GAS TURBINE ENGINE COMBUSTOR

• US 20160305663A1
• Filed: 04/17/2015
• Published: 10/20/2016
• Est. Priority Date: 04/17/2015
• Status: Active Grant

• Current Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: LEBEL, Larry
• Granted Patent: US 10,094,564 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F23R 2900/03041 Effusion cooled combustion chamber walls or domes
• CPC Class Codes: F23R 2900/03044 Impingement cooled combustion chamber walls or subassemblies
• CPC Class Codes: F23R 3/002 Wall structures F23R3/02 and F23R3/007 take precedence
• CPC Class Codes: F23R 3/06 Arrangement of apertures along the flame tube
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A combustor for a gas turbine engine including a combustor shell, a heat shield mounted to the combustor shell spaced-apart from the combustor shell to define an air gap therebetween, a core dilution passageway extending through the combustor shell and the heat shield, and a sub-chamber disposed within the air gap in fluid communication with the core dilution passageway. The sub-chamber is separated from a remainder of the air gap by at least one intermediate rail projecting across the air gap and forming an outer boundary of a peripheral area of the core dilution passageway. Impingement holes are formed through the combustor shell and in fluid communication with the sub-chamber. A method of cooling an area surrounding a dilution hole in a combustor is also presented.

Claims

1. A combustor for a gas turbine engine, comprising:

a combustor shell;

a heat shield mounted to the combustor shell spaced-apart from the combustor shell to define an air gap therebetween;

a core dilution passageway extending through the combustor shell and the heat shield;

a sub-chamber disposed within the air gap in fluid communication with the core dilution passageway, the sub-chamber being separated from a remainder of the air gap by at least one intermediate rail projecting across the air gap and forming an outer boundary of a peripheral area of the core dilution passageway; and

impingement holes formed through the combustor shell and in fluid communication with the sub-chamber.

2. The combustor as defined in claim 1, wherein the sub-chamber is part of a peripheral dilution passageway, the peripheral dilution passageway having an outlet adjacent to the core dilution passageway so that a peripheral dilution flow of the peripheral dilution passageway combines with a core dilution flow of the core dilution passageway to form a total dilution flow.

3. The combustor as defined in claim 1, wherein the sub-chamber is in fluid communication with the core dilution passageway via a peripheral dilution passageway, the peripheral dilution passageway having an outlet oriented in the direction of a core dilution flow of the core dilution passageway.

4. The combustor as defined in claim 2, wherein the outlet of the peripheral dilution passageway is in fluid flow communication with the core dilution passageway upstream of an exit of the core dilution passageway.

5. The combustor as defined in claim 1, wherein the sub-chamber is a first sub-chamber;

and

further comprising end rails extending across the air gap, the at least one intermediate rail being disposed between the end rails, a second sub-chamber being defined by a portion of the air gap extending between the at least one intermediate rail and the end rails.

6. The combustor as defined in claim 2, wherein the core dilution passageway is defined by a first dilution hole is defined in the combustor shell in registry with a corresponding second dilution hole defined in the heat shield;

and a surface area of the second dilution hole is larger than a surface area of the first dilution hole.

7. The combustor as defined in claim 6, wherein an annular radius of the peripheral dilution passageway is comprised between about 10% and about 30% of a diameter of the core dilution passageway.

8. The combustor as defined in claim 2, wherein the peripheral dilution passageway is configured to account for about between 5% and 50% of the total dilution flow.

9. The combustor as defined in claim 6, wherein a combined surface area of the impingement holes is smaller than a combined surface area of at least one of the first and second dilution holes.

10. The combustor as defined in claim 1, wherein the at least one intermediate rail includes two circumferentially extending rails disposed on each side of the dilution holes.

11. The combustor as defined in claim 1, wherein the at least one intermediate rail includes a circular rail encircling the core dilution passageway.

12. The combustor as defined in claim 1, further comprising a plurality of effusion holes defined in the heat shield and in fluid communication with the sub-chamber;

and

wherein a combined surface area of the effusion holes is smaller than a combined surface area of the impingement holes.

13. The combustor as defined in claim 1, wherein the heat shield is a heat shield panel, the peripheral area accounting for less than 50% of a surface of a heat shield panel.

14. The combustor as defined in claim 2, wherein the outlet of the peripheral dilution passageway is one of tangent and perpendicular to the core dilution passageway.

15. The combustor as defined in claim 1, wherein the at least one intermediate rail substantially seals the sub-chamber from the remainder of the air gap.

16. A gas turbine engine, comprising:

a combustor including;

a combustor shell;

a heat shield mounted to the combustor shell spaced-apart from the combustor shell to define an air gap therebetween, the combustor shell including impingement holes configured to provide impingement jets onto the heat shield;

a first dilution hole defined in the combustor shell in registry with a corresponding second dilution hole defined in the heat shield, the first dilution hole and the second dilution hole defining a core dilution passageway; and

the second dilution hole having a boss at its rim, spaced apart from the combustor shell, such that the gap fluidly communicates with the core dilution passageway.

17. The combustor as defined in claim 16, further comprising a sub-chamber disposed within the air gap in fluid communication with the core dilution passageway, the sub-chamber being separated axially from a remainder of the air gap by at least one intermediate rail, the at least one intermediate rail projecting radially into the air gap so as to form an outer boundary of a peripheral area of the core dilution passageway.

18. A method of cooling an area surrounding a dilution hole in a combustor, the combustor having a heat shield spaced-apartedly mounted to a combustor shell to define an air gap, the method comprising:

flowing a peripheral dilution flow through the combustor shell to a sub-chamber that is pressurised in relation to a remainder of the air gap and around a boss formed at a rim of the dilution hole, the sub-chamber extending within a peripheral area of the dilution hole, the peripheral dilution flow accounting for at least 5% of a total dilution flow; and

merging the peripheral dilution flow with a core dilution flow of the dilution hole to form the total dilution flow.

19. The method defined in claim 18, wherein flowing the peripheral dilution flow comprises impinging cooling air against a back face of the heat shield in the sub-chamber, and then using said cooling air as the peripheral dilution flow.

20. The method defined in claim 18, wherein the peripheral dilution flow accounts for between 10 to 30% of the total dilution flow.