Patent Description:
Gas turbine engines typically include a compressor and a turbine. The air is compressed in the compressor. From the compressor the air is introduced into a combustor where it is mixed with fuel and ignited. Products of this combustion pass downstream through a gas path in the turbine. The turbine may include turbine blades that extract energy from the combustion products in the gas path for driving the compressor. An end wall may be utilized to bound the gas path.

<CIT> discloses a turbine vane assembly incorporating ceramic matrix composite materials and cooling.

An assembly for a gas turbine engine according to an aspect of the present invention is provided in accordance with claim <NUM>.

Optionally, and in accordance with the above, the airfoil includes a fairing integrally formed with the end wall, and both the fairing and the end wall comprise a ceramic matrix composite (CMC) material.

Optionally, and in accordance with any of the above, the assembly further comprises a spring member dimensioned to bias the first end portion of the endwall radially outwardly relative to the assembly axis.

Optionally, and in accordance with any of the above, the static structure includes a case dimensioned to extend circumferentially about the end wall relative to the assembly axis. The end wall is attachable to the case at the first attachment point. The first end portion of the spar member is attachable to the case at the second attachment point, and the second attachment point is axially spaced apart from the first attachment point relative to the assembly axis.

Optionally, and in accordance with any of the above, the end wall includes a flange that extends radially outwardly from the first end portion of the end wall relative to the assembly axis, and the flange is dimensioned to establish a spline interface with the first end portion of the spar member.

Optionally, and in accordance with any of the above, the airfoil includes a fairing. The fairing includes an airfoil section extending from a platform section, and the platform section radially opposes the end wall with respect to assembly axis.

Optionally, and in accordance with any of the above, the end wall includes a circumferential face dimensioned to at least partially surround an outer periphery of the airfoil section.

Optionally, and in accordance with any of the above, the fairing is integrally formed with the end wall.

Optionally, and in accordance with any of the above, the spar member includes an inner cavity dimensioned to convey cooling flow from a coolant source to a plenum radially inwardly of the platform section relative to the assembly axis.

Optionally, and in accordance with any of the above, the airfoil section is moveable relative to the spar member.

Optionally, and in accordance with any of the above, the assembly further comprises a spring plate and a seal member captured between the spring plate and the end wall to establish a sealing relationship with an outer periphery of the airfoil section.

Optionally, and in accordance with any of the above, the airfoil is a turbine vane, and the rotatable blade is a turbine blade.

A gas turbine engine according to another aspect of the present invention is provided in accordance with claim <NUM>.

Optionally, and in accordance with the above, each of the arc segments comprises a ceramic material.

Optionally, and in accordance with any of the above, the arc segments are moveable in a radial direction relative to the spar members with respect to the longitudinal axis.

Optionally, and in accordance with any of the above, each of the spar members includes an inner cavity dimensioned to convey cooling flow from a coolant source to a plenum radially inward of the respective vane relative to the longitudinal axis.

Optionally, and in accordance with any of the above, each of the vanes includes an airfoil section and a platform section that bounds the gas path, the airfoil section extending radially between the platform section and the respective arc segment relative to the longitudinal axis.

Optionally, and in accordance with any of the above, the airfoil section is integrally formed with the main body of a respective one of the arc segments.

Optionally, and in accordance with any of the above, the gas turbine engine further comprises at least one spring member dimensioned to bias a first end portion of the respective one of the arc segments radially outwardly relative to the longitudinal axis. The at least one spring member is dimensioned to provide a radial reaction force that is between approximately <NUM> percent and approximately <NUM> percent of a peak total radial aerodynamic load acting on the respective one of the arc segments and a respective one of the vanes axially forward of the first attachment portion relative to the longitudinal axis in operation.

Optionally, and in accordance with any of the above, the gas turbine engine further comprises a plurality of seal members dimensioned to establish a sealing relationship with an outer periphery of a respective one of the airfoil sections. Each of the arc segments extends in a circumferential direction between a first mate face and a second mate face. The first mate face is dimensioned to establish an intersegment gap with the second mate face of an adjacent one of the arc segments, and the first and second mate faces includes respective slots dimensioned to receive a respective one of the seal members such that the seal member spans across the intersegment gap.

Optionally, and in accordance with any of the above, each of the arc segments includes a plurality of openings, and each of the openings is dimensioned to at least partially receive a spar body of a respective one of the spar members and the airfoil section of a respective one of the vanes such that the arc segment is radially aligned with at least two of the spar members and at least two of the vanes relative to the longitudinal axis.

The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description.

The engine parameters described above and those in this paragraph are measured at this condition unless otherwise specified. The low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about <NUM>, or more narrowly greater than or equal to <NUM>. The "Low corrected fan tip speed" as disclosed herein according to one non-limiting embodiment is less than about <NUM> ft / second (<NUM> meters/second), and can be greater than or equal to <NUM> ft / second (<NUM> meters/second).

<FIG> illustrates an exemplary section <NUM> for a gas turbine engine. The section <NUM> may be incorporated into the gas turbine engine <NUM> of <FIG>, such as the compressor section <NUM> or turbine section <NUM>. Other portions of the gas turbine engine <NUM> and other systems may benefit from the teachings disclosed herein, including gas turbine engines lacking a fan for propulsion.

The section <NUM> can include a rotor <NUM> carrying one or more rotatable airfoils or blades <NUM>. The blades <NUM> are rotatable about a longitudinal (or assembly) axis LA. The longitudinal axis LA can be collinear with or otherwise parallel to the engine axis A of <FIG>.

