US20220127975A1 - Compliant retention system for gas turbine engine - Google Patents
Compliant retention system for gas turbine engine Download PDFInfo
- Publication number
- US20220127975A1 US20220127975A1 US17/077,079 US202017077079A US2022127975A1 US 20220127975 A1 US20220127975 A1 US 20220127975A1 US 202017077079 A US202017077079 A US 202017077079A US 2022127975 A1 US2022127975 A1 US 2022127975A1
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- United States
- Prior art keywords
- pin
- shroud
- load
- load spreader
- case
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/24—Casings; Casing parts, e.g. diaphragms, casing fastenings
- F01D25/243—Flange connections; Bolting arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
- F01D11/005—Sealing means between non relatively rotating elements
- F01D11/006—Sealing the gap between rotor blades or blades and rotor
- F01D11/008—Sealing the gap between rotor blades or blades and rotor by spacer elements between the blades, e.g. independent interblade platforms
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/24—Casings; Casing parts, e.g. diaphragms, casing fastenings
- F01D25/246—Fastening of diaphragms or stator-rings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D9/00—Stators
- F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
- F01D9/04—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
- F01D11/005—Sealing means between non relatively rotating elements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
- F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
- F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
- F01D11/14—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing
- F01D11/16—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing by self-adjusting means
- F01D11/18—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing by self-adjusting means using stator or rotor components with predetermined thermal response, e.g. selective insulation, thermal inertia, differential expansion
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2220/00—Application
- F05D2220/30—Application in turbines
- F05D2220/32—Application in turbines in gas turbines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2230/00—Manufacture
- F05D2230/60—Assembly methods
- F05D2230/64—Assembly methods using positioning or alignment devices for aligning or centring, e.g. pins
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2240/00—Components
- F05D2240/10—Stators
- F05D2240/11—Shroud seal segments
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2240/00—Components
- F05D2240/10—Stators
- F05D2240/12—Fluid guiding means, e.g. vanes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2240/00—Components
- F05D2240/10—Stators
- F05D2240/14—Casings or housings protecting or supporting assemblies within
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
Definitions
- the present disclosure generally relates to gas turbine engines, and more particularly relates to a compliant retention system for a shroud associated with a gas turbine engine.
- Compressor or turbine rotor blade stages in gas turbine engines may be provided with shrouds that maintain tip clearances between the tips of the rotor blades and the shrouds during an operation of the gas turbine engine to improve engine performance.
- the shrouds may thermally expand or grow radially at a different rate than surrounding components.
- differences in the thermal growth rates may result in misalignment between the shroud and the tips of the rotor blades, which alters the tip clearance and affects efficiency of the compressor or turbine stage.
- point loads may be applied to the shroud, which may impact life of the shroud.
- a system for coupling a shroud to a case associated with a gas turbine engine includes the case defining a bore and the shroud retained within the case.
- the shroud defines a pocket.
- the system includes a pin received through the bore and at least partially positioned within the pocket.
- the pin has a perimeter.
- the system includes a load spreader including a first side and a second side opposite the first side. The first side is interconnected to the second side by a flexible portion. The first side, the second side and the flexible portion are received about a portion of the perimeter of the pin, and the load spreader is configured to transmit at least one of an axial point load and a circumferential point load from the pin over a surface of the shroud.
- the load spreader includes a fourth side connected to the second side, and the fourth side includes a tail that extends beyond the first side.
- the fourth side of the load spreader is spaced apart from the first side to define a gap.
- the load spreader includes a fourth side connected to the second side, and the fourth side is substantially coplanar with the first side.
- the flexible portion includes one or more undulations.
- the undulations comprise a first convex portion coupled to the first side, a second convex portion coupled to the second side and a concave portion that interconnects the first convex portion and the second convex portion.
- the pin has a first pin end opposite a second pin end, and the second pin end comprises the portion of the perimeter of the pin.
- the pin includes a pin coupling flange at the second pin end, and the pin coupling flange comprises the portion of the perimeter of the pin.
- the pin includes a first pin coupling flange defined between the first pin end and the second pin end, and the first pin coupling flange couples the pin to the bore.
- the load spreader is received within the pocket.
- the pin is composed of a first material, the shroud is composed of a second material and the load spreader is composed of a third material, and the first material, the second material and the third material are different.
- the gas turbine engine includes a case defining a bore, and a shroud retained within the case.
- the shroud defines a pocket.
- the gas turbine engine includes a pin received through the bore and at least partially positioned within the pocket.
- the gas turbine engine includes a load spreader positioned within the pocket to surround a portion of the pin.
- the load spreader includes a first side, a second side opposite the first side, a flexible portion that interconnects the first side to the second side and a fourth side. At least the first side, the second side and the fourth side are configured to contact the portion of the pin to transmit at least one of an axial point load and a circumferential point load from the pin over a surface of the shroud.
- the pocket includes a first sidewall, a second sidewall, a third sidewall opposite the first sidewall and a fourth sidewall opposite the first sidewall.
- the fourth sidewall is spaced apart from the first sidewall to define an opening, and the load spreader is positioned within the pocket such that the first side is adjacent to the first sidewall and the second side of the load spreader is adjacent to the third sidewall.
- the fourth side of the load spreader is substantially co-planar with the first side of the load spreader.
- the fourth side of the load spreader extends a distance beyond the first side of the load spreader.
- the fourth side of the load spreader is spaced apart from the first side to define a gap.
- the case includes a plurality of the bores defined about a perimeter of the case, and the shroud includes a plurality of the pockets defined about a perimeter of the shroud.
- the gas turbine engine includes a plurality of the pins and a plurality of the load spreaders, with each pin of the plurality of pins associated with a respective one of the plurality of the bores, and each load spreader of the plurality of load spreaders is associated with an alternate one of the plurality of pins about the perimeter of the shroud.
- the flexible portion comprises a first convex portion coupled to the first side, a second convex portion coupled to the second side and a concave portion that interconnects the first convex portion and the second convex portion.
- the pin has a first pin end opposite a second pin end, the second pin end includes a pin coupling flange, and the pin coupling flange is configured to contact at least the first side, the second side and the fourth side of the load spreader.
- the gas turbine engine includes a case defining a bore, and a shroud retained within the case.
- the shroud defines a pocket that includes a first sidewall, a second sidewall, a third sidewall opposite the first sidewall and a fourth sidewall opposite the first sidewall.
- the fourth sidewall is spaced apart from the first sidewall to define an opening.
- the gas turbine engine includes a pin received through the bore and at least partially positioned within the pocket.
- the gas turbine engine includes a load spreader positioned within the pocket to surround a portion of the pin.
- the load spreader includes a first side, a second side opposite the first side, a flexible portion that interconnects the first side to the second side and a fourth side.
- At least the first side, the second side and the fourth side are configured to contact the portion of the pin to transmit at least one of an axial point load and a circumferential point load from the pin over a surface of the shroud.
- the fourth side defines a tail that extends through the opening.
- FIG. 1 is a schematic cross-sectional illustration of a gas turbine engine, which includes an exemplary compliant retention system in accordance with the various teachings of the present disclosure
- FIG. 2 is a perspective view of the compliant retention system coupling a shroud to an engine case in accordance with various embodiments
- FIG. 3 is an exploded view of the compliant retention system, the shroud and the engine case
- FIG. 4 is a cross-sectional view of the compliant retention system, the shroud and the engine case, taken along line 4 - 4 of FIG. 2 ;
- FIG. 5 is a detail exploded view of the compliant retention system, the shroud and the engine case, which illustrates a load spreader pocket associated with the shroud;
- FIG. 6 is a cross-sectional view of the compliant retention system, the shroud and the engine case, taken along line 6 - 6 of FIG. 2 ;
- FIG. 7 is a perspective view of one anti-rotation pin associated with the compliant retention system
- FIG. 8 is a perspective view of one load spreader associated with the compliant retention system
- FIG. 8A is a perspective view of one load spreader coupled to the shroud, in which the engine case and anti-rotation pins are removed for clarity;
- FIG. 9 is a top view of the compliant retention system coupled to the shroud, in which a portion of the engine case is removed for clarity;
- FIG. 9A is a cross-sectional view of the compliant retention system, the shroud and the engine case, taken along line 9 A- 9 A of FIG. 2 ;
- FIG. 10 is a perspective view of another exemplary load spreader for use with the compliant retention system.
- compliant retention system is described herein as being used with a gas turbine engine onboard a mobile platform, such as a bus, motorcycle, train, motor vehicle, marine vessel, aircraft, rotorcraft and the like, the various teachings of the present disclosure can be used with a gas turbine engine on a stationary platform.
- a mobile platform such as a bus, motorcycle, train, motor vehicle, marine vessel, aircraft, rotorcraft and the like
- many alternative or additional functional relationships or physical connections may be present in an embodiment of the present disclosure.
- figures shown herein depict an example with certain arrangements of elements, additional intervening elements, devices, features, or components may be present in an actual embodiment. It should also be understood that the drawings are merely illustrative and may not be drawn to scale.
- the term “axial” refers to a direction that is generally parallel to or coincident with an axis of rotation, axis of symmetry, or centerline of a component or components.
- the “axial” direction may refer to the direction that generally extends in parallel to the centerline between the opposite ends or faces.
- the term “axial” may be utilized with respect to components that are not cylindrical (or otherwise radially symmetric).
- the “axial” direction for a rectangular housing containing a rotating shaft may be viewed as a direction that is generally parallel to or coincident with the rotational axis of the shaft.
- the term “radially” as used herein may refer to a direction or a relationship of components with respect to a line extending outward from a shared centerline, axis, or similar reference, for example in a plane of a cylinder or disc that is perpendicular to the centerline or axis.
- components may be viewed as “radially” aligned even though one or both of the components may not be cylindrical (or otherwise radially symmetric).
- the terms “axial” and “radial” (and any derivatives) may encompass directional relationships that are other than precisely aligned with (e.g., oblique to) the true axial and radial dimensions, provided the relationship is predominantly in the respective nominal axial or radial direction.
- the term “transverse” denotes an axis that crosses another axis at an angle such that the axis and the other axis are neither substantially perpendicular nor substantially parallel.
- FIG. 1 a partial, cross-sectional view of an exemplary gas turbine engine 100 is shown with the remaining portion of the gas turbine engine 100 being axisymmetric about a longitudinal axis 140 , which also comprises an axis of rotation for the gas turbine engine 100 .
- the gas turbine engine 100 is an annular multi-spool turbofan gas turbine jet engine within an aircraft 99 , although other arrangements and uses may be provided.
- the gas turbine engine 100 includes a compliant retention system 200 for coupling a shroud 202 to a casing or engine case 204 .
- the compliant retention system 200 , the shroud 202 and the engine case 204 are associated with a stage S 2 of a turbine section 108 of the gas turbine engine 100 , however, the compliant retention system 200 , the shroud 202 and the engine case 204 may be associated with a stage of a compressor section 104 of the gas turbine engine 100 .
- the compliant retention system 200 maintains the axial and circumferential alignment of the shroud 202 or concentricity of the shroud 202 relative to the engine case 204 even with differences in thermal growth between the shroud 202 and the engine case 204 , which maintains tip clearances.
- the compliant retention system 200 also eliminates axial and circumferential point loading of the shroud 202 when coupled to the engine case 204 via one or more load spreaders 302 ( FIG. 8 ), as will be discussed further herein.
- the gas turbine engine 100 includes a fan section 102 , the compressor section 104 , a combustor section 106 , the turbine section 108 , and an exhaust section 110 .
- the fan section 102 includes a fan 112 mounted on a rotor 114 that draws air into the gas turbine engine 100 and accelerates it. A fraction of the accelerated air exhausted from the fan 112 is directed through an outer (or first) bypass duct 116 and the remaining fraction of air exhausted from the fan 112 is directed into the compressor section 104 .
- the outer bypass duct 116 is generally defined between the inner bypass duct 118 and an outer casing 144 . In the embodiment of FIG.
- the compressor section 104 includes an intermediate pressure compressor 120 and a high pressure compressor 122 .
- the number of compressors in the compressor section 104 may vary.
- the intermediate pressure compressor 120 and the high pressure compressor 122 sequentially raise the pressure of the air and direct a majority of the high pressure air into the combustor section 106 .
- a fraction of the compressed air bypasses the combustor section 106 and is used to cool, among other components, turbine blades in the turbine section 108 .
- the high pressure air is mixed with fuel, which is combusted.
- the high-temperature combustion air is directed into the turbine section 108 .
