PILOT ARRANGEMENT, NOZZLE DEVICE, PRODUCTION METHOD, AND GAS TURBINE ARRANGEMENT

Description

This application claims priority to German Patent Application 102024128891.4 filed Oct. 8, 2024, the entirety of which is incorporated by reference herein.

The invention relates to a pilot arrangement for use in a nozzle device of a gas turbine arrangement, in particular of an aircraft engine, according to the preamble of claim 1. Furthermore, the invention relates to a nozzle device, to a production method and to a gas turbine arrangement.

In order for it to be possible carry out combustion processes stably in an aircraft engine over as wide an operating range as possible, fuel nozzles frequently have a pilot stage (pilot means). In this case, a smaller amount of fuel is supplied via the pilot means than via a main stage. The combustion process via the pilot stage is operated in a stable range, thus stabilizing the combustion process via the main stage.

A pilot arrangement of the type mentioned at the beginning, which allows a very compact design, is specified in DE 10 2022 208 337 A1.

Pilot arrangements in nozzle devices with comparatively large dimensions are specified in U.S. Pat. No. 10,072,845 B2 and EP 1 445 540 A1.

US 2014/0291418 A1 discloses a nozzle device comprising two air channels for operation with two air flows (“2-flow fuel nozzle”), without a pilot means.

The present invention addresses the problem of providing a pilot arrangement that is optimized in terms of manufacturing aspects, and a method for producing the pilot arrangement and a gas turbine arrangement.

The problem is solved with regard to the pilot arrangement by the features of claim 1. The problem is solved with regard to the nozzle device by the features of claim 11, with regard to the method by the features of claim 12, and with regard to the gas turbine arrangement by the features of claim 15.

In the case of the pilot arrangement, the pilot arrangement is made up of two components, in particular assembled therefrom, wherein a first component comprises the at least one swirling element and (at least largely) the central body, and a second component comprises the pilot fuel nozzle.

The separation between the two components is formed substantially in one or two plane(s) orthogonal to the longitudinal axis, in particular at (only) one or (only) two axial positions.

The cavity preferably has a substantially large flow cross section than the flow cross section of the pilot line. For example, the largest flow cross section of the cavity is larger than the largest flow cross section in a line element of the pilot line, upstream of the pilot fuel outlet, by at least a factor of 3, preferably by a factor of between 5 and 10, or at least a factor of 10.

In this case, provision is, in particular, advantageously made for the first component to be in the form of a cohesive, integral (one-piece) component. High manufacturing accuracy is achievable when the first component is manufactured in particular by means of milling, drilling and/or turning processes.

For a design that is as compact as possible, the first component preferably has at least one pilot fuel supply line for supplying fuel into the cavity, wherein the at least one pilot fuel supply line passes through the at least one swirling element in order to conduct pilot fuel from a circumferential wall of an inner air channel radially inwardly into the cavity. The flow cross section of the at least one pilot fuel supply line is at least as large as the flow cross section of the pilot line (upstream of the pilot fuel outlet). Swirling elements having a pilot fuel supply line are preferably formed in a thicker manner (in the circumferential direction) than those without a pilot fuel supply line.

Swirl is advantageously imparted on an air flow when the first component has at least five and at most eight swirling elements. When there are five swirling elements, preferably at least or exactly one has a pilot fuel supply line. When eight swirling elements are provided, preferably four of them have a pilot fuel supply line.

Preferably, the second component comprises a sleeve, in particular a ceramic sleeve, arranged circumferentially around the pilot line. The sleeve is made for example from Al₂O₃ or comprises Al₂O₃. Preferably, the sleeve is arranged in an in particular cylindrical interior of a lance coaxially with the pilot line and extends from the axial position of the upstream end of the lance (starting from the downstream end of the central body) to a downstream axial stop in a downstream end region of the lance (in particular a downstream quarter, fifth or sixth of the lance) upstream of the pilot fuel outlet. The ceramic sleeve acts as a heat shield in particular in place of an expansion space, wherein the sleeve is arranged with as precise a fit as possible between a boundary wall of the lance and the pilot line.

Preferably, the second component has a separating element, in particular a sealing separating element, arranged between the upstream end of the sleeve and the cavity. The separating element is in the form in particular of a collar and/or ring and/or funnel, preferably made of the same material as the pilot line (in particular of a nickel-based alloy or stainless steel), and is positioned between the cavity and the sleeve in the assembled state. The separating element may have been fastened retrospectively, as a separate element, to the pilot line or be manufactured integrally with the pilot line. The separating element serves as a mechanical separation between the cavity and the sleeve, and to axially fix the sleeve. The pilot line may project, upstream, through the separating element into the cavity.

