Combustor mounting assembly having a spring finger for forming a seal with a fuel injector assembly

A combustor assembly for a gas turbine engine is provided. The combustor assembly generally includes an annular dome and a liner that at least partially define a combustion chamber. The annular dome defines a plurality of circumferentially spaced fuel injection ports and a plurality of mounting assemblies are configured for receiving and supporting a plurality of fuel injector assemblies within the fuel injection ports. Each mounting assembly includes a ferrule positioned adjacent to and extending around a peripheral edge of the respective fuel injection port. A spring finger is coupled to an interior surface of the ferrule and extends toward a centerline of the fuel injection port to form a seal with the fuel injector assembly.

FIELD

The present subject matter relates generally to a gas turbine engine, or more particularly to a combustor assembly for a gas turbine engine.

BACKGROUND

A gas turbine engine generally includes a fan and a core arranged in flow communication with one another. Additionally, the core of the gas turbine engine general includes, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air is provided from the fan to an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section to the turbine section. The flow of combustion gases through the turbine section drives the turbine section and is then routed through the exhaust section, e.g., to atmosphere.

Conventional combustor assemblies include fuel injectors that are inserted into fuel injection ports on combustor domes to provide a fuel/air mixture into the combustion chamber. During operation, and particularly during transient operation such as start-up when large temperature differences may be experienced, thermal expansion causes the fuel injectors and combustor domes to move relative to each other. To reduce stress between the components and ensure proper operation, a clearance gap is often provided around the fuel injectors. However, such a clearance gap can allow air leakage between the dome and the fuel injector, which is inefficient and can affect the combustion aerodynamics. Certain combustion assemblies use floating collars that surround the fuel injectors, but such collars can complicate assembly and may not sufficiently reduce the size of the clearance gap.

Accordingly, a gas turbine engine with an improved combustor assembly would be useful. More specifically, a combustor assembly that reduces the introduction of leakage air into the combustion chamber and simplifies assembly would be particularly beneficial.

BRIEF DESCRIPTION

In one exemplary embodiment of the present disclosure, a combustor assembly for a gas turbine engine defining an axial direction is provided. The combustor assembly includes an annular liner extending between a forward end and an aft end generally along the axial direction and an annular dome positioned forward of the annular liner along the axial direction, the annular dome and the annular liner at least partially defining a combustion chamber. A plurality of fuel injection ports are defined by and spaced circumferentially around the annular dome, each of the fuel injection ports defining a peripheral edge, a centerline, and a radial direction perpendicular to the centerline. A plurality of mounting assemblies are operably coupled to one of the plurality of fuel injection ports and include a ferrule positioned adjacent to and extending around the peripheral edge of one of the plurality of fuel injection ports, the ferrule defining an interior surface along the radial direction. A spring finger has a first end coupled to the interior surface of the ferrule and a second end extending toward the centerline of the fuel injection port.

In another exemplary embodiment of the present disclosure, a gas turbine engine defining an axial direction is provided. The gas turbine engine includes a compressor section; a turbine section mechanically coupled to the compressor section through a shaft; and a combustor assembly disposed between the compressor section and the turbine section. The combustor assembly includes an annular liner extending between a forward end and an aft end generally along the axial direction and an annular dome positioned forward of the annular liner along the axial direction, the annular dome and the annular liner at least partially defining a combustion chamber. A plurality of fuel injection ports are defined by and spaced circumferentially around the annular dome, each of the fuel injection ports defining a peripheral edge, a centerline, and a radial direction perpendicular to the centerline. A plurality of fuel injector assemblies extend through the plurality of fuel injection ports and a plurality of mounting assemblies are operably coupled to one of the plurality of fuel injection ports and include a ferrule positioned adjacent to and extending around the peripheral edge of one of the plurality of fuel injection ports, the ferrule defining an interior surface along the radial direction. A spring finger has a first end coupled to the interior surface of the ferrule and a second end extending toward the centerline of the fuel injection port.

DETAILED DESCRIPTION

The present disclosure is generally directed to a combustor assembly for a gas turbine engine. The combustor assembly generally includes an annular dome and a liner that at least partially define a combustion chamber. The annular dome defines a plurality of circumferentially spaced fuel injection ports and a plurality of mounting assemblies are configured for receiving and supporting a plurality of fuel injector assemblies within the fuel injection ports. Each mounting assembly includes a ferrule positioned adjacent to and extending around a peripheral edge of the respective fuel injection port. A spring finger is coupled to an interior surface of the ferrule and extends toward a centerline of the fuel injection port to form a seal with the fuel injector assembly.