Each blade <NUM> can include a platform section 62P and an airfoil section 62A extending in a radial direction R from the platform section 62P to a tip 62T. The airfoil section 62A generally extends in a chordwise or axial direction X between a leading edge 62LE and a trailing edge 62TE. A root section 62R of the airfoil <NUM> can be mounted to, or can be integrally formed with, the rotor <NUM>.

The section <NUM> can include an airfoil or static vane <NUM> situated adjacent the blade <NUM>. The vane <NUM> can be a turbine vane and the rotatable blade <NUM> can be a turbine blade incorporated into the turbine section <NUM>, for example. Each vane <NUM> can include an airfoil section 63A and a platform section 63P. The airfoil section 63A can extend radially between a first end portion 63B and a second end portion 63C. The airfoil section 63A can be dimensioned to extend in the radial direction R from the platform section 63P. The airfoil section 63A generally extends in the chordwise direction X between a leading edge 63LE and trailing edge 63TE.

The section <NUM> can include a flow path (or endwall) assembly <NUM>. The assembly <NUM> can be arranged to bound and establish sealing relationships along flowpaths, with non-rotating or static components such as static vanes, and/or rotating components including rotatable airfoils and bladed disks, for example. The turbine section and other portions of the engine can benefit from the teachings disclosed herein, including the compressor section, combustor section, mid-turbine frame and exhaust nozzle.

The assembly <NUM> can include one or more end walls <NUM> that extend in a circumferential or thickness direction T at least partially or completely about the longitudinal axis LA to bound a gas path GP. The gas path GP may be a portion of the core flow path C of <FIG>, for example. The end wall <NUM> may be coupled to, or integrally formed with, one or more of the vanes <NUM>.

The end wall <NUM> may include one or more arc segments <NUM>. Each arc segment <NUM> may include a main body 68A that extends between a first end (e.g., leading edge) portion 68B and a second end (e.g., trailing edge) portion 68C to establish a seal face <NUM> dimensioned to bound the gas path GP. The seal face <NUM> can have a substantially arcuate geometry, as illustrated in <FIG>, or another geometry such as a generally planar profile.

Each arc segment <NUM> can be spaced radially outwardly from the tip 62T of the adjacent blades <NUM> to serve as a blade outer air seal (BOAS). The seal face <NUM> can be dimensioned to establish a clearance gap CG with the tip 62T of each of the blades <NUM> along the gas path GP. The tip 62T of each blade <NUM> and each adjacent arc segment <NUM> can be arranged in close proximity to reduce the amount of gas flow that is redirected toward and over the tip 62T through the corresponding clearance gap CG during engine operation.

The airfoil section 63A of the vane <NUM> may extend radially between the platform section 63P and the respective arc segment <NUM> relative to the longitudinal axis LA. For example, at least the airfoil section 63A of each of the vanes <NUM> may be dimensioned to extend radially inwardly from the seal face <NUM> of the respective arc segment <NUM> relative to the longitudinal axis LA such that the airfoil section 63A extends at least partially or completely across the gas path GP to the platform section 63P.

The arc segments <NUM> may be arranged to radially oppose the platform section 62P of the blades <NUM> and/or the platform section 63P of the vanes <NUM> to bound the gas path GP. For example, the arc segments <NUM> may be arranged to bound an outer periphery of the gas path GP, and the platform section 63P of the vane <NUM> may bound an inner periphery of the gas path GP such that the platform section 63P radially opposes the seal face <NUM> of the arc segment <NUM>.

The section <NUM> can include an array of blades <NUM>, an array of vanes <NUM>, and an array of arc segments <NUM> arranged circumferentially about the longitudinal axis LA. The array of vanes <NUM> can be situated adjacent to the array of blades <NUM>. The array of arc segments <NUM> can be arranged circumferentially about the array of blades <NUM> and array of vanes <NUM> relative to the longitudinal axis LA. The arc segments <NUM> can be circumferentially distributed in an annulus about the array of the blades <NUM> and array of vanes <NUM> to bound the gas path GP.

Various techniques may be utilized to position the vanes <NUM> relative to the end wall <NUM>. The first end portion 63B of the vane <NUM> may be positioned adjacent to the respective arc segment <NUM> of the end wall <NUM>. The arc segment <NUM> can include one or more openings 68O in the main body 68A. The opening 68O can be dimensioned to at least partially receive the airfoil section 63A of a respective vane <NUM>. For example, the airfoil section 63A of the vane <NUM> may be moved in a direction D1 through the opening 68O such that the first end portion 63B of the vane <NUM> is situated radially outward of the seal face <NUM> of the arc segment <NUM>. The direction D1 may be substantially parallel to the radial direction R. The opening 68O may be dimensioned to substantially complement a geometry of an outer periphery 63OP of the airfoil section 63A of the vane <NUM> (see also <FIG>). For the purposes of this disclosure, the terms "substantially" and "approximately" mean ±<NUM> percent of the stated value or relationship unless otherwise indicated.

Various techniques may be utilized to secure the arc segments <NUM> of the end wall <NUM> to a static structure. The static structure may be a portion of the gas turbine engine <NUM> of <FIG>, such as the engine static structure <NUM>. The section <NUM> may include an annular housing or case <NUM> dimensioned to extend about the longitudinal axis LA. The case <NUM> may form a portion of the static structure <NUM>. The case <NUM> may be a turbine case in the turbine section <NUM>, or may be a separate case at least partially surrounded by the turbine case, for example. The case <NUM> may be dimensioned to extend circumferentially about the arc segments <NUM> of the end wall <NUM> relative to the longitudinal axis LA.

