EFFUSION COOLED FUEL NOZZLE TIP

Description

BACKGROUND

The present disclosure relates to combustion systems, and more particularly, to features for cooling fuel injectors of combustion systems.

Fuel injectors deliver fuel and oxidant flows into a combustion chamber for combustion. Portions of fuel injectors exposed to high temperatures from combustion experience high heat flux, increased thermal stress, and increased coking risk to internal fuel passages. Heat shields are used to thermally protect fuel injectors, which are considered satisfactory for their intended purpose. However, portions of the fuel injector nozzle remain unprotected. Additional features for protecting fuel injectors from high-temperature exposure are needed.

SUMMARY

A fuel injector according to an example of this disclosure includes a nozzle and a cap configured to deliver an oxidant-fuel mixture along a nozzle axis. The nozzle includes a fuel passage and a swirler. The fuel passage extends along the nozzle axis. The swirler circumscribes the fuel passage and includes multiple oxidant passages that converge towards the nozzle axis. The cap surrounds at least a portion of the nozzle and includes a peripheral body, an end body, and an effusion passage. The peripheral body circumscribes the swirler. The end body joins with the peripheral body and extends radially towards the nozzle axis. The effusion passage extends through the cap to intersect at least one of the peripheral body and the end body from an inlet to an outlet. The outlet is radially outward from the oxidant passages relative to the nozzle axis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an example fuel injector.

FIG. 2 is an end view of an example cap and nozzle of the fuel injector depicting an effusion passage fluidly communicating with an oxidant passage of the nozzle.

FIG. 3 is a cross-sectional view of the cap and nozzle of FIG. 2.

FIG. 4 is an end view of another example cap and nozzle of the fuel injector an effusion passage fluidly communicating with a region exterior to the nozzle.

FIG. 5 is a cross-sectional view of the cap and nozzle of FIG. 4.

DETAILED DESCRIPTION

FIG. 1 is a cross-sectional view of injector 10 that can include one or more effusion passages for cooling exterior surfaces of injector 10 directly exposed to high-temperature combustion. Effusion passages divert oxidant flow across exposed surfaces of injector 10 and thereby provide thermal protection. For example, effusion passages can direct oxidant flow across the end face of injector 10.

While a particular injector 10 is depicted by FIG. 1, it shall be understood that effusion passages, as described below, can be incorporated into other examples of injector 10, or other components exposed to high temperature gas or fluid. Injector 10 can include a single fuel path and/or a single air path in some examples. Other examples of injector 10 can include multiple fuel paths connected to a single fuel source, or multiple fuel passages connected to multiple fuel sources. Fuel sources can include carbon-based fuel, other liquid or gaseous fuel, and/or multi-phase fuel (e.g., fuel with liquid and gaseous phases). In some examples, injector 10 can receive a carbon-based liquid fuel and a multi-phase fuel (e.g., liquid hydrogen). Injector 10 can include additional air paths directed towards and/or between two or more fuel paths.

Injector 10 is a fuel delivery device installed within a combustor of a gas turbine engine. In operation, injector 10 delivers fuel and oxidant (e.g., air) at specified mass flow rates to provide an oxidant-fuel mixture within the combustor combustion chamber. As depicted, injector 10 includes heat shield 12, mount 14, stem 16, nozzle 18, and manifold 20. Heat shield 12, mount 14, stem 16, nozzle 18, and manifold 20 can be an assembly of components joined at respective interfaces to form injector 10. In some examples, components of injector 10 are joined using a brazing process and/or a welding process. In other examples, heat shield 12, mount 14, stem 16, nozzle 18, and manifold 20 describe regions of a monolithic body formed by, for example, an additive manufacturing process. Further, certain features of injector 10 can be formed by a machining process or other subtractive manufacturing.

Mount 14 supports injector 10 from stationary structure 22 of the gas turbine engine. One or more flanges, lips, and/or pilot diameters allow mount 14 to interface with stationary structure 22. Mount 14 further includes one or more fasteners, keys, and/or pins for affixing injector 10 relative to stationary structure 22 and the combustor of gas turbine engine. As depicted, mount 14 is a flange that abuts stationary structure 22, which can be a casing of gas turbine engine that surrounds the combustor. Mount 14 further includes a pilot diameter received within an opening of stationary structure 22 and may include fasteners (not shown) for affixing mount 14 to stationary structure 22.