Preferably, the second component comprises a lance which extends along the longitudinal axis and accommodates the pilot line and/or the sleeve and/or the separating element. The lance comprising the pilot line has an axial length such that the fuel outlet is positioned at least in a downstream third or quarter, preferably at least substantially at an outlet, of an inner air channel of the nozzle device. The lance is formed in particular largely in a hollow cylindrical manner and preferably has, apart from a tapering downstream end portion, a constant height, in particular a constant outside diameter. The lance adjoins, for example, a downstream taper of the central body. The lance preferably has a, for example cylindrical, interior, extending along the longitudinal axis, for receiving the individual parts mounted on or in the lance. The individual parts arranged on or in the lance are preferably oriented coaxially with one another. The individual elements can be fastened on or in the lance, for example at the tip, by brazing. Preferably, upstream of the lance, a part of the central body is arranged on the second component with a conical part of the cavity as a transition between the cavity and the pilot line.

Advantageous fuel injection can be achieved when the pilot line tapers towards a pilot fuel outlet by means of a narrowing.

In a design variant that is optimized for manufacture, the narrowing is formed by a tubular element which is arranged in and/or downstream (immediately adjoining the line element) of a line element of the pilot line, and has a smaller flow cross section than the line element. The pilot line then has the line element and, at its downstream end, the tubular element, or is formed from these two elements. It is also possible for the narrowing to be manufactured integrally on the line element, wherein, in particular, the pilot line is formed (only) by means of the line element.

In a flow-optimized design, the flow cross section(s) of the pilot line and/or of the at least one pilot fuel supply line is/are round.

The nozzle device according to the invention has a pilot arrangement according to any of the preceding design variants and an inner air channel, which is arranged on a longitudinal axis of the nozzle device and within which the pilot arrangement is arranged coaxially with the inner air channel.

The method for producing a pilot arrangement which is designed according to any of the preceding design variants, comprises the steps of:

• • a. providing a first component comprising at least one swirling element and a central body, and a second component comprising a pilot fuel nozzle;
  • b. fastening the two components together by joining, for example brazing or welding.

An advantageous procedure during production is that, to produce the first component, this first component is manufactured, in particular integrally (in one piece), by means of milling, drilling and/or turning processes.

Preferably, to provide the second component, said second component is preassembled, wherein

• • for example a tubular element is fastened, in particular brazed in, at a downstream end of a line element comprising a pilot line coaxial with the line element as the downstream end of the pilot line;
  • a sleeve is introduced from an upstream end of a lance into an elongate interior of the lance;
  • the line element comprising the separating element and optionally the tubular element is introduced into the sleeve and is fixed to the tip of the lance, for example by means of brazing.

The invention will be explained in more detail in the following text by way of exemplary embodiments with reference to the drawings, in which:

FIGS. 1A, 1B, 1C show a nozzle device comprising a swirling arrangement according to the prior art in longitudinal section (FIG. 1A), an inner air channel of the nozzle device in longitudinal section (FIG. 1B), and a partial sectional view of the swirling arrangement along a section line A (FIG. 1C),

FIGS. 2A, 2B show the inner air channel of a nozzle device comprising a pilot arrangement according to the prior art in longitudinal section (FIG. 2A), and a partial sectional view of the pilot arrangement along a section line B (FIG. 2B),

FIG. 3 shows the inner air channel of a nozzle device comprising a pilot arrangement according to the invention in longitudinal section,

FIG. 4 shows steps of a manufacturing method with individual parts of a second component of the pilot arrangement in longitudinal section, and

FIG. 5 shows the inner air channel of a nozzle device in a further design variant of the pilot arrangement in longitudinal section.

FIG. 1A shows a nozzle device 100 in longitudinal section, comprising three air channels 5, 7 (3-flow fuel nozzle), as is known from the prior art. Nozzle devices 100 of this type are used in particular in aircraft engines. FIG. 1B shows an inner air channel 7 of the nozzle device 100 with an integrated central body 8 in longitudinal section. FIG. 1C shows a partial section through the inner air channel 7 along the section line A.