- the turbine section 108 includes three turbines disposed in axial flow series, namely, a high pressure turbine 126 , an intermediate pressure turbine 128 , and a low pressure turbine 130 .
- the number of turbines, and/or the configurations thereof may vary.
- the high-temperature air from the combustor section 106 expands through and rotates each turbine 126 , 128 , and 130 .
- each drives equipment in the gas turbine engine 100 via concentrically disposed shafts or spools.
- the high pressure turbine 126 drives the high pressure compressor 122 via a high pressure shaft 134
- the intermediate pressure turbine 128 drives the intermediate pressure compressor 120 via an intermediate pressure shaft 136
- the low pressure turbine 130 drives the fan 112 via a low pressure shaft 138 .
- the shroud 202 is circumferentially disposed about the intermediate pressure turbine 128
- the engine case 204 is coupled to a portion of a casing associated with the combustor section 106 .
- the compliant retention system 200 couples the shroud 202 to the engine case 204 .
- the casing associated with the combustor section 106 may be coupled to the inner bypass duct 118 .
- the placement of the shroud 202 and the engine case 204 about the intermediate pressure turbine 128 is merely exemplary, as the shroud 202 , the engine case 204 and the compliant retention system 200 may be employed with any turbine in the turbine section 108 or compressor in the compressor section 104 .
- FIG. 2 a perspective view of the compliant retention system 200 for coupling the shroud 202 to the engine case 204 is shown.
- the stage of the intermediate pressure turbine 128 is not shown for clarity.
- the shroud 202 is annular and surrounds the stage S 2 of the turbine section 108 , which in this example is the intermediate pressure turbine 128 ( FIG. 1 ).
- the shroud 202 is composed of any suitable material, such as a metal, metal alloy, composite, polymer based material, ceramic based material, etc.
- the shroud 202 may be formed by casting, molding, additive manufacturing, machining, etc.
- the shroud 202 is composed of a ceramic based material, which may have a thermal growth rate that is different than a thermal growth rate associated with the engine case 204 .
- the shroud 202 is composed of a ceramic matrix composite.
- the shroud 202 includes a first surface 210 opposite a second surface 212 .
- the first surface 210 defines an inner diameter of the shroud 202
- the second surface 212 defines an outer diameter of the shroud 202 .
- the first surface 210 surrounds a central bore 214 of the shroud 202 , which is sized to enable the shroud 202 to be positioned about the stage S 2 of the turbine section 108 or the intermediate pressure turbine 128 ( FIG.
- the first surface 210 is generally smooth.
- the second surface 212 includes a first flange 216 , a second flange 218 , a retaining lip 220 and at least one or a plurality of load spreader pockets 232 .
- the first flange 216 extends about an entirety of a perimeter or circumference of the second surface 212 .
- the first flange 216 cooperates with a first seal 224 ( FIG. 6 ) disposed or coupled between the first flange 216 and a portion of the engine case 204 .
- the second flange 218 extends about an entirety of a perimeter or circumference of the second surface 212 .
- the second flange 218 cooperates with a second seal 226 ( FIG. 6 ) disposed or coupled between the second flange 218 and a portion of the gas turbine engine 100 .
- the retaining lip 220 is defined at a first end 228 of the shroud 202 , and the first end 228 is opposite a second end 230 of the shroud 202 .
- the retaining lip 220 extends outwardly from the first end 228 to receive a portion of the engine case 204 ( FIG. 6 ).
- the first flange 216 is defined proximate the first end 228 so as to be spaced a distance apart from the retaining lip 220 .
- the second flange 218 is defined a distance D from the first flange 216 and is defined proximate the second end 230 .
- the at least one or the plurality of load spreader pockets 232 are defined between the first flange 216 and the second flange 218 , and thus, are defined between the first end 228 and the second end 230 of the shroud 202 along the outer diameter or second surface 212 of the shroud 202 .
- the first end 228 is a leading edge of the shroud 202
- the second end 230 is downstream and forms a trailing edge for the shroud 202 in a direction of working fluid flow through the gas turbine engine 100 .
- the shroud 202 includes a plurality of load spreader pockets 232 .
- the shroud 202 defines five load spreader pockets 232 , which are spaced apart about a circumference of the shroud 202 .
- the shroud 202 may be configured with a different number of load spreader pockets 232 in a different arrangement.
- FIG. 5 one of the load spreader pockets 232 is shown.
- each of the load spreader pockets 232 includes a first sidewall 236 , a second sidewall 238 , a third sidewall 240 and a fourth sidewall 242 .
- first sidewall 236 is opposite the third sidewall 240
- second sidewall 238 is opposite the fourth sidewall 242
- the first sidewall 236 is spaced apart from the fourth sidewall 242 to define an opening 244 for receipt of a portion of the compliant retention system 200 , as will be discussed.
- the first sidewall 236 extends axially from the second flange 218 , and may include a ramp surface 236 a for ease of manufacturing.
- the second sidewall 238 is defined by a portion of the second flange 218 .
- the third sidewall 240 extends axially between the first flange 216 and the second flange 218 .
- the third sidewall 240 may also include another ramp surface 240 a for ease of manufacturing.
- the fourth sidewall 242 is defined by a portion of the first flange 216 .
- the first sidewall 236 , the second sidewall 238 , the third sidewall 240 and the fourth sidewall 242 cooperate to define a substantially rectangular pocket, which receives a portion of a respective one of a plurality of anti-rotation pins 300 .
- the anti-rotation pins 300 received within and coupled to the load spreader pockets 232 provide concentricity; axial retention; axial compliance; circumferential retention; and radial compliance.
- Cooling fluid may be received from the engine case 204 and flow between the engine case 204 and the shroud 202 to provide impingement cooling to the engine case 204 and the shroud 202 .
- the engine case 204 surrounds the shroud 202 and is fluidly coupled to a source 248 of cooling fluid F.
- the source 248 of cooling fluid F may comprise any suitable source of cooling fluid F associated with the gas turbine engine 100 including, but not limited to, compressed air received from the compressor section 104 .
- the engine case 204 is composed of any suitable material, such as a metal, metal alloy, composite, etc.
- the engine case 204 is composed of a metal alloy, which has a thermal growth rate that is different than the thermal growth rate associated with the shroud 202 .
- the engine case 204 is composed of a nickel alloy, including, but not limited to Nickel Wasapaloy or Nickel Alloy 718.
- the engine case 204 may be formed by casting, molding, additive manufacturing, machining, etc.
- the engine case 204 includes a first surface 250 opposite a second surface 252 and a first end 253 opposite a second end 254 .
- the first end 253 is a leading edge of the engine case 204
- the second end 254 is downstream and forms a trailing edge for the engine case 204 in a direction of working fluid flow through the gas turbine engine 100 .
- the engine case 204 also defines a plurality of case bores 256 and a plurality of fluid inlets 258 ( FIG. 2 ).
- the first surface 250 defines an inner diameter of the engine case 204
- the second surface 252 defines an outer diameter of the engine case 204 .
- the first surface 250 surrounds a central bore 257 of the engine case 204 , which is sized to enable the engine case 204 to be positioned about the shroud 202 .
- the first surface 250 includes a first case flange 260 , which extends radially inward from the first surface 250 at the first end 253 .
- the first case flange 260 defines a channel 261 along a face of the first case flange 260 , which may receive a third seal 282 , for example.
- the channel 261 is substantially U-shaped, however, the channel 261 may have other shapes.
- the first case flange 260 also defines a plurality of impingement cooling conduits 262 and a second channel 263 .
- the impingement cooling conduits 262 are spaced apart about a circumference of the first case flange 260 .
- each of the impingement cooling conduits 262 are the same, and includes a first branch 264 fluidly coupled to a second branch 266 .
- the first branch 264 defines an inlet 264 a for the impingement cooling conduit 262
- the second branch 266 defines an outlet 266 a for the impingement cooling conduit 262
- the inlet 264 a is fluidly coupled to a plenum 267 defined between the engine case 204 and the shroud 202 .
- the first branch 264 directs the cooling fluid F the plenum 267 from between the engine case 204 and the shroud 202 through the first case flange 206 and onto the shroud 202 proximate the retaining lip 220 .
- each of the impingement cooling conduits 262 cooperate to cool both the engine case 204 and the shroud 202 at a leading edge of the engine case 204 and the shroud 202 .
- the second channel 263 cooperates with the second surface 212 of the shroud 202 to enclose the first seal 224 .
- the second surface 252 defines a second case flange 272 .
- the second case flange 272 is defined to extend radially outward from the second surface 252 at the second end 254 .
- the second case flange 272 includes a plurality of mounting bores 274 , which each receive a respective mechanical fastener 275 , such as a bolt, screw, etc. to couple the engine case 204 to a portion of the casing associated with the combustor section 106 ( FIG. 1 ).
- the plurality of mounting bores 274 are defined through the second case flange 272 about a perimeter or circumference of the second case flange 272 , as best shown in FIG. 2 .
- the case bores 256 receive a portion of the compliant retention system 200 to couple the engine case 204 to the shroud 202 .
- the case bores 256 are spaced apart about a perimeter or circumference of the engine case 204 , and in this example, the engine case 204 includes ten case bores 256 .
- a respective case bore 256 is associated with a respective one of the load spreader pockets 232 .
- Each case bore 256 includes a counterbore 276 and countersink 278 .
- the counterbore 276 is defined through the second surface 252 toward the first surface 250 .
- the counterbore 276 is coaxially aligned with the countersink 278 , and is shaped to correspond with a portion of the compliant retention system 200 .
- the counterbore 276 has a first diameter D 1 and a second diameter D 2 .
- the first diameter D 1 is different, and greater than the second diameter D 2 .
- the first diameter D 1 is defined from the second surface 252 to a transition 280 .
- the transition 280 is defined at about one-third of a length of the counterbore 276 .
- the counterbore 268 has the reduced second diameter D 2 to provide an interference or press-fit with a portion of the compliant retention system 200 .
- the second diameter D 2 of the counterbore 276 terminates at an inner surface 277 .
- the inner surface 277 provides a stop for the further advancement of the portion of the compliant retention system 200 .
- the second diameter D 2 is different and greater than a diameter of the countersink 278 .
- the counterbore 276 may also define a chamfered surface 276 a about the counterbore 276 at the second surface 252 to provide ease of assembly.
- the countersink 278 extends from the first surface 250 to the inner surface 277 .
- the countersink 278 also receives a portion of the compliant retention system 200 .
- the first diameter D 1 and the second diameter D 2 defined in the counterbore 276 is merely an example, and generally, the diameter D 1 may be employed to provide for alignment of the anti-rotation pin 300 prior to press-fitting the anti-rotation pin 300 into the diameter D 2 .
- the counterbore 276 may have a constant diameter D 2 , which extends along the entirety of the counterbore 276 , such that the anti-rotation pin 300 is press-fit with the engine case 204 over the depth of the counterbore 276 .
- the fluid inlets 258 are each fluidly coupled to the source 248 of the cooling fluid F. It should be noted that while the source 248 is shown schematically as a rectangle, the source 248 may be defined about a perimeter of the engine case 204 and fluidly coupled to the fluid inlets 258 . The source 248 is in fluid communication with each of the fluid inlets 258 via one or more ducts, conduits, etc. The fluid inlets 258 are defined in clusters of the fluid inlets 258 about a perimeter of the engine case 204 .
- a first predetermined number of the fluid inlets 258 are defined proximate or near the case bores 256 adjacent to the second case flange 272
- a second predetermined number of the fluid inlets 258 are defined between adjacent ones of the first predetermined number of fluid inlets 258 .
- the first predetermined number is different and greater than the second predetermined number of fluid inlets 258 to provide different or greater cooling of the engine case 204 and the shroud 202 proximate the compliant retention system 200 .
- Each of the fluid inlets 258 is in fluid communication with the plenum 267 ( FIG. 6 ) to direct the cooling fluid F from the source 248 to the impingement cooling conduits 262 .
- first seal 224 and the second seal 226 are coupled at the first end 228 and the second end 230 , respectively, of the shroud 202 .
- the first seal 224 and the second seal 226 are each coupled about a perimeter of the shroud 202 .
- the third seal 282 is coupled to the channel 261 defined in the first case flange 260 of the engine case 204 .
- the first seal 224 , the second seal 226 and the third seal 282 comprise elastomeric ring seals, which have an E cross-section.
- the first seal 224 is coupled between the second channel 263 of the first case flange 260 and the first flange 216 .
- the second seal 226 is coupled between the second flange 218 and an aft case 284 of the gas turbine engine 100 .
- the third seal 282 is coupled between the channel 261 and a structure (not shown) of the gas turbine engine 100 .
