METHOD AND APPARATUS FOR IMPROVING COOLING OF A TURBINE SHROUD

• US 20200131913A1
• Filed: 10/29/2018
• Published: 04/30/2020
• Est. Priority Date: 10/29/2018
• Status: Active Grant

• Current Assignee: Chromalloy Gas Turbine LLC (Blue Jay Acquisition Corp.)
• Original Assignee: Chromalloy Gas Turbine LLC (Blue Jay Acquisition Corp.)
• Inventors: STROHL, JAMES PAGE, MEDRANO, MARIANO, PARKER, DAVID G.
• Granted Patent: US 11,339,668 B2
• Time in Patent Office: Days
• CPC Class Codes: F01D 5/187 Convection cooling
• CPC Class Codes: F01D 5/225 by shrouding
• CPC Class Codes: F05D 2230/233 Electron beam welding
• CPC Class Codes: F05D 2230/234 Laser welding
• CPC Class Codes: F05D 2230/235 TIG or MIG welding
• CPC Class Codes: F05D 2230/237 Brazing
• CPC Class Codes: F05D 2240/307 related to the tip of a rotor blade
• CPC Class Codes: F05D 2240/81 Cooled platforms
• CPC Class Codes: F05D 2260/201 by impingement of a fluid
• CPC Class Codes: F05D 2260/22141 using fins or ribs
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A system and method for cooling a turbine blade tip shroud is provided. The turbine blade comprises a blade attachment, a platform extending radially outward from the attachment, an airfoil extending radially outward from the platform, and a tip shroud extending radially outward from the airfoil. The tip shroud has one or more knife edges extending radially outward from an outer surface of the tip shroud. One or more cooling passages extend through the airfoil and to the tip shroud. The turbine blade also includes one or more tip plates secured at or near the outer surface of the tip shroud thereby forming a plenum between the outer surface and the one or more tip plates. The one or more tip plates also include a plurality of cooling holes for flowing cooling air through the plenum to cool the tip shroud.

Claims

1. A turbine blade comprising:

a blade attachment;

a platform extending radially outward from the attachment;

an airfoil extending radially outward from the platform;

a tip shroud extending circumferentially from the airfoil, the tip shroud having one or more knife edges extending radially outward from an outer surface of the tip shroud;

one or more cooling passages extending through the airfoil and to the tip shroud;

one or more tip plates secured to the tip shroud thereby forming a plenum between the outer surface and the one or more tip plates; and

,

a plurality of cooling holes in the one or more tip plates, where the plurality of cooling holes is positioned at least adjacent the one or more knife edges.

2. The turbine blade of claim 1, wherein the one or more cooling passages are stem drilled cooling holes.

3. The turbine blade of claim 1, wherein the one or more cooling passages are cast into the airfoil.

4. The turbine blade of claim 1, wherein the plurality of cooling holes is located along a perimeter of the tip plate.

5. The turbine blade of claim 1 further comprising a plurality of shroud cooling holes located in an outer perimeter of the tip shroud, where the shroud cooling holes are in communication with the plenum.

6. The turbine blade of claim 1 wherein the one or more tip plates is secured to the tip shroud by a welding or brazing process.

7. The turbine blade of claim 6, wherein the tip plate further comprises a curved edge around at least a portion of a perimeter of the tip plate.

8. The turbine blade of claim 1, wherein the tip plate has an inner surface generally parallel to and adjacent the outer surface of the tip shroud.

9. A method of enhancing cooling of a turbine blade tip shroud comprising:

forming one or more tip plates sized to fit over at least a portion of the tip shroud;

placing a plurality of cooling holes in the one or more tip plates;

securing the one or more tip plates a distance from the tip shroud thereby forming a plenum between the tip plate and the one or more tip shrouds;

directing a flow of air through cooling passages in an airfoil of the blade and to the plenum; and

,

directing the flow of air through the plenum and through the plurality of cooling holes in the one or more tip plates.

10. The method of claim 9, wherein the one or more tip plates further comprises a curved edge around at least a portion of a perimeter of the one or more tip plates.

11. The method of claim 9, wherein the plurality of cooling holes is angled away from a center region of the one or more tip plates.

12. The method of claim 9, wherein the one or more tip plates extend between knife edges of the tip shroud.

13. The method of claim 12, wherein the flow of air is directed from the plenum, through the plurality of cooling holes, and towards the knife edges.

14. The method of claim 9, wherein the one or more tip plates is secured to the tip shroud by a welding or brazing process.

15. The method of claim 9 further comprising placing a plurality of shroud cooling holes in a perimeter of the tip shroud.

16. A method of forming a cooled tip shroud for a gas turbine blade comprising:

providing the gas turbine blade having an air cooled passageway and tip shroud;

determining an area of the tip shroud to be cooled;

forming a tip plate to be positioned in the area of the tip shroud to be cooled;

drilling a plurality of cooling holes in the tip plate;

cleaning a surface of the tip shroud to which the tip plate will be secured; and

,

fixing the tip plate to the tip shroud, thereby forming a plenum between the tip shroud and the tip plate.

17. The method of claim 16, wherein the air cooled passageway is one or more stem drilled cooling holes or one or more serpentine passageways.

18. The method of claim 16, wherein the area of the tip shroud to be cooled is between knife edges of the tip shroud.

19. The method of claim 16, wherein the area of the tip shroud to be cooled is between a knife edge of the tip shroud and an outer edge of the tip shroud.

20. The method of claim 16, wherein the plurality of cooling holes in the tip plate are positioned about a perimeter of the tip plate.