The present disclosure relates generally to gas turbine engines, and more specifically to biasing features for turbine shrouds adapted for use in gas turbine engines.
Gas turbine engines are used to power aircraft, watercraft, power generators, and the like. Gas turbine engines typically include a compressor, a combustor, and a turbine. The compressor compresses air drawn into the engine and delivers high pressure air to the combustor. In the combustor, fuel is mixed with the high pressure air and is ignited. Products of the combustion reaction in the combustor are directed into the turbine where work is extracted to drive the compressor and, sometimes, an output shaft. Left-over products of the combustion are exhausted out of the turbine and may provide thrust in some applications.
Compressors and turbines typically include alternating stages of static vane assemblies and rotating wheel assemblies. The rotating wheel assemblies include disks carrying blades around their outer edges. When the rotating wheel assemblies turn, tips of the blades move along blade tracks included in static shrouds that are arranged around the rotating wheel assemblies. Such static shrouds may be coupled to an engine case that surrounds the compressor, the combustor, and the turbine.
Some shrouds positioned in the turbine may be exposed to high temperatures from products of the combustion reaction in the combustor. Such shrouds sometimes include components made from materials that have different coefficients of thermal expansion. Due to the differing coefficients of thermal expansion, the components of some turbine shrouds expand at different rates when exposed to combustion products. In some examples, coupling such components with traditional arrangements may not allow for the differing levels of expansion and contraction during operation of the gas turbine engine.
The present disclosure may comprise one or more of the following features and combinations thereof.
A turbine shroud assembly for use with a gas turbine engine includes a carrier assembly, a blade track assembly, and a first biasing member. The carrier assembly includes a carrier segment made of metallic materials and arranged circumferentially at least partway around an axis, the carrier segment having an outer wall, a first mount flange that extends radially inward from the outer wall, and a second mount flange axially spaced apart from the first mount flange and that extends radially inward from the outer wall, the second mount flange including a radially extending wall and a chordal seal that extends axially away from the radially extending wall.
In some embodiments, the blade track assembly includes a blade track segment made of ceramic matrix composite materials and a first mount pin assembly, the blade track assembly supported by the carrier to locate the blade track segment radially outward of the axis and define a portion of a gas path of the turbine shroud assembly, and the blade track segment including a shroud wall that extends circumferentially partway around the axis and an attachment feature that extends radially outward from the shroud wall, and the first mount pin assembly extending into the first mount flange, through the attachment feature, and into the second mount flange so as to couple the blade track assembly to the carrier segment.
In some embodiments, the first biasing member is arranged axially between and engaged with the carrier segment and the blade track assembly so as to bias the attachment feature of the black track segment into engagement with the chordal seal of the second mount flange.
In some embodiments, the second mount flange is located at an axially aft end of the outer wall and the first mount flange is located axially forward of the second mount flange, and wherein the attachment feature is located axially between the first mount flange and the second mount flange.
In some embodiments, the first mount flange defines an axially aft facing surface and the second mount flange defines an axially forward facing surface, wherein the attachment feature includes a first attachment post that extends radially outward from the shroud wall and a second attachment post that extends radially outward from the shroud wall and that is spaced apart from and located axially aft of the first attachment post, wherein the first attachment post includes an axially forward facing surface, and wherein the first biasing member is located between and abuts the axially aft facing surface of the first mount flange and the axially forward facing surface of the first attachment post such that an axially aft facing wall of the second attachment post contacts an axially forward facing surface of the chordal seal.
In some embodiments, the carrier segment further includes a third mount flange that extends radially inward from the outer wall of the carrier segment, and wherein the third mount flange is located axially between the first mount flange and the second mount flange.
In some embodiments, the carrier segment further includes a fourth mount flange that extends radially inward from the outer wall of the carrier segment and that is spaced apart from and located axially aft of the third mount flange, and wherein the fourth mount flange is located axially between the third mount flange and the second mount flange.
In some embodiments, the turbine shroud assembly further includes a second biasing member, wherein the fourth mount flange defines an axially aft facing surface, wherein the first attachment post is located axially between the first mount flange and the third mount flange and the second attachment post is located axially between the fourth mount flange and the second mount flange, wherein the second attachment post defines an axially forward facing surface, and wherein the second biasing member is located axially between and abuts the axially aft facing surface of the fourth mount flange and the axially forward facing surface of the second attachment post.
