High shear swirler with recessed fuel filmer for a gas turbine engine

An assembly is provided for a turbine engine. This assembly includes a swirler and a fuel nozzle. The swirler is configured with an outer wall, an inner wall, an outer passage and an inner passage. The outer wall circumscribes the inner wall and extends axially along an axis to a distal outer wall end. The inner wall extends axially along the axis to a distal inner wall end that is axially recessed within the swirler from the distal outer wall end. The outer passage is formed by and radially between the inner wall and the outer wall. The inner passage is formed by and radially within the inner wall. The fuel nozzle projects into the inner passage. The fuel nozzle is configured with a plurality of orifices axially aligned with the inner wall and arranged circumferentially about the axis.

BACKGROUND OF THE DISCLOSURE

1. Technical Field

This disclosure relates generally to a fuel injector assembly and, more particularly, to a fuel injector assembly with a high shear swirler.

2. Background Information

Various types and configurations of fuel injector assemblies are known in the art. Some of these known fuel injector assemblies include a high shear swirler mated with a fuel injector nozzle. While these known fuel injector assemblies have various advantages, there is still room in the art for improvement. In particular, there is still room in the art for fuel injector assemblies capable of improving fuel-air mixing, reducing combustor dynamics and/or reducing undesirable combustor tones.

SUMMARY OF THE DISCLOSURE

According to an aspect of the present disclosure, an assembly is provided for a turbine engine. This turbine engine assembly includes a swirler and a fuel nozzle. The swirler is configured with an outer wall, an inner wall, an outer passage and an inner passage. The outer wall circumscribes the inner wall and extends axially along an axis to a distal outer wall end. The inner wall extends axially along the axis to a distal inner wall end that is axially recessed within the swirler from the distal outer wall end. The outer passage is formed by and radially between the inner wall and the outer wall. The inner passage is formed by and radially within the inner wall. The fuel nozzle projects into the inner passage. The fuel nozzle is configured with a plurality of orifices axially aligned with the inner wall and arranged circumferentially about the axis.

According to another aspect of the present disclosure, a fuel injector assembly with an axis is provided. This fuel injector assembly includes a swirler and a fuel nozzle. The swirler is configured with an outer wall, an inner wall, an outer passage and an inner passage. The outer wall extends axially along the axis to a distal outer wall end. The inner wall is radially within the outer wall and extends axially along the axis to a distal inner wall end. The distal inner wall end is axially offset from the distal outer wall end along the axis. The outer passage is radially between the inner wall and the outer wall. The inner passage is radially within the inner wall. The fuel nozzle projects into the inner passage. The fuel nozzle is configured to direct a plurality of jets of fuel against the inner wall.

According to still another aspect of the present disclosure, another fuel injector assembly with an axis is provided. This fuel injector assembly includes a swirler and a fuel nozzle. The swirler is configured with an outer wall, an inner wall, an outer passage and an inner passage. The outer wall extends circumferentially about the inner wall and extends axially along the axis to a distal outer wall end. The inner wall extends axially along the axis to a distal inner wall end. The outer passage is radially between the inner wall and the outer wall. The inner passage is radially within the inner wall. The fuel nozzle projects into the inner passage. The distal outer wall end is disposed a first distance along the axis from a tip of the fuel nozzle. The distal outer wall end is disposed a second distance along the axis from the distal inner wall end. The outer passage has a diameter at the distal outer wall end. A quotient of (the first distance minus the second distance) divided by the diameter is less than one.

The plurality of orifices may include a first orifice that is configured to direct a jet of fuel to impinge against the inner wall.

The fuel nozzle may be further configured with a second orifice that is coaxial with the axis.

The distal outer wall end may be disposed a first distance along the axis from a tip of the fuel nozzle. The distal outer wall end may be disposed a second distance along the axis from the distal inner wall end. The outer passage may have a diameter at the distal outer wall end. A quotient of (the first distance minus the second distance) divided by the diameter may be less than one.

The quotient may be less than or equal to 0.8.

The quotient may be greater than or equal to 0.25.

The quotient may be between 0.35 and 0.68; e.g., 0.35≤quotient≤0.68.

The distal outer wall end may be disposed a distance along the axis from a tip of the fuel nozzle. The outer passage may have a diameter at the distal outer wall end. A quotient of the distance divided by the diameter may be less than one.

The quotient may be between 0.5 and 0.75; e.g., 0.5≤quotient≤0.75.

The distal outer wall end may be disposed a first distance along the axis from a tip of the fuel nozzle. The distal outer wall end may be disposed a second distance along the axis from the distal inner wall end. The outer passage may have a diameter at the distal outer wall end. A quotient of the second distance divided by the diameter may be between 0.07 and 0.15; e.g., 0.07≤quotient≤0.15.

