Integrated steam/air cooling system for gas turbines

• US 5,340,274 A
• Filed: 03/20/1992
• Issued: 08/23/1994
• Est. Priority Date: 11/19/1991
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Cunha, Francisco J.
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): VERDIER, CHRISTOPHER M
• Application Number:
  US07/854,580
• Time in Patent Office: 886 Days
• Field of Search: 415/114, 415/115, 415/116, 415/177, 415/179, 415/47, 415/48, 416/96 R, 416/96 A, 416/97 R, 60/39.53, 60/39.54, 60/39.58, 60/39.59, 60/39.05
• US Class Current: 415/115
• CPC Class Codes: F01D 5/182 Transpiration cooling
• CPC Class Codes: F01D 5/189 the insert having a tubular cross-section, e.g. airfoil shape
• CPC Class Codes: F02C 6/18 using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants using waste heat as source of energy for refrigeration plants F25B27/02; using the waste heat of a gasturbine for steam generation or in a steam cycle see F01K23/10
• CPC Class Codes: F02C 7/16 characterised by cooling medium
• CPC Class Codes: F05D 2250/25 helical
• CPC Class Codes: F05D 2260/2322 steam
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A steam or air cooled combined cycle gas turbine includes first and second turbine stages and a second nozzle stage. During start-up, cooling air is supplied radially inwardly through the second stage nozzle for flow into the gas flow through the turbine and for combining with cooling air flowing radially outwardly from a high pressure compressor port. The combined air flow flows radially outwardly through the turbine blades. In normal operation, steam in lieu of air flows radially inwardly through the second nozzle stage and radially outwardly between the turbine wheels and spacer therebetween. Part of the steam through the nozzle stage combines with the radially outwardly flowing steam for cooling the turbine blades. The balance of the steam flows into the gas flow through the turbine. Combined steam/air cooling is effected for abnormally high turbine blade temperatures by combining cooling air from the high pressure discharge port of the compressor with the steam flowing radially outwardly through the turbine blades.

Claims

1. An integrated steam and air cooling system for a gas turbine comprising:

a pair of axially spaced, rotatable turbine stages, each having a plurality of turbine blades for disposition in a gas flow through said turbine;

a nozzle stage between said turbine stages and including a plurality of nozzle vanes for disposition in the gas flow through said turbine;

means for supplying cooling air to and for passage through said blades and vanes to air cool said turbine;

means for supplying steam to and for passage through said blades and vanes to steam cool said turbine;

means cooperable with said cooling air supply means and said steam supply means for effecting a transition between air cooling said turbine and steam cooling said turbine;

a turbine shaft, said blades and said vanes having interior passages, a spacer between said turbine stages and rotatable therewith, wheels about said shaft mounting said turbine blades and spaced axially from and on opposite sides of said spacer to define chambers on axially opposite sides of said spacer, said steam supplying means including first and second steam supply circuits, said first circuit including a steam supply, a channel adjacent said shaft and in communication with said steam supply for suppling steam to said chamber and said interior passages of said turbine blades, said second steam supply circuit including said steam supply, a manifold about said nozzle vanes for supplying steam from said steam supply to said interior passages of said nozzle vanes, means in communication between said interior passages of said nozzle vanes and said chambers for combining steam from said first circuit in said chambers with steam of said second circuit in said chambers, whereby the combined steam of said first and second circuits flows through the interior passages of said turbine blades.