Referring now to the drawings,FIG. 1is a schematic cross-sectional view of a gas turbine engine in accordance with an exemplary embodiment of the present disclosure. More particularly, for the embodiment ofFIG. 1, the gas turbine engine is a high-bypass turbofan jet engine10, referred to herein as “turbofan engine10.” As shown inFIG. 1, the turbofan engine10defines an axial direction A (extending parallel to a longitudinal centerline or central axis12provided for reference) and a radial direction R. In general, the turbofan10includes a fan section14and a core turbine engine16disposed downstream from the fan section14.

For the embodiment depicted, the fan section14includes a variable pitch fan38having a plurality of fan blades40coupled to a disk42in a spaced apart manner. As depicted, the fan blades40extend outwardly from disk42generally along the radial direction R. Each fan blade40is rotatable relative to the disk42about a pitch axis P by virtue of the fan blades40being operatively coupled to a suitable actuation member44configured to collectively vary the pitch of the fan blades40in unison. The fan blades40, disk42, and actuation member44are together rotatable about the longitudinal axis12by LP shaft36across a power gear box46. The power gear box46includes a plurality of gears for stepping down the rotational speed of the LP shaft36to a more efficient rotational fan speed.

It should be appreciated that the exemplary turbofan10depicted inFIG. 1is by way of example only and that in other exemplary embodiments, turbofan10may have any other suitable configuration. For example, it should be appreciated that in other exemplary embodiments, turbofan10may instead be configured as any other suitable turbine engine, such as a turboprop engine, turbojet engine, internal combustion engine, etc.

Referring now toFIG. 2, a perspective, a cross-sectional view is provided of a combustor assembly100in accordance with an exemplary embodiment of the present disclosure. For example, combustor assembly100ofFIG. 2may be positioned in the combustion section26of the exemplary turbofan engine10ofFIG. 1. Notably,FIG. 2illustrates only portions of combustor assembly100for the purpose of explaining aspects of the present subject matter, while other components are removed for clarity. In addition, combustor assembly100is only one exemplary combustor and other types and configurations of combustor assemblies may be used according to alternative embodiments.

As shown, the combustor assembly100generally includes an inner liner102extending between a forward end104and an aft end106generally along the axial direction A. In addition, combustor assembly100includes an outer liner108extending between a forward end110and an aft end112generally along the axial direction A. According to the illustrated embodiment, inner liner102and outer liner108each include a liner portion and a baffle portion spaced apart from and surrounding the liner portion. In this manner, for example, inner liner102and outer liner108define a plenum through which cooling air may be distributed along the liner. Other configurations of inner liner102and outer liner108may be used while remaining within the scope of the present subject matter. For example, the liners may include a plurality of film cooling holes, may have different shapes, and may include other cooling or air distribution features.

As illustrated, inner liner102and outer liner108together at least partially define a combustion chamber114therebetween. In addition, inner liner102and outer liner108are each attached to an annular dome116. More particularly, combustor assembly100includes annular dome116positioned forward of inner liner102and outer liner108along the axial direction A. Forward end104of inner liner102and forward end110of outer liner108are attached to annular dome116in any suitable manner. According to one exemplary embodiment, annular dome116defines an inner annular slot and an outer annular slot for receipt of the forward ends104,110of liners102,108, respectively.

Combustor assembly100further includes a plurality of fuel injector assemblies, referred to herein as fuel injectors120. Fuel injectors120, such as premixers, fuel-air mixers, or similar assemblies, are generally configured for supplying a mixture of fuel and air into combustion chamber114to facilitate combustion. The fuel injectors120are spaced circumferentially around annular dome116and positioned within or extending through a plurality of circumferentially-spaced fuel injection ports122.

More specifically, referring still toFIG. 2, annular dome116defines a plurality of fuel injection ports122spaced circumferentially around annular dome116. Fuel injection ports122receive fuel injectors120to generally control the flow of fuel and compressed air into combustion section114. For example, relatively high pressure compressed air from high pressure compressor24is provided into a high pressure plenum124defined between the combustor and a combustor casing (not shown). Fuel injectors120selectively mix the relatively high pressure compressed air with fuel in the desired proportion and supply the fuel-air mixture to the relatively low pressure combustion chamber114.