Manifold 20 is outboard of mount 14 and includes supply lines fluidly communicating with a fuel source and/or one or more other adjacent injectors 10. Manifold can include one or more pipes, conduits, hoses, and/or internal passages to define supply lines, which communicate with one or more fuel passages of stem 16.

Stem 16 extends longitudinally from mount 14 through stationary structure 22 into combustion chamber of the combustor. Stem 16 includes one or more fuel passages in fluid communication with one or more supply passages of manifold 20. Stem 16 can extend linearly from mount 14 such that stem 16 is devoid of bends or elbows. In other examples, stem 16 can include one or more linear sections connected by respective bends such that a longitudinal axis of stem 16 represented by dashed line L changes at each bend relative to an adjacent linear section of stem 16. As depicted, stem 16 extends radially inward from mount 14 relative to an axis of gas turbine engine. Stem 16 includes a bend spaced apart from mount and extends at an angle relative to the radial section of stem 16 to nozzle 18.

Nozzle 18 is disposed at a distal end of stem 16 within the combustion chamber and extends along nozzle axis A parallel to a distal portion of stem 16. Nozzle 18 includes a center body and one or more annular bodies concentrically disposed with respect to the center body to form one or more discharge fuel passages configured to direct fuel along nozzle axis A. Each of the one or more discharge fuel passages fluidly connects to at least one of the fuel passages of the stem 16 to define respective fuel paths between manifold 20 and nozzle 18. Further, the annular bodies of nozzle 18 form at least one gaseous passage for directing oxidant through nozzle 18 to mix with fuel discharged through fuel paths of injector 10.

Swirler 24 is an annular body surrounding nozzle 18 and circumscribing the one or more fuel passages extending through nozzle 18. Swirler 24 includes one or more oxidant passages that directs an oxidant flow towards fuel discharged from nozzle 18 and thereby produces a target oxidant-fuel mixture. In some examples, oxidant passages can converge towards nozzle axis A to encourage oxidant-fuel mixing.

Cap 26 surrounds at least a portion of nozzle 18 and swirler 24, extending from the discharge end of nozzle 18 towards heat shield 12 and stem 16. The radially interior periphery of cap 26 defines a bore communicating with discharge ends of nozzle 18 and swirler 24. Cap 26 includes one or more effusion passages that direct oxidant flow from one or more oxidant passages across an exterior end face of cap 26.

In operation, fuel injector 10 delivers fuel and oxidant within predetermined oxidant-fuel ratio range associated with one or more operating conditions of a gas turbine engine. Ignition of the oxidant-fuel mixture within combustion chamber produces high temperatures over 1,600 degrees Celsius. The high-temperature and pressure environment within combustion chamber exposes portions of nozzle 18, swirler 24, and cap 26 to high thermal stress and increasing coking potential of fuel within fuel discharge passages within nozzle 18, particularly portions of fuel discharge passages adjacent to exposed surfaces of injector 10.

FIG. 2 is an end view of cap 26 taken along line B-B in FIG. 1. FIG. 3 is a simplified cross-sectional view along line D-D in FIG. 2. FIG. 2 and FIG. 3 depict a schematic representation of effusion passages 28A-28M along with oxidant passages 30A-30N. Portions of nozzle 18 and swirler 24 are shown along with cap 26. Swirler FIG. 2 and FIG. 3 are discussed together.

