Turbine airfoil with pressure side trailing edge cooling slots

• US 9,228,437 B1
• Filed: 03/22/2012
• Issued: 01/05/2016
• Est. Priority Date: 03/22/2012
• Status: Active Grant

• Current Assignee: Florida Turbine Technologies, Inc. (Kratos Defense & Security Solutions Incorporated)
• Original Assignee: Florida Turbine Technologies, Inc. (Kratos Defense & Security Solutions Incorporated)
• Inventors: Liang, George
• Primary Examiner(s): Kershteyn, Igor
• Application Number:
  US13/427,250
• Time in Patent Office: 1,384 Days
• Field of Search: 415/115, 415/116, 416/97.R, 416/97.A, 416/96.A, 416/96.R, 416/232, 298/897, 298/890.25
• US Class Current: 1/1
• CPC Class Codes: B23P 15/02 turbine or like blades from one piece
• CPC Class Codes: B23P 15/04 turbine or like blades from several pieces
• CPC Class Codes: F01D 5/087 in the radial passages of the rotor disc
• CPC Class Codes: F01D 5/187 Convection cooling
• CPC Class Codes: F05D 2230/21 by casting
• CPC Class Codes: F05D 2230/61 using limited numbers of standard modules which can be adapted by machining
• CPC Class Codes: F05D 2240/304 related to the trailing edge of a rotor blade

Abstract

An air cooled turbine blade with a trailing edge cooling circuit that is formed by casting the airfoil with a pressure side trailing edge lip being oversized, and then machining away material from the pressure side wall to leave a pressure side bleed slot with a smaller (t/s) ratio than can be formed by casting alone. In another embodiment, the airfoil is cast with a trailing edge exit hole, and then the material on the pressure side wall in the trailing edge region is machined away to leave a pressure side bleed slot instead of an exit hole.

Claims

1. A process for producing an air cooled turbine airfoil with a trailing edge cooling region comprising the steps of:

casting an airfoil having a trailing edge region with a suction side trailing edge diameter and a pressure side trailing edge diameter in which the pressure side trailing edge diameter is oversized;

after casting, machining away the oversized pressure side trailing edge diameter such that a pressure side bleed slot is formed; and

,

machining away the oversized pressure side trailing edge diameter such that a small t/s ratio is produced that cannot be cast into the airfoil.

2. The process for producing an air cooled turbine airfoil of claim 1, and further comprising the step of:

machining away the oversized pressure side trailing edge diameter so that the pressure side bleed slot surface is tangent to the airfoil trailing edge diameter.

3. The process for producing an air cooled turbine airfoil of claim 1, and further comprising the steps of:

casting the airfoil with the trailing edge region having an exit hole opening onto the trailing edge of the airfoil; and

,

machining away a surface of the pressure side wall in the trailing edge region to form a pressure side bleed slot from the exit hole.

4. An air cooled turbine airfoil comprising:

a pressure side wall and a suction side wall;

a trailing edge region with a metering hole opening discharging into a pressure side bleed slot;

the pressure side bleed slot being formed by a pressure side trailing edge lip that has a smaller t/s ratio than can be formed by casting; and

,

the trailing edge region and the pressure side bleed slot being formed as a single piece.

5. The air cooled turbine airfoil of claim 4, and further comprising:

the pressure side bleed slot surface is tangent to an airfoil trailing edge diameter.

6. A process for producing an air cooled turbine airfoil with a trailing edge cooling region comprising the steps of:

casting an airfoil with a trailing edge region with a cooling air supply channel and a metering and a diffusion section opening into a pressure side bleed slot formed between a trailing edge diameter and a pressure side lip in which the pressure side lip bulges outward from a continuous straight contour formed along the pressure side wall to the trailing edge diameter; and

,

after casting, machining away a section of the pressure side lip and the pressure side wall to leave a continuous straight contour from the pressure side wall to the trailing edge diameter.

7. A process for producing an air cooled turbine airfoil with a trailing edge cooling region comprising the steps of:

casting an airfoil with a trailing edge region having a correct sized suction side wall and an oversized pressure side wall with a trailing edge exit hole; and

,

machining away a section of the oversized pressure side wall along a straight line to a point where the trailing edge exit hole and the suction side wall merge to form a pressure side exit slot from the trailing edge exit hole.