Methods and system for cooling integral turbine shround assemblies

• US 7,740,444 B2
• Filed: 11/30/2006
• Issued: 06/22/2010
• Est. Priority Date: 11/30/2006
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Placke, Dustin Alfred, Jones, Daniel Verner, Andersen, Katherine Jaynetorrence, Moore, George Elliott, Laflen, James Harvey, Lee, Ching-Pang
• Primary Examiner(s): Nguyen; Ninh H
• Application Number:
  US11/565,387
• Publication Number:
  US 20080131264A1
• Time in Patent Office: 1,300 Days
• Field of Search: 415/1, 415/173.1, 415/116, 415/209.2, 415/209.3, 415/213.1
• US Class Current: 415/173.1
• CPC Class Codes: F01D 11/24 by selectively cooling-heating stator or rotor components
• CPC Class Codes: F01D 25/246 Fastening of diaphragms or stator-rings
• CPC Class Codes: F05D 2260/201 by impingement of a fluid
• CPC Class Codes: F05D 2260/205 Cooling fluid recirculation, i.e. after cooling one or more components is the cooling fluid recovered and used elsewhere for other purposes
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A method for cooling a turbine shroud assembly includes providing a turbine shroud assembly including a shroud segment having a leading edge, a trailing edge and a midsection defined therebetween. A shroud support circumferentially spans and supports the shroud segment. The shroud support includes a forward hanger coupled to the leading edge, a midsection hanger coupled to the midsection and an aft hanger coupled to the trailing edge. An annular shroud ring structure includes a midsection position control ring coupled to the midsection hanger and an aft position control ring coupled to the aft hanger. Cooling air is extracted from a compressor positioned upstream of the turbine shroud assembly. Cooling air is metered through the shroud support directly into only at least one active convection cooling zone defined between the shroud segment and the shroud support while substantially preventing cooling air from entering an inactive convection cooling zone positioned radially outwardly from the at least one active convection cooling zone and defined between the shroud support and the shroud ring structure and between the midsection position control ring and the aft position control ring.

Claims

1. A method for cooling a turbine shroud assembly, said method comprising:

providing a turbine shroud assembly comprising a shroud segment having a leading edge, a trailing edge and a midsection defined therebetween, a shroud support circumferentially spanning and supporting the shroud segment, the shroud support comprising a forward hanger coupled to the leading edge, a midsection hanger coupled to the midsection and an aft hanger coupled to the trailing edge, and an annular shroud ring structure comprising less than three position control rings, the less than three position control rings including a midsection position control ring coupled to the midsection hanger and an aft position control ring coupled to the aft hanger;

extracting cooling air from a compressor positioned upstream of the turbine shroud assembly; and

metering cooling air through the shroud support directly into only at least one active convection cooling zone defined between the shroud segment and the shroud support.

2. A method in accordance with claim 1 further comprising substantially preventing cooling air from entering an inactive convection cooling zone positioned radially outwardly from the at least one active convection cooling zone and defined between the shroud support and the shroud ring structure and between the midsection position control ring and the aft position control ring.

3. A method in accordance with claim 1 wherein metering cooling air further comprises:

metering a first portion of cooling air into a first active convection cooling zone defined between the shroud segment and the shroud support and between the forward hanger and the midsection hanger through at least one first feed hole defined in the shroud support; and

metering at least a portion of the first portion of cooling air through a plurality of forwardly directed cooling holes defined in the leading edge to facilitate purging a gap defined between a high pressure turbine nozzle outer band positioned upstream of the turbine shroud assembly and the leading edge.

4. A method in accordance with claim 3 further comprising metering a portion of the first portion of cooling air through a plurality of rearwardly directed cooling holes defined in the shroud segment to facilitate film cooling a downstream portion of the shroud segment.

5. A method in accordance with claim 3 wherein metering cooling air further comprises:

metering a second portion of cooling air into a second active convection cooling zone defined between the shroud segment and the shroud support and between the midsection hanger and the aft hanger through at least one second feed hole defined in the shroud support; and

metering the second portion of cooling air through a plurality of rearwardly directed cooling holes defined in the trailing edge of the shroud segment to facilitate film cooling said trailing edge.

6. A method in accordance with claim 5 further comprising impinging the second portion of cooling air against a backside of the shroud segment as the second portion of cooling air is metered into the second active convection cooling zone.

