Abstract: A clearance control apparatus for a gas turbine engine including an annular turbine case having opposed inner and outer surfaces; an annular manifold surrounding a portion of the turbine case, the manifold including: an inlet port in fluid communication with the manifold and the outer surface of the turbine case, and an exit port; and a bypass pipe having an upstream end coupled to the exit port, a downstream end coupled to a low-pressure sink, and a valve disposed between upstream and downstream ends, the valve selectively moveable between a first position which blocks flow between the upstream and downstream ends, and a second position which permits flow between the upstream and downstream ends.

Abstract: A turbine blade sealing structure for a ceramic matrix composite component is provided. The turbine sealing structure includes at least one top ply abutting a top portion of a shank. The at least one top ply extends out over the top portion of the shank. The turbine sealing structure includes at least one side ply abutting a side portion of the shank. The at least one side ply extends along a side portion of the shank.

Abstract: An airfoil for a gas turbine engine includes a first sidewall and a second sidewall coupled together at a leading edge and a trailing edge, such that a cavity is defined therebetween. A plurality of cooling circuits are defined within the cavity. Each cooling circuit channels cooling fluid through at least one cooling chamber to facilitate cooling the airfoil. More specifically, a cascade impingement circuit, a down pass circuit, a flag tip circuit, and a trailing edge circuit are provided. The cascade impingement circuit includes a central chamber and a plurality of impingement chambers.

Abstract: A method of assembling a combustion system for a gas turbine engine includes providing a combustion chamber frame, an inner casing structure, and an outer casing structure. The method also includes mounting the combustion chamber frame between the inner casing structure and the outer casing structure such that the combustion chamber frame is coupled to the inner casing structure and the outer casing structure.

Abstract: A turbine shroud apparatus for a gas turbine engine having a central axis includes: an arcuate shroud segment comprising low-ductility material and having a cross-sectional shape defined by opposed forward and aft walls, and opposed inner and outer walls, the walls extending between opposed first and second end faces and collectively defining a shroud cavity; and an annular stationary structure surrounding the shroud segment, where the shroud segment is mechanically coupled to the stationary structure. The stationary structure includes at least one axially-facing bearing surface which is in direct contact with the shroud segment, and the shroud segment is disposed so as to absorb at least one axially-aligned force and transfer the axially-aligned force to the bearing surface.

Abstract: Hybrid components containing a ceramic material, in which detailed features of the components are formed of materials other than ceramic materials, yet result in a robust mechanical attachment of the ceramic and non-ceramic portions of the components. The components includes a first subcomponent formed of a ceramic-based material and a second subcomponent formed of a metallic material. The first subcomponent has a nub and the second subcomponent is separately formed and attached to the first subcomponent by casting the metallic material around the nub of the first subcomponent. The second subcomponent is attached to the first subcomponent by a compression fit and encapsulation of the second subcomponent on the nub of the first subcomponent. The nub has a compliant coating system that provides thermal expansion compliance between the metallic material of the second subcomponent and the ceramic-based material of the first subcomponent.

Abstract: A turbine shroud sealing apparatus for a gas turbine engine includes: (a) an arcuate shroud segment comprising a low-ductility material and having a cross-sectional shape defined by opposed forward and aft walls, and opposed inner and outer walls, the walls extending between opposed first and second end faces of the segment; and (b) a first seal assembly received in at least one slot formed in the first end face, the first seal assembly comprising one or more spline seals which protrude from the first end face and which are arranged to define a continuous sealing surface around the perimeter of the first end face.

Abstract: A turbine shroud apparatus for a gas turbine engine includes an arcuate turbine shroud segment of low-ductility material and having a cross-sectional shape defined by opposed forward and aft walls, and opposed inner and outer walls, the walls extending between opposed first and second end faces. At least a portion of each of the forward and aft walls is oriented at an acute angle to the outer wall. Radially inner ends of the forward and aft walls are substantially closer together than radially outer ends thereof.

Abstract: Processes for producing a component containing a ceramic-based material and having detailed features formed from materials other than ceramic materials. Such a process entails producing the component to include a first subcomponent and at least a second subcomponent having at least one off-axis geometric feature that results in the second subcomponent having a more complex geometry than the first subcomponent. The first subcomponent is formed of a ceramic-based material, and the second subcomponent and its off-axis geometric feature are separately formed of a metallic material and attached to the first subcomponent to yield a robust mechanical attachment. The component may be, for example, a gas turbine airfoil component.

Abstract: A process for producing airfoil components containing ceramic-based materials and having a tip cap. The process entails forming an airfoil portion of the component from an airfoil portion material that contains a precursor of a ceramic-based material. The airfoil portion material defines concave and convex walls of the airfoil portion, and the concave and convex walls define a tip region of the airfoil portion and at least one cavity within the airfoil portion. At least a first ply is formed that contains a precursor of a ceramic-based material, and the first ply at least partially closes the cavity at the tip region of the airfoil portion. The airfoil portion material and the first ply are then cured so that the first ply forms a tip cap that closes the cavity and the precursors of the airfoil portion material and first ply are converted to the ceramic-based materials thereof.

Abstract: A turbine shroud apparatus for a gas turbine engine having a central axis includes: an arcuate shroud segment comprising low-ductility material and having a cross-sectional shape defined by opposed forward and aft walls, and opposed inner and outer walls, the walls extending between opposed first and second end faces and collectively defining a shroud cavity; an annular stationary structure surrounding the shroud segment; and a load spreader received in the shroud cavity of the shroud segment and mechanically coupled to the stationary structure. The load spreader includes: a laterally-extending plate with opposed inner and outer faces; and a boss which protrudes radially from the outer face and extends through a mounting hole in the outer wall of one of the shroud segments. A fastener engages the boss and the stationary structure, so as to clamp the boss against the stationary structure in a radial direction.