In some embodiments, the axially aft facing surface of the first mount flange and the axially forward surface of the first attachment post each include at least one recess within which at least a portion of the first biasing member is arranged, and wherein the axially aft facing surface of the fourth mount flange and the axially forward facing surface of the second attachment post each includes at least one recess within which at least a portion of the second biasing member is arranged.
In some embodiments, the first mount pin assembly is a split-pin fastener that includes a forward pin that extends into the first mount flange, through the first attachment post, and through the third mount flange, and an aft pin circumferentially aligned with and aft of the forward pin that extends through the fourth mount flange, through the second attachment post, and into the second mount flange, and wherein the forward pin is separate from the aft pin so as to allow for independent loading during use in the gas turbine engine.
In some embodiments, the first biasing member is a first wave spring and the second biasing member is a second wave spring, wherein the first wave spring includes at least one first curved portion that is arranged within the at least one recess of the first mount flange and at least one second curved portion that is arranged within the at least one recess of the first attachment post, wherein the second wave spring includes at least one first curved portion that is arranged within the at least one recess of the fourth mount flange and at least one second curved portion that is arranged within the at least one recess of the second attachment post.
In some embodiments, the first biasing member is a ring spring that surrounds the first mount pin assembly and the second biasing member is a ring spring that surrounds the first mount pin assembly.
In some embodiments, the carrier segment further includes a third mount flange that extends radially inward from the outer wall of the carrier segment and a fourth mount flange that extends radially inward from the outer wall of the carrier segment and that is spaced apart from and located axially aft of the third mount flange, wherein the third mount flange is located axially between the first mount flange and the fourth mount flange, wherein the fourth mount flange is located axially between the third mount flange and the second mount flange and defines an axially aft facing surface, wherein the attachment feature includes a first attachment post that extends radially outward from the shroud wall and a second attachment post that extends radially outward from the shroud wall and that is spaced apart from and located axially aft of the first attachment post, wherein the first attachment post is located axially between the first mount flange and the third mount flange and the second attachment post is located axially between the fourth mount flange and the second mount flange, wherein the second attachment post defines an axially forward facing surface, and wherein the first biasing member is located axially between and abuts the axially aft facing surface of the fourth mount flange and the axially forward facing surface of the second attachment post such that an axially aft facing wall of the second attachment post contacts an axially forward facing surface of the chordal seal.
In some embodiments, a first portion of the first biasing member is located between and abutting a radially inner surface of the outer wall of the carrier segment and a radially outer surface of the at least one attachment post, wherein a second portion of the first biasing member extends radially away from the first portion and engages the second attachment post, and wherein the first portion of the first biasing member and the second portion of the first biasing member bias the attachment feature of the black track segment into sealing engagement with the chordal seal of the second mount flange.
In another embodiment, a turbine shroud assembly for use with a gas turbine engine includes a carrier segment, a blade track assembly, and a first biasing member. The carrier segment is arranged circumferentially at least partway around an axis, the carrier segment having a first mount flange that extends radially inward and a second mount flange axially spaced apart from the first mount flange and that extends radially inward, the second mount flange including a radially extending wall and a chordal seal that extends axially away from the radially extending wall.
In some embodiments, the blade track assembly includes a blade track segment and a first mount pin assembly, the blade track segment including a shroud wall and an attachment feature that extends radially outward from the shroud wall, and the first mount pin assembly coupling the blade track assembly to the carrier segment. The first biasing member is arranged axially between and engaged with the first mount flange of the carrier segment and the attachment feature of the blade track assembly so as to bias the attachment feature of the black track segment into engagement with the chordal seal.
In some embodiments, the attachment feature is located axially between the first mount flange and the second mount flange.
In some embodiments, the attachment feature includes a first attachment post that extends radially outward from the shroud wall and a second attachment post that extends radially outward from the shroud wall and that is axially spaced apart from the first attachment post, and wherein the first biasing member is located between the first mount flange and the first attachment post.
In some embodiments, the carrier segment further includes a third mount flange that extends radially inward from the outer wall of the carrier segment, and wherein the third mount flange is located axially between the first mount flange and the second mount flange.