Swirler 24 includes a circumferential array of guides, vanes, and/or internal passages that define oxidant passages 30A-30N, which are formed by circumferentially adjacent guides, vanes, and/or internal passages. Swirler 24 includes at least one oxidant passage 30A and up to oxidant passage 30N in which “N” denotes an arbitrary number of oxidant passages 30A-30N. Oxidant passages 30A-30N extend from oxidant plenum 32 to an outlet end of nozzle 18. A radially outer exterior of oxidant passages 30A-30N can be open to cap 26 in some examples. Oxidant passages 30A-30N have a radially converging orientation such that each oxidant passages 30A-30N direct oxidant flows towards nozzle axis A to mix with and/or atomize fuel discharged via nozzle 18. That is, oxidant passages 30A-30N permit oxidant to flow towards outlet end of nozzle 18 in operation. Oxidant passages 30A-30N may additionally include a circumferential orientation such that oxidant flows exit swirler with a circumferential velocity component about nozzle axis A (i.e., swirl).

Cap 26 includes peripheral body 34, end body 36, and at least one effusion passage 28A and up to effusion passage 28M, in which “M” denotes a maximum number of effusion passages 28A-28M. Peripheral body 34 is an annular section of cap 26 that circumscribes an outer periphery of swirler 24. Outer peripheral surface 34A delimits a radial outer surface of peripheral body 34 and inner peripheral surface 34B delimits a radial inner surface of peripheral body 34. Inner peripheral surface 34B can form a radially outer boundary of oxidant passages 30A-30N in some examples. End body 36 includes and is delimited by exterior end surface 36A and interior end surface 36B. End body 36 is joined with peripheral body 34 and extends radially inward toward nozzle axis A.

Peripheral body 34 and/or end body 36 of cap 26 can be spaced from swirler 24, or a portion thereof, to define oxidant plenum 32. Oxidant plenum 32 can be one or more cavities (e.g., an annular cavity) communicating with a suitable source of oxidant. In some examples, oxidant can be fed through oxidant passages (not shown) within stem 16 to one or more oxidant passages 30A-30N. In other examples, oxidant is supplied from combustor (e.g., a region between outer combustor wall and outer heat shield).

Exterior end surface 36A borders a combustion chamber and is exposed directly to the high-temperature combustion gas during operation of the combustor chamber. Interior end surface 36B faces inward towards nozzle 18 and swirler 24. Interior end surface 36B may contact mating surfaces of nozzle 18 and/or swirler 24. In some examples such as the exampled depicted by FIG. 3, interior end surface 36B borders oxidant passages 30A-30N. Exterior end surface 36A is depicted as a planar surface normal to nozzle axis A in FIG. 3. However, other surface profiles are contemplated herein for exterior end surface 36A. For instance, exterior end surface 36A can form a conical surface, a concave surface, and/or convex surface, or any combination thereof in some examples.

Effusion passages 28A-28M extend from inlets 38A-38M to respective outlets 40A-40M. Outlets 40A-40M of effusion passages 28A-28M can intersect cap 26 radially outward from oxidant passages of swirler 24 and the fuel passage of nozzle 18. Effusion passages 28A-28M are sized to produce oxidant flow across an exterior surface of cap 26. In some examples, the length of each effusion passage, or a metering portion thereof, can be at least four times the hydraulic diameter. Effusion passages 28A-28M can include a circular, rectangular, elliptical, ovular, or oblong cross-sectional shape. For example, effusion passages 28A-28M can have a constant, circular cross-section with a diameter greater than or equal to 0.254 millimeters (i.e., 0.010 inches) and less than or equal to 0.762 millimeters (i.e., 0.030 inches). In other examples, effusion passages 28A-28M can include complex cross-sections formed by one or cross-sectional shapes. Effusion passages 28A-28M with complex cross-sections can include a metering section and/or a diffusion section. The metering section can include a constant cross-section with any of the foregoing cross-sectional shapes whereas the diffusion section can include one or more lobes, and/or walls that diverge towards respective outlets 40A-40M.

Effusion passages 28A-28M divert a portion of oxidant flow across an exposed surface of cap 26. The percentage of oxidant flow diverted by effusion passages 28A-28M can be greater than or equal to one percent of all oxidant flow and less than or equal to ten percent of oxidant flow in some examples. In other examples, the percentage of oxidant flow diverted by effusion passages 28A-28M can be greater than or equal to one percent of all oxidant flow and less than or equal to five percent of oxidant flow.

