Apparatus and methods for localized cooling of gas turbine nozzle walls

• US 6,543,993 B2
• Filed: 12/28/2000
• Issued: 04/08/2003
• Est. Priority Date: 12/28/2000
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies Europe BV (Agilent Technologies, Inc.), General Electric Company
• Original Assignee: General Electric Company
• Inventors: Itzel, Gary Michael, Burdgick, Steven Sebastian
• Primary Examiner(s): VERDIER, CHRISTOPHER M
• Application Number:
  US09/749,616
• Publication Number:
  US 20020085910A1
• Time in Patent Office: 831 Days
• Field of Search: 415/114, 415/115, 415/116, 416/96.R, 416/96.A, 416/97.R
• US Class Current: 415/116
• CPC Class Codes: F01D 25/12 Cooling
• CPC Class Codes: F01D 5/188 with an insert in the blade cavity to guide the cooling fluid, e.g. forming a separation wall
• CPC Class Codes: F01D 5/189 the insert having a tubular cross-section, e.g. airfoil shape
• CPC Class Codes: F01D 9/04 forming ring or sector
• CPC Class Codes: F05D 2240/128 Nozzles
• CPC Class Codes: F05D 2260/201 by impingement of a fluid
• CPC Class Codes: F05D 2260/2322 steam

Abstract

In a closed-circuit steam-cooling system for the first-stage nozzle of a gas turbine, each vane has a plurality of cavities with inserts. In the second cavity, a main insert receives cooling steam from an inner plenum for impingement-cooling of the side walls of the vane, the spent cooling steam exhausting between the main insert and the cavity walls into a steam outlet. To steam-cool a localized surface area of the vane adjacent the outer band, a secondary insert receives steam under inlet conditions from a first chamber of the outer band for impingement-cooling the localized surface area. The spent impingement-cooling steam from the secondary insert combines with the spent cooling steam from the main insert for flow to the outlet. Consequently, low-cycle fatigue is improved in the localized area by the impingement-cooling afforded by the secondary insert because of the cooler steam supplied, as well as the increased pressure drop driving the steam through the impingement openings of the secondary insert.

Claims

1. In a gas turbine nozzle having inner and outer bands and a vane extending therebetween having at least one cavity between side walls of the vane, an insert within said cavity and extending from said outer band and along and spaced from one of the side walls of said vane terminating within said cavity short of one-half the length of the vane, said insert defining a passage for receiving a cooling medium and having openings through a wall thereof for flowing the cooling medium therethrough to impingement-cool said one side wall of said vane and a passage for exhausting spent impingement cooling medium from the vane cavity.

2. Apparatus according to claim 1, wherein said outer band includes a plenum for receiving the cooling medium, said insert lying in communication with said plenum.

3. Apparatus according to claim 2, wherein said outer band includes an impingement plate in said plenum spaced from a wall of said outer band forming part of a hot gas path through the turbine, said impingement plate dividing the plenum into first and second chambers on opposite sides thereof and having a plurality of openings therethrough for flowing the cooling medium from said first chamber through said openings into said second chamber for impingement cooling said outer band wall, said insert lying in communication with said first chamber for receiving a portion of the cooling medium from said first chamber.

4. Apparatus according to claim 1, wherein said one side wall is a convex side wall of the vane.

5. In a gas turbine having inner and outer bands and a vane extending therebetween having at least one cavity between side walls of the vane, a first insert within said one cavity for receiving a cooling medium, said insert having lateral walls spaced from said side walls and a plurality of openings therethrough for flowing a cooling medium through said openings to impingement-cool the side walls of the vane, and a second insert within said one cavity and having a lateral wall in spaced opposition to one of said side walls with a plurality of openings therethrough for flowing a cooling medium therethrough to impingement-cool a portion of said one side wall, said second insert extending from adjacent said outer band into said vane a distance short of an inner end of said first insert.

6. Apparatus according to claim 5, wherein said first insert extends substantially the full length of said vane.

7. Apparatus according to claim 5 wherein said outer band includes a plenum for receiving the cooling medium, said second insert lying in communication with said plenum.