In some embodiments, the turbine shroud assembly further includes a second biasing member, wherein the carrier segment further includes a fourth mount flange that extends radially inward from the outer wall of the carrier segment and that is axially spaced apart from the third mount flange, wherein the fourth mount flange is located axially between the third mount flange and the second mount flange, and wherein the first attachment post is located axially between the first mount flange and the third mount flange and the second attachment post is located axially between the fourth mount flange and the second mount flange, and wherein the second biasing member is located axially between the fourth mount flange and the second attachment post.
In some embodiments, the first mount flange, the fourth mount flange, the first attachment post, and the second attachment post each include an axially facing surface, wherein the axially facing surface of the first mount flange and the axially facing surface of the first attachment post each include at least one recess within which at least a portion of the first biasing member is arranged, and wherein the axially facing surface of the fourth mount flange and the axially facing surface of the second attachment post each includes at least one recess within which at least a portion of the second biasing member is arranged.
A method of forming a turbine shroud assembly includes providing a carrier assembly including a carrier segment made of metallic materials and arranged circumferentially at least partway around an axis, the carrier segment having an outer wall, a first mount flange that extends radially inward from the outer wall, and a second mount flange axially spaced apart from the first mount flange and that extends radially inward from the outer wall, the second mount flange including a radially extending wall and a chordal seal that extends axially away from the radially extending wall.
In some embodiments, the method further includes providing a blade track assembly including a blade track segment made of ceramic matrix composite materials and a first mount pin assembly, the blade track segment including a shroud wall that extends circumferentially partway around the axis and an attachment feature that extends radially outward from the shroud wall,
In some embodiments, the method further includes coupling the blade track assembly to the carrier segment via the first mount pin assembly extending into the first mount flange, through the attachment feature, and into the second mount flange so as to locate the blade track segment radially outward of the axis and define a portion of a gas path of the turbine shroud assembly, and
In some embodiments, the method further includes arranging a first biasing member axially between the carrier segment and the blade track assembly such that the first biasing member engages the carrier segment and the blade track assembly so as to bias the attachment feature of the black track segment into sealing engagement with the chordal seal of the second mount flange.
In some embodiments, the attachment feature of the blade track segment includes a first attachment post that extends radially outward from the shroud wall, and wherein the first biasing member is located between and abuts an axially aft facing surface of the first mount flange and an axially forward facing surface of the first attachment post.
These and other features of the present disclosure will become more apparent from the following description of the illustrative embodiments.
For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to a number of illustrative embodiments illustrated in the drawings and specific language will be used to describe the same.
An illustrative aerospace gas turbine engine 10 includes a fan 12, a compressor 14, a combustor 16, and a turbine 18 as shown in
The turbine section 18 includes at least one turbine wheel assembly 20 and a turbine shroud 22 positioned to surround the turbine wheel assembly 20 as shown in
In the illustrative embodiment, the turbine shroud 22 is made up of a number of turbine shroud assemblies 26 that each extend circumferentially partway around the axis 11 and cooperate to surround the turbine wheel assembly 20. In other embodiments, the turbine shroud 22 is annular and non-segmented to extend fully around the central axis 11 and surround the turbine wheel assembly 20. In yet other embodiments, certain components of the turbine shroud 22 are segmented while other components are annular and non-segmented.
