Thermal control damper for turbine rotors

• US 5,281,097 A
• Filed: 11/20/1992
• Issued: 01/25/1994
• Est. Priority Date: 11/20/1992
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Wilson, Paul S., Shelton, Monty L., Rankey, Dean A., Wallace, Thomas T.
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): Lee, Michael S.
• Application Number:
  US07/979,026
• Time in Patent Office: 431 Days
• Field of Search: 415/115, 415/116, 416/95, 416/193 A, 416/219 R, 416/220 R, 416/500
• US Class Current: 416/193.00A
• CPC Class Codes: F01D 11/006 Sealing the gap between rotor blades or blades and rotor
• CPC Class Codes: F01D 5/081 Cooling fluid being directed on the side of the rotor disc or at the roots of the blades F01D5/087 takes precedence
• CPC Class Codes: F01D 5/22 Blade-to-blade connections, e.g. for damping vibrations
• CPC Class Codes: F05D 2240/81 Cooled platforms
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft
• CPC Class Codes: Y10S 416/50 Vibration damping features

Abstract

Sheet Metal thermal control dampers are disposed in the cavities between turbine blades to bear against the undersides of opposed blade platforms portions of angularly adjacent blades under centrifugal loading to dampen blade vibrations and to seal the gaps between platforms against the radial flow of working fluid into the interblade cavities. The dampers are configured to cooperate with forward and aft seals to also block the axial flow of working fluid through the interblade cavities. Holes are provided in the dampers through which cooling air introduced into the interblade cavities can flow into contact with the platform undersides and cool the platforms, thereby controlling temperature rise in the blade attachment structure.

Claims

1. Apparatus for damping vibrations and for controlling the temperature of attachment structure securing blades to turbine disks of a gas turbine engine, said apparatus comprising, in combination:

A) a damper disposed in an interblade cavity between each adjacent pair of angularly spaced blades of a turbine disk, said damper comprised of a metallic sheet configured to assume an operative position under centrifugal loading in surface contact with the undersurfaces of circumferentially opposed platform portions of an adjacent pair of blades, whereby to dampen vibrations in the adjacent blade pair and to seal a gap between axially extending edges of the opposed platforms portions, said damper further including a plurality of holes therein open to the interblade cavity; and

B) means for cooling the blade attachment structure by introducing cooling air into the interblade cavity for flow through said holes to cool at least one of the opposed platform portions.

2. The apparatus defined in claim 1, wherein said metallic sheet of said damper is in the range of 15 to 40 mils thick.

3. The apparatus defined in claim 1, wherein said cooling means further includes a recess formed in the undersurface of said one opposed platform portions in registry with each said damper hole.

4. The apparatus defined in claim 3, wherein said cooling means further includes a separate groove formed in the undersurface of said one opposed platform portion extending from each said recess to the axially extending edge thereof, said cooling means operable to flow the cooling air such that the cooling air;

1) flows through said holes into said recesses to impingement cool said one opposed platform portion,

2) flows from said recesses through passages provided by said grooves and said damper to convection cool said one opposed platform portion, and

3) flows from said passages into the gap to film cool the axially extending edges of the opposed platform portions.

5. The apparatus defined in claim 4, wherein said cooling means further includes additional recesses and grooves formed in the undersurface of the other said opposed platform portion, a separate hole in said damper registered with each of said additional recesses.

6. The apparatus defined in claim 1, wherein each blade includes an airfoil projecting radially outwardly from the platform, a shank projecting radially inwardly from the platform, and a root joined to the radially inner end of the shank, the root being captured in a slot in the turbine disk periphery by forward and aft retainers, said damper is formed having an intermediate top face section containing said holes, an radially inwardly turned forward face section and a radially inwardly turned aft face section, all in contact with the undersurfaces of the opposed platform portions, said forward and aft face sections being in partially lapped relation with forward and aft seals, respectively, to block the axial flow of hot working fluid through the interblade cavity.

7. The apparatus defined in claim 1, wherein each said blade includes an airfoil projecting radially outwardly from the platform into an axially flowing working fluid stream, a shank projecting radially inwardly from the platform, and a root joined to the radially inner end of the shank, the root being captured in a slot in the turbine disk periphery, each adjacent pair of disk slots being separated by a disk post, said cooling means includes at least one cooling passage accommodating the flow of cooling air from a gap between the blade root and the disk slot into the interblade cavity.

8. The apparatus defined in claim 7, wherein each blade includes at least one internal passage extending radially through the root, shank and airfoil to accommodate cooling air flow therethrough from the gap between the blade root and disk slot, said cooling passage communicating with said internal passage.

9. The apparatus defined in claim 7, wherein said cooling passage is formed in the disk post.

10. The apparatus defined in claim 8, wherein said cooling passage is defined by a groove in a radial face surface of the disk post and one of the retainers.

11. The apparatus defined in claim 7, wherein said cooling means further includes a recess formed in the undersurface of at least one of said opposed platform portions in registry with each said damper hole.

12. The apparatus defined in claim 11, wherein said cooling means further includes a separate groove formed in the undersurface of said one opposed platform portion extending from each said recess to the axially extending edge thereof, said cooling means operable to flow the cooling air such that the cooling air;

1) flows through said holes into said recesses to impingement cool said one opposed platform portion,

2) flows from said recesses through passages provided by said grooves and said damper to convection cool said one opposed platform portion, and

3) flows from said passages into the gap to film cool the axially extending edges of the opposed platform portions.

13. The apparatus defined in claim 12, wherein said cooling means further includes additional recesses and grooves formed in the undersurface of the other said opposed platform portion, a separate hole in said damper registered with each said additional recess.

14. The apparatus defined in claim 13, wherein each blade includes at least one internal passage extending radially through the root, shank and airfoil to accommodate cooling air flow therethrough from the gap between the blade root and disk slot, said cooling passage communicating with said internal passage.

15. The apparatus defined in claim 13, wherein said cooling passage is formed in the disk post.

16. The apparatus defined in claim 14, wherein said cooling passage is defined by a groove in a radial face surface of the disk post and one of the retainers.

17. The apparatus defined in claim 13, wherein said damper is formed having an intermediate top face section containing said holes, a radially inwardly turned forward face section and a radially inwardly turned aft face section, all in contact with the undersurfaces of the opposed platform portions, said forward and aft face sections being in partially lapped relation with forward and aft seals, respectively, to block the axial flow of hot working fluid through the interblade cavity.

18. The apparatus defined in claim 17, wherein said metallic sheet of said damper is in the range of 15 to 40 mils thick.

19. The apparatus defined in claim 5, wherein said grooves formed in the undersurface of said opposed platform portions have serpentine shapes.