The nozzle device 100 shown in FIG. 1A to FIG. 1C is designed in particular for operation with a liquid fuel (kerosene-based or kerosene-related).

The nozzle device 100 has a fuel feed line 1, which is fluidically connected in order to supply an annular fuel reservoir 2 of the nozzle device 100 with fuel during operation. Arranged downstream of the annular fuel reservoir 2 is an annular fuel line 3, by means of which a fuel injector 4 of the nozzle device 100 is supplied with fuel during operation. By means of the fuel injector 4, the fuel is injected into a combustion chamber (not shown here).

The fuel injector 4 is surrounded radially by two circumferential air channels 5, a radially outer air channel and a radially central air channel. Swirling elements 6 are arranged within each of the air channels 5.

Centrally on a longitudinal axis L, the nozzle device 100 has the inner air channel 7, which is bounded by a wall 70, in particular a cylindrical wall. At its downstream end, the inner air channel 7 has an outlet 71 for adjoining the combustion chamber. An inside diameter D in a downstream portion and/or at the outlet 71 may be, for example, 7 mm to 15 mm.

Provided between the inner air channel 7 and the annular fuel line 3 and/or the fuel injector 4 is an air chamber 10 for thermally shielding (i.e. acting as a heat shield) these fuel-conducting lines.

Arranged within the inner air channel 7 is a swirling arrangement 9, which has a central body 8 centrally on the longitudinal axis L. Swirling elements 90 of the swirling arrangement 9 are arranged around the central body 8 for generating a swirl flow within the inner air channel 7 during operation, said swirling elements extending from the central body 8 in a radial-tangential direction to the wall 70. An example thickness d of the swirling elements 90 is 0.8 mm to 1.5 mm. The swirling elements 90 and the central body 8 are manufactured as separate components which are joined together prior to installation, for example during assembly of the nozzle device 100.

Stability problems can arise during operation using the nozzle device 100 according to FIG. 1A to FIG. 1C, it being possible, for example, for a lean blowout to occur. A pilot means can be used for stabilization purposes, but this is difficult to implement in particular in small nozzle devices 100 on account of a lack of installation space.

Shown in FIG. 2A in a longitudinal section through the inner air channel 7 and in FIG. 2B in a partial section along the section line B is a pilot arrangement 23, which, because it can be constructed in a compact manner, can be fitted easily in small nozzle devices 100, as shown, for example, in FIG. 1A. This construction is known from DE 10 2022 208 337 A1.

The pilot arrangement 23 has a cavity 12, which is arranged centrally on the longitudinal axis L and extends along the longitudinal axis L. The cavity 12 serves in particular as a settling chamber for the fuel flow.

Furthermore, the pilot arrangement 23 has a pilot fuel nozzle 13, which comprises a pilot line 130 axially extending centrally along the longitudinal axis L, and a fuel outlet 131 arranged at the downstream end of the pilot line 130. The pilot fuel nozzle 13 is arranged directly downstream of the cavity 12 and is fluidically connected thereto, and is fed with fuel from the cavity 12 during operation. The largest and the narrowest flow cross section of the pilot line 130 are smaller than the largest and the narrowest flow cross section of the cavity 12. For example, the largest flow cross section of the pilot line 130 is smaller than the largest flow cross section of the cavity 12 by at least a factor of 3, preferably by a factor of between 5 and 10, or at least a factor of 10.

The pilot arrangement 23 comprises, for example, a plurality of pilot fuel supply lines 11 for supplying fuel, in this case in particular liquid fuel (kerosene-based or kerosene-related), into the cavity 12. For a particularly compact design, the pilot fuel supply lines 11 are guided through the swirling elements 90 from the radially outer region, i.e. from the wall 70 of the inner air channel 7, inwardly to the cavity 12. For this purpose, preferably a corresponding distribution line for providing the pilot fuel supply lines 11 with fuel is arranged in the wall 70 (this not being shown here).

For thermally shielding the cavity 12 and/or the pilot line 130, a gas-filled hollow chamber 14 is arranged circumferentially around the pilot line 130 and the cavity 12, as a heat shield within the central body 8.

The known pilot arrangement 23 shown in FIG. 2A and FIG. 2B is integrated into the swirling arrangement 9 for a particularly compact construction. In this case, the cavity 12 is arranged in the central body 8 of the swirling arrangement 9, in particular symmetrically with respect to the longitudinal axis L. The swirling elements 90 are arranged radially in a circumferential manner around the central body 8 comprising the cavity 12. The pilot arrangement 23, having the swirling elements 90 and the central body 8 comprising the cavity 12, is formed as a cohesive, integral (one-piece) component with the pilot fuel nozzle 13.