The swirler may include a first set of vanes and a second set of vanes. The first set of vanes may be arranged with the outer passage. The second set of vanes may be arranged with the inner passage.

The swirler may further include a third set of vanes arranged with the inner passage. The third set of vanes may be axially offset from the second set of vanes.

A nozzle guide plate may be included that mounts the fuel nozzle to the swirler.

The distal inner wall end may be located axially between the distal outer wall end and a tip of the fuel nozzle along the axis.

The fuel nozzle may be configured with a plurality of orifices that are axially overlapped by the inner wall and arranged circumferentially about the axis.

DETAILED DESCRIPTION

FIG. 1is a side cutaway illustration of a geared turbine engine20. This turbine engine20extends along an axial centerline22between an upstream airflow inlet24and a downstream airflow exhaust26. The turbine 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 sections28,29A,29B,30,31A and31B are arranged sequentially along the centerline22within an engine housing32. This housing32includes an inner case34(e.g., a core case) and an outer case36(e.g., a fan case). The inner case34may house one or more of the engine sections29A-31B; e.g., an engine core. The outer case36may house at least the fan section28.

Each of the engine sections28,29A,29B,31A and31B includes a respective rotor38-42. Each of these rotors38-42includes a plurality of rotor blades arranged circumferentially around and connected to one or more respective rotor disks. The rotor blades, for example, may be formed integral with or mechanically fastened, welded, brazed, adhered and/or otherwise attached to the respective rotor disk(s).

The fan rotor38is connected to a gear train44, for example, through a fan shaft46. The gear train44and the LPC rotor39are connected to and driven by the LPT rotor42through a low speed shaft47. The HPC rotor40is connected to and driven by the HPT rotor41through a high speed shaft48. The shafts46-48are rotatably supported by a plurality of bearings50; e.g., rolling element and/or thrust bearings. Each of these bearings50is connected to the engine housing32by at least one stationary structure such as, for example, an annular support strut.

During operation, air enters the turbine engine20through the airflow inlet24. This air is directed through the fan section28and into a core gas path52and a bypass gas path54. The core gas path52extends sequentially through the engine sections29A-31B. The air within the core gas path52may be referred to as “core air”. The bypass gas path54extends through a bypass duct, which bypasses the engine core. The air within the bypass gas path54may be referred to as “bypass air”.

The core air is compressed by the compressor rotors39and40and directed into an annular combustion chamber56of a combustor58in the combustor section30. Fuel is injected into the combustion chamber56and mixed with the compressed core air to provide a fuel-air mixture. This fuel air mixture is ignited and combustion products thereof flow through and sequentially cause the turbine rotors41and42to rotate. The rotation of the turbine rotors41and42respectively drive rotation of the compressor rotors40and39and, thus, compression of the air received from a core airflow inlet. The rotation of the turbine rotor42also drives rotation of the fan rotor38, which propels bypass air through and out of the bypass gas path54. The propulsion of the bypass air may account for a majority of thrust generated by the turbine engine20, e.g., more than seventy-five percent (75%) of engine thrust. The turbine engine20of the present disclosure, however, is not limited to the foregoing exemplary thrust ratio.

Referring toFIG. 2, the combustor section30includes a plurality of fuel injector assemblies60(one visible inFIG. 2) arranged circumferentially about the centerline22in an annular array. The fuel injector assemblies60are mounted to an annular bulkhead62of the combustor58. The fuel injector assemblies60are configured to direct a mixture of fuel and compressed air into the combustion chamber56for combustion.

Each fuel injector assembly60includes a high shear swirler64and a fuel injector66. The fuel injector assembly60ofFIG. 2also includes a mount68configured to couple the fuel injector66to the swirler64.

Referring toFIG. 3, the swirler64extends circumferentially around an axis70(e.g., a centerline of the swirler64) thereby providing the swirler64with a full hoop body. The swirler64extends axially along the axis70between a swirler upstream end72and a swirler downstream end74.

The swirler64ofFIG. 3includes an upstream swirler segment76, a flanged intermediate swirler segment77and a flanged downstream swirler segment78. These swirler segments76-78configure the swirler64with a tubular swirler outer wall80, a tubular swirler inner wall82(e.g., a fuel filmer) and a plurality of swirler passages84and86.

The upstream swirler segment76extends circumferentially around the axis70. The upstream swirler segment76is located at (e.g., on, adjacent or proximate) the swirler upstream end72. The upstream swirler segment76ofFIG. 3, for example, extends axially along the axis70from the swirler upstream end72to an annular upstream swirler segment surface88.

