Air cooled fuel injector for a turbine engine

An assembly is provided for a turbine engine. The assembly includes a cooling tube through which a flow path extends. The assembly also includes a fuel injector, which includes a stem connected to a tip. The stem is arranged within the cooling tube. The tip extends from the cooling tube to a nozzle. The cooling tube is adapted to direct cooling air through the flow path.

BACKGROUND OF THE INVENTION

1. Technical Field

This disclosure relates generally to a turbine engine and, more particularly, to a combustor section of a turbine engine.

2. Background Information

A typical fuel delivery system for a turbine engine provides fuel to a plurality of fuel injectors. These fuel injectors are arranged in a plenum adjacent a combustor of the turbine engine. The fuel injectors inject the fuel into a combustion chamber of the combustor. The injected fuel is subsequently ignited to power the turbine engine.

When the fuel reaches a temperature above a certain temperature, the fuel can coke within the fuel injectors and reduce fuel flow through the injectors and into the combustion chamber. Each fuel injector therefore typically includes a heat shield that shields internal fuel conduits from relatively hot core air within the plenum. Such a heat shield, however, may have a limited heat shielding effect.

There is a need in the art for an improved fuel injector assembly that can shield fuel from relatively high engine temperatures.

SUMMARY OF THE DISCLOSURE

According to an aspect of the invention, an assembly is provided for a turbine engine. The assembly includes a cooling tube through which a flow path extends. The assembly also includes a fuel injector, which includes a stem connected to a tip. The stem is arranged within the cooling tube. The tip extends from the cooling tube to a nozzle. The cooling tube is adapted to direct cooling air through the flow path.

According to another aspect of the invention, another assembly is provided for a turbine engine. The assembly includes a combustor, a cooling tube and a fuel injector. The combustor includes a combustion chamber. The cooling tube is adjacent the combustor. The fuel injector includes a nozzle adapted to inject fuel into the combustion chamber. At least a portion of the fuel injector is arranged within a flow path that extends through the cooling tube. The cooling tube is adapted to direct cooling air through the flow path.

The fuel injector may include a stem connected to a tip. The stem may be arranged within the cooling tube. The tip may be interfaced with the combustor.

A portion of the flow path may have an annular cross-sectional geometry defined between the cooling tube and the stem.

At least a portion of the flow path may have a parti-annular cross-sectional geometry defined between the cooling tube and the fuel injector.

The cooling tube may include an outlet. A portion of the flow path may extend from the fuel injector to the outlet.

The stem may extend along an axis. The tip may extend radially out from the stem relative to the axis.

The fuel injector may include a fuel conduit that extends through the stem and is fluidly coupled with the nozzle. This fuel conduit may be one of a plurality of fuel conduits that extend through the stem and are fluidly coupled with the nozzle.

An air gap may extend around the fuel conduit and between the fuel conduit and the stem.

The assembly may include a base connected to the cooling tube and the stem. The base may be adapted to mount the cooling tube and the fuel injector to a case of the turbine engine. A portion of the flow path may extend through the base.

The assembly may include a heat exchanger. This heat exchanger may be adapted to provide the cooling air to the cooling tube.

The assembly may include a duct adapted to receive the cooling air from the cooling tube. The cooling tube may be connected to the duct by a moveable joint.

The assembly may include a turbine component. The duct may be adapted to provide the cooling air to the turbine component, for example, to cool the turbine component. The turbine component may be, for example, a rotor blade, a stator blade or a rotor disk.

The assembly may include a swirler mated with the tip.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a side cutaway illustration of a geared turbine engine20. This engine20extends along an axial centerline22between an upstream airflow inlet24and a downstream airflow exhaust26. The engine20includes a fan section28, a compressor section29, a combustor section30and a turbine section31. The compressor section29includes a low pressure compressor (LPC) section29A and a high pressure compressor (HPC) section29B. The turbine section31includes a high pressure turbine (HPT) section31A and a low pressure turbine (LPT) section31B. The engine sections28-31are arranged sequentially along the centerline22within an engine housing34, which includes a first engine case36(e.g., a fan nacelle) and a second engine case38(e.g., a core nacelle).

