ENDWALL COMPONENT FOR A TURBINE STAGE OF A GAS TURBINE ENGINE

• US 20120219401A1
• Filed: 02/08/2012
• Published: 08/30/2012
• Est. Priority Date: 02/24/2011
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: RAWLINSON, Anthony J., IRELAND, Peter, TURNER, Lynne H., TIBBOTT, Ian
• Granted Patent: US 9,068,472 B2
• Time in Patent Office: Days
• US Class Current: 415/115
• 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 11/122 with erodable or abradable material blades having cutting or grinding tips F01D5/20
• CPC Class Codes: F01D 25/12 Cooling
• CPC Class Codes: F01D 5/186 Film cooling F01D5/187 takes precedence
• CPC Class Codes: F01D 5/187 Convection cooling
• CPC Class Codes: F01D 9/06 Fluid supply conduits to nozzles or the like
• CPC Class Codes: F05D 2240/11 Shroud seal segments
• CPC Class Codes: F05D 2240/81 Cooled platforms
• CPC Class Codes: F05D 2260/20 Heat transfer, e.g. cooling
• CPC Class Codes: F05D 2260/202 by film cooling

Abstract

A component of a turbine stage of a gas turbine engine is provided, the component forming an endwall for the working gas annulus of the stage. The component has one or more internal plena behind the endwall which, in use, contain a flow of cooling air. The component further has a plurality of exhaust holes in the endwall. The holes connect the plena to a gas-washed surface of the endwall such that the cooling air effuses through the holes to form a cooling film over the gas-washed surface. Each exhaust hole has a flow cross-sectional area which is greater at an intermediate position between the entrance of the hole from the respective plenum and the exit of the hole to the gas-washed surface than it is at said exit.

Claims

1. A component of a turbine stage of a gas turbine engine, the component forming an endwall for the working gas annulus of the stage, and the component having:

one or more internal plena behind the endwall which, in use, contain a flow of cooling air, and

a plurality of exhaust holes in the endwall, the holes connecting the plena to a gas-washed surface of the endwall such that the cooling air effuses through the holes to form a cooling film over the gas-washed surface;

wherein each exhaust hole has a flow cross-sectional area which is greater at an intermediate position between the entrance of the hole from the respective plenum and the exit of the hole to the gas-washed surface than it is at the exit.

2. A component according to claim 1, wherein the flow cross-sectional area is greater at the intermediate position than it is at said exit by a factor of at least 1.5.

3. A component according to claim 1, wherein the flow cross-sectional area is greater at the intermediate position than it is at the entrance.

4. A component according to claim 3, wherein the flow cross-sectional area is greater at the intermediate position than it is at said entrance by a factor of at least 1.5.

5. A component according to claim 1 which is a shroud segment providing a close clearance to the tips of a row of turbine blades which sweep across the segment.

6. A component according to claim 1 which is a turbine blade, an inner platform of the blade forming the endwall.

7. A component according to claim 1 which is a static guide vane, an inner and/or an outer platform of the vane forming the endwall.