STRUT AND A GAS TURBINE STRUCTURE COMPRISING THE STRUT

• US 20120093642A1
• Filed: 05/07/2009
• Published: 04/19/2012
• Est. Priority Date: 05/07/2009
• Status: Active Grant

• Current Assignee: GKN Aerospace Sweden AB (Melrose Industries Plc)
• Original Assignee: Volvo Aero Corporation (Melrose Industries Plc)
• Inventors: Nilsson, Martin, Mårtensson, Hans
• Granted Patent: US 8,794,912 B2
• Time in Patent Office: Days
• US Class Current: 415/213.1
• CPC Class Codes: F01D 5/145 Means for influencing boundary layers or secondary circulations for compressors F04D29/68
• CPC Class Codes: F01D 9/04 forming ring or sector
• CPC Class Codes: F01D 9/06 Fluid supply conduits to nozzles or the like
• CPC Class Codes: F02C 7/20 Mounting or supporting of plant; Accommodating heat expansion or creep
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A strut for application between an outer ring and an inner ring in a gas turbine structure and a gas turbine structure including such a strut are provided. The strut includes an end portion which has a diverging shape so that an internal space is formed in the end portion for receiving at least part of an engine mount. Engine mounting lugs can be positioned at such struts.

Claims

1. A strut (32) for application between an outer ring (20) and an inner ring (28) in a gas turbine structure, characterized in that an end portion (37) of the strut (32) has a diverging shape so that an internal space (30) is formed in the end portion (37) for receiving at least part (39) of an engine mount (26).

2. A strut according to claim 1, characterized in that at the end portion (37) of the strut (32) at least the central parts of a first and a second opposed strut faces (42) diverge in direction towards a strut end (34).

3. A strut according to claim 1 or 2, characterized in that the end portion (37) of the strut (32) at least partially has a curved shape.

4. A strut according to any of claims 1-3, characterized in that said curved shape defines a concave surface.

5. A strut according to any of the preceding claims, characterized in that said curved shape has an inflexion line (43) where the end portion (37) changes from being concave to being convex

6. A strut according to any of the preceding claims, characterized in that said end portion of the strut includes a smooth strut area (56) where edge portions (52,54) of a cross section of the strut (32) in a plane in the radial direction has a curvature radius (C) which exceeds 0.15 L, where L equals a length of the strut.

7. A strut according to claim 6, characterized in that a recess (30) is located in the end portion (37) of said strut (32), said recess (30) being accessible externally of said outer ring (20), wherein said recess (30) is having a depth D.

8. A strut according to claim 7, characterized in that said smooth strut area (56) extending from a position located at a distance of D/2 to a distance 2D from an end (34) of the strut.

9. A strut according to any of claims 6-8, characterized in that said edge portions (52,54) are concave within said smooth strut area (56).

10. A strut according to claim 9, characterized in that said curvature radius (C) has its minimum at distance to said end (34) of the strut less than D.

11. A strut according to claim 10, characterized in that a derivative of said curvature radius (C) is monotonously increasing in said area (56) in a direction outwardly toward said end (34) of the strut.

12. A strut according to any of claims 6-8, characterized in that said edge portions (52,54) changes from being concave to being convex once within said smooth strut area (56).

13. A strut according to claim 12, characterized in that said curvature radius (C) has its minimum value at distance to said end (34) of the strut less than D.

14. A strut according to claim 12 or 13, characterized in that an inflection point (62) at which said edge portions (52,54) changes from being concave to being convex is located within an inner end area (64) extending from a location located between 5D/6 to 7D/6 from said end (34) of the strut.

15. A strut according to any preceding claim, characterized in that cross sections of the strut (32) taken at different distances from a strut end (34) should, at least in a part of the strut located closer to an end (34) of the strut housing said internal space (30) than an inner end (45) of the internal space (30), all have a shape of an aerodynamic air foil including a rounded front edge (46) and a relatively sharp rear edge (48) connected by curved strut faces (41, 42).