Each of the engine sections28,29A,29B,31A and31B includes a respective rotor40-44. Each of the rotors40-44includes a plurality of rotor blades arranged circumferentially around and connected to (e.g., formed integral with or mechanically fastened, welded, brazed, adhered or otherwise attached to) one or more respective rotor disks. The fan rotor40is connected to a gear train46(e.g., an epicyclic gear train) through a shaft47. The gear train46and the LPC rotor41are connected to and driven by the LPT rotor44through a low speed shaft48. The HPC rotor42is connected to and driven by the HPT rotor43through a high speed shaft50. The shafts47,48and50are rotatably supported by a plurality of bearings52. Each of the bearings52is connected to the second engine case38by at least one stator such as, for example, an annular support strut.

Air enters the engine20through the airflow inlet24, and is directed through the fan section28and into an annular core gas path54and an annular bypass gas path56. The air within the core gas path54may be referred to as “core air”. The air within the bypass gas path56may be referred to as “bypass air”.

The core air is directed through the engine sections29-31and exits the engine20through the airflow exhaust26. Within the combustor section30, fuel is injected into an annular combustion chamber58and mixed with the core air. This fuel-core air mixture is ignited to power the engine20and provide forward engine thrust. The bypass air is directed through the bypass gas path56and out of the engine20through a bypass nozzle60to provide additional forward engine thrust. Alternatively, the bypass air may be directed out of the engine20through a thrust reverser to provide reverse engine thrust.

FIG. 2illustrates an assembly62of the engine20. This assembly62includes a combustor64, one or more cooled fuel injector assemblies66, and a duct68. The assembly62also includes a fuel delivery system70and a heat exchanger system72.

The combustor64is arranged with in an annular plenum74of the combustor section30. Referring toFIGS. 2 and 3, the combustor64includes an annular combustor bulkhead76, a tubular combustor inner wall78, and a tubular combustor outer wall80. The bulkhead76extends radially between and is connected to the inner wall78and the outer wall80. The inner wall78and the outer wall80each extends axially along the centerline22from the bulkhead76towards the turbine section31A, thereby defining the combustion chamber58.

Referring toFIG. 2, the inner wall78and the outer wall80may each have a multi-walled structure; e.g., a hollow dual-walled structure. The inner wall78and the outer wall80ofFIG. 2, for example, each includes a tubular combustor shell82, a tubular combustor heat shield84, and one or more cooling cavities86(e.g., impingement cavities). These cooling cavities86fluidly couple cooling apertures (e.g., impingement apertures) in the shell82with cooling apertures (e.g., effusion apertures) in the heat shield84. The inner wall78and the outer wall80also each include a plurality of quench apertures88, which are arranged circumferentially around the centerline22.

The fuel injector assemblies66are disposed around the centerline22, and mated with the bulkhead76. Each of the fuel injector assemblies66includes a cooling tube90, a fuel injector92, and a base94(e.g., an annular flange). The base94is connected to the cooling tube90and the fuel injector92, and mounts the cooling tube90and the fuel injector92to a case96of the turbine engine20. One or more of the fuel injector assemblies66may also each interface with a swirler98mated with the bulkhead76.

The cooling tube90includes a sidewall100, a cooling air inlet102, and a cooling air outlet104. The sidewall100and, thus, the cooling tube90extend generally radially relative to the centerline22between an inner end106and an outer end108. The sidewall100partially defines a cooling air flow path110that extends through the cooling tube90between and fluidly couples the inlet102and the outlet104. The sidewall100may have an elliptical cross-sectional geometry as illustrated inFIG. 4. Alternatively, the sidewall100may have a circular cross-sectional geometry, a tear drop cross-sectional geometry, a rectangular cross-sectional geometry, or any other cross-sectional geometry. The sidewall100may also include heatshielding such as, for example, one or more coatings and/or the sidewall100may be configured as a multiple wall structure (e.g., a hollow double-layered wall).

