shown in FIG. 22, a shape of the driver holes can also be selected, as shown in FIGS. 23A and 23B. For example, a plurality of driver holes 2300 can have an oval shape, as shown in FIG. 23A. The oval shape of the plurality of driver holes 2300 can have a first dimension W and a second dimension L. For example, as shown in FIG. 23B, a plurality of driver holes 2302 can have an egg shape such that one end of the egg shape can have a first radius R₁ and an opposite end of the egg shape can have a second radius R₂ different from the first radius R₁. The egg shape can also have a dimension L in the elongated direction of the egg shape. In an embodiment, a ratio of the second radius R₂ to the first radius R₁ (R₂/R₁) can be from 0.2 to 5.0. In an embodiment, the egg shape can also be orientated at an angle θ relative to an axis 2304 corresponding to the longitudinal combustor centerline axis 112 (shown in FIG. 2). In an embodiment, the angle θ can be from −60° to 60°. The various shapes of the driver holes can be used to further improve airflow jet penetration and pattern factor.

FIG. 24A shows a schematic elevational view of an example driver slot having an “I” shape, according to an embodiment of the present disclosure. FIG. 24B shows a schematic elevational view of example driver slot having a wavy shape, according to another embodiment of the present disclosure. Instead of or in addition to providing driver holes as shown in FIG. 22 and FIG. 23, a plurality of annular slots 2400 and/or a plurality of annular slots 2402 can also be used. As shown in FIG. 24A, the plurality of annular slots 2400 can have an “I” shape with a width W along the circumference C of the combustor 206 (shown in FIG. 2) selected as being a fraction of the circumference C of the combustor 206. For example, the width W can be from a third of the circumference C (i.e., W=C/3) to a thirtieth of the circumference C (i.e., W=C/30). In addition, as shown in FIG. 24B, the plurality of annular slots 2402 can have a wavy shape. The wavy shape of the plurality of annular slots 2402 can have a thickness that can be the same along a width W of the wavy shape or a variable thickness along a width W of the wavy shape. For example, a portion of the wavy shape of the plurality of annular slots 2402 can have a first thickness t₁ while another portion of the of the wavy shape of the plurality of annular slots 2402 can have a second thickness t₂. In an embodiment, a ratio of the second thickness t₂ to the first thickness t₁ (t₂/t₁) can be from 0.25 to 4.0. The plurality of annular slots 2400 and/or the plurality of annular slots 2402 can be used along a circumference C of the combustor 206 (shown in FIG. 2) to create a more complete curtain of airflow to drive the vortex and reduce pattern factor. The plurality of annular slots 2402 can be shaped to vary slot thickness and/or direction about the circumference C of the combustor 206 (shown in FIG. 2) to align with fuel rich streaks from the vortex to reduce pattern factor.

FIG. 25A is a cutaway longitudinal cross-sectional view of an example of a driver hole 2500 having a conical shape, according to an embodiment of the present disclosure. FIG. 25B is a top transverse view of the driver hole 2500 shown in FIG. 25A. An airflow jet 2502 passes through the driver hole 2500. As shown in FIGS. 25A and 25B, the driver hole 2500 can have a conical shape or a funnel shape. The conical shape is tapering from upstream of the airflow jet 2502 within the driver hole 2500 to downstream of the airflow jet 2502 within the driver hole 2500. A first diameter 2504A of the driver hole 2500 at an upstream inlet 2506 of the driver hole 2500 is greater than a second diameter 2504B of the driver hole 2500 at a downstream outlet 2508 of the driver hole 2500. Although the driver hole 2500 is shown in FIG. 25A and FIG. 25B as having a circular shaped cross section, the driver hole 2500 is not limited to a circular shape, but can also have other rounded shapes, such as an oval shaped cross section, for example. In an embodiment, the driver hole is configured to improve drive jet momentum by reducing pressure drop of the airflow jet 2502 at the upstream inlet 2506 and focusing pressure drop at the downstream outlet 2508. In an embodiment, the driver hole 2500 is further configured to create a higher favorable pressure gradient in direction of airflow jet 2502 that helps stabilize airflow jet 2502 through the driver hole 2500.

FIG. 26A is a cutaway longitudinal cross-sectional view of an example of a driver hole 2600 having a fluted shape, according to another embodiment of the present disclosure. FIG. 26B is a top transverse view of the driver hole 2600 shown in FIG. 6A. An airflow jet 2602 passes through the driver hole 2600. As shown in FIGS. 26A and 26B, the driver hole 2600 can have a fluted shape cone. The fluted shape 2604 includes a wavy surface 2606 that is shown, distinctly, at an upstream inlet 2608 of the driver hole 2600 and at a downstream outlet 2609 of the driver hole 2600. Although the fluted shape 2604 is shown having a wavy surface 2606, the fluted shape 2604 can also have other surface shapes, such as polygonal (triangular, rectangular, etc.) shape. A radius 2610 of the fluted shape 2604 of the driver hole 2600 varies along a circumference of the driver hole 2600. Although the driver hole 2600 is shown in FIG. 26A and FIG. 26B as having generally a circular shaped cross section, the driver hole 2600 is not limited to a circular shape but can also have other rounded shapes, such as an oval shaped cross section, for example. In an embodiment, the driver hole 2600 having the fluted shape 2604 can further improve penetration of the airflow jet 2602 (driver jet) by local thickening around the airflow jet 2602 within the driver hole 2600 at the exit of the downstream outlet 2609 leading to reinforcement of the airflow jet 2602 to generate and/or to maintain, for example, the vortex 506 and the vortex 508 (shown in FIG. 5). In an embodiment, the driver hole 2600 having the fluted shape 2604 can improve local mixing around the airflow jet 2602 (driver jet) to potentially reduce pattern factor or reduce thermal gradients within the combustion chamber 267, shown in FIG. 5.

