Inter-component seals for ceramic matrix composite turbine vane assemblies

1. A turbine vane assembly, the assembly comprising

a turbine case that extends at least part way around a central axis, the turbine case comprising metallic materials having a first coefficient of thermal expansion such that the turbine case is configured to have a first case diameter at a first relatively-low temperature and a second case diameter at a second relatively-high temperature that is greater than the first relatively-low temperature,

a first turbine vane coupled to the turbine case, the first turbine vane including an airfoil and an end wall arranged to define a radial boundary of a primary gas path, the first turbine vane comprising ceramic matrix composite materials having a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion, wherein the end wall of the first turbine vane includes a primary panel and a seal extension that extends circumferentially from the primary panel, and

a second turbine vane coupled to the turbine case circumferentially adjacent to the first turbine vane, the second turbine vane including an airfoil and an end wall arranged to define a radial boundary of the primary gas path, the second turbine vane comprising ceramic matrix composite materials having the second coefficient of thermal expansion, wherein the end wall of the second turbine vane includes a primary panel and a seal extension that extends circumferentially from the primary panel,

wherein the seal extension of the first turbine vane is configured to radially overhang the seal extension of the second turbine vane and a circumferential vane interface seal is provided by the seal extension of the first turbine vane and the seal extension of the second turbine vane that resists the movement of hot gasses out of the primary gas path when the turbine case has either the first case diameter or the second case diameter.

2. The turbine vane assembly of claim 1 , wherein the primary panel of the first vane and the primary panel of the second vane have a first thickness and the seal extension of the first vane and the seal extension of the second vane have a second thickness which is less than the first thickness.

3. The turbine vane assembly of claim 2 , wherein the second thickness is about half of the first thickness.

4. The turbine vane assembly of claim 1 , wherein the vane interface seal includes a biasing member located circumferentially between the seal extension of the first vane and the primary panel of the second vane.

5. The turbine vane assembly of claim 1 , wherein vane interface seal includes a seal member located between the chamfered surface of the seal extension of the first vane and the primary panel of the second vane.

6. The turbine vane assembly of claim 5 , wherein the seal extension of the first vane includes a chamfered surface that faces the primary panel of the second vane and the seal member is a wire seal located between the chamfered surface and second vane.

7. The turbine vane assembly of claim 5 , wherein the seal member includes a strip seal located radially between the seal extension of the first vane and the seal extension of the second vane.

8. The turbine vane assembly of claim 1 , wherein the vane interface seal includes a seal plate coupled to the seal extension of the first vane and the primary panel of the second vane.

9. The turbine vane assembly of claim 8 , wherein the seal plate is formed from a compliant material and includes a first end fixed to the seal extension of the first vane and a second end fixed to the primary panel of the second vane.

10. The turbine vane assembly of claim 8 , wherein the seal plate is formed from a rigid material and includes a first end engaged slidingly with the seal extension of the first vane and a second end fixed to the primary panel of the second vane.

11. The turbine vane assembly of claim 10 , wherein the seal extension of the first vane and the primary panel of the second vane define a recess and the seal plate is located in the recess.

12. The turbine vane assembly of claim 8 , wherein the seal plate is formed from a rigid material and includes a first end engaged slidingly with the seal extension of the first vane and a second end fixed to the primary panel of the second vane, and the seal plate has a concave surface relative to the seal extension of the first vane.

13. The turbine vane assembly of claim 12 , wherein the first end of the seal plate engages the seal extension of the first vane and provides an axially extending line of contact between the first end of the seal plate and the seal extension of the first vane.

14. A turbine vane assembly, the assembly comprising

a metallic turbine case arranged circumferentially around a central axis,

a first turbine vane comprising ceramic matrix composite materials and including an airfoil and an end wall arranged to define a radial boundary of a primary gas path,

a second turbine vane comprising ceramic matrix composite materials and arranged circumferentially adjacent to the first turbine vane, the second turbine vane including an airfoil and an end wall arranged to define a radial boundary of the primary gas path, and

a vane interface seal arranged circumferentially between the first turbine vane and the second turbine vane, the vane interface seal including a first seal extension coupled to the end wall of the first turbine vane and a second seal extension coupled to the end wall of the second turbine vane,

wherein the first seal extension is configured to radially overhang the second seal extension to resist the movement of hot gasses out of the primary gas path.

15. The turbine vane assembly of claim 14 , wherein the primary panel of the first vane and the primary panel of the second vane have a first thickness and the seal extension of the first vane and the seal extension of the second vane have a second thickness which is less than the first thickness.

16. The turbine vane assembly of claim 15 , wherein the second thickness is about half of the first thickness.

17. The turbine vane assembly of claim 14 , wherein the vane interface seal includes a biasing member located circumferentially between the seal extension of the first vane and the primary panel of the second vane.

18. The turbine vane assembly of claim 14 , wherein vane interface seal includes a seal member located between the chamfered surface of the seal extension of the first vane and the primary panel of the second vane.

19. A method of assembling a turbine vane assembly, the method comprising

providing a turbine case that extends around a central axis, a first vane including an airfoil and an end wall arranged to define a radial boundary of a primary gas path, and a second vane including an airfoil and an end wall arranged to define a radial boundary of a primary gas path,

machining a first seal extension in the end wall of the first vane, the first seal extension extending circumferentially toward the end wall of the second vane and located a first radial distance from central axis,

machining a second seal extension in the end wall of the second vane, the second seal extension extending circumferentially toward the end wall of the first vane and located a second radial distance from central axis that is less than the first radial distance,

minimizing a distance between the first vane and the second vane while the turbine case has a first diameter, and

overhanging the first seal extension over the second seal extension to provide a vane interface seal between the first turbine vane and the second turbine vane while the turbine case has either the first diameter or a second diameter that is larger than the first diameter.

20. The method of claim 19 , further comprising providing a seal member included in the vane interface seal.