Referring again toFIG. 2, the inlet102is located at the outer end108. The inlet102is fluidly coupled with a duct112of the heat exchange system72. The cooling tube90, for example, may include an annular mounting flange114at the outer end108that is mounted (e.g., mechanically fastened) to the duct112.

The outlet104is located at the inner end106. The outlet104is fluidly coupled with the duct68. A portion116of the cooling tube90at the inner end106, for example, may extend into an annular mounting flange118of the duct68, thereby forming a movable joint. The cooling tube portion116may slide radially within the mounting flange118during engine operation. In this manner, the movable joint may accommodate thermally induced movement between the cooling tube90and the duct68and, more particularly, between the case96and the duct68.

Referring toFIG. 5, the fuel injector92includes an injector housing120, a nozzle122, and one or more fuel conduits124and126. The injector housing120includes a base128, a stem130and a tip132.

The base128includes an interior portion134and an exterior portion136. The interior portion134is arranged within the cooling tube90between the stem130and the exterior portion136. One or more metering valves for the fuel injector92, if utilized, may be in either the interior portion134or exterior portion136. Referring toFIGS. 5 and 6, the interior portion134is connected to the base94through the sidewall100. The interior portion134forms a portion138of the flow path110with the cooling tube90. The flow path portion138may have a parti-annular cross-sectional geometry as illustrated inFIG. 6. Referring toFIG. 5, the exterior portion136extends out from the cooling tube90to a distal end140.

The stem130is arranged within the cooling tube90. The stem130extends along an axis142(e.g., generally radially relative to the centerline22) between and is connected to the base128and the tip132. The stem130may have an elliptical cross-sectional geometry. Alternatively, the stem130may have a circular cross-sectional geometry, a tear drop cross-sectional geometry, a rectangular cross-sectional geometry, or any other cross-sectional geometry. Referring toFIGS. 4 and 5, the stem130forms a portion144of the flow path110with the cooling tube90. The flow path portion144may have an annular cross-sectional geometry as illustrated inFIG. 4. In this manner, the flow path portion144substantially thermally decouples the stem130from the sidewall100.

Referring toFIG. 5, the tip132extends along an axis146(e.g., generally radially relative to the axis142) through the sidewall100to the nozzle122. The tip132may or may not be integral with the cooling tube100. The tip132may have a circular cross-sectional geometry. Alternatively, the stem130may have an elliptical cross-sectional geometry, a tear drop cross-sectional geometry, a rectangular cross-sectional geometry, or any other cross-sectional geometry adapted to mate with the swirler98. The tip132may form a portion148of the flow path110with the cooling tube90. The flow path portion148may have a parti-annular cross-sectional geometry similar to that illustrated inFIG. 6.

Referring toFIG. 7, the nozzle122includes one or more nozzle apertures150and152. The nozzle apertures152are arranged circumferentially around the axis146(seeFIG. 5) and the nozzle aperture150. The nozzle aperture150is fluidly coupled with the fuel conduit124. The nozzle apertures152are fluidly coupled with the fuel conduit126, for example, through an annular fuel manifold154within the tip132. Each of the nozzle apertures150and152is adapted to receive fuel from the respective fuel conduit124,126, and inject the fuel into the combustion chamber58.

Referring toFIG. 2, the fuel conduits124and126are fluidly coupled with and receive the fuel from the fuel delivery system70. Referring toFIGS. 4-7, the fuel conduits124and126extend from the distal end140, through the injector housing120, to the nozzle122. In particular, the fuel conduits124and126are arranged within and extend through an interior housing cavity156(e.g., a sealed cavity) formed by the base128, the stem130, the tip132and the nozzle122. An air gap may extend circumferentially around each fuel conduit124,126. This air gap may also extend between the respective fuel conduit124,126and the injector housing120and/or the other fuel conduit126,124. In this manner, the air gap may substantially thermally decouple each of the fuel conduits124and126from the injector housing120.