Centerlines connecting geometric centers of inlets 38A-38M to respective outlets 40A-40M describe orientations of effusion passages 28A-28M. Effusion passages 28A-28M can radially diverge from nozzle axis A in a direction along centerlines from inlets 38A-38M to respective outlets 40A-40M. In this way, cooling provided by oxidant flows through effusion passages 28A-28M do not significantly impede or disrupt mixing and/or atomization of fuel discharged by nozzle 18. In other examples, some or all of effusion passages 28A-28M have a circumferential orientation in a direction along centerlines from inlets 38A-38M to respective outlets 40A-40M. The circumferential orientation of effusion passages 28A-28M can define a clockwise orientation, or a counterclockwise orientation as viewed in FIG. 2, which can be the same or counter to a circumferential orientation of oxidant passages 30A-30N. Examples of effusion passages 28A-28M with the same circumferential orientation as swirler 24 benefit from reduced shear between oxidant flow exiting effusion passages 28A-28M and oxidant flow exiting swirler 24.

The circumferential orientation and/or planar orientation of effusion passages 28A-28M can be described circumferential angles and planar angles. The circumferential angle of each effusion passage can be described by the angle between the effusion passage centerline and a radial line extending from nozzle axis A to intersect the centerline at the effusion passage outlet. The circumferential angles of respective effusion passages 28A-28M can be less than or equal to eighty degrees and greater than or equal to sixty degrees, in some examples. The planar angle of respective effusion passages 28A-28M can be described by the angle between the effusion passage centerline and exterior end surface 36A of cap 26. Planar angles can be greater than zero degrees and less than or equal to thirty degrees, for example.

While cap 26 can include a single effusion passage 28A, examples of cap 26 with multiple effusion passages 28A-28M include up to a maximum number “M” of effusion passages 28A-28M based on a number “N” of oxidant passages 30A-30N. In some examples, the maximum number “M” of effusion passages 28A-28M can be equal to two times a number “N” of oxidant passages 30A-30N. Further, each of oxidant passages 30A-30N can fluidly communicates with no more than two effusion passages in certain examples. In other examples, at least some oxidant passages 30A-30N fluidly communicate with less than two effusion passages, or do not fluidly communicate with any effusion passages 28A-28M. Distributing outlets 40A-40M among oxidant passages 30A-30N in this manner limits or avoids substantial disruptions to oxidant-fuel mixing of injector 10.

Outlets 40A-40M of effusion passages 28A-28M can be distributed equally about nozzle axis A. In other examples, outlets 40A-40M can have unequal circumferential spacing about nozzle axis A. Exterior end surface 36A of cap 26 can be partitioned into two or more equal sectors. In some examples, circumferential spacing of effusion passage outlets 40A-40M is less within a target sector relative to circumferential spacing of effusion passage outlets 40A-40M, if any, in one or more other sectors. In each sector, the number of effusion passage outlets within each sector does not exceed a total number “M” of effusion passage outlets divided by the number of sectors. In this way, a density of effusion cooling flow can be localized within the target sector in order to counteract local heat flux maximums imposed on end body 36 of cap 26 without significantly disrupting oxidant flow discharged through swirler 24.

Additionally, outlets 40A-40M of effusion passages 28A-28M can be arranged along a common radius, or at multiple radii relative to nozzle axis A. In each instance, outlets 40A-40M are radially outward from an outlet of swirler 24. Effusion passages 28A-28M with outlets 40A-40M arranged at multiple radii can include, for example, a radially staggered arrangement in which a first subset of outlets 40A-40M are radially outward from a second subset of outlets 40A-40M. In a further example, each outlet of the first subset can be circumferentially interposed between two adjacent outlets of the second subset to create staggered sets of effusion outlets.

Locations of inlets 38A-38M and outlets 40A-40M are selected to prevent reverse flow through effusion passages 28A-28M. Reverse flow occurs when flow occurs in a reverse direction from outlets 38A-38M to inlets 40A-40M of effusion passages 28A-28M. Inlets 38A-38M of effusion passages 28A-28M can be located where static pressures local to each of inlets 38A-38M exceeds static pressures local to respective outlets 40A-40M through the entire operational range of injector 10 by a margin sufficient to achieve a target oxidant flow in a forward direction from inlets 38A-38M to outlets 40A-40M. Ensuring forward flow through effusion passages 28A-28M prevents ingestion of high temperature fluids and thereby increasing the temperature of injector 10, and more particularly increasing the temperature of cap 26.