- the aft case 284 is coupled to the engine case 204 .
- the aft case 284 is downstream of the engine case 204 in the direction of working fluid flow through the gas turbine engine 100 ( FIG. 1 ).
- the aft case 284 surrounds a portion of the shroud 202 and is fluidly coupled to the source 248 of cooling fluid F.
- the aft case 284 includes one or more impingement cooling conduits, similar to the engine case 204 , for suppling the cooling fluid F to the aft case 284 and the shroud 202 .
- the aft case 284 is composed of any suitable material, such as a metal, metal alloy, composite, etc.
- the aft case 284 is composed of a metal alloy, which has a thermal growth rate that is different than the thermal growth rate associated with the shroud 202 .
- the aft case 284 is composed of a nickel alloy, including, but not limited to Nickel Wasapaloy or Nickel Alloy 718.
- the aft case 284 may be formed by casting, molding, additive manufacturing, machining, etc.
- the aft case 284 includes a first surface 286 opposite a second surface 288 and a first end 290 opposite a second end 292 .
- the first end 290 is a leading edge of the aft case 284 , while the second end 292 is downstream and forms a trailing edge for the aft case 284 in a direction of working fluid flow through the gas turbine engine 100 .
- the first surface 286 defines an inner diameter of the aft case 284
- the second surface 288 defines an outer diameter of the aft case 284 .
- the first surface 286 surrounds a central bore 287 of the aft case 284 , which is sized to enable the engine case 204 to be positioned about a portion of the shroud 202 .
- the first surface 286 includes a first aft flange 294 , which extends radially inward from the first surface 286 at the second end 292 .
- the first aft flange 294 extends from the first surface 286 and cooperates with the engine case 204 to surround the shroud 202 .
- the first aft flange 294 includes a seating surface 295 , which cooperates with the second flange 218 of the shroud 202 to retain the second seal 226 .
- the second surface 288 includes a second aft flange 296 , which extends radially outward from the second surface 288 at the first end 290 .
- the second aft flange 296 extends from the second surface 288 and defines a plurality of bores 297 .
- Each of the bores 297 is coaxially aligned with a respective mounting bore 274 of the engine case 204 to receive a respective mechanical fastener 275 to couple the aft case 284 to the engine case 204 .
- the compliant retention system 200 includes the plurality of anti-rotation pins 300 and at least one load spreader 302 .
- the compliant retention system 200 includes ten anti-rotation pins 300 and five load spreaders 302 . It should be noted that in other examples, the compliant retention system 200 may be configured with a different number of anti-rotation pins 300 and load spreaders 302 .
- the anti-rotation pins 300 and the load spreaders 302 are spaced apart about a perimeter of the engine case 204 and the shroud 202 .
- one of the load spreaders 302 is associated with a respective one of the load spreader pockets 232 of the shroud 202
- one of the anti-rotation pins 300 is associated with each one of the case bores 256 .
- every other anti-rotation pin 300 along the perimeter of the shroud 202 is received within and coupled to one of the load spreader pockets 232 .
- the load spreaders 302 are associated with an alternate one of the plurality of anti-rotation pins 300 about the perimeter of the shroud 202 .
- the anti-rotation pins 300 that are not associated with one of the load spreader pockets 232 are adjacent to and in contact with a portion of an adjacent load spreader 302 and the second surface 212 of the shroud 202 .
- the anti-rotation pins 300 positioned between the load spreader pockets 232 or that are not received in one of the load spreader pockets 232 provide for axial retention of the shroud 202 .
- the anti-rotation pins 300 may be composed of a metal or metal alloy, and may be cast, machined, molded, etc.
- the load spreaders 302 may be composed of a metal or metal alloy, and may be cast, machined, molded, etc.
- the anti-rotation pins 300 are composed of a metal or metal alloy that is different than the metal or metal alloy of the load spreaders 302 .
- the anti-rotation pins 300 are composed of INCONEL® alloy 718, and the load spreaders 302 are composed of HAYNES® alloy 188.
- the anti-rotation pins 300 are composed of a first material (metal or metal alloy) that is different than a second material from which the load spreaders 302 are composed, and the first material of the anti-rotation pins 300 and the second material of the load spreaders 302 is different than a third material (ceramic based material) from which the shroud 202 is composed.
- the anti-rotation pin 300 includes a first pin end 304 opposite a second pin end 306 and a pin coupling flange 308 defined between the first pin end 304 and the second pin end 306 .
- the anti-rotation pin 300 extends along a pin longitudinal axis PL from the first pin end 304 to the second pin end 306 .
- the first pin end 304 is cylindrical and is sized to be received within the respective case bore 256 ( FIG. 6 ).
- the first pin end 304 may include a first tapered surface 310 between the first pin end 304 and the pin coupling flange 308 to assist in the manufacturing of the anti-rotation pin 300 .
- the first pin end 304 may also include a chamfered surface 314 at a terminal end 304 a of the first pin end 304 .
- the first pin end 304 has a first pin diameter PD, which is different and greater than a second pin diameter PD 2 of an intermediate portion 316 of the second pin end 306 .
- the first pin end 304 defines a removal feature, such as a plurality of threads defined over the first pin end 304 .
- the first pin end 304 includes a plurality of threads defined over a portion of the first pin end 304 or may include an internal thread. In still other examples, the first pin end 304 may include a step or hexagonal shape to mate with a removal tool. Thus, generally, the first pin end 304 enables a removal of the anti-rotation pin 300 for disassembly.
- the second pin end 306 includes the intermediate portion 316 coupled to the pin coupling flange 308 via a fillet 318 , for example, and a second pin coupling flange 320 defined at a terminal end 306 a .
- the intermediate portion 316 has the second pin diameter PD 2 , which is sized to be received within the respective one of the load spreader pockets 232 of the shroud 202 .
- the intermediate portion 316 is substantially smooth and cylindrical.
- the intermediate portion 316 transitions to the second pin coupling flange 320 via a fillet 319 .
- the second pin coupling flange 320 is circular and has a third pin diameter PD 3 , which is different and greater than the second pin diameter PD 2 .
- the third pin diameter PD 3 is different and less than the first pin diameter PD.
- the second pin coupling flange 320 defines the interface between the anti-rotation pin 300 and the load spreader 302 .
- the second pin coupling flange 320 is sized to be received within and coupled to a respective one of the load spreaders 302 .
- the second pin coupling flange 320 defines a portion of a perimeter of the anti-rotation pin 300 .
- the pin coupling flange 308 extends outward from the anti-rotation pin 300 .
- the pin coupling flange 308 is defined on the anti-rotation pin 300 such that the first pin end 304 has a length along the pin longitudinal axis PL that is different and greater than a length of the second pin end 306 along the pin longitudinal axis PL. Stated another way, the pin coupling flange 308 is not centered between the first pin end 304 and the second pin end 306 .
- the pin coupling flange 308 is sized and shaped to be received within the case bore 256 such that one side 308 a of the pin coupling flange 308 contacts the inner surface 277 , and an opposed side 308 b is substantially flush or planar with the second surface 252 of the engine case 204 .
- the load spreader 302 includes a pin receptacle 330 and a tail 332 .
- the pin receptacle 330 is defined at a first spreader end 334 , which is opposite a second load spreader end 336 .
- the pin receptacle 330 is configured to receive the second pin end 306 of the anti-rotation pin 300 ( FIG. 7 ).
- the pin receptacle 330 includes a first receptacle side 338 opposite a second receptacle side 340 .
- the first receptacle side 338 and the second receptacle side 340 are interconnected by a flexible portion 342 , which forms a third receptacle side of the pin receptacle 330 .
- the first receptacle side 338 , the second receptacle side 340 and the flexible portion 342 cooperate with a fourth receptacle side 344 to define an opening 346 to receive the anti-rotation pin 300 .
- the first receptacle side 338 and the second receptacle side 340 are parallel and contact the second pin coupling flange 320 when the anti-rotation pin 300 is coupled to the load spreader 302 .
- the contact between the second pin coupling flange 320 , the first receptacle side 338 and the second receptacle side 340 maintains radial compliance between the shroud 202 and the engine case 204 .
- the contact between the second pin coupling flange 320 , the first receptacle side 338 and the second receptacle side 340 also transfers a circumferential point load from the anti-rotation pin 300 to the load spreader 302 , which reduces point loading applied to the shroud 202 as the load spreader 302 distributes the circumferential point load applied by the anti-rotation pin 300 over the load spreader 302 , and thus, over the second surface 212 of the shroud 202 .
- the contact between the second pin coupling flange 320 , the first receptacle side 338 and the second receptacle side 340 inhibits a rotation of the shroud 202 relative to the engine case 204 or provides for an anti-rotation feature to maintain concentricity of the shroud 202 or to maintain the tip clearance.
- the first receptacle side 338 extends for a length L 1 , which is different and less than a length L 2 of the second receptacle side 340 such that a gap 343 is defined between the first receptacle side 338 and the fourth receptacle side 344 .
- the second receptacle side 340 extends for the length L 2 , which is different and greater than the third pin diameter PD 3 .
- the third pin diameter PD 3 may be different or the same as the length L 1 of the first receptacle side 338 .
- the lengths L 1 , L 2 ensure that the second pin coupling flange 320 remains in contact with a portion of the first receptacle side 338 and the second receptacle side 340 during thermal growth of the shroud 202 .
- the first receptacle side 338 and the second receptacle side 340 also have a thickness T 1 , which is different and greater than a thickness T 2 of the flexible portion 342 .
- the difference in the thicknesses T 1 , T 2 ensures the flexibility of the flexible portion 342 relative to the first receptacle side 338 and the second receptacle side 340 .
- the first receptacle side 338 contacts and abuts the first sidewall 236 of the load spreader pocket 232
- the second receptacle side 340 contacts and abuts the third sidewall 240 of the load spreader pocket 232 .
- the flexible portion 342 interconnects the first receptacle side 338 and the second receptacle side 340 .
- the flexible portion 342 has a substantially undulating shape, and includes a first convex portion 348 a and a second convex portion 348 b connected to a concave portion 348 c .
- the first receptacle side 338 is coupled or connected to the first convex portion 348 a , which is connected to the concave portion 348 c .
- the concave portion 348 c is connected to the second convex portion 348 b
- the second convex portion 348 b is coupled to the second receptacle side 340 .
- the flexible portion 342 enables the anti-rotation pin 300 to be received within the opening 346 , and compensates for the thermal growth of the shroud 202 relative to the engine case 204 .
- the flexible portion 342 may expand or contract during the thermal growth of the shroud 202 , while enabling the load spreader 302 to maintain radial and axial compliance.
- the flexible portion 342 maintains contact between the load spreader 302 and the shroud 202 during the operation of the gas turbine engine 100 ( FIG. 1 ).
- the load spreader 302 includes the first receptacle side 338 , the second receptacle side 340 and the flexible portion 342 , which are received about the portion of the perimeter or the second pin coupling flange 320 of the anti-rotation pin 300 .
- the flexible portion 342 is compressed to insert and couple the load spreader 302 to the load spreader pocket 232 such that a snap-fit is formed between the respective load spreader 302 and load spreader pocket 232 .
- the compression of the flexible portion 324 also biases the first receptacle side 338 and the second receptacle side 340 against the second pin coupling flange 320 of the anti-rotation pin 300 .
- the fourth receptacle side 344 is opposite the flexible portion 342 .
- the fourth receptacle side 344 is connected to the second receptacle side 340 , but is spaced a distance apart from the first receptacle side 338 .
- the gap 343 defined between the first receptacle side 338 and the fourth receptacle side 344 enables the pin receptacle 330 to expand or contract if needed during the thermal growth of the shroud 202 .
- the fourth receptacle side 344 is perpendicular to the first receptacle side 338 and the second receptacle side 340 such that the pin receptacle 330 is substantially rectangular.
- the fourth receptacle side 344 cooperates with the flexible portion 342 to maintain axial compliance of the shroud 202 during thermal growth, and reduces axial point loading on the shroud 202 .
- the contact between the second pin coupling flange 320 and the fourth receptacle side 344 transfers an axial point load from the anti-rotation pin 300 to the load spreader 302 , which reduces point loading applied to the shroud 202 as the load spreader 302 distributes the axial point load applied by the anti-rotation pin 300 over the load spreader 302 .
- the second pin coupling flange 320 of the anti-rotation pin 300 contacts the fourth receptacle side 344 to provide axial compliance.
- the fourth receptacle side 344 is elongated to define the tail 332 .
- a terminal end 344 a of the fourth receptacle side 344 is spaced a predetermined distance away from the first receptacle side 338 and is not coplanar with the first receptacle side 338 .