The arc segments <NUM> may be fixedly attached or otherwise secured to the case <NUM> or static structure <NUM> at a respective first attachment point P1. Each of the arc segments <NUM> may include at least one or more first attachment portions 68AP for securing the end wall <NUM>. The first attachment portion 68AP may be dimensioned to fixedly attach or otherwise secure the main body 68A of the arc segment <NUM> to the static structure at the first attachment point P1. The first attachment portion 68AP may be dimensioned to fixedly attach the arc segment <NUM> to the case <NUM>.

The first attachment portion 68AP of the arc segment <NUM> can include one or more rails 68R. Each rail 68R can extend radially outwardly from the main body 68A of the arc segment <NUM>. The case <NUM> may include one or more mounting rails 67R that extend radially inwardly from the main body 67A of the case <NUM>. The mounting rails 67R can be dimensioned to cooperate with the rails 68R of the arc segment <NUM> to secure the arc segment <NUM> to the case <NUM>. One or more fasteners <NUM> can be positioned in a set of bores in the rails 67R and 68R to secure the arc segment <NUM> to the case <NUM>. A retaining plate <NUM> may be positioned to trap or otherwise secure the fastener <NUM> in the installed position.

The first attachment portion 68AP of each of the arc segments <NUM> can be fixedly attached or otherwise secured to the case <NUM> or static structure <NUM> at the first attachment point P1 such that the first end portion 68B of the arc segment <NUM> is cantilevered from the first attachment point P1, as illustrated in <FIG>. Each portion of the main body 68A of the arc segment <NUM> axially forward of the first attachment portion 68AP relative to the longitudinal axis LA can be cantilevered from the first attachment point P1.

Cantilevering the arc segment <NUM> at the first attachment point P1 can be established at a predetermined position relative to a dimension of the arc segment <NUM>. The arc segment <NUM> can extend axially between terminal ends of the first and second end portions 68B, 68C to establish a first length L1 relative to the longitudinal axis LA. The first attachment point P1 can be established at a second length L2 from the terminal end of the first end portion 68B relative to the longitudinal axis LA. The first and second lengths L1, L2 can be established with respect to an axial position along the seal face <NUM> of the arc segment <NUM>. The length L2 can be established at an axially forwardmost portion of the first attachment point P1 in which the main body 68A of the arc segment <NUM> is cantilevered. A ratio of L2:L1 can be less than or equal to <NUM>, or more narrowly less than or equal to <NUM>. The ratio of L2:L1 can be greater than or equal to <NUM>.

Various techniques may be utilized to construct each of the vanes <NUM>. Each of the vanes <NUM> can include a fairing 63F that establishes the airfoil section 63A and platform section 63P. Surfaces of the fairing 63F can establish an aerodynamic contour of the airfoil section 63A and a gas path surface of the platform section 63P. The fairing 63F can be constructed such that the airfoil section 63A is integrally formed with the platform section 63P.

The fairing 63F can include an inner cavity 63D (see also <FIG>). The inner cavity 63D can be dimensioned to extend radially between the first end portion 63B and the second end portion 63C of the respective vane <NUM>.

The case <NUM> may experience thermal growth due to relatively hot gases communicated in the adjacent gas path GP. The case <NUM> can be coupled to an active clearance control (ACC) system (shown in dashed lines for illustrative purposes) for positioning the case <NUM> relative to the longitudinal axis LA and/or static structure <NUM> during engine operation. The case <NUM> may include one or more control rails 67C that extend radially outwardly from a main body 67A of the case <NUM>. The ACC system can be coupled to the control rails 67C. The ACC system can be operable to move the case <NUM> in the radial direction R during engine operation to vary and/or maintain a predetermined dimension of the clearance gap CG between each of the seal faces <NUM> and the tips 62T of the blades <NUM>. One would understand how to configure the system ACC with logic to vary a position of the case <NUM> in accordance with the teachings disclosed herein. In other implementations, the case <NUM> forms a portion of the static structure <NUM> or is arranged at a fixed position relative to the static structure <NUM>.

The assembly <NUM> can include an array of spar members <NUM> secured or positioned in respective fairings 63F of the vanes <NUM>. The spar members <NUM> can be fixedly attached or otherwise secured to the case <NUM> or static structure <NUM>. Each of the spar members <NUM> can include a spar (or main) body 72A extending radially between a first end portion 72B and second end portion 72C. The spar body 72A can be dimensioned to extend at least partially through the inner cavity 63D of the respective vane <NUM>, as illustrated in <FIG>. A respective opening 68O of the arc segment <NUM> can be dimensioned to at least partially receive the spar body 72A of a respective spar member <NUM>. For example, the spar member <NUM> can be movable in a direction D3 such that each opening 68O at least partially receives the spar body 72A of a respective spar member <NUM>. The direction D3 can be substantially parallel to a radial direction R, and can be substantially opposed to direction D1. The spar member <NUM> can be situated relative to the opening 68O prior or subsequent to positioning the respective airfoil section 63A of the vane <NUM> in the opening 68O. The arc segment <NUM> can be moved together with the respective vane(s) <NUM> and spar member(s) <NUM> as a unit to situate the unit in a predetermined position relative to the static structure <NUM>.