Abstract: An airfoil for a gas turbine engine is provided that includes a first sidewall and a second sidewall coupled together at a leading edge and a trailing edge, such that a cavity is defined therebetween. A central plenum and an impingement chamber are defined within the cavity. The central plenum channels cooling fluid to the impingement chamber where cooling fluid impinges on the sidewalls. Cooling fluid is discharged from the impingement chamber via film cooling holes.

Abstract: An airfoil for a gas turbine engine includes a first sidewall and a second sidewall coupled together at a leading edge and a trailing edge, such that a cavity is defined therebetween. A plurality of cooling circuits are defined within the cavity. Each cooling circuit channels cooling fluid through at least one cooling chamber to facilitate cooling the airfoil. More specifically, a cascade impingement circuit, a down pass circuit, a flag tip circuit, and a trailing edge circuit are provided. The cascade impingement circuit includes a central chamber and a plurality of impingement chambers.

Abstract: A rotor blade assembly for a rotor of a gas turbine engine having an axis of rotation includes a shank portion formed from a ceramic matrix composite (CMC) material. The rotor blade assembly also includes a platform portion formed from a substantially similar CMC material as that of the shank portion. The platform portion is coupled to the shank portion. The platform portion and the shank portion cooperate to at least partially define two opposing side portions of the rotor blade assembly. The opposing side portions are angularly separated with respect to the axis of rotation. The rotor blade assembly further includes a damper retention apparatus. The damper retention apparatus is coupled to the shank portion. The damper retention apparatus includes at least one angled bracket apparatus extending toward a circumferentially adjacent rotor blade assembly.

Abstract: A shroud apparatus for a gas turbine engine includes: a shroud segment comprising low-ductility material and having a cross-sectional shape defined by opposed forward and aft walls, and opposed inner and outer walls, the walls extending between opposed first and second end faces, wherein the inner wall defines an arcuate inner flowpath surface, wherein the shroud segment includes: a radially-inward facing chordal forward mounting surface; and a radially-inward facing chordal aft mounting surface; and an annular case surrounding the shroud segment, the case including: a radially-outward facing chordal forward bearing surface which engages the forward mounting surfaces; and a radially-outward facing chordal aft bearing surface which engages the aft mounting surface of the shroud segment.

Abstract: A turbine shroud apparatus for a gas turbine engine having a central axis includes: an arcuate shroud segment comprising low-ductility material and having a cross-sectional shape defined by opposed forward and aft walls, and opposed inner and outer walls, the walls extending between opposed first and second end faces and collectively defining a shroud cavity; an annular stationary structure surrounding the shroud segment; and a load spreader received in the shroud cavity of the shroud segment and mechanically coupled to the stationary structure. The load spreader includes: a laterally-extending plate with opposed inner and outer faces; and a boss which protrudes radially from the outer face and extends through a mounting hole in the outer wall of one of the shroud segments. A fastener engages the boss and the stationary structure, so as to clamp the boss against the stationary structure in a radial direction.

Abstract: A turbine shroud apparatus for a gas turbine engine having a central axis includes: an arcuate shroud segment comprising low-ductility material and having a cross-sectional shape defined by opposed forward and aft walls, and opposed inner and outer walls, the walls extending between opposed first and second end faces and collectively defining a shroud cavity; and an annular stationary structure surrounding the shroud segment, where the shroud segment is mechanically coupled to the stationary structure. The stationary structure includes at least one axially-facing bearing surface which is in direct contact with the shroud segment, and the shroud segment is disposed so as to absorb at least one axially-aligned force and transfer the axially-aligned force to the bearing surface.

Abstract: Hybrid turbine airfoil components containing a ceramic material, in which detailed features of the components are formed of materials other than ceramic materials. The components include a first component formed of a ceramic-based material and a second component formed of a metallic material. The first component comprises an airfoil portion and a nub, and the second component is separately formed and attached to the first component by casting the metallic material around the nub of the first component. The second component includes a platform portion between the airfoil portion and the nub of the first component and a dovetail portion on the nub of the first component. Each of the platform and dovetail portions has at least one off-axis geometric feature that results in the second component having a more complex geometry than the first component.

Abstract: Processes for producing a component containing a ceramic-based material and having detailed features formed from materials other than ceramic materials. Such a process entails producing the component to include a first subcomponent and at least a second subcomponent having at least one off-axis geometric feature that results in the second subcomponent having a more complex geometry than the first subcomponent. The first subcomponent is formed of a ceramic-based material, and the second subcomponent and its off-axis geometric feature are separately formed of a metallic material and attached to the first subcomponent to yield a robust mechanical attachment. The component may be, for example, a gas turbine airfoil component.

Abstract: Hybrid components containing a ceramic material, in which detailed features of the components are formed of materials other than ceramic materials, yet result in a robust mechanical attachment of the ceramic and non-ceramic portions of the components. The components includes a first subcomponent formed of a ceramic-based material and a second subcomponent formed of a metallic material. The first subcomponent has a nub and the second subcomponent is separately formed and attached to the first subcomponent by casting the metallic material around the nub of the first subcomponent. The second subcomponent is attached to the first subcomponent by a compression fit and encapsulation of the second subcomponent on the nub of the first subcomponent. The nub has a compliant coating system that provides thermal expansion compliance between the metallic material of the second subcomponent and the ceramic-based material of the first subcomponent.