- the tail 332 has a curvature, which is predefined based on a radius of curvature of the shroud 202 .
- the tail 332 generally extends for an arc length AL.
- the arc length AL is predetermined such that the tail 332 extends from the fourth receptacle side 344 proximate the first receptacle side 338 through the opening 244 defined in the shroud 202 to proximate the third sidewall 240 of a directly adjacent one of the load spreader pockets 232 , as shown in FIG. 8A .
- the arc length AL of the tail 332 enables a reduced number of load spreaders 302 to be employed with the shroud 202 , while still reducing point loading on the shroud 202 and providing radial and axial compliance.
- the tail 332 extends between adjacent ones of the load spreader pockets 232 such that a respective one of the anti-rotation pins 300 is adjacent to the tail 332 along the arc length AL of the tail 332 (See also FIG. 4 ).
- the tail 332 of the load spreader 302 extends past and is uncoupled from the respective one of the anti-rotation pins 300 that is positioned between anti-rotation pins 300 received in adjacent load spreader pockets 232 .
- the tail 322 provides for increased distribution of the load applied by the respective anti-rotation pins 300 circumferentially about the second surface 212 of the shroud 202 .
- the load spreader 302 may be configured differently to distribute point loading from the anti-rotation pin 300 over the second surface 212 of the shroud 202 while providing radial and axial compliance.
- FIG. 10 another exemplary load spreader 402 for use with the compliant retention system 200 is shown.
- the load spreader 402 includes the same or substantially the same features as the load spreader 302 , the same reference numerals will be used.
- the load spreader 402 includes a pin receptacle 430 , but does not include a tail.
- the pin receptacle 430 is configured to receive the second pin end 306 of the anti-rotation pin 300 ( FIG. 7 ).
- the pin receptacle 430 includes the first receptacle side 338 opposite the second receptacle side 340 .
- the first receptacle side 338 and the second receptacle side 340 are interconnected by the flexible portion 342 , which forms a third receptacle side of the pin receptacle 430 .
- the first receptacle side 338 , the second receptacle side 340 and the flexible portion 342 cooperate with a fourth receptacle side 444 to define the opening 346 to receive the anti-rotation pin 300 .
- the first receptacle side 338 and the second receptacle side 340 are parallel and contact the second pin coupling flange 320 when the anti-rotation pin 300 is coupled to the load spreader 302 .
- the first receptacle side 338 extends for the length L 1 , which is different and less than the length L 2 of the second receptacle side 340 such that the gap 343 is defined between the first receptacle side 338 and the fourth receptacle side 444 .
- the contact between the second pin coupling flange 320 , the first receptacle side 338 and the second receptacle side 340 maintains radial compliance between the shroud 202 and the engine case 204 .
- the contact between the second pin coupling flange 320 , the first receptacle side 338 and the second receptacle side 340 also transfers the circumferential point load from the anti-rotation pin 300 to the load spreader 402 , which reduces point loading applied to the shroud 202 as the load spreader 402 distributes the load applied by the anti-rotation pin 300 over the load spreader 402 , and thus, the second surface 212 of the shroud 202 .
- the contact between the second pin coupling flange 320 , the first receptacle side 338 and the second receptacle side 340 also inhibits a rotation of the shroud 202 relative to the engine case 204 or provides an anti-rotation feature to maintain concentricity or the tip clearance.
- the first receptacle side 338 contacts and abuts the first sidewall 236 of the load spreader pocket 232 ( FIG. 9 ), and the second receptacle side 340 contacts and abuts the third sidewall 240 of the load spreader pocket 232 ( FIG. 9 ).
- the flexible portion 342 interconnects the first receptacle side 338 and the second receptacle side 340 .
- the flexible portion 342 includes the first convex portion 348 a and the second convex portion 348 b connected to the concave portion 348 c .
- the fourth receptacle side 444 is opposite the flexible portion 342 .
- the fourth receptacle side 444 is connected to the second receptacle side 340 , but is spaced a distance apart from the first receptacle side 338 .
- the gap 343 defined between the first receptacle side 338 and the fourth receptacle side 444 enables the pin receptacle 430 to expand or contract if needed during the thermal growth of the shroud 202 .
- the fourth receptacle side 444 is perpendicular to the first receptacle side 338 and the second receptacle side 340 such that the pin receptacle 430 is substantially rectangular.
- the fourth receptacle side 444 cooperates with the flexible portion 342 to maintain axial compliance of the shroud 202 during thermal growth.
- the second pin coupling flange 320 of the anti-rotation pin 300 contacts the fourth receptacle side 444 to provide axial compliance.
- the contact between the second pin coupling flange 320 and the fourth receptacle side 444 transfers an axial point load from the anti-rotation pin 300 to the load spreader 402 , which reduces point loading applied to the shroud 202 as the load spreader 402 distributes the axial point load applied by the anti-rotation pin 300 over the load spreader 402 , and thus, over the second surface 212 of the shroud 202 .
- the fourth receptacle side 444 is coplanar with the first receptacle side 338 such that a terminal end 444 a of the fourth receptacle side 444 is adjacent to or aligned with the first receptacle side 338 .
- the load spreader 402 does not include the tail.
- the load spreader 402 reduces point loading by the anti-rotation pins 300 by distributing the load through the pin receptacle 430 , while maintaining radial and axial compliance during thermal growth and concentricity.
- the load spreader 302 , 402 may not include the flexible portion 342 , but may include another feature to enable the load spreader 302 , 402 to be in contact with the load spreader pocket 232 during the operation of the gas turbine engine 100 .
- the load spreaders 302 , 402 are coupled to the load spreader pockets 232 ( FIG. 9 ) of the shroud 202 ( FIG. 9 ) via the snap-fit, for example.
- the shroud 202 is positioned adjacent to the engine case 204 , and with reference to FIG. 4 , the anti-rotation pins 300 are inserted into the case bores 256 and coupled to the case bores 256 via the press-fit.
- Alternative ones of the anti-rotation pins 300 are also coupled to and received within respective pin receptacles 330 , 430 of the load spreaders 302 , 402 .
- the anti-rotation pins 300 are coupled to the load spreader pockets 232 such that the first receptacle side 338 and the second receptacle side 340 are coupled to or in contact with the second pin coupling flange 320 of the anti-rotation pin 300 to provide radial compliance during thermal growth and anti-rotation or concentricity of the shroud 202 relative to the engine case 204 .
- the anti-rotation pins 300 are coupled to the load spreader pockets 232 such that at least the fourth receptacle side 344 , 444 is coupled to or in contact with the second pin coupling flange 320 of the anti-rotation pin 300 to provide axial compliance of the shroud 202 relative to the engine case 204 during thermal growth.
- the anti-rotation pins 300 when the anti-rotation pins 300 are coupled to the shroud 202 and the engine case 204 , the anti-rotation pins 300 retain the shroud 202 to the engine case 204 , and also react to forces applied to the shroud 202 during the operation of the gas turbine engine 100 ( FIG. 1 ).
- the anti-rotation pins 300 react to axial loads, which result due to an upstream and downstream pressure differential associated with the shroud 202 and from loads applied by the first seal 224 and the second seal 226 .
- the anti-rotation pins 300 also react to circumferential loads, which may be applied by contact to the shroud 202 by rotor blades associated with the intermediate pressure turbine 128 ( FIG. 1 ).
- the load spreaders 302 , 402 receive these axial and circumferential loads from the anti-rotation pins 300 and distribute these axial and circumferential loads along load spreader 302 , 402 and thus, along the second surface 212 of the shroud 202 , which improves a life of the shroud 202 .
- the engine case 204 may be coupled to the aft case 284 , for example, via the mechanical fasteners 275 and the shroud 202 may be positioned about the intermediate pressure turbine 128 ( FIG. 1 ).
- the source 248 of cooling fluid F may be fluidly coupled to the fluid inlets 258 to supply the cooling fluid F to the plenum 267 and the impingement cooling conduits 262 .
- the compliant retention system 200 maintains the radial and axial compliance of the shroud 202 as the shroud 202 and engine case 204 thermally grow due to the coupling of the anti-rotation pins 300 to the load spreaders 302 , 402 .
- the load spreaders 302 , 402 distribute the axial and the circumferential point load from the anti-rotation pins 300 over the surface of the load spreaders 302 , 402 , and thus, the second surface 212 of the shroud 202 .
- the compliant retention system 200 maintains tip clearance or a concentricity of the shroud 202 .
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Abstract
A system for coupling a shroud to a case associated with a gas turbine engine and a gas turbine engine including such a system includes the case defining a bore and the shroud retained within the case. The shroud defines a pocket. The system includes a pin received through the bore and at least partially positioned within the pocket. The pin has a perimeter. The system includes a load spreader including a first side and a second side opposite the first side. The first side is interconnected to the second side by a flexible portion. The first side, the second side and the flexible portion are received about a portion of the perimeter of the pin, and the load spreader is configured to transmit at least one of an axial point load and a circumferential point load from the pin over a surface of the shroud.
Description
- This invention was made with Government support under DTFAWA-15-A-80017 awarded by the Federal Aviation Administration. The Government has certain rights in the invention.
- The present disclosure generally relates to gas turbine engines, and more particularly relates to a compliant retention system for a shroud associated with a gas turbine engine.
- Compressor or turbine rotor blade stages in gas turbine engines may be provided with shrouds that maintain tip clearances between the tips of the rotor blades and the shrouds during an operation of the gas turbine engine to improve engine performance. In certain instances, the shrouds may thermally expand or grow radially at a different rate than surrounding components. Depending on how the shroud is coupled within the gas turbine engine, differences in the thermal growth rates may result in misalignment between the shroud and the tips of the rotor blades, which alters the tip clearance and affects efficiency of the compressor or turbine stage. Moreover, depending upon how the shroud is coupled within the gas turbine engine, point loads may be applied to the shroud, which may impact life of the shroud.
- Accordingly, it is desirable to provide a compliant retention system for coupling a shroud within a gas turbine engine, such as to an engine case, which reduces point loading on the shroud while maintaining an alignment of the shroud and tip clearance during the operation of the gas turbine engine. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
- According to various embodiments, provided is a system for coupling a shroud to a case associated with a gas turbine engine. The system includes the case defining a bore and the shroud retained within the case. The shroud defines a pocket. The system includes a pin received through the bore and at least partially positioned within the pocket. The pin has a perimeter. The system includes a load spreader including a first side and a second side opposite the first side. The first side is interconnected to the second side by a flexible portion. The first side, the second side and the flexible portion are received about a portion of the perimeter of the pin, and the load spreader is configured to transmit at least one of an axial point load and a circumferential point load from the pin over a surface of the shroud.
- The load spreader includes a fourth side connected to the second side, and the fourth side includes a tail that extends beyond the first side. The fourth side of the load spreader is spaced apart from the first side to define a gap. The load spreader includes a fourth side connected to the second side, and the fourth side is substantially coplanar with the first side. The flexible portion includes one or more undulations. The undulations comprise a first convex portion coupled to the first side, a second convex portion coupled to the second side and a concave portion that interconnects the first convex portion and the second convex portion. The pin has a first pin end opposite a second pin end, and the second pin end comprises the portion of the perimeter of the pin. The pin includes a pin coupling flange at the second pin end, and the pin coupling flange comprises the portion of the perimeter of the pin. The pin includes a first pin coupling flange defined between the first pin end and the second pin end, and the first pin coupling flange couples the pin to the bore. The load spreader is received within the pocket. The pin is composed of a first material, the shroud is composed of a second material and the load spreader is composed of a third material, and the first material, the second material and the third material are different.
- Further provided is a gas turbine engine. The gas turbine engine includes a case defining a bore, and a shroud retained within the case. The shroud defines a pocket. The gas turbine engine includes a pin received through the bore and at least partially positioned within the pocket. The gas turbine engine includes a load spreader positioned within the pocket to surround a portion of the pin. The load spreader includes a first side, a second side opposite the first side, a flexible portion that interconnects the first side to the second side and a fourth side. At least the first side, the second side and the fourth side are configured to contact the portion of the pin to transmit at least one of an axial point load and a circumferential point load from the pin over a surface of the shroud.
