METHOD AND APPARATUS FOR IMPROVING TURBINE BLADE SEALING IN A GAS TURBINE ENGINE

• US 20200131915A1
• 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, HERBER, PAUL, HARDEGREE, NATE
• Granted Patent: US 11,131,200 B2
• Time in Patent Office: Days
• CPC Class Codes: B22F 10/20 Direct sintering or melting
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 5/04 of turbine blades
• CPC Class Codes: B22F 7/08 with one or more parts not made from powder B22F7/062 takes precedence
• CPC Class Codes: B23P 15/04 turbine or like blades from several pieces
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: F01D 11/08 for sealing space between rotor blade tips and stator specially-shaped blade tips therefor F01D5/20
• CPC Class Codes: F01D 5/005 Repairing methods or devices
• CPC Class Codes: F01D 5/187 Convection cooling
• CPC Class Codes: F01D 5/20 Specially-shaped blade tips to seal space between tips and stator F01D5/225 takes precedence
• CPC Class Codes: F01D 5/225 by shrouding
• CPC Class Codes: F05D 2230/12 by spark erosion methods
• CPC Class Codes: F05D 2230/21 by casting
• CPC Class Codes: F05D 2230/22 by sintering
• CPC Class Codes: F05D 2230/234 Laser welding
• CPC Class Codes: F05D 2230/237 Brazing
• CPC Class Codes: F05D 2230/30 with deposition of material
• CPC Class Codes: F05D 2230/31 Layer deposition
• CPC Class Codes: F05D 2240/307 related to the tip of a rotor blade
• CPC Class Codes: F05D 2260/20 Heat transfer, e.g. cooling
• CPC Class Codes: Y02P 10/25 : Process efficiency
• CPC Class Codes: Y02T 50/60 : Efficient propulsion technologies, e.g. for aircraft

Abstract

A system and method for improving sealing at a turbine blade tip shroud, while reducing weight associated with the improved sealing is disclosed. The gas turbine blade incorporates a tip shroud having one or more pockets located therein, where the one or more pockets remove weight from the shroud, thus reducing load on the blade attachment generated by additional sealing at the turbine blade shroud. Methods for incorporating the one or more tip shrouds in a new turbine blade or a repaired turbine blade are also disclosed.

Claims

1. A method for reducing weight of a turbine blade and improving sealing of a blade tip region comprising:

providing the turbine blade having an airfoil, a tip shroud, and a knife edge extending radially outward from the tip shroud;

adding material to an outer surface of the tip shroud to form an additional knife edge; and

, placing a pocket in at least a portion of the tip shroud;

wherein a portion of a weight added by the material of the additional knife edge is removed by the pocket in the tip shroud.

2. The method of claim 1, wherein the pocket is placed in the tip shroud by an EDM process.

3. The method of claim 1, wherein the pocket is placed in the tip shroud during casting of the turbine blade.

4. The method of claim 1, wherein the pocket extends into a portion of the airfoil.

5. The method of claim 1, wherein the pocket surrounds one or more cooling holes extending into the tip shroud.

6. The method of claim 5, wherein the pocket distributes cooling flow from the one or more cooling holes to the tip shroud.

7. The method of claim 1, wherein the second knife edge is added by brazing a strip of material to the outer surface of the tip shroud.

8. The method of claim 1, wherein the second knife edge is added by an additive manufacturing process.

9. A gas turbine blade comprising:

an 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; and

,

one or more pockets in the tip shroud, the one or more pockets extending from an outer surface of the tip shroud and towards the airfoil.

10. The turbine blade of claim 9, wherein the one or more pockets have a tapered bottom surface such that the one or more pockets varies in depth.

11. The turbine blade of claim 9 further comprising one or more cooling channels extending through at least the airfoil.

12. The turbine blade of claim 11, wherein the one or more pockets encompass the one or more cooling channels.

13. The turbine blade of claim 9, wherein the one or more pockets are placed in the shroud by a machining process.

14. The turbine blade of claim 9, wherein the one or more pockets are cast into the tip shroud.

15. The turbine blade of claim 9, wherein the one or more pockets have an axial length greater than a circumferential width.

16. The turbine blade of claim 9, wherein the at least one pocket comprises at least two pockets with at least one pocket positioned on opposite sides of the knife edge.

17. A method of modifying a turbine blade to reduce airflow passing around a tip of the turbine blade comprising forming at least one additional knife edge extending radially outward from a tip shroud of the turbine blade, the at least one additional knife edge added to the tip shroud in a subsequent manufacturing process.

18. The method of claim 17 further comprising placing at least one pocket in the tip shroud.

19. The method of claim 17, wherein the at least one additional knife edge is added to the tip shroud by an additive manufacturing process.

20. The method of claim 17, wherein the at least one additional knife edge is added to the tip shroud by brazing material to an outer surface of the tip shroud.