Various techniques can be utilized to secure the spar members <NUM> to the static structure <NUM>. The first end portion 72B of the spar member <NUM> can be attachable to the case <NUM> or another portion of the static structure <NUM> at a second attachment point P2. Each spar member <NUM> can include a second attachment portion 72D extending outwardly from the first end portion 72B of the spar member <NUM>. The second attachment portion 72D can be dimensioned to cooperate with the case <NUM> or another portion of the static structure <NUM> to establish the second attachment point P2. The second attachment portion 72D can include one or more hooks <NUM> dimensioned to cooperate with one or more respective hooks <NUM> of the case <NUM>.

The second attachment point P2 can be axially spaced apart from the first attachment point P1 relative to the assembly axis LA. The second attachment portion 72D can be established at the first end portion 72B of the spar member <NUM> such that the second attachment point P2 is axially between a terminal end (e.g., leading edge) of the first end portion 68B and the first attachment portion 68AP of the arc segment <NUM> such that the first end portion 68B of the arc segment <NUM> of the end wall <NUM> is cantilevered from the first attachment point P1, as illustrated in <FIG>.

The spar members <NUM> can be non-structural components or can be structural components dimensioned to support the respective fairings 63F and/or a portion of the section <NUM> radially inward of the vane <NUM> to establish a load path with the case <NUM> or static structure <NUM>. The second end portion 72C of the spar member <NUM> can be fixedly attached or otherwise secured to an annular housing <NUM> with one or more fasteners F. The housing <NUM> can be a full circumferential hoop or can include one or more segments fastened to the respective spar members <NUM>. The housing <NUM> can be dimensioned to abut the fairing 63F to limit movement of fairing 63F relative to the longitudinal axis LA. The housing <NUM> can be utilized to interconnect the array of spar members <NUM>. The housing <NUM> can be dimensioned to support one or more of the bearing systems <NUM> (<FIG>). In other examples, the spar member <NUM> can be cantilevered from the case <NUM>.

The main body 72A of each spar member <NUM> can be an elongated hollow strut or conduit dimensioned to convey fluid such as coolant or lubricant to an adjacent portion of the section <NUM>. Each spar member <NUM> can include an inner cavity 72E dimensioned to convey the fluid. The inner cavity 72E can be dimensioned to extend radially through a thickness of the main body 72A between the first end portion 72B and second end portion 72C of the spar member <NUM>.

The inner cavity 72E of the spar member <NUM> can be dimensioned to interconnect a first plenum <NUM> and a second plenum <NUM>. The first plenum <NUM> can be radially outward of the gas path GP, and the second plenum <NUM> can be radially inward of the gas path GP, as illustrated in <FIG>. The first and second plenums <NUM>, <NUM> can extend generally in the circumferential direction T. The first plenum <NUM> can be bounded between surfaces of the case <NUM> and end wall <NUM>. The second plenum <NUM> can be radially inward of, and can be bounded by, a radially inner (e.g., cold side) surface of the platform section 63P.

The first plenum <NUM> and/or inner cavity 72E can be coupled to a coolant source CS (shown in dashed lines in <FIG> for illustrative purposes). The coolant source CS can be configured to supply or convey pressurized cooling flow to cool portions of the section <NUM> including the case <NUM> and each vane <NUM>. The coolant source CS can include bleed air from an upstream stage of the compressor section <NUM> (<FIG>), bypass air, or a secondary cooling system aboard the aircraft, for example. The inner cavity 72E of the spar member <NUM> can be dimensioned to convey fluid from the coolant source CS, either directly or from the first plenum <NUM>, to the second plenum <NUM>. The second plenum <NUM> can be dimensioned to convey fluid from the inner cavity 72E to a seal arrangement adjacent the gas path GP and/or a bearing compartment of one of the bearing systems <NUM> (<FIG>), for example.

The spar member <NUM> may be positioned in the arc segment <NUM> and vane <NUM>, which may be rotated as a unit in a rotational direction R1 about the longitudinal axis LA to clock or otherwise mount each hook <NUM> to the respective hook <NUM>. Thereafter, the spar member <NUM> may be fixedly attached or otherwise secured to the housing <NUM> with the fastener(s) F, and each fastener <NUM> can be positioned to fixedly attach or otherwise secure the rails 68R to the rails 67R. In other examples, the spar member <NUM> can be moved in a direction D2 to mount the hooks <NUM> to the hooks <NUM> of the case <NUM>. The direction D2 can be substantially parallel to the longitudinal axis LA.

Referring to <FIG> and <FIG>, the assembly <NUM> can include an indexing feature to limit relative circumferential movement between the arc segments <NUM> and spar members <NUM> with respect to the longitudinal axis LA. Each arc segment <NUM> can include one or more flanges 68F. Each flange 68F can be dimensioned to extend radially outward from the first end portion 68B of the arc segment <NUM> relative to the assembly axis LA. Each spar member <NUM> can include one or more flanges 72F. Each flange 72F can extend from the first end portion 72B of the spar member <NUM>. Each flange 68F may be dimensioned to establish a spline interface with a respective one of the flanges 72F to limit relative circumferential movement between the arc segment <NUM> and the respective spar member <NUM>. Limiting circumferential movement may reduce leakage of cooling flow through intersegment gaps established by mate faces <NUM> (<FIG>) of adjacent arc segments <NUM> (see also <FIG> and <FIG>).