During operation of the turbine engine assembly62ofFIG. 2, the plenum74receives compressed core air from the compressor section29B. The plenum74provides a portion of this core air to the combustor64for the combustion process. Each swirler98, for example, directs some of the core air from the plenum74into the combustion chamber58in a manner that facilitates mixing the core air with the fuel injected by the respective fuel injector92. The quench apertures88direct additional core air into the combustion chamber58to tailor the fuel-core air mixture within the combustion chamber58. The fuel-core air mixture is ignited to power the turbine engine20.

The plenum74also provides a portion of the core air to heat exchange system72through a duct158. The heat exchange system72includes a heat exchanger160that cools the core air to provide cooling air. The heat exchanger160may be configured as an air-air heat exchanger, which transfers heat energy from the core air into bypass air from the bypass gas path56. Alternatively, the heat exchanger160may be configured as a fuel-air heat exchanger, which transfers heat energy from the core air into the fuel provided by the fuel delivery system70. Still alternatively, the heat exchanger160may be configured as a oil-air heat exchanger, which transfers heat energy from the core air into lubrication oil utilized for lubricating one or more turbine engine components; e.g., the bearings52(seeFIG. 1). The heat exchange system72, however, is not limited to the foregoing heat exchanger configurations.

The heat exchange system72provides the cooling air to the cooling tube90. The cooling tube90directs the cooling air through the flow path110and into the duct68. Within the flow path110, the cooling air provides a thermal buffer between the relatively hot core air within the plenum74and the fuel injector92. The fuel within the conduits124and126therefore may be maintained within a temperature range that may reduce or prevent fuel coking within the fuel injector92. In addition to the foregoing, the cooling tube90also provides mechanical support for the injector housing120. The cooling tube90, for example, structurally ties the injector housing120to the case96and the duct68.

The duct68provides the cooling air received from the cooling tube90to one or more components162within the turbine section31(i.e., turbine components). Examples of one of the turbine components162include, but are not limited to, a turbine rotor blade, a turbine rotor disk and a turbine stator blade within the HPT section31A. The heat exchange system72and/or the duct68, of course, may also or alternatively provide the cooling air to one or more components in other sections of the engine20.

In some embodiments, the heat exchange system72may receive air other than core air from the plenum74. The heat exchange system72, for example, may receive bypass air from the bypass gas path56. In other embodiments, the assembly62may be configured without the heat exchange system72. The cooling tube90, for example, may receive bypass air from the bypass gas path56.

In some embodiments, the stem130may be connected to the sidewall100. In such an embodiment, the flow path portion144may have a parti-annular cross-sectional geometry similar to that of the flow path portion138illustrated inFIG. 6.

In some embodiments, the cooling tube90and the base94may be formed integral with the injector housing120. The cooling tube90, the base94and the injector housing120, for example, may be cast and/or machined having a unitary body. Alternatively, the cooling tube90, the base94and/or the injector housing120may be formed as discrete bodies that are mechanically fastened and/or bonded together.

The turbine engine assembly62may be included in various turbine engines other than the one described above. The assembly62, for example, may be included in a geared turbine engine where a gear train connects one or more shafts to one or more rotors in a fan section, a compressor section and/or any other engine section. Alternatively, the assembly62may be included in a turbine engine configured without a gear train. The assembly62may be included in a geared or non-geared turbine engine configured with a single spool, with two spools (e.g., seeFIG. 1), or with more than two spools. The turbine engine may be configured as a turbofan engine, a turbojet engine, a propfan engine, or any other type of turbine engine. The present invention therefore is not limited to any particular types or configurations of turbine engines.