Referring toFIG. 4A, the upstream swirler segment76is configured with an upstream set of vanes90. These upstream vanes90are arranged circumferentially around the axis70in an annular array. Each upstream vane90is circumferentially separated from each circumferentially adjacent (e.g., neighboring) upstream vane90by a respective air gap92. The gaps92collectively form an upstream airflow inlet94into the swirler64at the swirler upstream end72; see alsoFIG. 3. The upstream vanes90may be configured such that air entering the swirler64through the upstream airflow inlet94generally flows in a first circumferential direction96(e.g., a clockwise direction) about the axis70. Alternatively, referring toFIG. 4B, the upstream vanes90may be configured such that air entering the swirler64through the upstream airflow inlet94generally flows in a second circumferential direction98(e.g., a counterclockwise direction) about the axis70.

In the specific embodiment ofFIG. 3, the upstream vanes90are arranged at the swirler upstream end72. With this arrangement, each gap92may extend partially axially into the upstream swirler segment76from a castellated surface100of the segment76at the swirler upstream end72to a gap end surface102. Of course, in other embodiments, each gap92may be formed completely axially within the swirler64and, for example, its upstream swirler segment76.

The intermediate swirler segment77includes an annular intermediate swirler segment base104(e.g., a radial flange) and the swirler inner wall82. The intermediate swirler segment77and each of its components82and104extends circumferentially around the axis70.

The intermediate swirler segment base104is abutted axially against the upstream swirler segment76. The intermediate swirler segment base104, for example, may be coupled (e.g., bonded to) the upstream swirler segment surface88. The intermediate swirler segment base104extends axially along the axis70from the upstream swirler segment76to an annular intermediate swirler segment surface106.

Referring toFIG. 5A, the intermediate swirler segment base104is configured with an intermediate set of vanes108. These intermediate vanes108are arranged circumferentially around the axis70in an annular array. Each intermediate vane108is circumferentially separated from each circumferentially adjacent (e.g., neighboring) intermediate vane108by a respective gap110. The gaps110collectively form an intermediate airflow inlet112into the swirler64; see alsoFIG. 3. The intermediate vanes108may be configured such that air entering the swirler64through the intermediate airflow inlet112generally flows in the first circumferential direction96(e.g., the clockwise direction) about the axis70. Alternatively, referring toFIG. 5B, the intermediate vanes108may be configured such that air entering the swirler64through the intermediate airflow inlet112generally flows in the second circumferential direction98(e.g., the counterclockwise direction) about the axis70. This circumferential direction for the intermediate vanes108may be the same as the circumferential direction for the upstream vanes90. However, in other embodiments, the circumferential direction for the intermediate vanes108may be the opposite as the circumferential direction for the upstream vanes90.

In the specific embodiment ofFIG. 3, the intermediate vanes108are arranged at a joint between the swirler segments76and77. With this arrangement, each gap110may extend partially axially into the intermediate swirler segment77from a castellated surface114of the segment at the to a gap end surface116. Of course, in other embodiments, each gap may be formed completely axially within the swirler64and, for example, its intermediate swirler segment77.

The swirler inner wall82projects out from the intermediate swirler segment base104and extends axially (in a downstream direction along the axis70) to an annular distal inner wall end118. As the swirler inner wall82extends towards the distal inner wall end118, the swirler inner wall82may (e.g., smoothly and/or continuously) radially taper inwards towards the axis70. The swirler inner wall82may thereby have a tubular conical geometry with tubular conical inner and outer wall surfaces120and122. The swirler inner wall82and its distal end118are each disposed radially with and axially overlapped by the swirler outer wall80.

The downstream swirler segment78includes an annular downstream swirler segment base124(e.g., a radial flange) and the swirler outer wall80. The downstream swirler segment78and each of its components80and124extends circumferentially around the axis70.

The downstream swirler segment base124is abutted axially against the intermediate swirler segment77. The downstream swirler segment base124, for example, may be coupled (e.g., bonded to) the intermediate swirler segment surface106. The downstream swirler segment base124extends axially along the axis70from the intermediate swirler segment77to an annular downstream swirler segment surface126.