Various materials may be incorporated into the assembly <NUM> to establish the vanes <NUM>, arc segments <NUM> of the end wall <NUM>, and spar members <NUM>, including metallic and/or non-metallic materials. The spar members <NUM> may be formed of a metallic material, such as a high temperature metal or superalloy or a metal matrix composite. Each of the arc segments <NUM> and fairing 63F can comprise a ceramic material, such as a monolithic ceramic or a ceramic matrix composite (CMC) material. A CMC material can be utilized to establish the airfoil section 63A and/or platform section 63P of the vane <NUM>. The CMC materials disclosed herein can include continuous or discontinuous fibers in a matrix arranged in one or more layers to establish a CMC layup. In other examples, the vanes <NUM> are made of a metallic material, including any of the materials disclosed herein.

Various techniques can be utilized to establish a sealing relationship between the arc segment <NUM> and the outer periphery 63OP of the vane <NUM> to limit fluid flow between the first plenum <NUM> and the gas path GP, which can reduce cooling flow demands and improve efficiency. Referring to <FIG>, with continuing reference to <FIG>, the assembly <NUM> can include one or more seal members <NUM>, one or more spring members <NUM>, and one or more spring plates <NUM>. The seal member <NUM> can be a rope seal, for example, and can be made of any of the materials disclosed herein, including a ceramic fiber material available under the trade name Nextel and metallic sheathed Nextel. The seal member <NUM> can be captured between the spring plate <NUM> and the main body 68A of the arc segment <NUM> to establish a sealing relationship with the outer periphery 63OP of the airfoil section 63A. The spring plate <NUM> can have a generally L-shaped cross-sectional geometry including a circumferential lip to capture an end portion of the spring member <NUM>. The seal member <NUM>, spring plate <NUM> and/or spring member <NUM> can be dimensioned to extend at least partially or completely about the outer periphery 63OP of the vane <NUM>, as illustrated in <FIG>.

The airfoil section 63A of the vane <NUM> and spar member <NUM> may be movable relative to each other during engine operation. The arc segment <NUM> and/or vane <NUM> may be movable in the radial direction R relative to the spar member <NUM> with respect to the longitudinal axis LA, which may occur due to thermal growth of the case <NUM> and/or movement of the case <NUM> in response to actuation of the system ACC (<FIG>). The spring member <NUM> can be dimensioned to bias or seat the spring plate <NUM> and seal member <NUM> against the main body 68A of the arc segment <NUM> to establish and maintain the sealing relationship.

<FIG> illustrates an exemplary section <NUM> including a flowpath assembly <NUM> for a gas turbine engine. In this disclosure, like reference numerals designate like elements where appropriate and reference numerals with the addition of one-hundred or multiples thereof designate modified elements that are understood to incorporate the same features and benefits of the corresponding original elements.

The assembly <NUM> can include an end wall <NUM> including an array of arc segments <NUM>, an array of vanes <NUM> and an array of spar members <NUM>. A first end portion 172B of each spar member <NUM> can be fixedly attached or otherwise secured to case <NUM> with one or more fasteners F at a second attachment point P2. A main body 172A of the spar member <NUM> can be moveable in the direction D3 at least partially through a respective opening <NUM> in the case <NUM> towards the longitudinal axis LA such that a second end portion 172C of the spar member <NUM> is at least partially received in and/or extends through a cavity 163D of the vane <NUM>.

The assembly <NUM> can include an indexing feature to limit relative circumferential movement between the respective arc segment <NUM> and case <NUM> with respect to the longitudinal axis LA. Each arc segment <NUM> can include one or more flanges 168F. The flange 168F can extend radially outward from a main body 168A of the arc segment <NUM>. The case <NUM> can include one or more flanges 167F. The flange 167F can extend radially inward from a main body 167A of the case <NUM>. Each flange 168F can be dimensioned to establish a spline interface with a respective one of the flanges 167F to limit relative circumferential movement between the arc segment <NUM> and the case <NUM>.

The assembly <NUM> can include one or more seal members <NUM>, one or more spring members <NUM>, and one or more spring plates <NUM>. The seal member <NUM> can be captured between the spring plate <NUM> and the main body 168A of the arc segment <NUM> to establish a sealing relationship with an outer periphery 163OP of the airfoil section 163A of the respective vane <NUM>. The spring member <NUM> can extend between the main body 167A of the case <NUM> and the spring plate <NUM> to bias or seat the spring plate <NUM> and seal member <NUM> against the main body 168A of the arc segment <NUM>.

The spar member <NUM> can include one or more passages 172P extending through a thickness of the main body 172A to interconnect a first plenum <NUM> and an inner cavity 172E of the spar member <NUM>. The passages 172P can serve as inlet holes and can be dimensioned to convey fluid such as cooling flow from a coolant source CS to the inner cavity 172E. The inner cavity 172E can be dimensioned to convey the fluid to a second plenum <NUM>.

<FIG> illustrates an exemplary section <NUM> including a flowpath assembly <NUM> for a gas turbine engine. The assembly <NUM> can include an end wall <NUM> including an array of arc segments <NUM>, an array of vanes <NUM> and an array of spar members <NUM>. A main body 272A of the spar member <NUM> can be moveable in a direction D3 at least partially through a respective opening 267O in a case <NUM> towards the longitudinal axis LA such that a second end portion 272C of the spar member <NUM> is at least partially received in and/or extends through a cavity 263D of the vane <NUM>.