2. An integrated steam and air cooling system for a gas turbine comprising:

a pair of axially spaced, rotatable turbine stages, each having a plurality of turbine blades for disposition in a gas flow through said turbine;

a nozzle stage between said turbine stages and including a plurality of nozzle vanes for disposition in the gas flow through said turbine;

means for supplying cooling air to and for passage through said blades and vanes to air cool said turbine;

means for supplying steam to and for passage through said blades and vanes to steam cool said turbine;

means cooperable with said cooling air supply means and said steam supply means for effecting a transition between air cooling said turbine and steam cooling said turbine;

a turbine shaft, a spacer between said turbine stages and rotatable therewith, wheels about said shaft mounting said turbine blades and spaced axially from and on opposite sides of said spacer to define chambers on axially opposite sides of said spacer, certain of said vanes having interior passages and certain of said blades having interior passages, said steam supplying means including a manifold about radially outermost portions of said nozzle vanes in communication with said nozzle vane interior passages for supplying steam thereto during steam cooling of said turbine, a channel adjacent said shaft for supplying steam to said chambers, said chambers lying in communication with said turbine blade passages whereby cooling steam is supplied from said channel and said nozzle vanes to said chambers for flow to said turbine blades.

3. An integrated steam and air cooling system for a gas turbine comprising:

a pair of axially spaced, rotatable turbine stages, each having a plurality of turbine blades for disposition in a gas flow through said turbine;

a nozzle stage between said turbine stages and including a plurality of nozzle vanes for disposition in the gas flow through said turbine;

means for supplying cooling air to and for passage through said blades and vanes to air cool said turbine;

means for supplying steam to and for passage through said blades and vanes to steam cool said turbine;

means cooperable with said cooling air supply means and said steam supply means for effecting a transition between air cooling said turbine and steam cooling said turbine; and

a turbine shaft, a spacer between said turbine stages and rotatable therewith, wheels about said shaft mounting said turbine blades and spaced axially from and on opposite sides of said spacer to define chambers on axially opposite sides of said spacer, said cooling air supply means including a cooling air inlet adjacent said shaft for supplying cooling air to said chambers, a valve movable between open and closed positions to selectively control the flow of air from said cooling air supply means through said air inlet, a heat exchanger, certain of said blades having interior passages for conveying steam therethrough, means operable during steam cooling of said turbine for conveying steam from said passages of said turbine blades to said heat exchanger, said cooling air supply means including an air bypass circuit for directing air from said cooling air supply means, when said valve is in said closed position, to said heat exchanger in heat exchange relation with the steam conveyed thereto for heating the air, and means for conveying the heated air into the gas flow of the turbine.

4. An integrated steam and air cooling system for a gas turbine comprising:

a pair of axially spaced, rotatable turbine stages, each having a plurality of turbine blades for disposition in a gas flow through said turbine;

a nozzle stage between said turbine stages and including a plurality of nozzle vanes for disposition in the gas flow through said turbine;

means for supplying cooling air to and for passage through said blades and vanes to air cool said turbine;

means for supplying steam to and for passage through said blades and vanes to steam cool said turbine;

said steam supplying means including passages within the turbine for communicating steam passing through one of said blades and vanes to another of said blades and said vanes; and

means cooperable with said cooling air supply means and said steam supply means for effecting a transition between air cooling said turbine and steam cooling said turbine.

5. A cooling system according to claim 4 wherein certain of said nozzle stage vanes have two interior passages, said cooling air supply means supplying cooling air to one of said two interior passages during steam cooling of said turbine, said steam supply means supplying steam to the other of said two interior passages during steam cooling of said turbine whereby combined steam and air cooling of said turbine is effected.

6. A cooling system according to claim 4 including a turbine shaft, a spacer between said turbine stages and rotatable therewith, wheels about said shaft mounting said turbine blades and spaced axially from and on opposite sides of said spacer to define chambers on axially opposite sides of said spacer, said cooling air supply means including a cooling air inlet adjacent said shaft for supplying cooling air to said chambers, a valve movable between open and closed positions to selectively control the flow of air from said cooling air supply means through said air inlet, a heat exchanger, certain of said blades having interior passages for conveying steam therethrough, means operable during steam cooling of said turbine for conveying steam from said passages of said turbine blades to said heat exchanger, said cooling air supply means including an air bypass circuit for directing air from said cooling air supply means, when said valve is in said closed position, to said heat exchanger in heat exchange relation with the steam conveyed thereto for heating the air, and means for conveying the heated air into the gas flow of the turbine.