Referring toFIG. 6A, the downstream swirler segment base124is configured with a downstream set of vanes128. These downstream vanes128are arranged circumferentially around the axis70in an annular array. Each downstream vane128is circumferentially separated from each circumferentially adjacent (e.g., neighboring) downstream vane128by a respective gap130. The gaps130collectively form a downstream airflow inlet132into the swirler64; see alsoFIG. 3. The downstream vanes128may be configured such that air entering the swirler64through the downstream airflow inlet132generally flow in the first circumferential direction96(e.g., the clockwise direction) about the axis70. Alternatively, referring toFIG. 6B, the downstream vanes128may be configured such that air entering the swirler64through the downstream airflow inlet132generally flows in the second circumferential direction98(e.g., the counterclockwise direction) about the axis70. This circumferential direction for the downstream vanes128may be the same as the circumferential direction for the upstream vanes90and/or the intermediate vanes108. However, in other embodiments, the circumferential direction for the downstream vanes128may be the opposite as the circumferential direction for the upstream vanes90and/or the intermediate vanes108.

In the specific embodiment ofFIG. 3, the downstream vanes128are arranged at a joint between the swirler segments77and78. With this arrangement, each gap130may extend partially axially into the downstream swirler segment78from a castellated surface134of the segment at the to a gap end surface136. Of course, in other embodiments, each gap130may be formed completely axially within the swirler64and, for example, its downstream swirler segment78.

The swirler outer wall80projects out from the downstream swirler segment base124and extends axially (in the downstream direction along the axis70) to an annular distal outer wall end138. As the swirler outer wall80extends towards the distal outer wall end138, the swirler outer wall80may (e.g., smoothly and/or continuously) radially taper inwards towards the axis70. The swirler outer wall80may thereby have a generally tubular conical geometry with a tubular conical inner wall surface140. The swirler outer wall80axially overlaps and circumscribes the swirler outer wall80.

The swirler64is configured such that the distal inner wall end118and the distal outer wall end138are axially offset from one another along the axis70. The distal inner wall end118ofFIG. 3, for example, is axially recessed into the swirler64from the distal outer wall end138. More particularly, the distal inner wall end118is disposed an axial distance (d) upstream of the distal outer wall end138. The distal outer wall end138may thereby define a downstream most surface of the swirler64; e.g., a dump plane of the swirler64.

The inner passage84ofFIG. 3is an inner bore of the swirler64. This inner passage84is formed radially within and by each of the swirler segments76and77. The inner passage84is fluidly coupled with the upstream airflow inlet94and the intermediate airflow inlet112. The inner passage84ofFIG. 3extends from the airflow inlets94and112to an inner nozzle outlet142. This inner nozzle outlet142is defined by and radially within the swirler inner wall82at the distal inner wall end118.

The outer passage86ofFIG. 3is an annular passage formed by the swirler segments77and78. This outer passage86is formed radially between the swirler inner wall82and the swirler outer wall80. The outer passage86is fluidly coupled with the downstream airflow inlet132. The outer passage86ofFIG. 3extends from the downstream airflow inlet132to an outer nozzle outlet144. This outer nozzle outlet144is defined by and radially between the swirler inner and outer walls82and80at their distal ends118and138.

The outer passage86and its nozzle outlet144are configured with an inner diameter (Dsw-ex) at the distal outer wall end138. This diameter (Dsw-ex) is measured from, for example, the inner wall surface140of the swirler outer wall80on a corner between that surface140and an annular distal outer wall end surface146.

Referring toFIG. 2, the swirler64is mated with the bulkhead62. In particular, the swirler inner and outer walls82and80project axially into or through a respective aperture148in the bulkhead62. The swirler64is mounted to the bulkhead62. The downstream swirler segment78, for example, may be bonded (e.g., brazed or welded) and/or otherwise connected to the bulkhead62and, for example, a shell150of the bulkhead62.

The fuel injector66includes a fuel injector stem152and a fuel injector nozzle154. The fuel injector stem152is configured to support and route fuel to the fuel injector nozzle154. The fuel injector nozzle154is cantilevered from the fuel injector stem152, and projects along the axis70partially into the inner bore of the swirler64. A tip156of the fuel injector nozzle154is thereby disposed within the inner passage84.

Referring toFIG. 7, the fuel injector nozzle154includes a plurality of nozzle orifices158arranged circumferentially about the axis70in an annular array; see alsoFIG. 8. These nozzle orifices158may be axially aligned with (e.g., axially overlapped by) the swirler inner wall82and its inner wall surface120. One or more or each of these nozzle orifices158is configured to direct a jet of fuel to impinge against the swirler inner wall82and its inner wall surface120.

The fuel injector nozzle154may also include a central nozzle orifice160; see alsoFIG. 8. This central nozzle orifice160may be coaxial with the axis70and thereby centrally located between the nozzle orifices158. The central nozzle orifice160is configured to direct a jet of fuel along the axis70, through the inner nozzle outlet142, and into the combustion chamber56. A quantity of fuel provided by this central nozzle orifice160may be less than a collective quantity of fuel provided by the nozzle orifices158; however, the present disclosure is not limited to such a relationship.

