Ceramic matrix composite component with corrugated wall
The disclosure describes CMC components having structures which ameliorate stress induced by thermal expansion and methods for manufacturing CMC components with such structures. The CMC component, for example, a blade outer air seals (BOAS) is provided with a cooling cavity having a cavity top wall. The cavity top wall is provided with curvatures, such as corrugations or dimples, that allow the cavity top wall to expand and thereby reduce stress induced by thermal expansion.
1 . A ceramic matrix composite (CMC) component comprising:
a ceramic matrix composite substrate comprising ceramic fiber tows within a ceramic matrix, the substrate having a bottom surface and an upper surface; and
a cooling cavity within an interior region of the substrate, the cooling cavity being defined by a cavity bottom wall, a cavity top wall, and cavity side walls;
wherein the cavity top wall is provided with curvatures to allow for expansion of the cavity top wall of the substrate.
2 . The CMC component to according to claim 1 , wherein the curvatures are in the form of corrugations.
3 . The CMC component to according to claim 2 , wherein the corrugations have a uniform height.
4 . The CMC component to according to claim 2 , wherein the corrugations have heights that vary.
5 . The CMC component to according to claim 2 , wherein the distance between adjacent corrugations is uniform.
6 . The CMC component to according to claim 2 , wherein the distance between adjacent corrugations varies.
7 . The CMC component to according to claim 2 , wherein the substrate has an axial direction and a circumferential direction perpendicular to the axial direction, and the corrugations extend in the circumferential direction.
8 . The CMC component to according to claim 2 , wherein the substrate has an axial direction and a circumferential direction perpendicular to the axial direction, and the corrugations extend in the axial direction.
9 . The CMC component to according to claim 1 , wherein the curvatures are in the form of dimples.
10 . The CMC component to according to claim 9 , wherein the dimples have a uniform height.
11 . The CMC component to according to claim 2 , wherein the dimples have heights that vary.
12 . The CMC component to according to claim 9 , wherein the distance between adjacent dimples is uniform.
13 . The CMC component to according to claim 9 , wherein the distance between adjacent dimples varies.
14 . The CMC component according to claim 1 , further comprising at least one cooling air inlet to permit cooling air to enter the cooling cavity and at least one cooling air outlet to permit cooling air to be discharged from the cooling cavity.
15 . The CMC component to according to claim 1 , wherein the component is a combustor liner.
16 . The CMC component according to claim 1 , wherein the component is a blade outer air seal (BOAS) segment.
17 . A BOAS assembly comprising a plurality of BOAS segments according claim 16 , wherein the BOAS segments are arranged to form an annular shaped structure.
18 . A method of preparing a ceramic matrix composite comprising:
providing a ceramic matrix composite preform comprising a preform substrate having ceramic fiber tows, the preform substrate having a bottom surface and an upper surface;
forming a cooling cavity within the preform, the cooling cavity being defined by a cavity bottom wall, a cavity top wall, and cavity side wall; and
wherein the cavity top wall is provided with curvatures to allow for expansion of the cavity top wall of the substrate; and
subjecting the preform to densification to form the ceramic matrix composite.
19 . The method according to claim 18 , wherein the curvatures of the cavity top wall formed in the preform using tooling or sacrificial materials that are removed before any densification, after an initial pre-densification, or after a final densification.
20 . A turbine engine comprising:
a fan section, a compressor section, a combustion chamber, and a turbine section, the turbine section including at least one rotor and one or more turbine blade(s) extending radially outwardly from the at least one rotor; and
a blade outer air seal assembly positioned between the one or more turbine blade(s) and an outer casing to the engine;
wherein the blade outer air seal assembly is formed of a plurality blade outer air seal segments, wherein each blade outer air seal segment comprises:
a ceramic matrix composite substrate comprising ceramic fiber tows within a ceramic matrix, the substrate having a bottom surface and an upper surface; and
a cooling cavity within an interior region of the substrate, the cooling cavity being defined by a cavity bottom wall, a cavity top wall, and cavity side walls;
wherein the cavity top wall is provided with curvatures to allow for expansion of the cavity top wall of the substrate.