The spar member <NUM> can include a second attachment portion 272D dimensioned to mechanically attach or otherwise secure the spar member <NUM> to the case <NUM>. The second attachment portion 272D can be a flange established along a first end portion 272B of the spar member <NUM>. The second attachment portion 272D can be fixedly attached or otherwise secured to the case <NUM> with one or more fasteners F at the second attachment point P2.

The second attachment portion 272D of the spar member <NUM> can be mechanically attached or otherwise secured to a respective conduit (e.g., cooling pipe) <NUM> with one or more of the fasteners F. The conduit <NUM> can be fluidly coupled to a coolant source CS. The conduit <NUM> can be dimensioned to convey fluid from the coolant source CS to an inner cavity 272E of the spar member <NUM>.

Each arc segment <NUM> can include a first attachment portion 268AP dimensioned to be fixedly attached or otherwise secured to the case <NUM> or static structure <NUM> at a first attachment point P1. The first attachment portion 268AP can include one or more interface members 268I. Each interface member 268I can be dimensioned in the shape of an elongated hollow box extending in a circumferential or thickness direction T. The first attachment portion 268AP can include one or more recesses or openings 268O. The openings 268O can be established in the interface members 268I. The case <NUM> can include one or more hooks 267HB extending inwardly from the main body 267A of the case <NUM>. Each opening 268O can be dimensioned to at least partially receive a respective hook 267HB to secure the arc segment <NUM> to the case <NUM>. The arc segment <NUM> can be moved in a direction D4 to mount the hooks 267HB in the openings 268O. The direction D4 can be substantially parallel to the longitudinal axis LA.

<FIG> illustrates an exemplary flowpath assembly <NUM> for a gas turbine engine. The flowpath assembly <NUM> can be incorporated into any of the flowpath assemblies and sections disclosed herein. The assembly <NUM> can include a seal member <NUM>, spring member <NUM>, and spring plate <NUM>. The seal member <NUM> can be captured between the spring plate <NUM> and a main body 368A of the arc segment <NUM> to establish a sealing relationship with an outer periphery 363OP of an airfoil section 363A of a respective vane <NUM>.

The seal member <NUM> can be a wedge seal having a sloped face 374SF dimensioned to interface with a sloped face 368SF along the main body 368A of the arc segment <NUM> to establish a sealing relationship. The seal member <NUM> can have a unitary construction or can include one or more segments joined together. Various materials can be utilized to form the seal member <NUM>, such as a ceramic matrix composite material, a nickel or cobalt based superalloy material, or a Nextel material with a superalloy jacket. The spring member <NUM> is dimensioned to seat or bias the sloped face 374SF of the seal member <NUM> against the sloped face 368SF of the arc segment <NUM> such that the seal member <NUM> is urged against the outer periphery 363OP of the vane <NUM> to establish a sealing relationship.

<FIG> illustrates an exemplary flowpath assembly <NUM> for a gas turbine engine. The flowpath assembly <NUM> can be incorporated into any of the flowpath assemblies and sections disclosed herein. The assembly <NUM> can include a plurality of seal members <NUM> to establish primary and secondary sealing relationships with an outer periphery 463OP of a respective vane <NUM> to limit fluid flow between a first plenum <NUM> and a gas path GP. The seal members <NUM> can include a first (e.g., primary) seal member <NUM>-<NUM> and a second (e.g., secondary) seal member <NUM>-<NUM>. The first seal member <NUM>-<NUM> can be a rope seal, and the second seal member <NUM>-<NUM> can be a wedge seal, for example. The first seal member <NUM>-<NUM> can have a relatively lesser stiffness, rigidity and/or conformance than the second seal member <NUM>-<NUM>, and may be be utilized without pressure matching to situate the first seal member <NUM>-<NUM>.

A spring member <NUM> can be dimensioned to seat or bias a sloped face 474SF of the seal member <NUM>-<NUM> against a sloped face 468SF of the arc segment <NUM> such that the seal member <NUM>-<NUM> is urged against the outer periphery 463OP of the vane <NUM> to establish a sealing relationship. Biasing the seal member <NUM>-<NUM> inwardly can cause the seal member <NUM>-<NUM> to seat against a main body 468A of the arc segment <NUM> to establish a sealing relationship. The first seal member <NUM>-<NUM> can be trapped between the main body 468A of the arc segment <NUM> and the second seal member <NUM>-<NUM> such that biasing the seal member <NUM>-<NUM> inwardly causes the first seal member <NUM>-<NUM> to seat against the main body 468A of the arc segment <NUM>.

<FIG> illustrates an exemplary section <NUM> including a flowpath assembly <NUM>. The assembly <NUM> can include an end wall <NUM> including an array of arc segments <NUM>, an array of vanes <NUM> and an array of spar members <NUM>.

Portions of each vane <NUM> can be integrally formed with the end wall <NUM>. Each vane <NUM> can include a fairing 563F that establishes an airfoil section 563A and a platform section 563P of the vane <NUM>. The airfoil section 563A can be integrally formed with a main body 568A of a respective one of the arc segments <NUM>. Each arc segment <NUM> can be integrally formed with a first end section 563B established by the fairing 563F of one or more vanes <NUM>, which may be utilized such that a separate seal member to seal along an outer periphery 563OP of the vane <NUM> can be omitted thereby reducing complexity and leakage. the fairing 563F and arc segments <NUM> can be made of any of the materials disclosed herein, including ceramic materials such as a CMC material.