- The pocket includes a first sidewall, a second sidewall, a third sidewall opposite the first sidewall and a fourth sidewall opposite the first sidewall. The fourth sidewall is spaced apart from the first sidewall to define an opening, and the load spreader is positioned within the pocket such that the first side is adjacent to the first sidewall and the second side of the load spreader is adjacent to the third sidewall. The fourth side of the load spreader is substantially co-planar with the first side of the load spreader. The fourth side of the load spreader extends a distance beyond the first side of the load spreader. The fourth side of the load spreader is spaced apart from the first side to define a gap. The case includes a plurality of the bores defined about a perimeter of the case, and the shroud includes a plurality of the pockets defined about a perimeter of the shroud. The gas turbine engine includes a plurality of the pins and a plurality of the load spreaders, with each pin of the plurality of pins associated with a respective one of the plurality of the bores, and each load spreader of the plurality of load spreaders is associated with an alternate one of the plurality of pins about the perimeter of the shroud.
- The flexible portion comprises a first convex portion coupled to the first side, a second convex portion coupled to the second side and a concave portion that interconnects the first convex portion and the second convex portion. The pin has a first pin end opposite a second pin end, the second pin end includes a pin coupling flange, and the pin coupling flange is configured to contact at least the first side, the second side and the fourth side of the load spreader.
- Also provided is a gas turbine engine. The gas turbine engine includes a case defining a bore, and a shroud retained within the case. The shroud defines a pocket that includes a first sidewall, a second sidewall, a third sidewall opposite the first sidewall and a fourth sidewall opposite the first sidewall. The fourth sidewall is spaced apart from the first sidewall to define an opening. The gas turbine engine includes a pin received through the bore and at least partially positioned within the pocket. The gas turbine engine includes a load spreader positioned within the pocket to surround a portion of the pin. The load spreader includes a first side, a second side opposite the first side, a flexible portion that interconnects the first side to the second side and a fourth side. At least the first side, the second side and the fourth side are configured to contact the portion of the pin to transmit at least one of an axial point load and a circumferential point load from the pin over a surface of the shroud. The fourth side defines a tail that extends through the opening.
- The exemplary embodiments will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
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FIG. 1 is a schematic cross-sectional illustration of a gas turbine engine, which includes an exemplary compliant retention system in accordance with the various teachings of the present disclosure; -
FIG. 2 is a perspective view of the compliant retention system coupling a shroud to an engine case in accordance with various embodiments; -
FIG. 3 is an exploded view of the compliant retention system, the shroud and the engine case; -
FIG. 4 is a cross-sectional view of the compliant retention system, the shroud and the engine case, taken along line 4-4 ofFIG. 2 ; -
FIG. 5 is a detail exploded view of the compliant retention system, the shroud and the engine case, which illustrates a load spreader pocket associated with the shroud; -
FIG. 6 is a cross-sectional view of the compliant retention system, the shroud and the engine case, taken along line 6-6 ofFIG. 2 ; -
FIG. 7 is a perspective view of one anti-rotation pin associated with the compliant retention system; -
FIG. 8 is a perspective view of one load spreader associated with the compliant retention system; -
FIG. 8A is a perspective view of one load spreader coupled to the shroud, in which the engine case and anti-rotation pins are removed for clarity; -
FIG. 9 is a top view of the compliant retention system coupled to the shroud, in which a portion of the engine case is removed for clarity; -
FIG. 9A is a cross-sectional view of the compliant retention system, the shroud and the engine case, taken alongline 9A-9A ofFIG. 2 ; and -
FIG. 10 is a perspective view of another exemplary load spreader for use with the compliant retention system. - The following detailed description is merely exemplary in nature and is not intended to limit the application and uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. In addition, those skilled in the art will appreciate that embodiments of the present disclosure may be practiced in conjunction with any type of arrangement that would benefit from a compliant retention system and the use of the compliant retention system for coupling a shroud to a case associated with a gas turbine engine described herein is merely one exemplary embodiment according to the present disclosure. In addition, while the compliant retention system is described herein as being used with a gas turbine engine onboard a mobile platform, such as a bus, motorcycle, train, motor vehicle, marine vessel, aircraft, rotorcraft and the like, the various teachings of the present disclosure can be used with a gas turbine engine on a stationary platform. Further, it should be noted that many alternative or additional functional relationships or physical connections may be present in an embodiment of the present disclosure. In addition, while the figures shown herein depict an example with certain arrangements of elements, additional intervening elements, devices, features, or components may be present in an actual embodiment. It should also be understood that the drawings are merely illustrative and may not be drawn to scale.
- As used herein, the term “axial” refers to a direction that is generally parallel to or coincident with an axis of rotation, axis of symmetry, or centerline of a component or components. For example, in a cylinder or disc with a centerline and generally circular ends or opposing faces, the “axial” direction may refer to the direction that generally extends in parallel to the centerline between the opposite ends or faces. In certain instances, the term “axial” may be utilized with respect to components that are not cylindrical (or otherwise radially symmetric). For example, the “axial” direction for a rectangular housing containing a rotating shaft may be viewed as a direction that is generally parallel to or coincident with the rotational axis of the shaft. Furthermore, the term “radially” as used herein may refer to a direction or a relationship of components with respect to a line extending outward from a shared centerline, axis, or similar reference, for example in a plane of a cylinder or disc that is perpendicular to the centerline or axis. In certain instances, components may be viewed as “radially” aligned even though one or both of the components may not be cylindrical (or otherwise radially symmetric). Furthermore, the terms “axial” and “radial” (and any derivatives) may encompass directional relationships that are other than precisely aligned with (e.g., oblique to) the true axial and radial dimensions, provided the relationship is predominantly in the respective nominal axial or radial direction. As used herein, the term “transverse” denotes an axis that crosses another axis at an angle such that the axis and the other axis are neither substantially perpendicular nor substantially parallel.
- With reference to
FIG. 1 , a partial, cross-sectional view of an exemplarygas turbine engine 100 is shown with the remaining portion of thegas turbine engine 100 being axisymmetric about alongitudinal axis 140, which also comprises an axis of rotation for thegas turbine engine 100. In the depicted embodiment, thegas turbine engine 100 is an annular multi-spool turbofan gas turbine jet engine within anaircraft 99, although other arrangements and uses may be provided. As will be discussed herein, with brief reference toFIG. 2 , thegas turbine engine 100 includes acompliant retention system 200 for coupling ashroud 202 to a casing orengine case 204. In one example, thecompliant retention system 200, theshroud 202 and theengine case 204 are associated with a stage S2 of aturbine section 108 of thegas turbine engine 100, however, thecompliant retention system 200, theshroud 202 and theengine case 204 may be associated with a stage of acompressor section 104 of thegas turbine engine 100. As will be discussed, thecompliant retention system 200 maintains the axial and circumferential alignment of theshroud 202 or concentricity of theshroud 202 relative to theengine case 204 even with differences in thermal growth between theshroud 202 and theengine case 204, which maintains tip clearances. In addition, thecompliant retention system 200 also eliminates axial and circumferential point loading of theshroud 202 when coupled to theengine case 204 via one or more load spreaders 302 (FIG. 8 ), as will be discussed further herein. - In this example, with reference back to
FIG. 1 , thegas turbine engine 100 includes afan section 102, thecompressor section 104, acombustor section 106, theturbine section 108, and anexhaust section 110. Thefan section 102 includes afan 112 mounted on arotor 114 that draws air into thegas turbine engine 100 and accelerates it. A fraction of the accelerated air exhausted from thefan 112 is directed through an outer (or first)bypass duct 116 and the remaining fraction of air exhausted from thefan 112 is directed into thecompressor section 104. Theouter bypass duct 116 is generally defined between theinner bypass duct 118 and anouter casing 144. In the embodiment ofFIG. 1 , thecompressor section 104 includes anintermediate pressure compressor 120 and ahigh pressure compressor 122. However, in other embodiments, the number of compressors in thecompressor section 104 may vary. In the depicted embodiment, theintermediate pressure compressor 120 and thehigh pressure compressor 122 sequentially raise the pressure of the air and direct a majority of the high pressure air into thecombustor section 106. A fraction of the compressed air bypasses thecombustor section 106 and is used to cool, among other components, turbine blades in theturbine section 108. - In the embodiment of
FIG. 1 , in thecombustor section 106, which includes acombustion chamber 124, the high pressure air is mixed with fuel, which is combusted. The high-temperature combustion air is directed into theturbine section 108. In this example, theturbine section 108 includes three turbines disposed in axial flow series, namely, ahigh pressure turbine 126, anintermediate pressure turbine 128, and alow pressure turbine 130. However, it will be appreciated that the number of turbines, and/or the configurations thereof, may vary. In this embodiment, the high-temperature air from thecombustor section 106 expands through and rotates eachturbine turbines gas turbine engine 100 via concentrically disposed shafts or spools. In one example, thehigh pressure turbine 126 drives thehigh pressure compressor 122 via ahigh pressure shaft 134, theintermediate pressure turbine 128 drives theintermediate pressure compressor 120 via anintermediate pressure shaft 136, and thelow pressure turbine 130 drives thefan 112 via alow pressure shaft 138. In this example, theshroud 202 is circumferentially disposed about theintermediate pressure turbine 128, and theengine case 204 is coupled to a portion of a casing associated with thecombustor section 106. Thecompliant retention system 200 couples theshroud 202 to theengine case 204. The casing associated with thecombustor section 106, in turn, may be coupled to theinner bypass duct 118. It should be noted that the placement of theshroud 202 and theengine case 204 about theintermediate pressure turbine 128 is merely exemplary, as theshroud 202, theengine case 204 and thecompliant retention system 200 may be employed with any turbine in theturbine section 108 or compressor in thecompressor section 104. - With reference to
FIG. 2 , a perspective view of thecompliant retention system 200 for coupling theshroud 202 to theengine case 204 is shown. InFIG. 2 , the stage of theintermediate pressure turbine 128 is not shown for clarity. In one example, theshroud 202 is annular and surrounds the stage S2 of theturbine section 108, which in this example is the intermediate pressure turbine 128 (FIG. 1 ). Theshroud 202 is composed of any suitable material, such as a metal, metal alloy, composite, polymer based material, ceramic based material, etc. Theshroud 202 may be formed by casting, molding, additive manufacturing, machining, etc. In one example, theshroud 202 is composed of a ceramic based material, which may have a thermal growth rate that is different than a thermal growth rate associated with theengine case 204. For example, theshroud 202 is composed of a ceramic matrix composite. With reference toFIG. 3 , theshroud 202 includes afirst surface 210 opposite asecond surface 212. Thefirst surface 210 defines an inner diameter of theshroud 202, while thesecond surface 212 defines an outer diameter of theshroud 202. Thefirst surface 210 surrounds acentral bore 214 of theshroud 202, which is sized to enable theshroud 202 to be positioned about the stage S2 of theturbine section 108 or the intermediate pressure turbine 128 (FIG. 1 ) at a predefined distance from tips of the rotor blades associated with theintermediate pressure turbine 128. Thefirst surface 210 is generally smooth. Thesecond surface 212 includes afirst flange 216, asecond flange 218, a retaininglip 220 and at least one or a plurality of load spreader pockets 232. - The
first flange 216 extends about an entirety of a perimeter or circumference of thesecond surface 212. Thefirst flange 216 cooperates with a first seal 224 (FIG. 6 ) disposed or coupled between thefirst flange 216 and a portion of theengine case 204. Thesecond flange 218 extends about an entirety of a perimeter or circumference of thesecond surface 212. Thesecond flange 218 cooperates with a second seal 226 (FIG. 6 ) disposed or coupled between thesecond flange 218 and a portion of thegas turbine engine 100. The retaininglip 220 is defined at afirst end 228 of theshroud 202, and thefirst end 228 is opposite asecond end 230 of theshroud 202. The retaininglip 220 extends outwardly from thefirst end 228 to receive a portion of the engine case 204 (FIG. 6 ). Generally, thefirst flange 216 is defined proximate thefirst end 228 so as to be spaced a distance apart from the retaininglip 220. Thesecond flange 218 is defined a distance D from thefirst flange 216 and is defined proximate thesecond end 230. The at least one or the plurality of load spreader pockets 232 are defined between thefirst flange 216 and thesecond flange 218, and thus, are defined between thefirst end 228 and thesecond end 230 of theshroud 202 along the outer diameter orsecond surface 212 of theshroud 202. Thefirst end 228 is a leading edge of theshroud 202, while thesecond end 230 is downstream and forms a trailing edge for theshroud 202 in a direction of working fluid flow through thegas turbine engine 100. - In this example, the