FIG. 3 shows, in a longitudinal section through the inner air channel 7, a development according to the invention of the pilot arrangement 23 known from DE 10 2022 208 337 A1, which has been optimized in particular in terms of manufacturing aspects.

In this case, a lance 16, which extends along the longitudinal axis L coaxially with the inner air channel 7 and the cavity 12, is arranged at the downstream end of the central body 8. By means of the lance 16, the pilot fuel outlet 131 is arranged in the downstream third of the inner air channel 7 close to the outlet 71 (or, preferably, at the level of the outlet 71, this not being shown here). The lance 16 is formed in particular largely in a hollow cylindrical manner and preferably has, apart from a tapering downstream end portion, a constant height, in particular a constant outside diameter. The lance 16 adjoins a downstream taper of the central body 8. At least the majority of the pilot line 130 extends within the lance 16. By means of the lance 16, the heat release zone can be located further downstream, axially at a distance from the cavity 12, during the pilot combustion process.

The flow cross sections of the pilot line 130 and/or of the pilot fuel supply lines 11 are preferably round.

As FIG. 3 shows, the pilot arrangement 23 is made up of, in particular exactly, two components, a first component 21 and a second component 22. The two components 21, 22 have been joined together for example by means of brazing or welding.

A separation T between the components 21, 22, at which the components 21, 22 have been joined together, extends in particular substantially perpendicularly to the longitudinal axis L, for an assembly-friendly design for example at two axial positions. In this case, for example, an upstream end of the second component 22 is in the form of a circumferential collar 161 acting as an axial stop during assembly. The course of the outer wall of the first component 21 continues at the separation T so as to have a course of the wall at the second component 22 that is constant as far as possible. The inner wall for delimiting the cavity 12 ends at the first component 21 further upstream than the outer wall of the first component 21, wherein the outer wall ends at a stop at the collar 161.

Downstream of the separation T, the inner wall of the cavity 12 is formed within the second component 22 for example in a conical manner, for the transition to the pilot line 130.

The first component 21 comprises the swirling elements 90 comprising at least one, preferably between one and four, pilot fuel supply line(s) 11, and at least the majority of the central body 8, with at least the majority of the cavity 12. The first component 21 is arranged entirely in the upstream half of the inner air channel 7. A part of the second component 22 also extends, for example, into the upstream half of the inner air channel 7.

Preferably, there are between five and eight swirling elements 90, wherein in each case one of the pilot fuel supply lines 11 extends radially inwardly into the cavity 12 in one (when there are five swirling elements 90) or up to four swirling elements 90 (in particular when there are eight of them). The swirling elements 90 which comprise one of the pilot fuel supply lines 11 are each thicker than those without a pilot fuel supply line 11.

The first component 21 is, in particular, in the form of a cohesive, integral (one-piece) component and has been manufactured, for example, by means of milling, drilling and/or turning processes. The cavity 12 is formed substantially, in particular apart from a downstream end portion, for example in a hollow cylindrical manner. A maximum height H of the cavity 12 (for example a diameter) corresponds, for example, to ¼ to ¾ of the (smallest) diameter D of the inner air channel 7.

The second component 22 comprises the pilot fuel nozzle 13 having the lance 16 and the pilot line 130. A downstream end portion of the cavity 12 may likewise be arranged in the second component 22.

The second component 22 is made up, in particular, of a plurality of individual parts, which have been preassembled to form the second component 22. The individual parts are in this case arranged on the lance 16, and have preferably been largely inserted into a cylindrical interior 160 of the lance 16.

In this case, the second component 22 comprises a sleeve 17 arranged circumferentially around the pilot line 130 in the interior 160. The sleeve 17 is in the form, in particular, of a ceramic element 170, i.e. made of ceramic material (for example of Al₂O₃), and acts as a heat shield for thermally shielding the pilot line 130, in particular in place of an expansion space around the pilot line 130. By means of the sleeve 17, the pilot line 130 is additionally positioned in a stable and reliable manner.