The section <NUM> can include an arcuate housing <NUM> dimensioned to extend about the array of arc segments <NUM>. The housing <NUM> can have a generally rectangular cross sectional geometry. The housing <NUM> can include an inner cavity (or plenum) 581C coupled to a coolant source CS. The inner cavity 581C can be dimensioned to interconnect the coolant source CS and an inner cavity 572E' of one or more of the spar members <NUM> of the end wall <NUM>, as illustrated by the cooling scheme of <FIG>. In other examples, the housing <NUM> is omitted and the inner cavity 572E of the spar member <NUM> is coupled to the coolant source CS through the plenum <NUM>.

Each arc segment <NUM> can include one or more flanges 668F. Each flange 668F may extend outwardly from a main body 668A of the arc segment <NUM>. The section <NUM> can include a housing <NUM> fixedly attached or otherwise secured to static structure <NUM>. The housing <NUM> can be fixed attached to case <NUM> utilizing one or more fasteners F. The housing <NUM> can include one or more flanges 682F moveable in a direction D2 and at least partially into a passage (or opening) 668P of the flange 668F such that each flange 682F axially overlaps or otherwise opposes the flange 668F of a respective one of the arc segments <NUM>. The passage 668P can be dimensioned to limit or permit relative radial and/or circumferential movement between the flange 668F and flange 682F relative to the longitudinal axis LA.

The assembly <NUM> can include one or more spring members <NUM> trapped or otherwise positioned between an opposing pair of the flanges 668F, 682F. The spring member <NUM> can be dimensioned to extend circumferentially about the longitudinal axis LA. The spring member <NUM> can be contiguous or can include one or more segments. Each spring member <NUM> can be dimensioned to bias the first end portion 668B of the arc segment <NUM> radially outward relative to the longitudinal axis LA. The spring member <NUM> can serve to provide a predetermined amount of radial stiffness to a cantilevered portion of the arc segment <NUM>. The predetermined amount of radial stiffness may correspond to a predetermined spring bias of the spring member <NUM>. The radial stiffness feature can reduce bending and can reduce variation in a distance between a seal face <NUM> of the arc segment <NUM> and the longitudinal axis LA, which can improve efficiency by reducing variation of a clearance gap CG established between the seal face <NUM> and airfoils <NUM>. The predetermined spring bias of the spring member <NUM> can be selected such that the spring member <NUM> provides a radial reaction force that is between approximately <NUM> percent and approximately <NUM> percent of a peak total radial aerodynamic load acting on the arc segment <NUM> and vane <NUM> axially forward of the first attachment portion 668AP relative to the longitudinal axis LA in operation.

<FIG> illustrates an exemplary section <NUM> including a flowpath assembly <NUM> for a gas turbine engine. The assembly <NUM> can include an array of vanes <NUM>, an array of spar members <NUM>, and an end wall <NUM> including an array of arc segments <NUM>. An array of rotatable airfoils or blades <NUM> are shown in dashed lines for illustrative purposes. Each arc segment <NUM> can accommodate various quantities of airfoil sections 763A and spar bodies 772A of the spar members <NUM>, including only one airfoil section 763A and/or only one spar body 772A, or more than one airfoil section 763A and/or more than one spar body 772A, such as a quantity of <NUM>, <NUM>, <NUM>, or even more airfoil sections 763A and spar bodies 772A. Each arc segment <NUM> can be axially and circumferentially aligned with one or more airfoil sections 763A of the vanes <NUM> and/or one or more spar bodies 772A of the spar members <NUM> relative to a longitudinal axis LA, including any of the quantities disclosed herein, such as two airfoil sections 763A and two spar bodies 772A as illustrated in <FIG>. Each arc segment <NUM> can have two or more spar members <NUM> passing through a main body 768A of the arc segment <NUM>. The arc segment <NUM> can be coupled to the vanes <NUM>. The arc segments <NUM> can be integrally formed with one or more adjacent vanes <NUM> or can be separate and distinct components. For example, each arc segment <NUM> can include two or more openings 768O (shown in dashed lines for illustrative purposes) established in a main body 768A of the arc segment <NUM>. Each of the openings 768O can be dimensioned to at least partially receive a respective airfoil section 763A and spar body 772A such that the arc segment <NUM> is radially aligned with at least two vanes <NUM> and at least two spar members <NUM> relative to the longitudinal axis LA. The array of arc segments <NUM> can be axially aligned with a single row of the vanes <NUM> and a single row of the blades <NUM>, as illustrated in <FIG>. The first end portion 768B of the arc segment <NUM> can be positioned axially aft of at least one row of the rotatable blades <NUM> in the section <NUM>.

Each of the arc segments <NUM> can extend in a circumferential or thickness direction T between a first mate face <NUM>-<NUM> and a second mate face <NUM>-<NUM>. The first mate face <NUM>-<NUM> can be dimensioned to establish an intersegment gap IG with the second mate face <NUM>-<NUM> of an adjacent one of the arc segments <NUM>. In an assembled position, the first mate face <NUM>-<NUM> circumferentially opposes an adjacent second mate face <NUM>-<NUM>. At least the airfoil section 763A of each vane <NUM> can be circumferentially offset from the mate faces <NUM> of the respective arc segment <NUM>.

