Ceramic matrix composite turbine engine vane

1. A vane comprising:

an airfoil shell having:

a leading edge;

a trailing edge;

a pressure side; and

a suction side;

a spar within the shell;

an outboard shroud at an outboard end of the shell; and

an inboard platform at an inboard end of the shell,

wherein:

the shell comprises a region having a depth-wise coefficient of thermal expansion and a second coefficient of thermal expansion tranverse thereto, the depth-wise coefficient of thermal expansion being greater than the second coefficient of thermal expansion; and

along the region, the vane includes first fibers and second fibers, a relative positioning of the first and second fibers being such that the first fibers have a relatively greater association with the depth-wise coefficient of thermal expansion and the second fibers have a relatively greater association with the second coefficient of thermal expansion.

2. The vane of claim 1 wherein:

the airfoil shell consists essentially of a ceramic matrix composite;

the spar consists essentially of a first metallic casting;

the platform consists essentially of a second metallic casting; and

the shroud consists essentially of a third metallic casting.

3. The vane of claim 1 wherein:

the shell lacks tensile webs connecting the shell pressure and suction sides.

4. The vane of claim 1 wherein:

at least along part of said region, said region forms at least 50% of a local thickness of the shell.

5. The vane of claim 1 wherein:

along said region the depth-wise coefficient of thermal expansion is at least 105% of the second coefficient of thermal expansion.

6. The vane of claim 1 wherein:

the second coefficient of thermal expansion is a streamwise coefficient of thermal expansion.

7. The vane of claim 1 wherein:

the first fibers have a lengthwise coefficient of thermal expansion greater than a lengthwise coefficient of thermal expansion of the second fibers.

8. The vane of claim 7 wherein:

the first fibers' lengthwise coefficient of thermal expansion is at least 5% greater than the second fibers' lengthwise coefficient of thermal expansion.

9. The vane of claim 1 wherein:

the region includes the leading edge.

10. The vane of claim 9 wherein:

the region extends at least 5% of a streamwise distance from the leading edge to the trailing edge along the suction side; and

the region extends at least 5% of a streamwise distance from the leading edge to the trailing edge along the pressure side.

11. The vane of claim 9 wherein:

the region extends 5-20% of a streamwise distance S S from the leading edge to the trailing edge along the suction side; and

the region extends 5-20% of a streamwise distance S P from the leading edge to the trailing edge along the pressure side.

12. A method of manufacturing the vane of claim 1 comprising:

casting the shroud;

casting the platform;

casting the spar; and

ceramic matrix infiltration of a ceramic fiber preform to form the shell.

13. A method of manufacturing a vane, the vane comprising:

an airfoil shell having:

a leading edge;

a trailing edge;

a pressure side; and

a suction side;

a spar within the shell;

an outboard shroud at an outboard end of the shell; and

an inboard platform at an inboard end of the shell,

wherein the shell comprises:

a region having a depth-wise coefficient of thermal expansion and a second coefficient of thermal expansion tranverse thereto, the depth-wise coefficient of thermal expansion being greater than the second coefficient of thermal expansion,

the method comprising:

casting the shroud;

casting the platform;

casting the spar;

forming a ceramic fiber preform by stitching a higher coefficient of thermal expansion fiber in the depth-wise direction than a lower coefficient of thermal expansion fiber transverse thereto; and

ceramic matrix infiltration of the ceramic fiber preform to form the shell.

14. The method of claim 13 wherein:

forming the preform comprises braiding or filament winding the lower coefficient of thermal expansion fiber before the stitching.

15. A method for engineering a vane having:

an airfoil shell having:

a leading edge;

a trailing edge;

a pressure side; and

a suction side;

a spar within the shell;

an outboard shroud at an outboard end of the shell; and

an inboard platform at an inboard end of the shell,

the method comprising:

providing a shell configuration having a local anisotropy of coefficient of thermal expansion along a region; and

determining a thermal-mechanical stress profile,

wherein:

the method is a reengineering from a baseline configuration to a reengineered configuration wherein:

operational extreme magnitudes of positive axial stress, negative axial stress, positive interlaminar tensile stress, and negative interlaminar tensile stress are all reduced by at least 50% from the baseline configuration to the reengineered configuration.

16. The method of claim 15 wherein:

the providing and determining are iteratively performed as a simulation.

17. The method of claim 15 wherein:

an external sectional shape of the shell is preserved from a baseline.

18. The method of claim 15 wherein the region extends 5-20% of a streamwise distance S S from the leading edge to the trailing edge along the suction side and 5-20% of a streamwise distance S P from the leading edge to the trailing edge along the pressure side.

19. A method for engineering a vane having:

an airfoil shell having:

a leading edge;

a trailing edge;

a pressure side; and

a suction side;

a spar within the shell;

an outboard shroud at an outboard end of the shell; and

an inboard platform at an inboard end of the shell,

the method comprising:

providing a shell configuration having a local anisotropy of coefficient of thermal expansion along a region; and

determining a thermal-mechanical stress profile,

wherein the method is a reengineering from a baseline configuration to a reengineered configuration wherein:

the shell is thinned at least at one location along a leading tenth of the shell from the baseline configuration to the reengineered configuration.

20. A method for engineering a vane having:

an airfoil shell having:

a leading edge;

a trailing edge;

a pressure side; and

a suction side;

a spar within the shell;

an outboard shroud at an outboard end of the shell; and

an inboard platform at an inboard end of the shell,

the method being a reengineering from baseline configuration to a reengineered configuration comprising:

providing a shell configuration having an anisotropy of coefficient of thermal expansion along a region; and

thinning the shell at least at one location along a leading tenth of the shell from the baseline configuration to the reengineered configuration.

21. A method for engineering a vane having:

an airfoil shell having:

a leading edge;

a trailing edge;

a pressure side; and

a suction side;

a spar within the shell;

an outboard shroud at an outboard end of the shell; and

an inboard platform at an inboard end of the shell,

the method being a reengineering from baseline configuration to a reengineered configuration comprising:

providing a shell configuration having an anisotropy of coefficient of thermal expansion along a region; and

reducing operational extreme magnitudes of positive axial stress, negative axial stress, positive interlaminar tensile stress, and negative interlaminar tensile stress by at least 50% from the baseline configuration to the reengineered configuration.