As depicted in FIG. 2 and FIG. 3, inlets 38A-38M are disposed along interior end surface 36B in fluid communication with one of oxidant passages 30A-30N, and outlets 40A-40M are disposed along exterior end surface 36A of cap 26. Inlets 38A-38M of the depicted effusion passages 28A-28M fluidly communicate with one of oxidant passages 30A-30N, and direct a portion of oxidant flow within oxidant passages 30A-30N across exterior end surface 36A of cap 26.

FIG. 4 is an end view of cap 26 taken along line B-B in FIG. 1 depicting an alternative arrangement of effusion passages 28A-28M. FIG. 5 is a simplified cross-sectional view along line E-E in FIG. 4. FIG. 4 and FIG. 5 depict another schematic representation of effusion passages 28A-28M along with oxidant passages 30A-30N. Effusion passages 28A-28M can have a circumferential orientation and planar orientation characterized by radial angles and planar angles, respectively, as described above. As depicted in FIG. 4, and FIG. 5, however, inlets 38A-38M of effusion passages 28A-28M are disposed along outer peripheral surface 34A of cap 26 in lieu of interior end surface 36B. Accordingly, effusion passages 28A-28M, as depicted in FIG. 4 and FIG. 5, fluidly communicate with oxidant plenum 32, or a region exterior to injector 10.

Discussion of Possible Embodiments

Fuel Injector with Effusion Passages

The following are non-exclusive descriptions of possible embodiments of the present invention.

A fuel injector configured to deliver an oxidant-fuel mixture along a nozzle axis includes, among other possible things, a nozzle and a cap. The nozzle includes a fuel passage and a swirler. The fuel passage extends along the nozzle axis. The swirler circumscribes the fuel passage and includes a plurality of oxidant passages that converge towards the nozzle axis. The cap includes a peripheral body, an end body, and an effusion passage. The peripheral body circumscribes the swirler. The end body joins to the peripheral body and extends radially towards the nozzle axis. The effusion passage extends through the cap to intersect at least one of the peripheral body and the end body from an inlet to an outlet. The outlet is radially outward from the plurality of oxidant passages relative to the nozzle axis.

The fuel injector of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components.

A further embodiment of the foregoing fuel injector, wherein the effusion passage can extend along a passage centerline from the inlet to the outlet that diverges radially from the axis.

A further embodiment of any of the foregoing fuel injectors, wherein the inlet of the effusion passage can fluidly communicate with a first oxidant passage of the plurality of oxidant passages.

A further embodiment of any of the foregoing fuel injectors, wherein the plurality of oxidant passages can fluidly communicate with a region exterior to the nozzle.

A further embodiment of any of the foregoing fuel injectors, wherein the inlet of the effusion passage can intersect the peripheral body and can fluidly communicate with the region.

A further embodiment of any of the foregoing fuel injectors, wherein the effusion passage can form a circumferential angle with respect to a radial line extending from the axis.

A further embodiment of any of the foregoing fuel injectors, wherein the effusion passage can form a planar angle with respect to the end body.

A further embodiment of any of the foregoing fuel injectors, wherein the circumferential angle can be greater than or equal to sixty degrees and less than or equal to eighty degrees.

A further embodiment of any of the foregoing fuel injectors, wherein the planar angle can be greater than zero degrees and less than or equal to thirty degrees.

A further embodiment of any of the foregoing fuel injectors, wherein circumferential orientations of the plurality of effusion passages and the swirler can be the same.

A further embodiment of any of the foregoing fuel injectors, wherein circumferential orientations of the plurality of effusion passages and the swirler can be different.

A further embodiment of any of the foregoing fuel injectors, wherein respective outlets of the plurality of effusion passages can be equally spaced about the nozzle axis.