16. A strut according to any preceding claim, characterized in that the strut end portion (37) comprises a wall (47) which is continuous around said internal space.

17. A strut according to any preceding claim, characterized in that the strut forms a one-piece unit.

18. A gas turbine structure comprising an outer ring (20) and an inner ring (28) and a plurality of circumferentially spaced struts (22) extending between the inner ring (28) and the outer ring (20), characterized in that at least one of said struts (22) is formed by the strut (32) according to any one of claims 1-16 and that said end portion (37) is connected to the outer ring (20).

19. A gas turbine structure according to claim 18, characterized in that the outer ring (20) comprises at least one radial opening (30), that the strut (32) is connected to the outer ring (20) so that the internal space in the end portion faces the radial opening (30) and that the gas turbine structure comprises an engine mount (39), which is positioned in the internal space.

20. A gas turbine structure according to claim 19, characterized in that the engine mount (39) is positioned at least partially radially inside the outer ring (20).

21. A strut for application between an outer ring and an inner ring in a gas turbine structure, wherein an end portion of the strut has a diverging shape so that an internal space is formed in the end portion for receiving at least part of an engine mount.

22. A strut according to claim 21, wherein at the end portion of the strut at least the central parts of a first and a second opposed strut faces diverge in direction towards a strut end.

23. A strut according to claim 21 or 22, wherein the end portion of the strut at least partially has a curved shape.

24. A strut according to any of claims 21-23, wherein said curved shape defines a concave surface.

25. A strut according to any of the claims 21-24, wherein said curved shape has an inflexion line where the end portion changes from being concave to being convex

26. A strut according to any of the claims 21-25, wherein said end portion of the strut includes a smooth strut area where edge portions of a cross section of the strut in a plane in the radial direction has a curvature radius C which exceeds 0.15 L, where L equals a length of the strut.

27. A strut according to claim 26, wherein a recess is located in the end portion of said strut, said recess being accessible externally of said outer ring, wherein said recess is having a depth D.

28. A strut according to claim 27, wherein said smooth strut area extending from a position located at a distance of D/2 to a distance 2D from an end of the strut.

29. A strut according to any of claims 26-28, wherein said edge portions are concave within said smooth strut area.

30. A strut according to claim 29, wherein said curvature radius C has its minimum at distance to said end of the strut less than D.

31. A strut according to claim 30, wherein a derivative of said curvature radius C is monotonously increasing in said area in a direction outwardly toward said end of the strut.

32. A strut according to any of claims 26-28, wherein said edge portions changes from being concave to being convex once within said smooth strut area.

33. A strut according to claim 32, wherein said curvature radius C has its minimum value at distance to said end of the strut less than D.

34. A strut according to claim 32 or 33, wherein an inflection point 62 at which said edge portions changes from being concave to being convex is located within an inner end area extending from a location located between 5D/6 to 7D/6 from said end of the strut.

35. A strut according to any of claims 21-34, wherein cross sections of the strut taken at different distances from a strut end should, at least in a part of the strut located closer to an end of the strut housing said internal space than an inner end of the internal space, all have a shape of an aerodynamic air foil including a rounded front edge and a relatively sharp rear edge connected by curved strut faces.

36. A strut according to any of claims 21-35, wherein the strut end portion comprises a wall which is continuous around said internal space.

37. A strut according to any of claims 21-36, the strut forms a one-piece unit.

38. A gas turbine structure comprising an outer ring and an inner ring and a plurality of circumferentially spaced struts extending between the inner ring and the outer ring wherein at least one of said struts is formed by the strut according to any one of claims 21-37 and that said end portion is connected to the outer ring.

39. A gas turbine structure according to claim 38, wherein the outer ring comprises at least one radial opening, that the strut is connected to the outer ring so that the internal space in the end portion faces the radial opening and that the gas turbine structure comprises an engine mount, which is positioned in the internal space.

40. A gas turbine structure according to claim 39, wherein the engine mount is positioned at least partially radially inside the outer ring.