7. A cooling system according to claim 6 wherein said turbine includes a combustor having a steam injector and a compressor having a discharge port, said heated air conveying means being adapted to convey the heated air to one of said steam injector and said compressor discharge port.

8. A cooling system according to claim 4 including a turbine shaft, a spacer between said turbine stages and rotatable therewith, wheels about said shaft mounting said turbine blades and spaced axially from and on opposite sides of said spacer to define chambers on axially opposite sides of said spacer, certain of said vanes having interior passages and certain of said blades having interior passages, said steam supplying means including a manifold about radially outermost portions of said nozzle vanes in communication with said nozzle vane interior passages for supplying steam thereto during steam cooling of said turbine, a channel adjacent said shaft for supplying steam to said chambers, said chambers lying in communication with said turbine blade passages whereby cooling steam is supplied from said channel and said nozzle vanes to said chambers for flow to said turbine blades.

9. A cooling system according to claim 4 including a turbine shaft, certain of said blades having interior passages, said cooling air supply means including a cooling air inlet adjacent said shaft for supplying cooling air to said interior passages of said turbine blades, a valve for selectively controlling the flow of air through said air inlet, a sensor for sensing the temperature of the turbine blades and means responsive to said sensor sensing a predetermined temperature of said blades for opening said valve to admit cooling air through said cooling air inlet.

10. A cooling system according to claim 4 including a turbine shaft, said blades and said vanes having interior passages, a spacer between said turbine stages and rotatable therewith, wheels about said shaft mounting said turbine blades and spaced axially from and on opposite sides of said spacer to define chambers on axially opposite sides of said spacer, said steam supplying means including first and second steam supply circuits, said first circuit including a steam supply, a channel adjacent said shaft and in communication with said steam supply for suppling steam to said chamber and said interior passages of said turbine blades, said second steam supply circuit including said steam supply, a manifold about said nozzle vanes for supplying steam from said steam supply to said interior passages of said nozzle vanes, means in communication between said interior passages of said nozzle vanes and said chambers for combining steam from said first circuit in said chambers with steam of said second circuit in said chambers, whereby the combined steam of said first and second circuits flows through the interior passages of said turbine blades.

11. In a gas turbine having a pair of axially spaced, rotatable turbine stages, each having a plurality of turbine blades for disposition in a gas flow through said turbine with at least certain of said turbine blades each having at least one interior passage, a nozzle stage between said turbine stages and including a plurality of nozzle vanes for disposition in the gas flow through said turbine with at least certain of said vanes each having at least one interior passage, a method of operating a cooling system for the gas turbine including the steps of:

providing passages within the turbine for communicating steam passing through one of said blades and vanes to another of said blades and said vanes for passage through the interior passage of said another of said blades and said vanes;

initially supplying cooling air to said interior passages of said turbine blades to air cool said turbine during start-up of said turbine;

thereafter supplying steam to said interior passages of said turbine blades to steam cool said turbine during normal operation of said turbine after turbine start-up; and

effecting a transition between air cooling said turbine and steam cooling said turbine.

12. A method according to claim 11 including, during normal operation of said turbine, cooling said turbine solely by steam cooling.

13. A method according to claim 11 wherein said turbine stages includes a pair of turbine wheels and a spacer between said wheels defining chambers between the spacer and the turbine wheels, said step of supplying steam including the step of providing steam to said chambers to minimize or eliminate thermal gradients across the wheels and spacer.

14. A method according to claim 11 including providing steam supply lines for supplying steam to said turbine blades and preheating said steam supply lines.

15. A method according to claim 11 including, during normal operation of said turbine, cooling said turbine solely by steam cooling, sensing the temperature of the turbine blades at at least one of said stages, and supplying cooling air for combining with the cooling steam for cooling the turbine in response to sensing a predetermined temperature of said turbine blades.