FIG. 27A is a cutaway longitudinal cross-sectional view of an example of a driver hole 2700 having a rifled shape, according to another embodiment of the present disclosure. FIG. 27B is a top transverse view of the driver hole 2700 shown in FIG. 7A. An airflow jet 2702 passes through the driver hole 2700. As shown in FIGS. 27A and 27B, the driver hole 2700 can have a rifled shape 2704. The rifled shape 2704 includes a wavy surface 2706 that is shown, distinctly, at an upstream inlet 2708 of the driver hole 2700 and at a downstream outlet 2709 of the driver hole 2700. The wavy surface 2706 is also twisted in a circumferential direction Ci of the driver hole 2700 to create the rifled shape 2704. Although the rifled shape 2704 is shown having a wavy surface 2706, the rifled shape 2704 can also have other surface shapes, such as polygonal (triangular, rectangular, etc.) shape. A radius 2710 of the rifled shape 2704 of the driver hole 2700 varies along a circumference Ci of the driver hole 2700. Although the driver hole 2700 is shown in FIG. 27A and FIG. 27B as having a generally circular shaped cross section, the driver hole 2700 is not limited to a circular shape but can also have other rounded shapes, such as an oval shaped cross section, for example. In an embodiment, the driver hole 2700 having the rifled shape 2704 can induce a twisting effect on the airflow jet 2702 that can help produce more turbulence within the combustion chamber 267 (shown in FIG. 5, for example) than the driver hole 2600 with the fluted shape 2604 (without the twisting effect on the airflow jet 2602) shown in FIGS. 26A and 26B. A balance between desired airflow jet turbulence and desired airflow jet penetration can be adjusted as needed.

For example, the driver hole 2500, the driver hole 2600, and/or the driver hole 2700 can be provided, for example, in the first segment 502 in the outer liner 252 and/or in the second segment 504 in the inner liner 254, shown in FIG. 5.

FIGS. 25A, 25B, 26A, 26B, 27A and 27B show various examples of driver holes with various shapes. Similar shapes (e.g., conical shape, fluted shape, and/or rifled shape) can also be used for slots. For example, the plurality of annular slots 2400 described above and/or the plurality of slots 2402, described above can also have a conical shape or a tapered shape, a fluted shape, and/or a rifled shape.

The present disclosure uses driver airflow jets to both stabilize an un-trapped or partially trapped vortex as well as to improve the pattern factor. By implementing shaped circumferentially distributed driver holes and/or driver slots in the combustor, vortex stabilization can be improved by reducing circumferential variation.

In addition, vortex stabilization can be achieved by locally increasing the thickness of the liner either by using a separate piece or an integral piece to the liner of the combustor to increase of the ratio L/D of the driver holes or slots, where L represents a length of the driver hole or slot and D represents a diameter of the driver hole or thickness or width of the slot. The use of thin liners with crossflow on the inlet side results in the driver airflow jet(s) leaning more aft. Greater L/D ratios can better align the airflow jet normal to the liner, thus improving jet penetration to close of the vortex. Greater L/D ratios also reduce sensitivity of airflow jet direction to the inlet crossflow.

Increased L/D ratios also enable using vanes instead of holes, as vanes have a more elongated shape, and thus greater length L, than driver holes. More vanes can be used than driver holes, and the vanes can be shaped to further optimize the vortex and adjacent flow field. Whether using a driver hole or using a vane, a tangential component can be added that is not possible with thin liners. The tangential component can then impart a bulk swirler that increases residence time and allows for the same or greater combustion efficiency in shorter combustors with less volume.

Driver holes or driver slots can be used to induce a toroidal vortex in a combustor. The driver holes and the driver slots can be of varying size and shape to optimize balance between driving vortex and minimizing pattern factor, where the driver holes or the driver slots are drilled, machined, or grown into the liner of constant or near constant thickness.

Driver holes or driver slots can be provided in a thicker section of the liner that is welded or otherwise attached to the liners or integral to liners. The driver slots can also include a tangential component such that air coming out of the driver slots generates a tangential airflow component to impart bulk swirl within the combustor. Near continuous slots can also be used to create driver sheet of air to reduce pattern factor.

Vanes can be used in a thicker segment of the liner instead of the driver slots or the driver holes. The vanes may have a different leading edge than a trailing edge angle compared to a combustor radial line. In addition, the vanes can have a different angle from axial forward to axial aft. The vanes can impart smaller wakes for greater turbulence levels and also produce an airflow sheet similar to a continuous driver slot. In addition, vanes can also provide structural connection between forward and aft sections of the liner.

A shorter combustor with less volume allows for a lighter weight combustor that may provide reduced shaft dynamics and fuel savings. In addition, this may also allow more aircraft volume and weight to be used for carrying capacity. Improving the pattern factor provides the added benefit of reducing necessary cooling for the turbine, leading to reduced parasitic loss and higher specific fuel consumption (SFC).

Further aspects are provided by the subject matter of the following clauses.