7. A turbine shroud assembly for a gas turbine engine, said turbine shroud assembly comprising:

a shroud segment comprising a leading edge, a trailing edge and a midsection defined therebetween, said shroud segment comprising a forward mounting hook at said leading edge, a midsection mounting hook at said midsection and an aft mounting hook at said trailing edge;

a shroud support circumferentially spanning and supporting said shroud segment, said shroud support comprising a forward section, a midsection and an aft section, said forward section forming a forward hanger coupled to said forward mounting hook, said midsection forming a midsection hanger coupled to said midsection mounting hook, said aft section forming an aft hanger coupled to said aft mounting hook;

an annular shroud ring structure configured to support said shroud support, said annular shroud ring structure comprising less than three position control rings, the less than three position control rings including a midsection position control ring coupled to said midsection hanger and an aft position control ring coupled to said aft hanger;

a first active convection cooling zone defined between said shroud segment and said shroud support and between said forward mounting hook and said midsection mounting hook;

at least one feed hole extending through said shroud support and configured to meter a first portion of cooling air into said first active convection cooling zone; and

a first inactive convection cooling zone defined between said shroud support and said annular shroud ring structure and between said midsection position control ring and said aft position control ring, said shroud support substantially preventing cooling air from entering said first inactive convection cooling zone.

8. A turbine shroud assembly in accordance with claim 7 further comprising a plurality of forwardly directed cooling holes defined in said leading edge and configured to meter an amount of cooling air exiting said first active convection cooling zone to facilitate purging a gap defined at least partially by said leading edge.

9. A turbine shroud assembly in accordance with claim 7 further comprising a plurality of rearwardly directed cooling holes defined in said shroud segment and configured to meter an amount of cooling air exiting said first active convection cooling zone to facilitate film cooling a downstream portion of said shroud segment.

10. A turbine shroud assembly in accordance with claim 7 further comprising an impingement baffle positioned within said first active convection cooling zone, said impingement baffle comprises an upper plenum and a lower plenum, said impingement baffle defining a plurality of perforations configured to meter the first portion of cooling air into said lower plenum.

11. A turbine shroud assembly in accordance with claim 10 wherein said plurality of perforations are configured to facilitate impingement cooling a backside of said shroud segment.

12. A turbine shroud assembly in accordance with claim 7 further comprising:

a second active convection cooling zone defined between said shroud segment and said shroud support and between said midsection mounting hook and said aft mounting hook;

at least one feed hole extending through said shroud support and configured to meter a second portion of cooling air into said second active convection cooling zone; and

a plurality of rearwardly directed cooling holes defined in said trailing edge and configured to meter an amount of cooling air exiting said second active convection cooling zone to facilitate film cooling a portion of said trailing edge.

13. A turbine shroud assembly in accordance with claim 7 wherein said midsection position control ring is axially aligned with said midsection mounting hook, said aft position control ring is axially aligned with said aft mounting hook.

14. A turbine shroud cooling system for providing cooling air through a turbine shroud assembly to facilitate cooling the turbine shroud assembly, the turbine shroud assembly comprising a shroud segment having a leading edge, a trailing edge and a midsection defined therebetween, a shroud support circumferentially spanning and supporting the shroud segment, the shroud support comprising a forward hanger coupled to the leading edge, a midsection hanger coupled to the midsection and an aft hanger coupled to the trailing edge, and a shroud ring structure comprising less than three position control rings, the less than three position control rings including a midsection position control ring coupled to the midsection hanger and an aft position control ring coupled to the aft hanger, said turbine shroud cooling system configured to:

direct cooling air into a duct defined at least partially between a high pressure turbine nozzle outer band positioned upstream of the turbine shroud assembly and the shroud ring structure; and

meter cooling air through the shroud support directly into only at least one active convection cooling zone defined between the shroud segment and the shroud support to facilitate shroud segment cooling.

15. A turbine shroud cooling system in accordance with claim 14 further configured to prevent cooling air from entering an inactive convection cooling zone defined between the shroud support and the shroud ring structure and between the midsection position control ring and the aft position control ring.

16. A turbine shroud cooling system in accordance with claim 14 further configured to meter a first portion of cooling air through a plurality of first feed holes into a first active convection cooling zone defined between the shroud segment and the shroud support and between the forward hanger and the midsection hanger to facilitate shroud segment impingement cooling in a high pressure turbine section of the turbine shroud assembly.

17. A turbine shroud cooling system in accordance with claim 16 further configured to meter spent impingement cooling air through a plurality of cooling holes defined in the shroud segment at the leading edge to facilitate purging a gap between the high pressure turbine nozzle outer band and the shroud segment.

18. A turbine shroud cooling system in accordance with claim 16 further configured to meter a portion of spent impingement cooling air through a plurality of cooling holes defined in the shroud segment to facilitate film cooling a downstream portion of the shroud segment.

19. A turbine shroud cooling system in accordance with claim 16 further configured to meter a second portion of cooling air through a plurality of second feed holes defined in the shroud support into a second active convection cooling zone defined between the shroud segment and the shroud support and between the midsection hanger and the aft hanger to facilitate shroud segment impingement cooling in a low pressure turbine section of the turbine shroud assembly.

20. A turbine shroud cooling system in accordance with claim 19 further configured to meter spent impingement cooling air exiting the shroud segment through a plurality of cooling holes defined at the trailing edge of the shroud segment.