The assembly <NUM> can include one or more seal members <NUM> dimensioned to establish a sealing relationship along the intersegment gap IG between the mate faces <NUM>-<NUM>, <NUM>-<NUM> of opposed arc segments <NUM>. The seal member <NUM> can be a feather seal having a generally rectangular or planar geometry, as illustrated in <FIG>. The seal member <NUM> can comprise any of the materials disclosed herein, including metallic and ceramic matrix composite (CMC) materials. The mate faces <NUM>-<NUM>, <NUM>-<NUM> can include respective slots <NUM> dimensioned to receive a respective one of the seal members <NUM> such that the seal member <NUM> spans across the intersegment gap IG to establish a sealing relationship. The assembly <NUM> of <FIG> can be utilized to reduce a total number of intersegment gaps IG established by the end wall <NUM> (e.g., at least half), which can reduce leakages and improve efficiency.

<FIG> illustrates an exemplary section <NUM> including a flowpath assembly <NUM> for a gas turbine engine. The assembly <NUM> can include an end wall <NUM> including an array of arc segments <NUM>, an array of vanes <NUM> and an array of spar members <NUM>. The arc segments <NUM> can be arranged in an annulus about an array of rotatable airfoils or blades (see, e.g., <FIG>). The arc segment <NUM> can be coupled to the vanes <NUM>. The arc segments <NUM> can be integrally formed with one or more of the vanes <NUM>, or can be separate and distinct components as illustrated in <FIG>. Each of the arc segments <NUM> can extend in a circumferential or thickness direction T between a first mate face <NUM>-<NUM> and a second mate face <NUM>-<NUM>.

The assembly <NUM> can include one or more seal members <NUM> dimensioned to establish a sealing relationship along an intersegment gap IG established between the mate faces <NUM> of opposed arc segments <NUM>, as illustrated by the mate faces <NUM>-<NUM>, <NUM>-<NUM>. The seal member <NUM> can be a feather seal and can comprise any of the materials disclosed herein, including a metallic material or a ceramic matrix composite (CMC) material. The seal member <NUM> can have a unitary construction or can include two or more segments (e.g., halves) mechanically attached or otherwise secured to each other. The mate faces <NUM>-<NUM>, <NUM>-<NUM> can include respective slots <NUM> dimensioned to receive a respective one of the seal members <NUM> such that the seal member <NUM> spans across the intersegment gap IG to establish a sealing relationship.

Each seal member <NUM> can be dimensioned to establish a sealing relationship with an outer periphery 863OP of the airfoil section 863A of a respective one of the vanes <NUM>. The seal member <NUM> can include a main body 884A and a flange 884F extending radially outwardly from the main body 884A, as illustrated in <FIG>. The seal member <NUM> can include a circumferential face 884C established along the flange 884F. The circumferential face 884C can be dimensioned to substantially follow the outer periphery 863OP of the airfoil section 863A to establish the sealing relationship with the respective vane <NUM>, including along a pressure side 863PS and/or suction side of 863SS the airfoil section 863A. The seal member <NUM> may be utilized such that a separate rope seal, spring plate and/or spring member is omitted.

The disclosed flowpath assemblies can incorporate an endwall utilized to bound a gas path through the gas turbine engine. The disclosed assemblies may improve sealing effectiveness and reduce parts counts by utilizing an integral platform section and BOAS. The integral platform section and BOAS can be utilized to omit an axial purge gap and reduce purge, leakage, and cooling flow requirements along the adjacent gas path. The assemblies may be utilized to establish sealing relationships with components incorporating CMC materials, which may otherwise be associated with additional leak paths and increased effective leakage per interface location, and variability due to interaction between CMC components and metallic components. The number of mate faces established by the end wall may be reduced, which can further reduce leakage flow and improve efficiency.

Mounting the arc segments adjacent to the rotating blades at the first attachment point may reduce an impact on tip clearances of the adjacent blades as compared to cantilevering or mounting the arc segments at a position axially forward of the adjacent blades. Additionally, mounting schemes for the end wall at the first attachment point can be axially aligned with ACC rails of the respective case which can improve effectiveness of a case-blown ACC system.

It should be understood that relative positional terms such as "forward," "aft," "upper," "lower," "above," "below," and the like are with reference to the normal operational altitude of the vehicle and should not be considered otherwise limiting.

Claim 1:
An assembly (<NUM>) for a gas turbine engine (<NUM>) comprising:
an end wall (<NUM>) including a main body (68A) extending between a first end portion (68B) and a second end portion (68C) to establish a seal face (<NUM>), the seal face (<NUM>) dimensioned to establish a clearance gap (CG) with a rotatable blade (<NUM>) along a gas path (GP), and the end wall (<NUM>) including a first attachment portion (68AP) dimensioned to fixedly attach the main body (68A) to a static structure (<NUM>) at a first attachment point (P1);
a vane (<NUM>) extending radially inwardly from the end wall (<NUM>) relative to an assembly axis (LA), the vane (<NUM>) including an inner cavity (63D) extending between a first end portion (63B) and a second end portion (63C), the first end portion (63B) adjacent the end wall (<NUM>); and
a spar member (<NUM>) including a spar body (72A) extending between a first end portion (72B) and a second end portion (72C), the spar body (72A) extending at least partially through the inner cavity (63D),
characterised in that:
the first end portion (72B) of the spar member (<NUM>) attachable to the static structure (<NUM>) at a second attachment point (P2) axially between the first end portion (68B) of the end wall (<NUM>) and the first attachment portion (P1) such that the first end portion (68B) of the end wall (<NUM>) is cantilevered from the first attachment point (P1).