8. Apparatus according to claim 5 wherein said vane has convex and concave side walls, said second insert being located adjacent the convex side wall, with said plurality of openings through said lateral wall disposed to flow the cooling medium to impingement-cool a portion of said convex side wall.

9. Apparatus according to claim 5 wherein said second insert lies laterally between said one side wall and said first insert.

10. Apparatus according to claim 5 wherein said lateral wall of said second insert and said one wall lie closer to said outer band than said inner band.

11. In a gas turbine having inner and outer bands, a vane extending therebetween having at least one cavity between side walls of the vane and a closed circuit cooling system for flowing a cooling medium through said vane to cool the vane, a method of cooling a localized area along the vane wall comprising the steps of:

flowing a first portion of the cooling medium through a first insert in the one cavity for impingement cooling a first portion of the side walls of the vane;

flowing a second portion of the cooling medium through a second insert in said one cavity for cooling the localized area of the vane wall, and

supplying the second portion of the cooling medium to said second insert at a lower temperature than the temperature of the first portion of the cooling medium supplied to said first insert.

12. A method according to claim 11, including supplying the first and second portions of the cooling medium from a common source, passing the first portion of the cooling medium from said common source through said vane in one direction for cooling the vane and subsequently passing the first portion of the cooling medium into said first insert through said vane in a generally opposite direction to cool said vane.

13. A method according to claim 12, including passing the second portion of the cooling medium from said common source directly into said second insert.

14. A method according to claim 11, including providing a plenum for the cooling medium in said outer band, passing the first portion of the cooling medium from the plenum in a generally radial inward direction through said vane for cooling the vane and into a plenum in said inner band, subsequently passing the first portion of the cooling medium from the plenum in the inner band into said first insert for flow in a generally radial outward direction to cool said vane and passing the second portion of the cooling medium from the plenum in said outer band into said second insert.

15. A method according to claim 14, including combining spent first and second portions of the cooling medium for flow to a spent cooling medium outlet in said outer band.

16. A method according to claim 11, including forming a plurality of cavities in said vane, providing another insert in another of said cavities, providing a plenum for the cooling medium in said outer band, passing the first portion of the cooling medium from the plenum in a generally radial inward direction through said another insert for impingement cooling of another portion of the side walls of said vane and into a plenum in said inner band, subsequently passing the first portion of the cooling medium from the plenum in the inner band into said first insert for flow in a generally radial outward direction for impingement cooling of said side walls of said vane, passing the second portion of the cooling medium from the plenum in said outer band into said second insert, and combining spent first and second portions of the cooling medium for flow to a spent cooling medium outlet in said outer band.

17. A method according to claim 11, including supplying the second portion of the cooling medium to said second insert at a higher pressure than the pressure of the first cooling medium portion supplied to said first insert.

18. In a gas turbine having inner and outer bands, a vane extending therebetween having at least one cavity between side walls of the vane and a closed circuit cooling system for flowing a cooling medium through said vane to cool the vane, a method of cooling a localized area along the vane wall comprising the steps of:

flowing a first portion of the cooling medium through a first insert in the one cavity for impingement cooling a first portion of the side walls of the vane;

flowing a second portion of the cooling medium through a second insert in said one cavity for cooling the localized area of the vane wall; and

supplying the second portion of the cooling medium to said second insert at a higher pressure than the pressure of the first cooling medium portion supplied to said first insert.

19. A method according to claim 18, including supplying the first and second portions of the cooling medium from a common source, passing the first portion of the cooling medium from said common source through said vane in one direction for cooling the vane and subsequently passing the first portion of the cooling medium into said first insert through said vane in a generally opposite direction to cool said vane.

20. A method according to claim 19, including passing the second portion of the cooling medium from said common source directly into said second insert.

