Bucket platform cooling scheme and related method

• US 20020076324A1
• Filed: 12/19/2000
• Published: 06/20/2002
• Est. Priority Date: 12/19/2000
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Starkweather, John Howard, Nellian, Sankar, Kercher, David Max, Lupe, Douglas Arthur, Chopra, Sanjay, Lenahan, Dean Thomas, Kellock, Iain Robertson, Barb, Kevin Joseph, Abuaf, Nesim
• Granted Patent: US 6,478,540 B2
• Time in Patent Office: Days
• US Class Current: 416/1
• CPC Class Codes: F01D 5/187 Convection cooling
• CPC Class Codes: F05D 2240/81 Cooled platforms
• CPC Class Codes: F05D 2260/201 by impingement of a fluid
• CPC Class Codes: F05D 2260/2214 by increasing the heat transfer surface

Abstract

A turbine bucket includes an airfoil extending from a platform, having high and low pressure sides; a wheel mounting portion; a hollow shank portion located radially between the platform and the wheel mounting portion, the platform having an under surface. An impingement cooling plate is located in the hollow shank portion, spaced from the under surface, and the impingement plate is formed with a plurality of impingement cooling holes therein.

Claims

1. A turbine bucket comprising:

an airfoil extending from a platform, having high and low pressure sides;

a wheel mounting portion;

a hollow shank portion located radially between the platform and the wheel mounting portion, said platform having an under surface; and

an impingement cooling plate located in said hollow shank portion, spaced from said under surface, said impingement plate having a plurality of impingement cooling holes therein.

2. The turbine bucket of claim 1 and further including an elongated rib between said under surface and said impingement plate, dividing said impingement plate into plural impingement zones.

3. The turbine bucket of claim 1 wherein said impingement plate is formed with plural, discrete arrays of said impingement cooling holes.

4. The turbine bucket of claim 3 wherein said impingement holes are substantially normal to upper and lower surfaces of said impingement plate.

5. The turbine bucket of claim 3 wherein said impingement plate includes a blank area without impingement holes, and wherein said platform is formed with an array of film cooling holes adapted to discharge air from said hollow shank portion, said array of film cooling holes substantially aligned with said blank area of said impingement plate.

6. The turbine bucket of claim 1 wherein said impingement plate is spaced from said under surface of said platform by about 0.10″

to about 0.30″

.

7. The turbine bucket of claim 1 wherein said impingement cooling holes have diameters of about 0.020 inch.

8. The turbine bucket of claim 1 wherein said impingement plate is located radially inward of said high pressure side of said airfoil.

9. The turbine bucket of claim 1 wherein said impingement plate is formed with plural, discrete arrays of said impingement cooling holes;

and wherein said impingement plate includes a blank area without impingement holes, and wherein said platform is formed with an array of film cooling holes adapted to discharge air from said hollow shank portion, said array of film cooling holes substantially aligned with said blank area of said impingement plate; and

further wherein said impingement plate is located radially inward of said high pressure side of said airfoil.

10. A gas turbine bucket comprising:

an airfoil extending from a platform, having high and low pressure sides;

a wheel mounting portion;

a hollow shank portion located radially between the platform and the wheel mounting portion, said platform having an under surface;

means for enabling impingement cooling of said under surface, and means for discharging cooling air from said hollow shank portion.

11. A method of cooling a turbine bucket platform located radially between an airfoil and a mounting portion, said platform forming a radially outer wall of a hollow shank portion comprising:

fixing an impingement cooling plate within said hollow shank portion, spaced from an under surface of said platform, said impingement cooling plate having a plurality of impingement cooling holes therein;

providing discharge holes in said platform; and

directing turbine wheelspace air flow through said impingement cooling holes and said discharge holes in said platform.

12. The method of claim 11 wherein said impingement plate is formed with plural, discrete arrays of said impingement cooling holes.

13. The method of claim 11 wherein said impingement holes are substantially normal to upper and lower surfaces of said impingement plate.

14. The method of claim 12 wherein said impingement plate includes a blank area without impingement holes, and wherein said platform is formed with an array of film cooling holes adapted to discharge air from said hollow shank portion, said array of film cooling holes substantially aligned with said blank area of said impingement plate.

15. The method of claim 14 wherein said impingement plate is formed with plural, discrete arrays of said impingement cooling holes;

and wherein said impingement plate includes a blank area without impingement holes, and wherein said platform is formed with an array of film cooling holes adapted to discharge air from said hollow shank portion, said array of film cooling holes substantially aligned with said blank area of said impingement plate; and

further wherein said impingement plate is located radially inward of said high pressure side of said airfoil.