shroud 202 includes a plurality of load spreader pockets 232. With reference toFIG. 4 , in this example, theshroud 202 defines five load spreader pockets 232, which are spaced apart about a circumference of theshroud 202. It should be noted that in other examples, theshroud 202 may be configured with a different number of load spreader pockets 232 in a different arrangement. With reference toFIG. 5 , one of the load spreader pockets 232 is shown. In this example, each of the load spreader pockets 232 includes afirst sidewall 236, asecond sidewall 238, athird sidewall 240 and afourth sidewall 242. In this example, thefirst sidewall 236 is opposite thethird sidewall 240, and thesecond sidewall 238 is opposite thefourth sidewall 242. Thefirst sidewall 236 is spaced apart from thefourth sidewall 242 to define anopening 244 for receipt of a portion of thecompliant retention system 200, as will be discussed. Thefirst sidewall 236 extends axially from thesecond flange 218, and may include aramp surface 236 a for ease of manufacturing. Thesecond sidewall 238 is defined by a portion of thesecond flange 218. Thethird sidewall 240 extends axially between thefirst flange 216 and thesecond flange 218. Thethird sidewall 240 may also include anotherramp surface 240 a for ease of manufacturing. Thefourth sidewall 242 is defined by a portion of thefirst flange 216. Thus, thefirst sidewall 236, thesecond sidewall 238, thethird sidewall 240 and thefourth sidewall 242 cooperate to define a substantially rectangular pocket, which receives a portion of a respective one of a plurality of anti-rotation pins 300. Generally, the anti-rotation pins 300 received within and coupled to the load spreader pockets 232 provide concentricity; axial retention; axial compliance; circumferential retention; and radial compliance. Cooling fluid may be received from theengine case 204 and flow between theengine case 204 and theshroud 202 to provide impingement cooling to theengine case 204 and theshroud 202. - The
engine case 204 surrounds theshroud 202 and is fluidly coupled to asource 248 of cooling fluid F. Thesource 248 of cooling fluid F may comprise any suitable source of cooling fluid F associated with thegas turbine engine 100 including, but not limited to, compressed air received from thecompressor section 104. Theengine case 204 is composed of any suitable material, such as a metal, metal alloy, composite, etc. In one example, theengine case 204 is composed of a metal alloy, which has a thermal growth rate that is different than the thermal growth rate associated with theshroud 202. For example, theengine case 204 is composed of a nickel alloy, including, but not limited to Nickel Wasapaloy or Nickel Alloy 718. Theengine case 204 may be formed by casting, molding, additive manufacturing, machining, etc. With reference toFIG. 3 , theengine case 204 includes afirst surface 250 opposite asecond surface 252 and afirst end 253 opposite asecond end 254. Thefirst end 253 is a leading edge of theengine case 204, while thesecond end 254 is downstream and forms a trailing edge for theengine case 204 in a direction of working fluid flow through thegas turbine engine 100. Theengine case 204 also defines a plurality of case bores 256 and a plurality of fluid inlets 258 (FIG. 2 ). Thefirst surface 250 defines an inner diameter of theengine case 204, while thesecond surface 252 defines an outer diameter of theengine case 204. Thefirst surface 250 surrounds acentral bore 257 of theengine case 204, which is sized to enable theengine case 204 to be positioned about theshroud 202. Thefirst surface 250 includes afirst case flange 260, which extends radially inward from thefirst surface 250 at thefirst end 253. - With reference to
FIG. 6 , thefirst case flange 260 defines achannel 261 along a face of thefirst case flange 260, which may receive athird seal 282, for example. In this example, thechannel 261 is substantially U-shaped, however, thechannel 261 may have other shapes. Thefirst case flange 260 also defines a plurality ofimpingement cooling conduits 262 and asecond channel 263. Theimpingement cooling conduits 262 are spaced apart about a circumference of thefirst case flange 260. In this example, each of theimpingement cooling conduits 262 are the same, and includes afirst branch 264 fluidly coupled to asecond branch 266. Thefirst branch 264 defines aninlet 264 a for theimpingement cooling conduit 262, and thesecond branch 266 defines anoutlet 266 a for theimpingement cooling conduit 262. Theinlet 264 a is fluidly coupled to a plenum 267 defined between theengine case 204 and theshroud 202. Thefirst branch 264 directs the cooling fluid F the plenum 267 from between theengine case 204 and theshroud 202 through the first case flange 206 and onto theshroud 202 proximate the retaininglip 220. Thus, each of theimpingement cooling conduits 262 cooperate to cool both theengine case 204 and theshroud 202 at a leading edge of theengine case 204 and theshroud 202. Thesecond channel 263 cooperates with thesecond surface 212 of theshroud 202 to enclose thefirst seal 224. - The
second surface 252 defines asecond case flange 272. Thesecond case flange 272 is defined to extend radially outward from thesecond surface 252 at thesecond end 254. Thesecond case flange 272 includes a plurality of mountingbores 274, which each receive a respectivemechanical fastener 275, such as a bolt, screw, etc. to couple theengine case 204 to a portion of the casing associated with the combustor section 106 (FIG. 1 ). The plurality of mountingbores 274 are defined through thesecond case flange 272 about a perimeter or circumference of thesecond case flange 272, as best shown inFIG. 2 . - With reference to
FIG. 6 , the case bores 256 receive a portion of thecompliant retention system 200 to couple theengine case 204 to theshroud 202. The case bores 256 are spaced apart about a perimeter or circumference of theengine case 204, and in this example, theengine case 204 includes ten case bores 256. A respective case bore 256 is associated with a respective one of the load spreader pockets 232. Each case bore 256 includes acounterbore 276 and countersink 278. Thecounterbore 276 is defined through thesecond surface 252 toward thefirst surface 250. Thecounterbore 276 is coaxially aligned with thecountersink 278, and is shaped to correspond with a portion of thecompliant retention system 200. In one example, thecounterbore 276 has a first diameter D1 and a second diameter D2. The first diameter D1 is different, and greater than the second diameter D2. The first diameter D1 is defined from thesecond surface 252 to atransition 280. Thetransition 280 is defined at about one-third of a length of thecounterbore 276. At thetransition 280, thecounterbore 268 has the reduced second diameter D2 to provide an interference or press-fit with a portion of thecompliant retention system 200. The second diameter D2 of thecounterbore 276 terminates at aninner surface 277. Theinner surface 277 provides a stop for the further advancement of the portion of thecompliant retention system 200. The second diameter D2 is different and greater than a diameter of thecountersink 278. Thecounterbore 276 may also define a chamfered surface 276 a about thecounterbore 276 at thesecond surface 252 to provide ease of assembly. Thecountersink 278 extends from thefirst surface 250 to theinner surface 277. Thecountersink 278 also receives a portion of thecompliant retention system 200. It should be noted that the first diameter D1 and the second diameter D2 defined in thecounterbore 276 is merely an example, and generally, the diameter D1 may be employed to provide for alignment of theanti-rotation pin 300 prior to press-fitting theanti-rotation pin 300 into the diameter D2. In other embodiments, thecounterbore 276 may have a constant diameter D2, which extends along the entirety of thecounterbore 276, such that theanti-rotation pin 300 is press-fit with theengine case 204 over the depth of thecounterbore 276. - With reference to
FIG. 2 , the fluid inlets 258 (FIG. 2 ) are each fluidly coupled to thesource 248 of the cooling fluid F. It should be noted that while thesource 248 is shown schematically as a rectangle, thesource 248 may be defined about a perimeter of theengine case 204 and fluidly coupled to thefluid inlets 258. Thesource 248 is in fluid communication with each of thefluid inlets 258 via one or more ducts, conduits, etc. Thefluid inlets 258 are defined in clusters of thefluid inlets 258 about a perimeter of theengine case 204. Generally, a first predetermined number of thefluid inlets 258 are defined proximate or near the case bores 256 adjacent to thesecond case flange 272, while a second predetermined number of thefluid inlets 258 are defined between adjacent ones of the first predetermined number offluid inlets 258. The first predetermined number is different and greater than the second predetermined number offluid inlets 258 to provide different or greater cooling of theengine case 204 and theshroud 202 proximate thecompliant retention system 200. Each of thefluid inlets 258 is in fluid communication with the plenum 267 (FIG. 6 ) to direct the cooling fluid F from thesource 248 to theimpingement cooling conduits 262. - With reference back to
FIG. 6 , thefirst seal 224 and thesecond seal 226 are coupled at thefirst end 228 and thesecond end 230, respectively, of theshroud 202. Thefirst seal 224 and thesecond seal 226 are each coupled about a perimeter of theshroud 202. Thethird seal 282 is coupled to thechannel 261 defined in thefirst case flange 260 of theengine case 204. In one example, thefirst seal 224, thesecond seal 226 and thethird seal 282 comprise elastomeric ring seals, which have an E cross-section. Thefirst seal 224 is coupled between thesecond channel 263 of thefirst case flange 260 and thefirst flange 216. Thesecond seal 226 is coupled between thesecond flange 218 and anaft case 284 of thegas turbine engine 100. Thethird seal 282 is coupled between thechannel 261 and a structure (not shown) of thegas turbine engine 100. - The
aft case 284 is coupled to theengine case 204. Theaft case 284 is downstream of theengine case 204 in the direction of working fluid flow through the gas turbine engine 100 (FIG. 1 ). Theaft case 284 surrounds a portion of theshroud 202 and is fluidly coupled to thesource 248 of cooling fluid F. Although not shown inFIG. 6 , generally, theaft case 284 includes one or more impingement cooling conduits, similar to theengine case 204, for suppling the cooling fluid F to theaft case 284 and theshroud 202. Theaft case 284 is composed of any suitable material, such as a metal, metal alloy, composite, etc. In one example, theaft case 284 is composed of a metal alloy, which has a thermal growth rate that is different than the thermal growth rate associated with theshroud 202. For example, theaft case 284 is composed of a nickel alloy, including, but not limited to Nickel Wasapaloy or Nickel Alloy 718. Theaft case 284 may be formed by casting, molding, additive manufacturing, machining, etc. With reference toFIG. 3 , theaft case 284 includes afirst surface 286 opposite asecond surface 288 and afirst end 290 opposite asecond end 292. Thefirst end 290 is a leading edge of theaft case 284, while thesecond end 292 is downstream and forms a trailing edge for theaft case 284 in a direction of working fluid flow through thegas turbine engine 100. Thefirst surface 286 defines an inner diameter of theaft case 284, while thesecond surface 288 defines an outer diameter of theaft case 284. Thefirst surface 286 surrounds acentral bore 287 of theaft case 284, which is sized to enable theengine case 204 to be positioned about a portion of theshroud 202. - The
first surface 286 includes a firstaft flange 294, which extends radially inward from thefirst surface 286 at thesecond end 292. The firstaft flange 294 extends from thefirst surface 286 and cooperates with theengine case 204 to surround theshroud 202. The firstaft flange 294 includes a seating surface 295, which cooperates with thesecond flange 218 of theshroud 202 to retain thesecond seal 226. Thesecond surface 288 includes a secondaft flange 296, which extends radially outward from thesecond surface 288 at thefirst end 290. The secondaft flange 296 extends from thesecond surface 288 and defines a plurality ofbores 297. Each of thebores 297 is coaxially aligned with a respective mounting bore 274 of theengine case 204 to receive a respectivemechanical fastener 275 to couple theaft case 284 to theengine case 204. - The
compliant retention system 200 includes the plurality ofanti-rotation pins 300 and at least oneload spreader 302. In one example, with reference toFIG. 3 , thecompliant retention system 200 includes tenanti-rotation pins 300 and fiveload spreaders 302. It should be noted that in other examples, thecompliant retention system 200 may be configured with a different number ofanti-rotation pins 300 andload spreaders 302. The anti-rotation pins 300 and theload spreaders 302 are spaced apart about a perimeter of theengine case 204 and theshroud 202. Generally, one of theload spreaders 302 is associated with a respective one of the load spreader pockets 232 of theshroud 202, and one of the anti-rotation pins 300 is associated with each one of the case bores 256. Thus, in this example, every otheranti-rotation pin 300 along the perimeter of theshroud 202 is received within and coupled to one of the load spreader pockets 232. As theload spreaders 302 are received within the load spreader pockets 232 defined about the perimeter of theshroud 202, generally, theload spreaders 302 are associated with an alternate one of the plurality ofanti-rotation pins 300 about the perimeter of theshroud 202. Generally, the anti-rotation pins 300 that are not associated with one of the load spreader pockets 232 are adjacent to and in contact with a portion of anadjacent load spreader 302 and thesecond surface 212 of theshroud 202. The anti-rotation pins 300 positioned between the load spreader pockets 232 or that are not received in one of the load spreader pockets 232 provide for axial retention of theshroud 202. - The anti-rotation pins 300 may be composed of a metal or metal alloy, and may be cast, machined, molded, etc. The