21. A method according to claim 18, including providing a plenum for the cooling medium in said outer band, passing the first portion of the cooling medium from the plenum in a generally radial inward direction through said vane for cooling the vane and into a plenum in said inner band, subsequently passing the first portion of the cooling medium from the plenum in the inner band into said first insert for flow in a generally radial outward direction to cool said vane and passing the second portion of the cooling medium from the plenum in said outer band into said second insert.

22. A method according to claim 21, including combining spent first and second portions of the cooling medium for flow to a spent cooling medium outlet in said outer band.

23. A method according to claim 18, including forming a plurality of cavities in said vane, providing another insert in another of said cavities, providing a plenum for the cooling medium in said outer band, passing the first portion of the cooling medium from the plenum in a generally radial inward direction through said another insert for impingement cooling of another portion of the side walls of said vane and into a plenum in said inner band, subsequently passing the first portion of the cooling medium from the plenum in the inner band into said first insert for flow in a generally radial outward direction for impingement cooling of said side walls of said vane, passing the second portion of the cooling medium from the plenum in said outer band into said second insert, and combining spent first and second portions of the cooling medium for flow to a spent cooling medium outlet in said outer band.

24. In a gas turbine having inner and outer bands and a vane extending therebetween having at least one cavity between side walls of the vane, a first insert within said one cavity for receiving a cooling medium, said insert having lateral walls spaced from said side walls and a plurality of openings therethrough for flowing a cooling medium through said openings to impingement-cool the side walls of the vane, and a second insert within said one cavity and having a lateral wall in spaced opposition to one of said side walls with a plurality of openings therethrough for flowing a cooling medium therethrough to impingement-cool a portion of said one side wall, said second insert extending a distance in said vane less than one-half the length of said vane between said inner and outer bands.

25. In a gas turbine having inner and outer bands and a vane extending therebetween having at least one cavity between side walls of the vane, a first insert within said one cavity for receiving a cooling medium, said insert having lateral walls spaced from said side walls and a plurality of openings therethrough for flowing a cooling medium through said openings to impingement-cool the side walls of the vane, and a second insert within said one cavity and having a lateral wall in spaced opposition to one of said side walls with a plurality of openings therethrough for flowing a cooling medium therethrough to impingement-cool a portion of said one side wall, said outer band including a plenum for receiving the cooling medium, said second insert lying in communication with said plenum, said outer band including an impingement plate in said plenum spaced from a wall of said outer band forming part of a hot gas path through the turbine, said impingement plate dividing the plenum into first and second chambers on opposite sides thereof and having a plurality of openings therethrough for flowing the cooling medium from said first chamber through said openings into said second chamber to impingement-cool said outer band wall, said second insert lying in communication with said first chamber for receiving a portion of the cooling medium from said first chamber.

26. In a gas turbine having a plurality of circumferentially arranged segments of a nozzle stage, each segment comprising inner and outer bands and a vane extending therebetween having a plurality of cavities between side walls of the vane, a closed-circuit cooling system for cooling the side walls of the vane including a plenum in said outer band for receiving a cooling medium for flow through one of said cavities into a plenum in said inner band and return flow through another of said plurality of cavities in said vane and through said outer band, the cooling system including a first insert within said another of said cavities for receiving the cooling medium from said inner band plenum, said first insert having lateral walls spaced from said side walls of the vane and a plurality of openings therethrough for flowing a cooling medium received from the inner band plenum through said openings to impingement-cool the side walls of the vane, and a second insert within said another cavity and having a lateral wall in spaced opposition to one of said side walls of said another cavity, said second insert lying in communication with said outer band plenum for receiving cooling medium therefrom and flowing the cooling medium through a plurality of openings through the lateral wall of said second insert to impingement-cool a portion of said one side wall.

27. Apparatus according to claim 26 wherein said vane has convex and concave side walls, said second insert being located adjacent the convex side wall, with said plurality of openings through said lateral wall disposed to flow the cooling medium to impingement-cool a portion of said convex side wall.

28. Apparatus according to claim 26 wherein said lateral wall of said second insert and said one side wall lie closer to said outer band than said inner band.