MOUNTING APPARATUS FOR LOW-DUCTILITY TURBINE SHROUD

• US 20130156550A1
• Filed: 12/15/2011
• Published: 06/20/2013
• Est. Priority Date: 12/15/2011
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Franks, Michael John, Shapiro, Jason David, Rulli, Samuel Ross, Doughty, Roger Lee
• Granted Patent: US 9,726,043 B2
• Time in Patent Office: Days
• US Class Current: 415/126
• CPC Class Codes: F01D 11/08 for sealing space between rotor blade tips and stator specially-shaped blade tips therefor F01D5/20
• CPC Class Codes: F01D 11/12 using a rubstrip, e.g. erodible. deformable or resiliently-biased part
• CPC Class Codes: F01D 11/24 by selectively cooling-heating stator or rotor components
• CPC Class Codes: F01D 25/246 Fastening of diaphragms or stator-rings
• CPC Class Codes: F01D 5/284 Selection of ceramic materials
• CPC Class Codes: F05D 2240/11 Shroud seal segments
• CPC Class Codes: F05D 2250/41 with one degree of freedom
• CPC Class Codes: F05D 2260/38 by a spring, i.e. spring loaded or biased towards a certain position
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A shroud apparatus for a gas turbine engine includes: an annular metallic hanger; a shroud segment disposed inboard of the hanger, comprising low-ductility material and having a cross-sectional shape defined by opposed forward and aft walls, and opposed inner and outer walls, the walls extending between opposed first and second end faces, wherein the inner wall defines an arcuate inner flowpath surface; and a retainer mechanically coupled to the hanger which engages the shroud segment to retain the shroud segment to the hanger while permitting movement of the shroud segment in a radial direction.

Claims

1. A shroud apparatus for a gas turbine engine, comprising:

an annular metallic hanger;

a shroud segment disposed inboard of the hanger, comprising low-ductility material and having a cross-sectional shape defined by opposed forward and aft walls, and opposed inner and outer walls, the walls extending between opposed first and second end faces, wherein the inner wall defines an arcuate inner flowpath surface; and

a retainer mechanically coupled to the hanger which engages the shroud segment to retain the shroud segment to the hanger while permitting movement of the shroud segment in a radial direction.

2. The apparatus of claim 1 wherein the retainer includes a central portion with a pair of opposed arms extending laterally outward therefrom.

3. The apparatus of claim 1 wherein a surface of the retainer is clamped against the hanger, and the outer wall of the shroud segment is trapped between the hanger and a portion of the retainer.

4. The apparatus of claim 3 wherein a spring is clamped between the hanger and the retainer and resiliently bears against the shroud segment so as to urge it radially inboard against the retainer.

5. The apparatus of claim 1 wherein the inner wall extends axially forward past the forward wall to define a forward overhang and the inner wall extends axially aft past the aft wall to define an aft overhang.

6. The apparatus of claim 1 wherein the hanger is surrounded and carried by an annular turbine case.

7. The apparatus of claim 6 wherein the hanger includes axially-spaced-apart forward and aft hooks which are received by forward and aft rails of the turbine case, respectively.

8. The apparatus of claim 1 wherein the hanger has an annular body with a forward end disposed radially inboard relative to an aft end thereof.

9. The apparatus of claim 8 wherein the shroud segment includes a transition wall disposed between the forward and outer walls and extending at acute angles to both the forward and outer walls.

10. The apparatus of claim 9 wherein the transition wall extends generally parallel to the body of the hanger.

11. The apparatus of claim 8 wherein the hanger includes a resilient aft inner leg which resiliently loads the shroud segment axially forward against a bearing surface of a forward inner leg of the hanger.

12. The apparatus of claim 1 further comprising a hollow impingement baffle disposed inside the shroud segment.

13. The apparatus of claim 12 wherein a coolant feed passage extends through the hanger and connects to the interior of the impingement baffle.

14. The apparatus of claim 1 wherein the shroud segment comprises a ceramic matrix composite material.

15. The apparatus of claim 1 wherein an annular ring of shroud segments are arranged in an annular array within the casing.

16. A shroud apparatus for a gas turbine engine, comprising:

a shroud segment comprising low-ductility material and having an inner wall defining an arcuate inner flowpath surface and axially-spaced-apart forward and aft walls extending radially outward from the inner wall;

wherein the inner wall extends axially past at least one of the forward wall or the aft wall to define an overhang.

17. The apparatus of claim 16 wherein the inner wall extends axially forward past the forward wall to define a forward overhang and the inner wall extends axially aft past the aft wall to define an aft overhang.

18. The apparatus of claim 16 wherein the shroud segment includes an outer wall spaced away from the inner wall and extending between the forward and aft walls.

19. The apparatus of claim 18 further including a transition wall disposed between the forward and outer walls and extending at acute angles to both the forward and outer walls.

20. The apparatus of claim 16 wherein an array of the shroud segments are arranged to form a closed annulus.

21. The apparatus of claim 16 wherein the shroud segment comprises a ceramic matrix composite material.

22. The apparatus of claim 16 further comprising an abradable coating disposed on the inner flowpath surface.

23. The apparatus of claim 22 wherein the coating includes a pattern of grooves therein.

24. The apparatus of claim 23 wherein the pattern includes a plurality of parallel side-by-side grooves.

25. The apparatus of claim 23 wherein the grooves are curved, each groove having a central portion disposed between forward and aft ends, the central portion being offset in a tangential direction relative to the forward and aft ends.

26. A shroud apparatus for a gas turbine engine, comprising:

an annular metallic hanger including an arcuate body and axially-spaced-apart forward and aft inner legs extending radially inward from the body, the forward inner leg including an arcuate forward bearing surface and the aft inner leg including an arcuate aft bearing surface; and

a shroud segment disposed inboard of the hanger, comprising low-ductility material and having an inner wall defining an arcuate inner flowpath surface and axially-spaced-apart forward and aft walls extending radially outward from the inner wall;

wherein the shroud segment is mounted relative to the hanger such that the forward bearing surface bears against the forward wall and the aft bearing surface bears against the aft wall, such that the shroud segment and the hanger cooperatively define a plenum therebetween.

27. The shroud apparatus of claim 26 further comprising a retainer mechanically coupled to the hanger which engages the shroud segment to retain the shroud segment to the hanger while permitting movement of the shroud segment in a radial direction.

28. The shroud apparatus of claim 26 wherein the aft inner leg resiliently loads the shroud segment axially forward against the forward bearing surface of the hanger.