Ceramic matrix composite blade outer air seal feather seal configuration and method
A feather seal arrangement for a ceramic matrix composite (CMC) blade outer air seal (BOAS) of a turbine engine includes a CMC BOAS segment having a specific geometry and a first feather seal. The CMC BOAS segment includes a shoe having a flowpath side, an opposing non-flowpath side, and first and second matefaces extending axially between the flowpath side and the non-flowpath side from an upstream leading edge to a downstream trailing edge. One or more support flanges extend substantially transverse from the non-flowpath side. A geometry of the CMC BOAS segment allows a substantially flat first feather seal surface to be disposed on the non-flowpath side adjacent and substantially transverse to the first mateface. A first feather seal is disposed atop the non-flowpath side on the first feather seal surface and extends to an adjacent feather seal surface of an adjacent CMC BOAS segment.
1 . A feather seal arrangement for a ceramic matrix composite (CMC) blade outer air seal (BOAS) of a turbine engine, comprising:
a CMC BOAS segment including:
a shoe having a flowpath side configured for exposure to a hot gas path of the turbine engine, an opposing non-flowpath side, and first and second matefaces extending axially between the flowpath side and the non-flowpath side from an upstream leading edge to a downstream trailing edge;
one or more support flanges extending substantially transverse from the non-flowpath side; and
a substantially flat first feather seal surface disposed on the non-flowpath side adjacent and substantially transverse to the first mateface;
a first feather seal disposed atop the non-flowpath side on the first feather seal surface and extending to an adjacent feather seal surface of an adjacent CMC BOAS segment; and
a first full hoop retainer configured for retaining an upstream end of the first feather seal and/or a second full hoop retainer configured for retaining a downstream end of the first feather seal,
wherein the first and/or second full hoop retainer comprises an axial recess configured to axially hold the upstream and/or downstream end of the first feather seal, respectively.
2 . The feather seal arrangement of claim 1 , wherein the one or more flanges extend between the first and second matefaces.
3 . The feather seal arrangement of claim 2 , wherein at least one of the one or more flanges are set back from the first mateface to provide the first feather seal surface.
4 . The feather seal arrangement of claim 2 , wherein at least one of the one or more flanges includes an undercut portion to provide the first feather seal surface.
5 . The feather seal arrangement of claim 2 , wherein the one or more flanges comprise two flanges that are set back from the first mateface, a plateau extends from the non-flowpath side between the two flanges, and the first feather seal is disposed on the plateau.
6 . The feather seal arrangement of claim 2 , wherein the one or more flanges comprise two flanges that include a first flange set back from the first mateface, and a second flange having an undercut portion adjacent the first mateface.
7 . The feather seal arrangement of claim 6 , further comprising a ramp that extends between the first flange and the second flange, and the first feather seal surface is disposed on the ramp.
8 . A feather seal method for a ceramic matrix composite (CMC) blade outer air seal (BOAS) of a turbine engine, comprising:
providing a CMC BOAS segment including:
a shoe having a flowpath side configured for exposure to a hot gas path of the turbine engine, an opposing non-flowpath side, and first and second matefaces extending axially between the flowpath side and the non-flowpath side from an upstream leading edge to a downstream trailing edge;
one or more support flanges extending substantially transverse from the non-flowpath side; and
a substantially flat first feather seal surface disposed on the non-flowpath side adjacent and substantially transverse to the first mateface;
disposing a first feather seal atop the non-flowpath side on the first feather seal surface and extending the feather seal to an adjacent feather seal surface of an adjacent CMC BOAS segment;
disposing a first full hoop retainer to retain an upstream end of the first feather seal and/or a second full hoop retainer to retain a downstream end of the first feather seal; and
axially holding the upstream and/or downstream end of the first feather seal in an axial recess of the first and/or second full hoop retainer, respectively.
9 . The feather seal method of claim 8 , further comprising disposing the one or more flanges to extend between the first and second matefaces.
10 . The feather seal method of claim 9 , further comprising setting at least one of the one or more flanges back from the first mateface to provide the first feather seal surface.
11 . The feather seal method of claim 9 , further comprising undercutting a portion of at least one of the one or more flanges to provide the first feather seal surface.
12 . The feather seal method of claim 9 , wherein providing the one or more flanges comprises providing two flanges that are setback from the first mateface, and further providing a plateau that extends from the non-flowpath side between the two flanges, and disposing the first feather seal on the plateau.
13 . The feather seal method of claim 9 , wherein providing the one or more flanges comprises providing two flanges including a first flange set back from the first mateface, and a second flange having an undercut portion adjacent the first mateface.
14 . The feather seal method of claim 13 , further comprising providing a ramp that extends between the first flange and the second flange, and disposing the first feather seal surface on the ramp.