A combustor having driver jets to drive a vortex inside a combustion chamber of the combustor. The combustor includes: a dome structure, an inner liner and an outer liner connected to the dome structure to define a combustion chamber, and a first segment coupled to the outer liner and a second segment coupled to the inner liner, the first segment including a first geometric ramp and the second segment including a second geometric ramp. The first geometric ramp and the second geometric ramp have one or more driver holes, one or more driver slots, or a plurality of driver vanes, or any combination thereof. The one or more driver holes, the one or more driver slots, or the plurality of driver vanes are configured and arranged so that an upstream crossflow enters the one or more driver holes, the one or more driver slots, or the plurality of driver vanes to generate an airflow jet having an increased angle at an exit of the one or more to driver holes, the one or more driver slots, or the plurality of driver vanes relative to a surface of the inner liner or a surface of the outer liner and to enhance penetration into the combustion chamber to generate and to drive a vortex inside the combustion chamber.

The combustor according to the preceding clause, wherein a ratio of a diameter of the one or more driver holes to a length of the one or more driver holes is from 0.20 to 5.0.

The combustor according to any preceding clause, wherein a ratio of a length of the one or more driver holes to a diameter of the one or more driver holes is increased to reduce sensitivity of the airflow jet to back side velocity of the upstream crossflow.

The combustor according to any preceding clause, wherein the one or more driver holes, the one or more driver slots, or the plurality of driver vanes define an angle relative to a tangent to the surface of the inner liner or the outer liner, and the angle varies from 30° to 150°.

The combustor according to any preceding clause, wherein the first geometric ramp has a body, and a conduit provided within the body configured to cause fuel to flow into the combustion chamber, wherein the conduit communicates with the combustion chamber via a fuel channel provided in the body to generate a fuel jet through a nozzle of the fuel channel.

The combustor according to any preceding clause, wherein the one or more driver holes include an inlet chamfer or an inlet curvature or both.

The combustor according to any preceding clause, wherein the inlet chamfer forms an angle with a sidewall of the one or more driver holes, and the angle opens from a chamfer depth of the one or more driver holes to an exit of the one or more driver holes.

The combustor according to any preceding clause, wherein a ratio of the chamfer depth of the one or more driver holes to a diameter of the one or more driver holes is selected to maximize a discharge coefficient of the airflow jet.

The combustor according to any preceding clause, wherein the first geometric ramp has a body, and a hood coupled to the body, the hood being spaced apart from the body to define an airflow channel.

The combustor according to any preceding clause, wherein the hood curves to form an upstream curved portion, the upstream curved portion being spaced apart from the body and contouring the body to define an inlet, wherein the hood is configured to guide a portion of the upstream crossflow captured by the upstream curved portion through the airflow channel.

The combustor according to any preceding clause, wherein the hood curves to form a downstream curved portion, the downstream curved portion being spaced apart from the body at an interface of the first geometric ramp with the outer liner to define an outlet, the portion of the upstream crossflow that enters through the inlet and guided through the airflow channel splits into a first airflow portion to enter the one or more driver holes and a second airflow portion exits the airflow channel through the outlet.

The combustor according to any preceding clause, wherein the second geometric ramp has a body, and the one or more driver holes traverse an entire thickness of the body, the one or more driver holes being configured to guide the airflow jet into the combustion chamber.

The combustor according to any preceding clause, wherein the body includes a single scoop that forms a single ridge extending 360° around a circumference of the inner liner, the one or more driving holes ending near the single scoop, the single scoop being configured to intercept a first portion of an upstream crossflow to guide the first portion through the one or more driver holes to generate the airflow jet, and a second portion of the upstream crossflow passes over single scoop.

The combustor according to any preceding clause, wherein the body has a trapezoid cross-sectional shape and the one or more driver holes are provided in a thicker portion of the trapezoid cross-sectional shape.

The combustor according to any preceding clause, wherein the body includes one or more scoops, each of the one or more scoops is located near each of the one or more driver holes, the one or more scoops being configured to intercept a first portion of an upstream crossflow to guide the first portion through the one or more driver holes to generate the airflow jet, and a second portion of the upstream crossflow passes between or over the one or more scoops.

The combustor according to any preceding clause, wherein the one or more scoops are configured to convert more of a total pressure of the upstream crossflow to increase pressure supply to the one or more airflow jets and to increase momentum of the one or more airflow jets to increase penetration of the one or more airflow jets to drive the vortex.

The combustor according to any preceding clause, wherein the body includes grooves at opposite ends of the body, the grooves being configured to couple the body with the inner liner.

The combustor according to any preceding clause, wherein the body is brazed or welded to the inner liner at the grooves.

The combustor according to any preceding clause, wherein the body is attached to the inner liner using fasteners at an interface of the inner liner with the grooves.

The combustor according to any preceding clause, wherein the body includes a plurality of flanges, the plurality of flanges being configured to be coupled to a plurality of arm extensions of the inner liner.

The combustor according to any preceding clause, wherein the plurality of flanges are coupled to the plurality of arm extensions of the inner liner using a plurality of fasteners.

The combustor according to any preceding clause, wherein the body of the second geometric ramp is integrally formed as one piece with the inner liner.

The combustor according to any preceding clause, wherein the body of the second geometric ramp includes voids to reduce weight of the body of the second geometric ramp.