Each turbine shroud assembly 26 includes a carrier assembly 30, a blade track assembly 50, and at least one biasing member 70, as shown in
In the illustrative embodiment, the first mount flange 36 is located at an axially forward end of the outer wall 34 and the second mount flange 38 is located at an axially aft end of the outer wall 34, as shown in
The blade track assembly 50 of the turbine shroud assembly 26 includes a blade track segment 52 and a first mount pin assembly 53, as shown in
The blade track segment 52 includes a shroud wall 56 and at least one attachment feature 58, as shown in
The at least one attachment feature 58 extends radially outward from the outer surface 59 of the shroud wall 56, as shown in
In the illustrative embodiment, the carrier segment 32 further includes a third mount flange 42 that extends radially inward from the outer wall 34 of the carrier segment 32 and a fourth mount flange 44 that extends radially inward from the outer wall 34 of the carrier segment and that is spaced apart from and located axially aft of the third mount flange 42, as shown in
The first attachment post 60 extends radially outwardly such that the first attachment post 60 is located axially between the first mount flange 36 and the third mount flange 42, as shown in
The turbine shroud assembly 26 includes a first biasing member 70 located axially between the first mount flange 36 and the first attachment post 60, as shown in
In the illustrative embodiment, the turbine shroud assembly 26 further includes a second biasing member 72 located axially between the fourth mount flange 44 and the second attachment post 62, as shown in
The first mount flange 36 includes a radially outer biasing member recess 74 formed within the first mount flange 36 that is recessed away from the axially aft facing wall 41, as shown in
In the illustrative embodiment, the first attachment post 60 also includes a radially outer biasing member recess 82 formed within the first attachment post 60 that is recessed away from the axially forward facing wall 43, as shown in
Each of the biasing member recesses 74, 76, 78, 80, 82, 84, 86, 88 is configured to receive a portion of the biasing members 70, 72, as shown in
In the illustrative embodiment, the second wave spring 72 may have at least one curved portion 94 that is arranged in the recess 78 formed in the axially aft facing surface 45 of the fourth mount flange 44. The second wave spring 72 may have at least one second curved portion 96 that is arranged in the recess 86 formed in the axially forward facing surface 47 of the second attachment post 62. Each of the first and second wave springs 70, 72 may have additional curves, some of which would be located within the recesses 76, 80, 84, and 88, as shown in
In the illustrative embodiment, each wave spring 70, 72 is a linear wave spring that includes an elongated, relatively flat body having the curves described above, as shown in
Alternatively, the first biasing member 70 and the second biasing member 72 may be formed as annular ring springs that circumferentially surround the first mount pin assembly 53, as shown in
In the embodiments discussed above, the turbine shroud assembly 26 includes both a first and second attachment post 60, 62, and both a first and second biasing member 70, 72. In other embodiments, the turbine shroud assembly 26 may include a single biasing member located between one of the first mount flange 36 and the first attachment post 60 or the fourth mount flange 44 and the second attachment post 62. Likewise, the turbine shroud assembly 26 may only include a single, fully radially extending attachment post that extends nearly to the inner surface of the outer wall 34. For example, the turbine shroud assembly 26 may only include the second attachment post 62, and only a single biasing spring located between the fourth mount flange 44 and the second attachment post 62. As a further example, the turbine shroud assembly 26 may only include the first attachment post 60, and only a single biasing spring located between the first mount flange 36 and the first attachment post 60. In this case, the blade track assembly 52 includes a radially extending wall where the second attachment post 62 is located in
In the illustrative embodiment, the turbine shroud assembly 26 includes the first mount pin assembly 53, as shown in
In other embodiments, the first mount pin assembly 53 is a split-pin fastener that includes a forward pin 54 that extends into the first mount flange 36, through the first attachment post 60, and through the third mount flange 42, and an aft pin 55 circumferentially aligned with and aft of the forward pin 54 that extends through the fourth mount flange 44, through the second attachment post 62, and into the second mount flange 38, and shown in
Another embodiment of a turbine shroud assembly 126 in accordance with the present disclosure is shown in
The turbine shroud assembly 126 includes a carrier assembly 130 having a carrier segment 132, a blade track assembly 150 having a blade track segment 152, a first mount pin assembly 153, and a first biasing member 170, as shown in
The blade track segment 152 includes a shroud wall 156 and at least one attachment feature 158, as shown in
In the illustrative embodiment, the turbine shroud assembly 126 includes the first mount pin assembly 153, as shown in
In some embodiments, the pin segment 181 may have a circular cross-section, or may have any other suitable cross-section. The pin segment 181 may be formed as a single monolithic pin that extends through the first mount flange 136, the first attachment post 160, the third and fourth mount flanges 142, 144, the second attachment post 162, and into the second mount flange 138. In other embodiments, the pin segment 181 is a split-pin fastener that includes a forward pin 154 that extends into the first mount flange 136, through the first attachment post 160, and through the third mount flange 142, and an aft pin 155 circumferentially aligned with and aft of the forward pin 154 that extends through the fourth mount flange 144, through the second attachment post 162, and into the second mount flange 138. The forward pin 154 is separate from the aft pin 155 so as to allow for independent loading during use in the gas turbine engine.