load spreaders 302 may be composed of a metal or metal alloy, and may be cast, machined, molded, etc. In this example, the anti-rotation pins 300 are composed of a metal or metal alloy that is different than the metal or metal alloy of theload spreaders 302. For example, the anti-rotation pins 300 are composed of INCONEL® alloy 718, and theload spreaders 302 are composed of HAYNES® alloy 188. Thus, the anti-rotation pins 300 are composed of a first material (metal or metal alloy) that is different than a second material from which theload spreaders 302 are composed, and the first material of the anti-rotation pins 300 and the second material of theload spreaders 302 is different than a third material (ceramic based material) from which theshroud 202 is composed. - With reference to
FIG. 7 , one of the anti-rotation pins 300 is shown in greater detail. As each of the anti-rotation pins 300 is the same, a singleanti-rotation pin 300 will be discussed herein. Theanti-rotation pin 300 includes afirst pin end 304 opposite asecond pin end 306 and apin coupling flange 308 defined between thefirst pin end 304 and thesecond pin end 306. Theanti-rotation pin 300 extends along a pin longitudinal axis PL from thefirst pin end 304 to thesecond pin end 306. Thefirst pin end 304 is cylindrical and is sized to be received within the respective case bore 256 (FIG. 6 ). Thefirst pin end 304 may include a first tapered surface 310 between thefirst pin end 304 and thepin coupling flange 308 to assist in the manufacturing of theanti-rotation pin 300. Thefirst pin end 304 may also include achamfered surface 314 at aterminal end 304 a of thefirst pin end 304. Thefirst pin end 304 has a first pin diameter PD, which is different and greater than a second pin diameter PD2 of anintermediate portion 316 of thesecond pin end 306. In one example, thefirst pin end 304 defines a removal feature, such as a plurality of threads defined over thefirst pin end 304. In other examples, thefirst pin end 304 includes a plurality of threads defined over a portion of thefirst pin end 304 or may include an internal thread. In still other examples, thefirst pin end 304 may include a step or hexagonal shape to mate with a removal tool. Thus, generally, thefirst pin end 304 enables a removal of theanti-rotation pin 300 for disassembly. - The
second pin end 306 includes theintermediate portion 316 coupled to thepin coupling flange 308 via afillet 318, for example, and a secondpin coupling flange 320 defined at aterminal end 306 a. Theintermediate portion 316 has the second pin diameter PD2, which is sized to be received within the respective one of the load spreader pockets 232 of theshroud 202. Theintermediate portion 316 is substantially smooth and cylindrical. Theintermediate portion 316 transitions to the secondpin coupling flange 320 via afillet 319. The secondpin coupling flange 320 is circular and has a third pin diameter PD3, which is different and greater than the second pin diameter PD2. The third pin diameter PD3 is different and less than the first pin diameter PD. By providing the third pin diameter PD3 greater than PD2, the secondpin coupling flange 320 defines the interface between theanti-rotation pin 300 and theload spreader 302. The secondpin coupling flange 320 is sized to be received within and coupled to a respective one of theload spreaders 302. The secondpin coupling flange 320 defines a portion of a perimeter of theanti-rotation pin 300. - The
pin coupling flange 308 extends outward from theanti-rotation pin 300. Generally, thepin coupling flange 308 is defined on theanti-rotation pin 300 such that thefirst pin end 304 has a length along the pin longitudinal axis PL that is different and greater than a length of thesecond pin end 306 along the pin longitudinal axis PL. Stated another way, thepin coupling flange 308 is not centered between thefirst pin end 304 and thesecond pin end 306. With reference toFIG. 6 , thepin coupling flange 308 is sized and shaped to be received within the case bore 256 such that oneside 308 a of thepin coupling flange 308 contacts theinner surface 277, and anopposed side 308 b is substantially flush or planar with thesecond surface 252 of theengine case 204. - With reference to
FIG. 8 , one of theload spreaders 302 is shown in greater detail. As each of theload spreaders 302 is the same, asingle load spreader 302 will be discussed herein. In this example, theload spreader 302 includes apin receptacle 330 and atail 332. Thepin receptacle 330 is defined at afirst spreader end 334, which is opposite a secondload spreader end 336. Thepin receptacle 330 is configured to receive thesecond pin end 306 of the anti-rotation pin 300 (FIG. 7 ). Thepin receptacle 330 includes afirst receptacle side 338 opposite asecond receptacle side 340. Thefirst receptacle side 338 and thesecond receptacle side 340 are interconnected by aflexible portion 342, which forms a third receptacle side of thepin receptacle 330. Thefirst receptacle side 338, thesecond receptacle side 340 and theflexible portion 342 cooperate with afourth receptacle side 344 to define anopening 346 to receive theanti-rotation pin 300. With reference toFIG. 9A , thefirst receptacle side 338 and thesecond receptacle side 340 are parallel and contact the secondpin coupling flange 320 when theanti-rotation pin 300 is coupled to theload spreader 302. The contact between the secondpin coupling flange 320, thefirst receptacle side 338 and thesecond receptacle side 340 maintains radial compliance between theshroud 202 and theengine case 204. The contact between the secondpin coupling flange 320, thefirst receptacle side 338 and thesecond receptacle side 340 also transfers a circumferential point load from theanti-rotation pin 300 to theload spreader 302, which reduces point loading applied to theshroud 202 as theload spreader 302 distributes the circumferential point load applied by theanti-rotation pin 300 over theload spreader 302, and thus, over thesecond surface 212 of theshroud 202. In addition, the contact between the secondpin coupling flange 320, thefirst receptacle side 338 and thesecond receptacle side 340 inhibits a rotation of theshroud 202 relative to theengine case 204 or provides for an anti-rotation feature to maintain concentricity of theshroud 202 or to maintain the tip clearance. - With reference to
FIG. 9 , thefirst receptacle side 338 extends for a length L1, which is different and less than a length L2 of thesecond receptacle side 340 such that agap 343 is defined between thefirst receptacle side 338 and thefourth receptacle side 344. Thesecond receptacle side 340 extends for the length L2, which is different and greater than the third pin diameter PD3. The third pin diameter PD3 may be different or the same as the length L1 of thefirst receptacle side 338. The lengths L1, L2 ensure that the secondpin coupling flange 320 remains in contact with a portion of thefirst receptacle side 338 and thesecond receptacle side 340 during thermal growth of theshroud 202. Thefirst receptacle side 338 and thesecond receptacle side 340 also have a thickness T1, which is different and greater than a thickness T2 of theflexible portion 342. The difference in the thicknesses T1, T2 ensures the flexibility of theflexible portion 342 relative to thefirst receptacle side 338 and thesecond receptacle side 340. Thefirst receptacle side 338 contacts and abuts thefirst sidewall 236 of theload spreader pocket 232, and thesecond receptacle side 340 contacts and abuts thethird sidewall 240 of theload spreader pocket 232. - The
flexible portion 342 interconnects thefirst receptacle side 338 and thesecond receptacle side 340. In one example, theflexible portion 342 has a substantially undulating shape, and includes a firstconvex portion 348 a and a secondconvex portion 348 b connected to aconcave portion 348 c. Generally, thefirst receptacle side 338 is coupled or connected to the firstconvex portion 348 a, which is connected to theconcave portion 348 c. Theconcave portion 348 c is connected to the secondconvex portion 348 b, and the secondconvex portion 348 b is coupled to thesecond receptacle side 340. Theflexible portion 342 enables theanti-rotation pin 300 to be received within theopening 346, and compensates for the thermal growth of theshroud 202 relative to theengine case 204. Generally, theflexible portion 342 may expand or contract during the thermal growth of theshroud 202, while enabling theload spreader 302 to maintain radial and axial compliance. Theflexible portion 342 maintains contact between theload spreader 302 and theshroud 202 during the operation of the gas turbine engine 100 (FIG. 1 ). Thus, theload spreader 302 includes thefirst receptacle side 338, thesecond receptacle side 340 and theflexible portion 342, which are received about the portion of the perimeter or the secondpin coupling flange 320 of theanti-rotation pin 300. In this example, theflexible portion 342 is compressed to insert and couple theload spreader 302 to theload spreader pocket 232 such that a snap-fit is formed between therespective load spreader 302 andload spreader pocket 232. The compression of the flexible portion 324 also biases thefirst receptacle side 338 and thesecond receptacle side 340 against the secondpin coupling flange 320 of theanti-rotation pin 300. - The
fourth receptacle side 344 is opposite theflexible portion 342. Thefourth receptacle side 344 is connected to thesecond receptacle side 340, but is spaced a distance apart from thefirst receptacle side 338. Thegap 343 defined between thefirst receptacle side 338 and thefourth receptacle side 344 enables thepin receptacle 330 to expand or contract if needed during the thermal growth of theshroud 202. Thefourth receptacle side 344 is perpendicular to thefirst receptacle side 338 and thesecond receptacle side 340 such that thepin receptacle 330 is substantially rectangular. Thefourth receptacle side 344 cooperates with theflexible portion 342 to maintain axial compliance of theshroud 202 during thermal growth, and reduces axial point loading on theshroud 202. In this regard, the contact between the secondpin coupling flange 320 and thefourth receptacle side 344 transfers an axial point load from theanti-rotation pin 300 to theload spreader 302, which reduces point loading applied to theshroud 202 as theload spreader 302 distributes the axial point load applied by theanti-rotation pin 300 over theload spreader 302. With brief reference toFIG. 6 , the secondpin coupling flange 320 of theanti-rotation pin 300 contacts thefourth receptacle side 344 to provide axial compliance. - In one example, with reference back to
FIG. 8 , thefourth receptacle side 344 is elongated to define thetail 332. Stated another way, aterminal end 344 a of thefourth receptacle side 344 is spaced a predetermined distance away from thefirst receptacle side 338 and is not coplanar with thefirst receptacle side 338. Thetail 332 has a curvature, which is predefined based on a radius of curvature of theshroud 202. Thetail 332 generally extends for an arc length AL. The arc length AL is predetermined such that thetail 332 extends from thefourth receptacle side 344 proximate thefirst receptacle side 338 through theopening 244 defined in theshroud 202 to proximate thethird sidewall 240 of a directly adjacent one of the load spreader pockets 232, as shown inFIG. 8A . As shown inFIG. 3 , the arc length AL of thetail 332 enables a reduced number ofload spreaders 302 to be employed with theshroud 202, while still reducing point loading on theshroud 202 and providing radial and axial compliance. Thus, generally, thetail 332 extends between adjacent ones of the load spreader pockets 232 such that a respective one of the anti-rotation pins 300 is adjacent to thetail 332 along the arc length AL of the tail 332 (See alsoFIG. 4 ). Stated another way, thetail 332 of theload spreader 302 extends past and is uncoupled from the respective one of the anti-rotation pins 300 that is positioned betweenanti-rotation pins 300 received in adjacent load spreader pockets 232. The tail 322 provides for increased distribution of the load applied by the respective anti-rotation pins 300 circumferentially about thesecond surface 212 of theshroud 202. - It should be noted that in other embodiments, the
load spreader 302 may be configured differently to distribute point loading from theanti-rotation pin 300 over thesecond surface 212 of theshroud 202 while providing radial and axial compliance. For example, with reference toFIG. 10 , anotherexemplary load spreader 402 for use with thecompliant retention system 200 is shown. As theload spreader 402 includes the same or substantially the same features as theload spreader 302, the same reference numerals will be used. Theload spreader 402 includes apin receptacle 430, but does not include a tail. Thepin receptacle 430 is configured to receive thesecond pin end 306 of the anti-rotation pin 300 (FIG. 7 ). Thepin receptacle 430 includes thefirst receptacle side 338 opposite thesecond receptacle side 340. Thefirst receptacle side 338 and thesecond receptacle side 340 are interconnected by theflexible portion 342, which forms a third receptacle side of thepin receptacle 430. Thefirst receptacle side 338, thesecond receptacle side 340 and theflexible portion 342 cooperate with afourth receptacle side 444 to define theopening 346 to receive theanti-rotation pin 300. Thefirst receptacle side 338 and thesecond receptacle side 340 are parallel and contact the secondpin coupling flange 320 when theanti-rotation pin 300 is coupled to theload spreader 302. Thefirst receptacle side 338 extends for the length L1, which is different and less than the length L2 of thesecond receptacle side 340 such that thegap 343 is defined between thefirst receptacle side 338 and thefourth receptacle side 444. - The contact between the second
pin coupling flange 320, thefirst receptacle side 338 and thesecond receptacle side 340 maintains radial compliance between theshroud 202 and theengine case 204. The contact between the secondpin coupling flange 320, thefirst receptacle side 338 and thesecond receptacle side 340 also transfers the circumferential point load from theanti-rotation pin 300 to theload spreader 402, which reduces point loading applied to theshroud 202 as theload spreader 402 distributes the load applied by theanti-rotation pin 300 over theload spreader 402, and thus, thesecond surface 212 of theshroud 202. The contact between the secondpin coupling flange 320, thefirst receptacle side 338 and thesecond receptacle side 340 also inhibits a rotation of theshroud 202 relative to theengine case 204 or provides an anti-rotation feature to maintain concentricity or the tip clearance. Thefirst receptacle side 338 contacts and abuts thefirst sidewall 236 of the load spreader pocket 232 (FIG. 9 ), and thesecond receptacle side 340 contacts and abuts thethird sidewall 240 of the load spreader pocket 232 (FIG. 9 ). - The