The combustor according to any preceding clause, wherein the first geometric ramp includes a body and a plurality of driver vanes distributed circumferentially within the body, wherein the plurality of driver vanes define a plurality of openings, each opening having a center axis that forms an angle α with a tangent to a surface of the outer liner, wherein the angle α of the center axis with the tangent to the surface of the outer liner is from 30° to 150°.

The combustor according to any preceding clause, wherein the first geometric ramp includes a body and a plurality of driver vanes distributed circumferentially within the body, the plurality of driver vanes define a plurality of openings, each driver vane in the plurality of driver vanes having a first lateral axis that forms a first angle β_L with a radial line of the combustor and a second lateral axis that forms a second angle β_T with respect to the radial line of the combustor so that the plurality of openings curve relative to the radial line, the first angle β_L and the second angle β_T vary from −60° to +60°.

The combustor according to any preceding clause, wherein the second geometric ramp includes a body and a plurality of driver vanes distributed circumferentially within the body, the plurality of driver vanes define a plurality of openings, each driver vane having a center axis that forms an angle ϕ with a tangent to a surface of the inner liner, and the angle ϕ of the center axis with the tangent to the surface of the inner liner is from 30° to 150°.

The combustor according to any preceding clause, wherein the second geometric ramp includes a body and a plurality of driver vanes distributed circumferentially within the body, the plurality of driver vanes define a plurality of openings, each driver vane in the plurality of driver vanes having a first lateral axis that forms a first angle ψ_L with a radial line of the combustor and a second lateral axis that forms a second angle ψ_T with respect to the radial line of the combustor so that the plurality of openings curve relative to the radial line, and the first angle ψ_L and the second angle ψ_T vary from −60° to +60°.

The combustor according to any preceding clause, wherein the first geometric ramp includes a body and a plurality of driver holes distributed circumferentially within the body, each driver hole having a center axis that forms an angle α with a tangent to a surface of the outer liner, and the angle α of the center axis with the tangent to the surface of the outer liner is from 30° to 150°.

The combustor according to any preceding clause, wherein the first geometric ramp includes a body and a plurality of driver holes distributed circumferentially within the body, each driver hole in the plurality of driver holes having a lateral axis that forms an angle β with a radial line of the combustor so that the plurality of openings curve relative to the radial line, the angle β varying from −60° to +60°.

The combustor according to any preceding clause, wherein the second geometric ramp includes a body and a plurality of driver holes distributed circumferentially within the body, each driver hole in the plurality of driver holes having a center axis that forms an angle ϕ with a tangent to a surface of the inner liner, the angle ϕ of the center axis with the tangent to the surface of the inner liner being from 30° to 150°.

The combustor according to any preceding clause, wherein the second geometric ramp includes a body and a plurality of driver holes distributed circumferentially within the body, each driver hole in the plurality of driver holes having a lateral axis that forms an angle ψ with a radial line of the combustor so that the plurality of openings curve relative to the radial line, the angle ψ varying from −60° to +60°.

The combustor according to any preceding clause, wherein the first geometric ramp or the second geometric ramp has a plurality of driver holes, the plurality of driver holes having a circular shape with different radii.

The combustor according to any preceding clause, wherein the first geometric ramp or the second geometric ramp has a plurality of driver holes, the plurality of driver holes having an oval shape or an egg shape.

The combustor according to any preceding clause, wherein the first geometric ramp or the second geometric ramp has a plurality of driver slots, the plurality of driver slots having an “I” shape or a wavy shape.

The combustor according to any preceding clause, wherein a width of a driver slot of the plurality of driver slots is from a third of a circumference of the combustor to a thirtieth of the circumference of the combustor.

The combustor according to any preceding clause, wherein a portion of the wavy shape of the plurality of driver slots has a first thickness t₁ and another portion of the of the wavy shape of the plurality of driver slots has a second thickness t₂, a ratio of the second thickness t₂ to the first thickness t₁ is from 0.20 to 5.0, and the plurality of driver slots are distributed along a circumference of the combustor to create a curtain of airflow to drive the vortex and to improve the pattern factor.

The combustor according to any preceding clause, wherein the one or more driver holes have a conical shape, the conical shape tapering from upstream of the airflow jet within the one or more driver holes to a downstream of the airflow jet within the one or more driver holes such that a first diameter of the one or more driver holes at an upstream inlet of the one or more driver holes is greater than a second diameter of the one or more driver holes at a downstream outlet of the one or more drover holes.

The combustor according to any preceding clause, wherein the conical shape is configured to improve drive jet momentum by reducing pressure drop of the airflow jet at the upstream inlet and focusing pressure drop at the downstream outlet so as to create a higher favorable pressure gradient in direction of airflow jet to help stabilize the airflow jet through the driver hole.

The combustor according to any preceding clause, wherein the one or more driver holes have a fluted shape, the fluted shape including a wavy surface such that a radius of the fluted shape varies along a circumference of the one or more driver holes.

The combustor according to any preceding clause, wherein the one or more driver holes are configured to improve penetration of the airflow jet by local thickening around the airflow jet within the one or more driver holes at an exit of a downstream outlet of the one or more driver holes to reinforce the airflow jet to generate and/or to maintain the vortex with the combustion chamber.

The combustor according to any preceding clause, wherein the one or more driver holes have a rifled shape, the rifled shape including a wavy surface that is twisted in a circumferential direction Ci of the one or more driver holes, wherein a radius of the rifled shape of the driver hole varies along a circumference of the one or more driver holes.

The combustor according to any preceding clause, wherein the one or more driver holes are configured to induce a twisting effect on the airflow jet to increase turbulence within the combustion chamber.