In the illustrative embodiment in which the pin segment 181 is a split-pin fastener, the forward pin 154 includes an aft axial end face and a connection tab 184 having a smaller diameter than the forward pin that extends axially away from the aft axial end face, as shown in
In the illustrative embodiment, the first mount flange 136 includes an axially-extending installation aperture 137 that receives a portion 186 of the retainer plug 180 and a portion of the forward axial end of the pin segment 181, as shown in
In the illustrative embodiment, the first biasing member 170 is arranged between the portion 186 of the retain plug 180 that extends into the first mount flange 136 and the portion of the forward axial end of the pin segment 181 that also extends into the first mount flange 136, as shown in
Alternatively, as shown in
Another embodiment of a turbine shroud assembly 226 in accordance with the present disclosure is shown in
The turbine shroud assembly 226 includes a carrier assembly 230 having a carrier segment 232, a blade track assembly 250 having a blade track segment 252, a first mount pin assembly 253, a first biasing member 270, and a second biasing member 272 as shown in
The blade track segment 252 includes a shroud wall 256 and at least one attachment feature 258, as shown in
The turbine shroud assembly 226 includes the first mount pin assembly 253, as shown in
In the illustrative embodiment, the turbine shroud assembly 226 includes a first biasing member 270 and a second biasing member 272, the first and second biasing members 270, 272 being braid seals that extend circumferentially at least partway around the blade track segment 252, as shown in
In the illustrative embodiment, the turbine shroud assembly 226 further includes a second braid seal 272 located axially between the fourth mount flange 244 and the second attachment post 262, as shown in
Another embodiment of a turbine shroud assembly 326 in accordance with the present disclosure is shown in
The turbine shroud assembly 326 includes a carrier assembly 330 having a carrier segment 332, a blade track assembly 350 having a blade track segment 352, a first mount pin assembly 353, a first biasing member 370, and a second biasing member 372 as shown in
The blade track segment 352 includes a shroud wall 356 and at least one attachment feature 358, as shown in
The turbine shroud assembly 326 includes the first mount pin assembly 353, as shown in
In the illustrative embodiment, the turbine shroud assembly 326 includes a first biasing member 370 and a second biasing member 372, the first and second biasing members 370, 372 being radial springs, as shown in
In at least some embodiments, a turbine shroud assembly includes a wave spring that is placed between an aft side of an inner clevis of a carrier segment of the turbine shroud assembly and an aft leg of a CMC blade track segment. Alternatively, a wave spring may be placed between a forward vertical leg extending away from the carrier segment and a front leg of the CMC blade track segment. As a further alternative, a wave spring may be placed between both the inner clevis and aft leg of the CMC blade track segment and the front carrier leg and the front leg of the CMC blade track segment. The wave spring is compressed upon installation and forces the seal segment aft and into contact with a chordal seal of the carrier segment. Such an embodiment may be utilized with a single mount pin or a split-pin assembly, both of which are inserted through the forward leg of the carrier segment. The wave spring could be of a typical ring configuration, linear wave springs, or both. The ring configuration may be arranged around the mount pin and be self-contained.
In an alternative embodiment, a stepped pin is inserted through the forward leg of the carrier segment. The stepped pin is configured such that the major diameter of the pin is larger than the hole in the aft flange or forward flange of the CMC blade track segment. This allows the pin to push aft on the CMC blade track segment. A spring, such as a coil, wave spring, ring spring, or Bellville washer, is inserted in front of the pin and is compressed by a retaining cap. The retaining cap also acts to retain the pin and seal in the cavity from air leaks. The retaining cap may be press fit, threaded, tack welded in place, retained by the vane in front of it, or a combination of the aforementioned methods. Alternatively, the mount pin may include two pins or be a split-pin assembly in which the forward pin has a single large diameter and the aft pin is stepped as discussed above.
In order to facilitate ease of installation, the forward pin may have a nose that inserts into the aft pin. In other embodiments, the mount pin may be inserted from the aft side through an aft leg or flange extending from the outer wall of the carrier segment. The embodiments including the pin inserted from the forward end are simpler to install, provide more options for the type of spring and the location of the spring, and any leakage is to a higher pressure source, reducing the leakage relative to an aft inserted pin. Also, such embodiments can use the vane to retain the plug, thus eliminating any tack welding.
While the disclosure has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments thereof have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.
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