Each fuel injection port122defines a peripheral edge130, a centerline C2, and a radial direction R2perpendicular to the centerline C2(seeFIG. 5). Fuel injection ports122and peripheral edges130are generally shaped to receive fuel injectors120. For example, conventional fuel injectors are substantially circular and may be received within circular injection ports. However, according to the illustrated exemplary embodiment, fuel injectors120are non-circular and fuel injection ports122are substantially the same shape. It should be appreciated, that as used herein, terms of approximation, such as “approximately,” “substantially,” or “about,” refer to being within a ten percent margin of error.

Notably, as explained briefly above, positioning fuel injectors120within fuel injection ports122presents a problem due to the differing mechanical characteristics of the components. More specifically, because the components are attached to different portions of turbofan engine10, are constructed of materials having different coefficients of thermal expansion, and are exposed to different temperatures, thermal expansion can cause significant relative movement between the fuel injectors120and the fuel injection ports122. Accordingly, fuel injection ports122are sized to define a clearance gap132between peripheral edge130and fuel injectors120. Clearance gap132accommodates relative thermal expansion to reduce potential stresses between the components while ensuring operability of combustor assembly100. However, clearance gap132also allows some air leakage between annular dome116and the fuel injectors120, which is inefficient and can affect the combustion aerodynamics.

Therefore, combustor assembly100further includes a plurality of mounting assemblies140which are generally configured for receiving and supporting fuel injectors120within fuel injection ports122. For example, as will be described below, mounting assemblies140are configured for reducing or eliminating leakage between annular dome116and fuel injectors120while allowing relative movement between the two components. In this regard, referring again toFIG. 2, mounting assemblies140are generally coupled to fuel injection ports122in floating engagement such that fuel injectors120may float within fuel injection ports122while an aft face142(FIG. 5) maintains at least a partial seal with annular dome116. As illustrated, combustor assembly100may further include one or more retention members144(which may include both radially inner and outer retention members144) for retaining mounting assemblies140within combustor assembly100. For example, according to the illustrated embodiment, outer retention members144are T-shaped brackets mounted to annular dome116and positioned between adjacent mounting assemblies140to retain mounting assemblies140while allowing some movement relative to annular dome116.

Referring now generally toFIGS. 3 through 6, various mounting assemblies140will be described according to exemplary embodiments of the present subject matter. Each mounting assembly140generally includes a ferrule150positioned adjacent to and extending around peripheral edge130of the respective fuel injection port122. As best illustrated inFIGS. 4 through 6, ferrule150generally includes an axial flange152extending substantially along the axial direction A and a radial flange154extending from axial flange152toward centerline C2along the radial direction R2.

In this regard, aft face142of ferrule150forms at least a partial seal with annular dome116while radial flange154extends toward fuel injectors120to reduce the size of clearance gap132. In this regard, for example, when fuel injectors120is mounted within mounting assembly140, a radially inner surface156of ferrule150and fuel injectors120define a ferrule gap158that is smaller than clearance gap132, thus resulting in less leakage air into combustion chamber114.

As illustrated inFIG. 4, radial flange154extends from an aft end of axial flange152and forms a face seal with annular dome116, thereby allowing little leakage through the dome/ferrule interface. However, according to alternative embodiments as illustrated inFIG. 6, ferrule150may define a recess160positioned between annular dome116and radial flange154along the axial direction A. Recess160allows the pressure differential to be applied across a larger area, increasing the force pushing ferrule150against annular dome116.

To provide a better seal between mounting assembly140and fuel injectors120, mounting assembly140further includes a spring finger170that generally extends from ferrule150and engages fuel injectors120to create a fluid seal or at least minimize a gap between mounting assembly140and fuel injectors120. According to the illustrated embodiment, spring finger170is mounted to an interior surface172of axial flange, e.g., a radially inner surface positioned forward of radial flange154. More specifically, spring finger170has a first end174that is coupled to interior surface172and spring finger170extends toward the centerline C2of fuel injection port122toward a contact region176of spring finger170. According to the illustrated embodiment ofFIG. 6, ferrule150may define a chamfered end proximate first end174to allow braze rope to be applied and spring finger170to be brazed to ferrule150.