A method of operating the combustor of any preceding clause, the method including flowing an upstream crossflow through the one or more driver holes, the one or more driver slots, or the plurality of driver vanes.

The method of the preceding clause, further including generating an airflow jet having an increased angle at an exit of the one or more to driver holes, the one or more driver slots, or the plurality of driver vanes relative to a surface of the inner liner or a surface of the outer liner and to enhance penetration into the combustion chamber.

The method of any preceding clause, further including driving a vortex inside the combustion chamber using the airflow jet.

The method of any preceding clause, further including selecting a ratio a ratio of a diameter of the one or more driver holes to a length of the one or more driver holes is from 0.20 to 5.0.

The method of any preceding clause, further including increasing a ratio of a length of the one or more driver holes to a diameter of the one or more driver holes.

The method of any preceding clause, further including reducing sensitivity of the airflow jet to back side velocity of the upstream crossflow.

The method of any preceding clause, further including defining an angle relative to a tangent to the surface of the inner liner or the outer liner, and the angle varies from 30° to 150°.

The method of any preceding clause, further including distributing a plurality of driver holes circumferentially within the body, each driver hole having a center axis that forms an angle α with a tangent to a surface of the outer liner, and the angle α of the center axis with the tangent to the surface of the outer liner is from 30° to 150°.

The method of any preceding clause, further including distributing a plurality of driver holes circumferentially within the body, each driver hole in the plurality of driver holes having a lateral axis that forms an angle 3 with a radial line of the combustor so that the plurality of openings curve relative to the radial line, the angle β varying from −60° to +60°.

The method of any preceding clause, further including distributing the plurality of driver holes circumferentially within the body, each driver hole in the plurality of driver holes having a center axis that forms an angle ϕ with a tangent to a surface of the inner liner, the angle ϕ of the center axis with the tangent to the surface of the inner liner being from 30° to 150°.

The method of any preceding clause, further including distributing the plurality of driver holes circumferentially within the body, each driver hole in the plurality of driver holes having a lateral axis that forms an angle ψ with a radial line of the combustor so that the plurality of openings curve relative to the radial line, the angle ψ varying from −60° to +60°.

The method of any preceding clause, further including selecting a ratio of the chamfer depth of the one or more driver holes to a diameter of the one or more driver holes to maximize a discharge coefficient of the airflow jet.

The method of any preceding clause, further including causing fuel to flow into the combustion chamber, and generating a fuel jet through a nozzle of the fuel channel provided in the body of the geometric ramp.

The method of any preceding clause, further including guiding a portion of the upstream crossflow captured by the upstream curved portion through the airflow channel.

The method of any preceding clause, further including flowing a portion of the upstream crossflow through the inlet and guided through the airflow channel.

The method of any preceding clause, further including splitting into a first airflow portion to enter the one or more driver holes and a second airflow portion to exit the airflow channel through the outlet.

The method of any preceding clause, further including guiding the airflow jet into the combustion chamber.

The method of any preceding clause, further including intercepting with the single scoop a first portion of an upstream crossflow.

The method of any preceding clause, further including guiding the first portion through the one or more driver holes; and generating the airflow jet.

The method of any preceding clause, further including intercepting by the one or more scoops a first portion of an upstream crossflow.

The method of any preceding clause, further including guiding the first portion through the one or more driver holes.

The method of any preceding clause, further including generating the airflow jet, and flowing a second portion of the upstream crossflow between or over the one or more scoops.

The method of any preceding clause, further including converting by the one or more scoops more of a total pressure of the upstream crossflow.

The method of any preceding clause, further including increasing pressure supply to the one or more airflow jets to increase momentum of the one or more airflow jets, and increasing penetration of the one or more airflow jets to drive the vortex.

The method of any preceding clause, further including converting more of a total pressure of the upstream crossflow to increase pressure supply to the one or more airflow jets and to increase momentum of the one or more airflow jets to increase penetration of the one or more airflow jets to drive the vortex.

The method of any preceding clause, further including distributing circumferentially within the body a plurality of driver vanes, the plurality of driver vanes defining a plurality of openings, each opening having a center axis that forms an angle α with a tangent to a surface of the outer liner, wherein the angle α of the center axis with the tangent to the surface of the outer liner is from 30° to 150°.

The method of any preceding clause, further including improving drive jet momentum by using one or more driver holes having a conical shape, and reducing pressure drop of the airflow jet at the upstream inlet and focusing pressure drop at the downstream outlet so as to create a higher favorable pressure gradient in direction of airflow jet to help stabilize the airflow jet through the driver hole.

The method of any preceding clause, further including improving penetration of the airflow jet by using one or more driver holes having a fluted shape by local thickening around the airflow jet within the one or more driver holes at an exit of a downstream outlet of the one or more driver holes and reinforce the airflow jet to generate and/or to maintain the vortex with the combustion chamber.

The method of any preceding clause, further including inducing a twisting effect on the airflow jet to increase turbulence within the combustion chamber by using one or more driver holes having a rifled shape.