A further embodiment of any of the foregoing fuel injectors, wherein respective outlets of the plurality of effusion passages can be asymmetrically spaced about the nozzle axis.

A further embodiment of any of the foregoing fuel injectors, wherein the cap includes a plurality of effusion passages.

A further embodiment of any of the foregoing fuel injectors, wherein a maximum number of effusion passages is equal to or less than two times a number of oxidant passages.

A further embodiment of any of the foregoing fuel injectors, wherein the exterior peripheral surface of the cap can be divided into a discrete number of sectors.

A further embodiment of any of the foregoing fuel injectors, wherein a number of effusion passages within a sector does not exceed an equal portion of the maximum number of effusion passages per sector.

A further embodiment of any of the foregoing fuel injectors, wherein less than or equal to twenty five percent of respective outlets can be disposed within each of four equal sectors of the end face.

A further embodiment of any of the foregoing fuel injectors, wherein respective inlets of the plurality of effusion passages can fluidly communicate with one of the oxidant passages.

A further embodiment of any of the foregoing fuel injectors, wherein each inlet of the plurality of effusion passages can fluidly communicate with a different oxidant passage of the plurality oxidant passages.

A further embodiment of any of the foregoing fuel injectors, wherein each oxidant passage can fluidly communicate with a maximum of two inlets of the plurality of effusion passages.

A further embodiment of any of the foregoing fuel injectors, wherein each effusion passage can have a length at least four times its hydraulic diameter.

A further embodiment of any of the foregoing fuel injectors, wherein each effusion passage can have a rectangular cross-section.

A further embodiment of any of the foregoing fuel injectors, wherein each effusion passage can have an elliptical cross-section.

A further embodiment of any of the foregoing fuel injectors, wherein each effusion passage can have an ovular cross-section.

A further embodiment of any of the foregoing fuel injectors, wherein each effusion passage can have oblong cross-section.

A further embodiment of any of the foregoing fuel injectors, wherein each effusion passage can have a metering section.

A further embodiment of any of the foregoing fuel injectors, wherein each effusion passage can have a diffusion section.

A further embodiment of any of the foregoing fuel injectors, wherein the diffusion section of each effusion passage can have one or more lobes.

A further embodiment of any of the foregoing fuel injectors, wherein the diffusion section of each effusion passage can have walls that diverge towards the outlet.

A further embodiment of any of the foregoing fuel injectors, wherein each effusion passage can have a circular cross-section.

A further embodiment of any of the foregoing fuel injectors, wherein each effusion passage can have a diameter greater than or equal to 0.254 millimeters and less than or equal to 0.762 millimeters.

A further embodiment of any of the foregoing fuel injectors, wherein the plurality of effusion passages can divert a portion of the oxidant flow.

A further embodiment of any of the foregoing fuel injectors, wherein the plurality of effusion passages collectively can divert greater than or equal to one percent of the oxidant flow.

A further embodiment of any of the foregoing fuel injectors, wherein the plurality of effusion passages collectively can divert less than or equal to ten percent of the oxidant flow.

A further embodiment of any of the foregoing fuel injectors, wherein the plurality of effusion passages collectively can divert less than or equal to five percent of the oxidant flow.

A further embodiment of any of the foregoing fuel injectors, wherein outlets of the plurality of effusion passages can be arranged along a common radius relative to the nozzle axis.

A further embodiment of any of the foregoing fuel injectors, wherein a first subset of the outlets can be arranged along a first radius relative to the nozzle axis.

A further embodiment of any of the foregoing fuel injectors, wherein a second subset of the outlets can be arranged along a second radius relative to the nozzle axis that is different than the first radius.

A further embodiment of any of the foregoing fuel injectors, wherein the first subset of outlets can be disposed radially outward from the second subset of outlets relative to the nozzle axis.

A further embodiment of any of the foregoing fuel injectors, wherein each outlet of the first subset of the outlets can be circumferentially interposed between two adjacent outlets of the second subset of outlets.

A further embodiment of any of the foregoing fuel injectors, wherein static pressures local to inlets of the plurality of effusion exceed static pressure local to respective outlets of the plurality of effusion passages.

While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.