16. In a gas turbine having a pair of axially spaced, rotatable turbine stages, each having a plurality of turbine blades for disposition in a gas flow through said turbine with at least certain of said turbine blades each having at least one interior passage, a nozzle stage between said turbine stages and including a plurality of nozzles vanes for disposition in the gas flow through said turbine with at least certain of said vanes each having at least one interior passage, a method of operating a cooling system for the gas turbine including the steps of:

initially supplying cooling air to said interior passages of said turbine blades to air cool said turbine during normal start-up of said turbine;

thereafter supplying steam to said interior passages of said turbine blades to steam cool said turbine during normal operation of said turbine after turbine start-up;

effecting a transition between air cooling said turbine and steam cooling said turbine; and

exhausting the steam used to cool said turbine during normal operation through a heat exchanger, said turbine having a compressor, supplying cooling air from said compressor to said heat exchanger in heat exchange relation with the exhaust steam from the turbine blades to heat the air, and directing the air from the heat exchanger into the turbine gas flow.

17. In a gas turbine having a pair of axially spaced, rotatable turbine stages, each having a plurality of turbine blades for disposition in a gas flow through said turbine with at least certain of said turbine blades each having at least one interior passage, a nozzle stage between said turbine stages and including a plurality of nozzle vanes for disposition in the gas flow through said turbine with at least certain of said vanes each having at least one interior passage, a method of operating a cooling system for the gas turbine including the steps of:

initially supplying cooling air to said interior passages of said turbine blades to air cool said turbine during start-up of said turbine;

thereafter supplying steam to said interior passages of said turbine blades to steam cool said turbine during normal operation of said turbine after turbine start-up;

effecting a transition between air cooling said turbine and steam cooling said turbine;

during normal operation of said turbine, cooling said turbine solely by steam cooling, sensing the temperature of the turbine blades at at least one of said stages, and supplying cooling air for combining with the cooling steam for cooling the turbine in response to sensing a predetermined temperature of said turbine blades; and

wherein the step of supplying cooling air includes supplying cooling air from a turbine compressor discharge port for flowing radially outwardly past a solenoid actuated valve, the step of supplying cooling steam including flowing the steam into chambers defined between turbine wheels of said stages, and actuating said solenoid to open said valve in response to sensing said predetermined temperature to supply said cooling air through said open valve for combining with the cooling steam in said chambers.

18. In a gas turbine having a pair of axially spaced, rotatable turbine stages, each having a plurality of turbine blades for disposition in a gas flow through said turbine with at least certain of said turbine blades each having at least one interior passage, a nozzle stage between said turbine stages and including a plurality of nozzle vanes for disposition in the gas flow through said turbine with at least certain of said vanes each having at least one interior passage, a method of operating a cooling system for the gas turbine including the steps of:

initially supplying cooling air to said interior passages of said turbine blades to air cool said turbine during start-up of said turbine; and

thereafter supplying steam to said interior passages of said turbine blades to steam cool said turbine during normal operation of said turbine after turbine start-up;

effecting a transition between air cooling said turbine and steam cooling said turbine; and

wherein the step of supplying cooling steam includes directing steam generally radially inwardly through the nozzle stage from a steam supply line radially outwardly of said nozzle stage, directing steam generally radially outwardly through said turbine blades from a steam supply line radially inwardly of said turbine blades and adjacent a shaft for said turbine, and combining at least part of the steam flowing radially inwardly through the nozzle stage with the steam flowing radially outwardly from adjacent said shaft for combined flows through said turbine blades.

19. A method according to claim 18 wherein the step of supplying cooling air includes supplying cooling air from a turbine compressor discharge port for flow radially outwardly past a solenoid actuated valve, and actuating said valve to supply cooling air for combination with said at least part of the cooling steam for combined steam and air flow through said turbine blades.