A turbine engine including a combustor having driver jets to drive a vortex inside a combustion chamber of the combustor. The combustor includes a dome structure, an inner liner and an outer liner connected to the dome structure to define a combustion chamber, and a first segment coupled to the outer liner and a second segment coupled to the inner liner, the first segment including a first geometric ramp and the second segment including a second geometric ramp. The first geometric ramp and the second geometric ramp have one or more driver holes, one or more driver slots, or a plurality of driver vanes, or any combination thereof. The one or more driver holes, the one or more driver slots, or the plurality of driver vanes are configured and arranged so that an upstream crossflow enters the one or more driver holes, the one or more driver slots, or the plurality of driver vanes to generate an airflow jet having an increased angle at an exit of the one or more to driver holes, the one or more driver slots, or the plurality of driver vanes relative to a surface of the inner liner or a surface of the outer liner and enhance penetration into the combustion chamber to generate and to drive a vortex inside the combustion chamber.

The turbine engine according to the preceding clause, wherein a ratio of a diameter of the one or more driver holes to a length of the one or more driver holes is from 0.20 to 5.0.

The turbine engine according to any preceding clause, wherein a ratio of a length of the one or more driver holes to a diameter of the one or more driver holes is increased to reduce sensitivity of the airflow jet to back side velocity of the upstream crossflow.

The turbine engine according to any preceding clause, wherein the one or more driver holes, the one or more driver slots, or the plurality of driver vanes define an angle relative to a tangent to the surface of the inner liner or the outer liner, and the angle varies from 30° to 150°.

The turbine engine according to any preceding clause, wherein the first geometric ramp has a body, and a conduit provided within the body configured to cause fuel to flow into the combustion chamber, wherein the conduit communicates with the combustion chamber via a fuel channel provided in the body to generate a fuel jet through a nozzle of the fuel channel.

The turbine engine according to any preceding clause, wherein the one or more driver holes include an inlet chamfer or an inlet curvature or both.

The turbine engine according to any preceding clause, wherein the inlet chamfer forms an angle with a sidewall of the one or more driver holes, and the angle opens from a chamfer depth of the one or more driver holes to an exit of the one or more driver holes.

The turbine engine according to any preceding clause, wherein a ratio of the chamfer depth of the one or more driver holes to a diameter of the one or more driver holes is selected to maximize a discharge coefficient of the airflow jet.

The turbine engine according to any preceding clause, wherein the first geometric ramp has a body, and a hood coupled to the body, the hood being spaced apart from the body to define an airflow channel.

The turbine engine according to any preceding clause, wherein the hood curves to form an upstream curved portion, the upstream curved portion being spaced apart from the body and contouring the body to define an inlet, wherein the hood is configured to guide a portion of the upstream crossflow captured by the upstream curved portion through the airflow channel.

The turbine engine according to any preceding clause, wherein the hood curves to form a downstream curved portion, the downstream curved portion being spaced apart from the body at an interface of the first geometric ramp with the outer liner to define an outlet, the portion of the upstream crossflow that enters through the inlet and guided through the airflow channel splits into a first airflow portion to enter the one or more driver holes and a second airflow portion exits the airflow channel through the outlet.

The turbine engine according to any preceding clause, wherein the second geometric ramp has a body, and the one or more driver holes traverse an entire thickness of the body, the one or more driver holes being configured to guide the airflow jet into the combustion chamber.

The turbine engine according to any preceding clause, wherein the body includes a single scoop that forms a single ridge extending 360° around a circumference of the inner liner, the one or more driving holes ending near the single scoop, the single scoop being configured to intercept a first portion of an upstream crossflow to guide the first portion through the one or more driver holes to generate the airflow jet, and a second portion of the upstream crossflow passes over single scoop.

The turbine engine according to any preceding clause, wherein the body has a trapezoid cross-sectional shape and the one or more driver holes are provided in a thicker portion of the trapezoid cross-sectional shape.

The turbine engine according to any preceding clause, wherein the body includes one or more scoops, each of the one or more scoops is located near each of the one or more driver holes, the one or more scoops being configured to intercept a first portion of an upstream crossflow to guide the first portion through the one or more driver holes to generate the airflow jet, and a second portion of the upstream crossflow passes between or over the one or more scoops.

The turbine engine according to any preceding clause, wherein the one or more scoops are configured to convert more of a total pressure of the upstream crossflow to increase pressure supply to the one or more airflow jets and to increase momentum of the one or more airflow jets to increase penetration of the one or more airflow jets to drive the vortex.

The turbine engine according to any preceding clause, wherein the body includes grooves at opposite ends of the body, the grooves being configured to couple the body with the inner liner.

The turbine engine according to any preceding clause, wherein the body is brazed or welded to the inner liner at the grooves.

The turbine engine according to any preceding clause, wherein the body is attached to the inner liner using fasteners at an interface of the inner liner with the grooves.

The turbine engine according to any preceding clause, wherein the body includes a plurality of flanges, the plurality of flanges being configured to be coupled to a plurality of arm extensions of the inner liner.

The turbine engine according to any preceding clause, wherein the plurality of flanges are coupled to the plurality of arm extensions of the inner liner using a plurality of fasteners.

The turbine engine according to any preceding clause, wherein the body of the second geometric ramp is integrally formed as one piece with the inner liner.

The turbine engine according to any preceding clause, wherein the body of the second geometric ramp includes voids to reduce weight of the body of the second geometric ramp.

The turbine engine according to any preceding clause, wherein the first geometric ramp includes a body and a plurality of driver vanes distributed circumferentially within the body, wherein the plurality of driver vanes define a plurality of openings, each opening having a center axis that forms an angle α with a tangent to a surface of the outer liner, wherein the angle α of the center axis with the tangent to the surface of the outer liner is from 30° to 150°.

