Wall elements for gas turbine engine combustors

• US 20070193216A1
• Filed: 01/11/2007
• Published: 08/23/2007
• Est. Priority Date: 01/25/2006
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: White, Kevin, Mills, Stephen, Woolford, James
• Granted Patent: US 8,650,882 B2
• Time in Patent Office: Days
• US Class Current: 52/782.1
• CPC Class Codes: F23R 2900/03041 Effusion cooled combustion chamber walls or domes
• CPC Class Codes: F23R 2900/03042 Film cooled combustion chamber walls or domes
• CPC Class Codes: F23R 2900/03043 Convection cooled combustion chamber walls with means for guiding the cooling air flow
• CPC Class Codes: F23R 2900/03045 Convection cooled combustion chamber walls provided with turbolators or means for creating turbulences to increase cooling
• CPC Class Codes: F23R 3/002 Wall structures F23R3/02 and F23R3/007 take precedence
• CPC Class Codes: F23R 3/04 Air inlet arrangements
• CPC Class Codes: F28F 3/022 the means being wires or pins
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A wall element, of a double walled combustor of a gas turbine engine, comprises an inner, in use, hot surface, and an outer, in use, cooler surface. A plurality of projections is provided on the outer surface to facilitate heat transfer to a coolant flow. The projections are arranged in a first density pattern and in a second higher density pattern for increased cooling. The denser pattern is positioned adjacent a hotter region of the tile than the less dense pattern thereby reducing the thermal gradient throughout the wall element.

Claims

1. A wall element for a wall structure of a gas turbine engine combustor, the wall element having an inner, in use, hot surface, and an outer, in use, cooler surface;

a plurality of projections being provided on the outer surface to facilitate heat transfer to a coolant flow, characterised in that the projections are arranged in a first density pattern and in a second higher density pattern for increased cooling;

the denser pattern adjacent a hotter region of the tile than the less dense pattern thereby reducing the thermal gradient throughout the wall element.

2. A wall element according to claim 1, wherein the density of the projections is graduated between first and second regions.

3. A wall element according to claim 1, wherein a third pattern or more of projections are provided between the first and second patterns, the third or more pattern having a density of projections between those densities of the first and second patterns.

4. A wall element according to claim 1, wherein some or all of the projections have a substantially circular cross section.

5. A wall element according to claim 1, wherein the second higher density pattern comprises rows of projections in a staggered array.

6. A wall element according to claim 1, wherein the first density pattern comprises rows of projections in a staggered array.

7. A wall element according to claim 5, wherein the there are at least two regions of pedestals which comprises rows of projections in a staggered array, wherein adjacent rows are offset by different amounts.

8. A wall element according to claim 1, wherein at least some of the rows of projections in the first pattern are arranged in line in the general direction of coolant flow, thereby lowering heat transfer.

9. A wall element according to claim 1, wherein at least some of the projections in the first pattern are elongate and are arranged in the general direction of coolant flow, thereby lowering heat transfer.

10. A wall element according to claim 9, wherein the elongate projections in the first pattern extend substantially in the downstream direction of the coolant flow.

11. A wall element according to claim 1, wherein the cross-section size of the projections in the second pattern is greater than the projections in the first pattern.

12. A wall element according to claim 1, wherein the number of the projections in the second pattern is greater than the projections in the first pattern within an equivalently sized area.

13. A wall element according to claim 11, wherein the number of projections in the second pattern is greater than the projections in the first pattern by virtue of the spacing of projections in at least one column of projections.

14. A wall element according to claim 11, wherein the number of projections in the second pattern is greater than the projections in the first pattern by virtue of the spacing of projections in at least one row of projections.

15. A wall element according to claim 1, wherein the density of projections increases in the downstream direction of coolant flow.

16. A wall element according to claim 1, wherein the tile defines a feed hole and the density of projections increases radially away from the feed hole.

17. A combustor wall structure of a gas turbine engine, the wall structure comprising radially inner and outer walls, wherein the inner wall includes at least one wall element according to claim 1.

18. A wall element according to claim 12, wherein the number of projections in the second pattern is greater than the projections in the first pattern by virtue of the spacing of projections in at least one row of projections.