Feather seal for CMC BOAS
A blade outer air seal assembly includes a support structure. A blade outer air seal has a plurality of segments that extends circumferentially about an axis and is mounted in the support structure. At least two of the segments have a base portion that extends from a first circumferential side to a second circumferential side. A first protrusion extends from the first circumferential side and has a first radially extending slot. A second protrusion extends from a second circumferential side and has a second radially extending slot. A feather seal is arranged in the first radially extending slot and the second radially extending slot between at least two segments.
1. A blade outer air seal assembly, comprising:
a support structure;
a blade outer air seal having a plurality of segments extending circumferentially about an axis and mounted in the support structure, at least two segments of the plurality of segments having a base portion extending from a first circumferential side to a second circumferential side, a first protrusion extending from the first circumferential side and having a first radially extending slot and a second protrusion extending from the second circumferential side and having a second radially extending slot, wherein the base portion extends from a first axial side of the at least two segments of the plurality of segments to a second axial side of the at least two segments of the plurality of segments to define a segment axial length; and
a feather seal arranged in the first radially extending slot and the second radially extending slot between the at least two segments, the feather seal extends in an axial direction for most of the seal segment axial length, wherein the feather seal has a thickness and a rounded end having a greater thickness at a radially inner end, the greater thickness is larger than a thickness at a radially outer end.
2. The blade outer air seal assembly of claim 1 , wherein at least one segment of the at least two segments has at least one hook extending radially outward from the base portion, wherein the first and second radially extending slots are circumferentially outward of the at least one hook.
3. The blade outer air seal assembly of claim 1 , wherein the feather seal has a thickness that is less than a circumferential width of the first and second radially extending slots.
4. The blade outer air seal assembly of claim 3 , wherein a ratio of the circumferential width of the first and second radially extending slots to the thickness of the feather seal is between about 1.5 and 2.5.
5. The blade outer air seal assembly of claim 1 , wherein the feather seal is configured to rotate about the rounded end.
6. The blade outer air seal assembly of claim 5 , wherein the feather seal is configured to rotate less than about 10°.
7. The blade outer air seal assembly of claim 1 , wherein the thickness of the feather seal is about 0.010 to 0.030 inches (0.254-0.762 mm).
8. The blade outer air seal assembly of claim 1 , wherein the feather seal extends in the axial direction for at least about 80% of the segment axial length.
9. The blade outer air seal assembly of claim 1 , wherein the first and second protrusions are offset in a radial direction and overlap one another in a circumferential direction.
10. The blade outer air seal assembly of claim 9 , wherein a gap is arranged between each of the plurality of segments to accommodate thermal expansion, the gap is less than about 0.040 inches (0.254-1.016 mm).
11. The blade outer air seal assembly of claim 1 , wherein the at least two segments are a ceramic matrix composite material.
12. The blade outer air seal assembly of claim 1 , wherein the at least two segments are a monolithic ceramic material.
13. The blade outer air seal assembly of claim 1 , wherein the feather seal is a ceramic matrix composite material.
14. The blade outer air seal assembly of claim 1 , wherein the feather seal is a metallic material.
15. The blade outer air seal assembly of claim 1 , wherein the first radially extending slot extends radially outward and the second radially extending slot extends radially inward, the first radially extending slot aligned with the second radially extending slot in the circumferential direction.
16. A gas turbine engine, comprising:
a compressor section, a combustor section, and a turbine section arranged about an axis of rotation;
an assembly having a plurality of segments arranged circumferentially about the axis of rotation, at least two segments of the plurality of segments having a base portion extending from a first circumferential side to a second circumferential side, a first protrusion extending from the first circumferential side and having a first radially extending slot circumferentially inward of a first end of the first protrusion and a second protrusion extending from the second circumferential side, having a second radially extending slot circumferentially inward of a second end of the second protrusion, wherein the base portion extends from a first axial side of the at least two segments of the plurality of segments to a second axial side of the at least two segments of the plurality of segments to define a segment axial length, wherein the at least two segments are a ceramic material; and
a feather seal arranged in the first radially extending slot and the second radially extending slot between the at least two segments, the feather seal extends in an axial direction for most of the segment axial length, wherein the feather seal has a thickness and a rounded end having a greater thickness at a radially inner end, the greater thickness is larger than a thickness at a radially outer end.
17. The gas turbine engine of claim 16 , wherein the feather seal is a ceramic material.
18. The gas turbine engine of claim 16 , wherein the feather seal is a metallic material.