The turbine engine according to any preceding clause, wherein the first geometric ramp includes a body and a plurality of driver vanes distributed circumferentially within the body, the plurality of driver vanes define a plurality of openings, each driver vane in the plurality of driver vanes having a first lateral axis that forms a first angle β_L with a radial line of the combustor and a second lateral axis that forms a second angle β_T with respect to the radial line of the combustor so that the plurality of openings curve relative to the radial line, the first angle β_L and the second angle β_T vary from −60° to +60°.

The turbine engine according to any preceding clause, wherein the second geometric ramp includes a body and a plurality of driver vanes distributed circumferentially within the body, the plurality of driver vanes define a plurality of openings, each driver vane having a center axis that forms an angle ϕ with a tangent to a surface of the inner liner, and the angle ϕ of the center axis with the tangent to the surface of the inner liner is from 30° to 150°.

The turbine engine according to any preceding clause, wherein the second geometric ramp includes a body and a plurality of driver vanes distributed circumferentially within the body, the plurality of driver vanes define a plurality of openings, each driver vane in the plurality of driver vanes having a first lateral axis that forms a first angle ψ_L with a radial line of the combustor and a second lateral axis that forms a second angle ψ_T with respect to the radial line of the combustor so that the plurality of openings curve relative to the radial line, and the first angle ψ_L and the second angle ψ_T vary from −60° to +60°.

The turbine engine according to any preceding clause, wherein the first geometric ramp includes a body and a plurality of driver holes distributed circumferentially within the body, each driver hole having a center axis that forms an angle α with a tangent to a surface of the outer liner, and the angle α of the center axis with the tangent to the surface of the outer liner is from 30° to 150°.

The turbine engine according to any preceding clause, wherein the first geometric ramp includes a body and a plurality of driver holes distributed circumferentially within the body, each driver hole in the plurality of driver holes having a lateral axis that forms an angle β with a radial line of the combustor so that the plurality of openings curve relative to the radial line, the angle β varying from −60° to +60°.

The turbine engine according to any preceding clause, wherein the second geometric ramp includes a body and a plurality of driver holes distributed circumferentially within the body, each driver hole in the plurality of driver holes having a center axis that forms an angle ϕ with a tangent to a surface of the inner liner, the angle ϕ of the center axis with the tangent to the surface of the inner liner being from 30° to 150°.

The turbine engine according to any preceding clause, wherein the second geometric ramp includes a body and a plurality of driver holes distributed circumferentially within the body, each driver hole in the plurality of driver holes having a lateral axis that forms an angle ψ with a radial line of the combustor so that the plurality of openings curve relative to the radial line, the angle ψ varying from −60° to +60°.

The turbine engine according to any preceding clause, wherein the first geometric ramp or the second geometric ramp has a plurality of driver holes, the plurality of driver holes having a circular shape with different radii.

The turbine engine according to any preceding clause, wherein the first geometric ramp or the second geometric ramp has a plurality of driver holes, the plurality of driver holes having an oval shape or an egg shape.

The turbine engine according to any preceding clause, wherein the first geometric ramp or the second geometric ramp has a plurality of driver slots, the plurality of driver slots having an “I” shape or a wavy shape.

The turbine engine according to any preceding clause, wherein a width of a driver slot of the plurality of driver slots is from a third of a circumference of the combustor to a thirtieth of the circumference of the combustor.

The turbine engine according to any preceding clause, wherein a portion of the wavy shape of the plurality of driver slots has a first thickness t₁ and another portion of the of the wavy shape of the plurality of driver slots has a second thickness t₂, a ratio of the second thickness t₂ to the first thickness t₁ is from 0.20 to 5.0, and the plurality of driver slots are distributed along a circumference of the combustor to create a curtain of airflow to drive the vortex and to improve the pattern factor.

The turbine engine according to any preceding clause, wherein the one or more driver holes have a conical shape, the conical shape tapering from upstream of the airflow jet within the one or more driver holes to a downstream of the airflow jet within the one or more driver holes such that a first diameter of the one or more driver holes at an upstream inlet of the one or more driver holes is greater than a second diameter of the one or more driver holes at a downstream outlet of the one or more drover holes.

The turbine engine according to any preceding clause, wherein the conical shape is configured to improve drive jet momentum by reducing pressure drop of the airflow jet at the upstream inlet and focusing pressure drop at the downstream outlet so as to create a higher favorable pressure gradient in direction of airflow jet to help stabilize the airflow jet through the driver hole.

The turbine engine according to any preceding clause, wherein the one or more driver holes have a fluted shape, the fluted shape including a wavy surface such that a radius of the fluted shape varies along a circumference of the one or more driver holes.

The turbine engine according to any preceding clause, wherein the one or more driver holes are configured to improve penetration of the airflow jet by local thickening around the airflow jet within the one or more driver holes at an exit of a downstream outlet of the one or more driver holes to reinforce the airflow jet to generate and/or to maintain the vortex with the combustion chamber.

The turbine engine according to any preceding clause, wherein the one or more driver holes have a rifled shape, the rifled shape including a wavy surface that is twisted in a circumferential direction Ci of the one or more driver holes, wherein a radius of the rifled shape of the driver hole varies along a circumference of the one or more driver holes.

The turbine engine according to any preceding clause, wherein the one or more driver holes are configured to induce a twisting effect on the airflow jet to increase turbulence within the combustion chamber.