flexible portion 342 interconnects thefirst receptacle side 338 and thesecond receptacle side 340. Theflexible portion 342 includes the firstconvex portion 348 a and the secondconvex portion 348 b connected to theconcave portion 348 c. Thefourth receptacle side 444 is opposite theflexible portion 342. Thefourth receptacle side 444 is connected to thesecond receptacle side 340, but is spaced a distance apart from thefirst receptacle side 338. Thegap 343 defined between thefirst receptacle side 338 and thefourth receptacle side 444 enables thepin receptacle 430 to expand or contract if needed during the thermal growth of theshroud 202. Thefourth receptacle side 444 is perpendicular to thefirst receptacle side 338 and thesecond receptacle side 340 such that thepin receptacle 430 is substantially rectangular. Thefourth receptacle side 444 cooperates with theflexible portion 342 to maintain axial compliance of theshroud 202 during thermal growth. The secondpin coupling flange 320 of the anti-rotation pin 300 (FIG. 6 ) contacts thefourth receptacle side 444 to provide axial compliance. In addition, the contact between the secondpin coupling flange 320 and thefourth receptacle side 444 transfers an axial point load from theanti-rotation pin 300 to theload spreader 402, which reduces point loading applied to theshroud 202 as theload spreader 402 distributes the axial point load applied by theanti-rotation pin 300 over theload spreader 402, and thus, over thesecond surface 212 of theshroud 202. In this example, thefourth receptacle side 444 is coplanar with thefirst receptacle side 338 such that aterminal end 444 a of thefourth receptacle side 444 is adjacent to or aligned with thefirst receptacle side 338. Thus, in this example, theload spreader 402 does not include the tail. Theload spreader 402 reduces point loading by the anti-rotation pins 300 by distributing the load through thepin receptacle 430, while maintaining radial and axial compliance during thermal growth and concentricity. It should be noted that in certain embodiments, theload spreader flexible portion 342, but may include another feature to enable theload spreader load spreader pocket 232 during the operation of thegas turbine engine 100. - In one example, in order to assemble the
shroud 202 to theengine case 204 with thecompliant retention system 200, theload spreaders FIG. 9 ) of the shroud 202 (FIG. 9 ) via the snap-fit, for example. Theshroud 202 is positioned adjacent to theengine case 204, and with reference toFIG. 4 , the anti-rotation pins 300 are inserted into the case bores 256 and coupled to the case bores 256 via the press-fit. Alternative ones of the anti-rotation pins 300 are also coupled to and received withinrespective pin receptacles load spreaders FIG. 9A , the anti-rotation pins 300 are coupled to the load spreader pockets 232 such that thefirst receptacle side 338 and thesecond receptacle side 340 are coupled to or in contact with the secondpin coupling flange 320 of theanti-rotation pin 300 to provide radial compliance during thermal growth and anti-rotation or concentricity of theshroud 202 relative to theengine case 204. With reference toFIG. 6 , the anti-rotation pins 300 are coupled to the load spreader pockets 232 such that at least thefourth receptacle side pin coupling flange 320 of theanti-rotation pin 300 to provide axial compliance of theshroud 202 relative to theengine case 204 during thermal growth. - Generally, when the anti-rotation pins 300 are coupled to the
shroud 202 and theengine case 204, the anti-rotation pins 300 retain theshroud 202 to theengine case 204, and also react to forces applied to theshroud 202 during the operation of the gas turbine engine 100 (FIG. 1 ). For example, the anti-rotation pins 300 react to axial loads, which result due to an upstream and downstream pressure differential associated with theshroud 202 and from loads applied by thefirst seal 224 and thesecond seal 226. The anti-rotation pins 300 also react to circumferential loads, which may be applied by contact to theshroud 202 by rotor blades associated with the intermediate pressure turbine 128 (FIG. 1 ). Theload spreaders load spreader second surface 212 of theshroud 202, which improves a life of theshroud 202. - With the
shroud 202 coupled to theengine case 204 via thecompliant retention system 200, theengine case 204 may be coupled to theaft case 284, for example, via themechanical fasteners 275 and theshroud 202 may be positioned about the intermediate pressure turbine 128 (FIG. 1 ). Thesource 248 of cooling fluid F may be fluidly coupled to thefluid inlets 258 to supply the cooling fluid F to the plenum 267 and theimpingement cooling conduits 262. With theshroud 202, theengine case 204 and theaft case 284 installed within thegas turbine engine 100 to surround the intermediate pressure turbine 128 (FIG. 1 ), during operation of thegas turbine engine 100, due to the differences in the thermal growth rates of the materials that compose theshroud 202 and theengine case 204, theshroud 202 and theengine case 204 grow or expand at different rates. Thecompliant retention system 200 maintains the radial and axial compliance of theshroud 202 as theshroud 202 andengine case 204 thermally grow due to the coupling of the anti-rotation pins 300 to theload spreaders load spreaders load spreaders second surface 212 of theshroud 202. By distributing the axial and the circumferential point load from the anti-rotation pins 300 over the surface of theload spreaders second surface 212 of theshroud 202, a life of theshroud 202 is improved. In addition, thecompliant retention system 200 maintains tip clearance or a concentricity of theshroud 202. - In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Numerical ordinals such as “first,” “second,” “third,” etc. simply denote different singles of a plurality and do not imply any order or sequence unless specifically defined by the claim language. The sequence of the text in any of the claims does not imply that process steps must be performed in a temporal or logical order according to such sequence unless it is specifically defined by the language of the claim. The process steps may be interchanged in any order without departing from the scope of the invention as long as such an interchange does not contradict the claim language and is not logically nonsensical.
- While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the disclosure as set forth in the appended claims and the legal equivalents thereof.
Claims (20)
1. A system for coupling a shroud to a case associated with a gas turbine engine, comprising:
the case defining a bore;
the shroud retained within the case, the shroud defining a pocket;
a pin received through the bore and at least partially positioned within the pocket, the pin having a perimeter; and
a load spreader including a first side and a second side opposite the first side, with the first side interconnected to the second side by a flexible portion including undulations, the first side, the second side and the undulations of the flexible portion cooperate to define a pin receptacle to receive the pin, the first side, the second side and the undulations of the flexible portion are positioned about a portion of the perimeter of the pin, and the load spreader is configured to transmit at least one of an axial point load and a circumferential point load from the pin over a surface of the shroud.
2. The system of claim 1 , wherein the load spreader includes a fourth side connected to the second side, and the fourth side includes a tail that extends beyond the first side.
3. The system of claim 2 , wherein the fourth side of the load spreader is spaced apart from the first side to define a gap.
4. The system of claim 1 , wherein the load spreader includes a fourth side connected to the second side, and the fourth side is substantially coplanar with the first side.
5. The system of claim 11 , wherein the flexible portion includes one or more undulations.
6. The system of claim 1 , wherein the undulations comprise a first convex portion coupled to the first side, a second convex portion coupled to the second side and a concave portion that interconnects the first convex portion and the second convex portion.
7. The system of claim 1 , wherein the pin has a first pin end opposite a second pin end, and the second pin end comprises the portion of the perimeter of the pin.
8. The system of claim 7 , wherein the pin further comprises a pin coupling flange at the second pin end, and the pin coupling flange comprises the portion of the perimeter of the pin.
9. The system of claim 8 , wherein the pin further comprises a first pin coupling flange defined between the first pin end and the second pin end, and the first pin coupling flange couples the pin to the bore.
10. The system of claim 1 , wherein the load spreader is received within the pocket.
11. A system for coupling a shroud to a case associated with a gas turbine engine, comprising:
the case defining a bore;
the shroud retained within the case, the shroud defining a pocket;
a pin received through the bore and at least partially positioned within the pocket, the pin having a perimeter, the pin is composed of a first material and the shroud is composed of a second material; and
a load spreader including a first side and a second side opposite the first side, with the first side interconnected to the second side by a flexible portion, the first side, the second side and the flexible portion received about a portion of the perimeter of the pin, the load spreader configured to transmit at least one of an axial point load and a circumferential point load from the pin over a surface of the shroud, the load spreader is composed of a third material, and the first material, the second material and the third material are different.
12. A gas turbine engine, comprising:
a case defining a bore;
a shroud retained within the case, the shroud defining a pocket;
a pin received through the bore and at least partially positioned within the pocket, the pin is composed of a first material and the shroud is composed of a second material; and
a load spreader positioned within the pocket to surround a portion of the pin, the load spreader including a first side, a second side opposite the first side, a flexible portion that interconnects the first side to the second side and a fourth side, at least the first side, the second side and the fourth side configured to contact the portion of the pin to transmit at least one of an axial point load and a circumferential point load from the pin over a surface of the shroud, the load spreader is composed of a third material, and the first material, the second material and the third material are different.
13. The gas turbine engine of claim 12 , wherein the pocket includes a first sidewall, a second sidewall, a third sidewall opposite the first sidewall and a fourth sidewall opposite the second sidewall, the fourth sidewall spaced apart from the first sidewall to define an opening, and the load spreader is positioned within the pocket such that the first side is adjacent to the first sidewall and the second side of the load spreader is adjacent to the third sidewall.
14. The gas turbine engine of claim 12 , wherein the fourth side of the load spreader is substantially co-planar with the first side of the load spreader.
15. The gas turbine engine of claim 12 , wherein the fourth side of the load spreader extends a distance beyond the first side of the load spreader.
16. The gas turbine engine of claim 12 , wherein the fourth side of the load spreader is spaced apart from the first side to define a gap.
17. The gas turbine engine of claim 12 , wherein the bore comprises a plurality of bores defined about a perimeter of the case, the pocket comprises a plurality of pockets defined about a perimeter of the shroud, the pin comprises a plurality of pins and the load spreader comprises a plurality of load spreaders, with each pin of the plurality of pins associated with a respective one of the plurality of the bores, and each load spreader of the plurality of load spreaders is associated with an alternate one of the plurality of pins about the perimeter of the shroud.
18. The gas turbine engine of claim 12 , wherein the flexible portion comprises a first convex portion coupled to the first side, a second convex portion coupled to the second side and a concave portion that interconnects the first convex portion and the second convex portion.
19. The gas turbine engine of claim 12 , wherein the pin has a first pin end opposite a second pin end, the second pin end includes a pin coupling flange, and the pin coupling flange is configured to contact at least the first side, the second side and the fourth side of the load spreader.
20. (canceled)
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US17/077,079 US11326476B1 (en) | 2020-10-22 | 2020-10-22 | Compliant retention system for gas turbine engine |
EP21190451.1A EP3988764B1 (en) | 2020-10-22 | 2021-08-09 | Compliant retention system for gas turbine engine |
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US17/077,079 US11326476B1 (en) | 2020-10-22 | 2020-10-22 | Compliant retention system for gas turbine engine |
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US11326476B1 US11326476B1 (en) | 2022-05-10 |
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US20200157963A1 (en) * | 2018-08-16 | 2020-05-21 | United Technologies Corporation | Machinable coatings fabricated by slurry methods for use on ceramic matrix composites |
US20210025284A1 (en) * | 2019-07-24 | 2021-01-28 | Rolls-Royce Corporation | Turbine shroud with ceramic matrix composite seal segments mounted to metallic carriers |
US20210108531A1 (en) * | 2019-10-09 | 2021-04-15 | Rolls-Royce Corporation | Turbine shroud segment having a seal segment perimeter seal with separated buffer cavities |
US20210148252A1 (en) * | 2019-11-19 | 2021-05-20 | Rolls-Royce North American Technologies Inc. | Turbine shroud cartridge assembly with sealing features |
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EP3988764A1 (en) | 2022-04-27 |
US11326476B1 (en) | 2022-05-10 |
EP3988764B1 (en) | 2023-06-21 |
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