Spring finger170may generally be any shape suitable for extending from ferrule150to engage and seal against fuel injectors120. However, according to the illustrated embodiment, spring finger170includes a first segment180extending from first end174toward annular dome116substantially along the axial direction A. A second segment182that bends approximately 180 degrees away from annular dome116, e.g., toward fuel injectors120and a forward portion of mounting assembly140. A third segment184extends further away from annular dome116and toward the centerline C2of the fuel injection port122, e.g., terminating in contact region176which forms a seal with fuel injectors120. According to the exemplary embodiment, spring finger170further includes a fourth segment186that flares out away from the centerline C2and annular dome116, e.g., to simplify assembly of fuel injectors120within mounting assembly140.

When configured as shown in the illustrated embodiment, spring finger170is in spring-loaded contact with fuel injectors120. In this manner, leakage between mounting assembly140and fuel injectors120may be reduced or eliminated. In addition, spring finger170defines a high pressure surface190exposed to high pressure compressed air within high pressure plenum124and a low pressure surface192on the radially inner surface of spring finger170. Therefore, the pressure difference across spring finger170further urges contact region176to firmly engage fuel injectors120and form a tight seal. By contrast, however, the hairpin configuration of spring finger170still has enough resiliency and flexibility to allow for the necessary movement between fuel injectors120and annular dome116.

However, it should be appreciated that according to alternative embodiments, spring finger170could have a slight gap when compressed air is not being supplied to high pressure plenum124. In such an embodiment, a gap is defined between spring finger170and fuel injectors120such that pressure exerted on high pressure surface190of spring finger170during operation bends spring finger170to create a seal with fuel injectors120. Other configurations, shapes, and sizes of spring finger170are possible and are contemplated as within the scope of the present subject matter.

Notably, mounting assembly140as described above may have any suitable shape for receiving a complementary fuel injectors120. However, referring generally toFIGS. 2 and 3, fuel injectors120, fuel injection ports122, and mounting assemblies140each have a non-circular profile. Referring to mounting assembly140for example, ferrule150and spring finger170each include a plurality of longitudinal segments196that are coupled to each other in a plane perpendicular to the centerline C2or parallel with a surface of annular dome116. More specifically, as illustrated, each have eight substantially linear longitudinal segments196. Although eight longitudinal segments196are illustrated, forming an elongated octagon, it should be appreciated that any suitable number of linear segment, non-linear segments, or both may be used according to alternative embodiments.

Because the spring finger170is intended to flex and move during operation of turbofan engine10, each of the longitudinal segments196of spring finger170are separated by a gap198which allows relative motion between adjacent longitudinal segments196and proper sealing with fuel injectors120. For example, gap198may be a less than a millimeter, e.g., about 0.25 millimeters, or any other suitable size. It should be appreciated that ferrule150and spring finger170as described herein are used only as examples for explaining aspects of the present subject matter. Variations and modifications to these components may be made to reduce air leakage and allow relative movement of components while remaining within the scope of the present subject matter.

In aeroderivative gas turbine engines, fuel injector assemblies such as premixers are attached to the outer case of the engine and must interface with the annular dome of the combustor assembly. Due to the relative movement between these components, e.g., due to thermal expansion, a clearance gap is defined between the fuel injector and the dome. The mounting assembly described herein is designed to accommodate relatively large amounts of relative movement between the components while reducing the gap and therefore the air leakage between a fuel injector assembly and an annular dome of a combustor. This reduced leakage has benefits in the performance of the engine as the amount of air available can be used for more beneficial cooling or combustion. Additionally, the reduced leakage decreases the effects of the leaked air on the combustion aerodynamics, benefiting the flame structure and emissions. In sum, the mounting assemblies described herein improved the operability, efficiency, and performance of combustor assemblies and gas turbine engines.

Additionally, although mounting assemblies140as described above are used for generating a seal between fuel injector assemblies120and annular dome116, it should be appreciated that mounting assemblies140may be used in alternative applications for providing a suitable seal between any two components that translate relative to each other. For example, mounting assemblies can also be used in other locations within combustion section26, such as borescope and igniter interfaces with outer liner108. In addition, mounting assemblies140can be used to provide seals in other locations within a combustor, within turbofan engine10, or in any other suitable location or application.