A method of operating the turbine engine of any preceding clause, the method including guiding by a dome structure of the combustor a portion of compressed airflow to flow to an outer flow passage, and guiding another portion of the compressed airflow to flow to an inner flow passage.

The method of the preceding clause, further including flowing an upstream crossflow through the one or more driver holes, the one or more driver slots, or the plurality of driver vanes.

The method of any preceding clause, further including generating an airflow jet having an increased angle at an exit of the one or more to driver holes, the one or more driver slots, or the plurality of driver vanes relative to a surface of the inner liner or a surface of the outer liner and to enhance penetration into the combustion chamber.

The method of any preceding clause, further including driving a vortex inside the combustion chamber using the airflow jet.

The method of any preceding clause, further including selecting a ratio a ratio of a diameter of the one or more driver holes to a length of the one or more driver holes is from 0.20 to 5.0.

The method of any preceding clause, further including increasing a ratio of a length of the one or more driver holes to a diameter of the one or more driver holes.

The method of any preceding clause, further including reducing sensitivity of the airflow jet to back side velocity of the upstream crossflow.

The method of any preceding clause, further including defining an angle relative to a tangent to the surface of the inner liner or the outer liner, and the angle varies from 30° to 150°.

The method of any preceding clause, further including distributing a plurality of driver holes circumferentially within the body, each driver hole having a center axis that forms an angle α with a tangent to a surface of the outer liner, and the angle α of the center axis with the tangent to the surface of the outer liner is from 30° to 150°.

The method of any preceding clause, further including distributing a plurality of driver holes circumferentially within the body, each driver hole in the plurality of driver holes having a lateral axis that forms an angle β with a radial line of the combustor so that the plurality of openings curve relative to the radial line, the angle β varying from −60° to +60°.

The method of any preceding clause, further including distributing the plurality of driver holes circumferentially within the body, each driver hole in the plurality of driver holes having a center axis that forms an angle ϕ with a tangent to a surface of the inner liner, the angle ϕ of the center axis with the tangent to the surface of the inner liner being from 30° to 150°.

The method of any preceding clause, further including distributing the plurality of driver holes circumferentially within the body, each driver hole in the plurality of driver holes having a lateral axis that forms an angle ψ with a radial line of the combustor so that the plurality of openings curve relative to the radial line, the angle ψ varying from −60° to +60°.

The method of any preceding clause, further including selecting a ratio of the chamfer depth of the one or more driver holes to a diameter of the one or more driver holes to maximize a discharge coefficient of the airflow jet.

The method of any preceding clause, further including causing fuel to flow into the combustion chamber, and generating a fuel jet through a nozzle of the fuel channel provided in the body of the geometric ramp.

The method of any preceding clause, further including guiding a portion of the upstream crossflow captured by the upstream curved portion through the airflow channel.

The method of any preceding clause, further including flowing a portion of the upstream crossflow through the inlet and guided through the airflow channel.

The method of any preceding clause, further including splitting into a first airflow portion to enter the one or more driver holes and a second airflow portion to exit the airflow channel through the outlet.

The method of any preceding clause, further including guiding the airflow jet into the combustion chamber.

The method of any preceding clause, further including intercepting with the single scoop a first portion of an upstream crossflow.

The method of any preceding clause, further including guiding the first portion through the one or more driver holes; and generating the airflow jet.

The method of any preceding clause, further including intercepting by the one or more scoops a first portion of an upstream crossflow.

The method of any preceding clause, further including guiding the first portion through the one or more driver holes.

The method of any preceding clause further including generating the airflow jet, and flowing a second portion of the upstream crossflow between or over the one or more scoops.

The method of any preceding clause, further including converting by the one or more scoops more of a total pressure of the upstream crossflow.

The method of any preceding clause further including increasing pressure supply to the one or more airflow jets to increase momentum of the one or more airflow jets, and increasing penetration of the one or more airflow jets to drive the vortex.

The method of any preceding clause, further including converting more of a total pressure of the upstream crossflow to increase pressure supply to the one or more airflow jets and to increase momentum of the one or more airflow jets to increase penetration of the one or more airflow jets to drive the vortex.

The method of any preceding clause, further including distributing circumferentially within the body a plurality of driver vanes, the plurality of driver vanes defining a plurality of openings, each opening having a center axis that forms an angle α with a tangent to a surface of the outer liner, wherein the angle α of the center axis with the tangent to the surface of the outer liner is from 30° to 150°.

The method of any preceding clause, further including improving drive jet momentum by using one or more driver holes having a conical shape, and reducing pressure drop of the airflow jet at the upstream inlet and focusing pressure drop at the downstream outlet so as to create a higher favorable pressure gradient in direction of airflow jet to help stabilize the airflow jet through the driver hole.

The method of any preceding clause, further including improving penetration of the airflow jet by using one or more driver holes having a fluted shape by local thickening around the airflow jet within the one or more driver holes at an exit of a downstream outlet of the one or more driver holes and reinforce the airflow jet to generate and/or to maintain the vortex with the combustion chamber.

The method of any preceding clause, further including inducing a twisting effect on the airflow jet to increase turbulence within the combustion chamber by using one or more driver holes having a rifled shape.

Although the foregoing description is directed to the preferred embodiments of the present disclosure, other variations and modifications will be apparent to those skilled in the art and may be made without departing from the disclosure. Moreover, features described in connection with one embodiment of the present disclosure may be used in conjunction with other embodiments, even if not explicitly stated above.