The mount68is configured to couple the fuel injector nozzle154to the swirler64. The mount68ofFIG. 7, for example, includes a mount base162and a nozzle guide plate164. The mount base162is connected (e.g., bonded) to the upstream swirler segment76and, for example, to its castellated surface100. The mount base162is configured to capture the nozzle guide plate164in such a fashion that the nozzle guide plate164may float, to a limited degree, relative to the swirler64. The nozzle guide plate164in turn is mated with the fuel injector nozzle154. The fuel injector nozzle154, for example, projects through a bore in the nozzle guide plate164. The bore is sized such that the fuel injector nozzle154may slide axially along the axis70relative to the nozzle guide plate164. The mount68thereby may (e.g., loosely) couple and locate the fuel injector nozzle154to the swirler while enabling for slight shifts due to differential thermal expansion as well as vibrations.

During operation of the fuel injector assembly60ofFIG. 7, the nozzle orifices158direct the jets of fuel to impinge against the swirler inner wall82. Upon hitting the inner wall surface120, the swirling air introduced into the inner passage84form the airflow inlets94and112(seeFIG. 3) may cause the fuel from the jets to form a thin film of fuel on the inner wall surface120. This film of fuel travels along the inner wall surface120towards the inner nozzle outlet142. At the inner nozzle outlet142, the film of fuel separates from the swirler inner wall82and is acted upon by swirling air exiting both the inner nozzle outlet142and the outer nozzle outlet144. The air may exit the nozzle outlets142and144at different speeds and thereby subject the separated fuel to a shear force. This shear force may cause the separated fuel to break up and atomize for combustion within the combustion chamber56.

Atomization quality may depend upon a thickness of the film of fuel as well as a velocity and swirl of the air from the inner and the outer passages84and86. The thickness of the film of fuel may depend upon an amount of fuel injected by the nozzle orifices158onto the swirler inner wall82and a length of travel along the swirler inner wall82. Therefore, in general, decreasing the length of travel of the film of fuel along the swirler inner wall82may result in a thinner film thickness. Thus, the distal inner wall end118is positioned forward of the distal outer wall end138as described above. By providing a thinner film thickness, the fuel injector assembly60of the present disclosure may be operable to facilitate improved fuel and air mixing and/or a reduction in combustion dynamics.

Referring toFIG. 9, the tip156of the fuel injector nozzle154is disposed an axial distance (D) along the axis70from the distal outer wall end138. By minimizing the equation (D−d)/Dsw-ex, by decreasing the equation D/Dsw-exand/or by increasing the equation d/Dsw-ex, it has been found that combustion tones within the combustion chamber56may be reduced. For example, the fuel injector assembly60may be configured such that the equation (D−d)/Dsw-exis less than or equal to one (e.g., less than 0.80) and/or greater than or equal to 0.25 (e.g., greater than 0.30). The fuel injector assembly60, for example, may be configured such that the equation (D−d)/Dsw-exis between 0.35 and 0.68.

The fuel injector assembly60may be configured such that the equation D/Dsw-exis less than or equal to one and/or greater than or equal to 0.40. The fuel injector assembly60, for example, may be configured such that the equation D/Dsw-exis between 0.50 and 0.75.

The fuel injector assembly60may be configured such that the equation d/Dsw-exis less than or equal to 0.20 and/or greater than or equal to 0.05. The fuel injector assembly60, for example, may be configured such that the equation d/Dsw-exis between 0.07 and 0.15.

The swirler64is described above with a multi-segment body, where each segment76-78may be discretely formed and subsequently connected (e.g., bonded and/or mechanically fastened) to the other segment(s). However, in other embodiments, the swirler64may be configured such that any two or all of the segments76-78are formed integrally together as a unitary, monolithic body via, for example, casting and/or additive manufacturing.

In some embodiments, the swirler64may be configured with two airflow inlets. The swirler64, for example, may be configured without the upstream swirler segment76. In still other embodiments, the swirler64may be configured with more than three airflow inlets.

The fuel injector assembly60may be included in various turbine engines other than the one described above as well as in other types of fuel powered equipment. The fuel injector assembly60, 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 fuel injector assembly60may be included in a turbine engine configured without a gear train. The fuel injector assembly60may 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, a pusher fan engine or any other type of turbine engine. The present disclosure therefore is not limited to any particular types or configurations of turbine engines or equipment.