Furthermore, the second component 22 has a separating element 18 arranged between the upstream end of the sleeve 17 and the cavity 12. The separating element 18 is in the form of a collar and/or ring and/or funnel, preferably made of the same material as the pilot line (in particular of a nickel-based alloy or stainless steel), and is positioned between the cavity 12 and the sleeve 17 in the assembled state. In this case, the separating element 18 bears with as precise a fit as possible against (the outside of) the inner walls of the cavity 12 and/or of the lance 16 and against (the inside of) the wall of the pilot line 130, or is connected to the wall of the pilot line 130. Thus, the separating element 18 acts as an upstream axial stop for the ceramic sleeve 17 in order to prevent the sleeve 17, comprising in particular ceramic material, from entering the fuel path. The pilot line 130 may project, upstream, through the separating element 18 into the cavity 12 (cf. FIG. 5).

In addition, the second component 22 may have a tubular element 200, which comprises or forms a downstream narrowing 20 of the pilot line 130 towards the pilot fuel outlet 131. The pilot fuel outlet 131 is then arranged at the downstream end of the tubular element 200. The upstream portion of the pilot line 130 is formed by means of a line element 132 having, in this case, for example, a constant flow cross section. The tubular element 200 is arranged at the downstream end of the line element 132 and has a smaller flow cross section than the line element 132, wherein it may have been introduced at least partially into the line element 132. By means of the overhang of the tubular element 200, the exact axial position of the pilot fuel outlet 131 can be set.

Alternatively, it is possible for the narrowing 20 with the pilot fuel outlet 131 to be arranged at the downstream end of the line element 132 and to have been manufactured integrally thereon.

FIG. 4 shows steps of a method for manufacturing the pilot arrangement 23 with preassembly of the second component 22 from a plurality of individual parts. In a first step i) shown in FIG. 4, the tubular element 200 is introduced at the downstream end of the line element 132, coaxially therewith, and preferably fastened thereto, in particular brazed in.

The separating element 18 is or has been arranged at the downstream end of the line element 132, for example fastened (retrospectively) thereto or manufactured integrally with the line element 132, in this case, for example, such that the upstream end of the separating element 18 ends substantially flush with the upstream end of the line element 132.

In a step ii) (which may also be carried out at the same time as or before step i)), the sleeve 17 is introduced from upstream into the interior 160 of the lance 16 until the sleeve 17 butts against a downstream cross-sectional narrowing of the interior 160. In this case, the sleeve 17 has in particular an outside diameter such that it is received in a form-fitting manner by the interior 160 but is also easily displaceable.

In a step iii), the line element 132 preassembled in step i) with the tubular element 200 and the separating element 18 is introduced into the sleeve 17 located inside the lance 16 until the separating element 18 butts axially against the upstream end of the sleeve 17.

In a step iv), the line element 132 and/or the tubular element 200 is/are fixed to the tip of the lance 16, for example by means of brazing.

The second component 22 preassembled in this way is then fastened to the first component 21 by means of brazing or welding, wherein the pilot arrangement 23 shown in FIG. 3 is formed.

FIG. 5 shows the inner air channel 7 of the nozzle device 100 with a further design variant of the pilot arrangement 23 in longitudinal section. In this case, the line element 132 comprising the pilot line 13 projects upstream beyond the separating element 18 into the cavity 12 and/or axially into the first component 21.

The pilot arrangement 23 may, with a particularly compact possible construction, be manufactured advantageously for use in small nozzle devices, for example in so-called 3-flow fuel nozzles.

LIST OF REFERENCE SIGNS

• • 100 Nozzle device
  • 1 Fuel feed line
  • 2 Annular fuel reservoir
  • 3 Annular fuel line
  • 4 Fuel injector
  • 5 Outer and central air channel
  • 6 Swirling element
  • 7 Inner air channel
  • 70 Wall
  • 71 Outlet
  • 8 Central body
  • 9 Swirling arrangement
  • 90 Swirling element
  • 10 Air chamber
  • 11 Pilot fuel supply line
  • 12 Cavity
  • 13 Pilot fuel nozzle
  • 130 Pilot line
  • 131 Pilot fuel outlet
  • 132 Line element
  • 16 Lance
  • 160 Interior
  • 161 Collar
  • 17 Sleeve
  • 170 Ceramic element
  • 18 Separating element
  • 19 Brazing
  • 20 Narrowing
  • 200 Tubular element
  • 21 First component
  • 22 Second component
  • 23 Pilot arrangement
  • D Diameter
  • d Thickness
  • T Separation