TURBINE CYLINDER CAVITY HEATED RECIRCULATION SYSTEM

Abstract

A turbine engine heating system configured to heat compressor and turbine blade assemblies to eliminate turbine and compressor blade tip rub during warm restarts of gas turbine engines is disclosed. The turbine engine heating system may include a heating air extraction system configured to withdraw air from the turbine engine and to pass that air thru a heating element configured to increase a temperature of the air supplied by the heating air extraction system. The air may then be passed to a heating air supply system via an air movement device. The heating air supply system may be in communication with a turbine cylinder cavity of the turbine engine positioned radially outward from at least one turbine assembly. The heated air may be passed into the turbine cylinder cavity to reduce the cooling rate of the turbine vane carriers after shutdown and before a warm restart to limit tip rubbing.

Description

FIELD OF THE INVENTION

This invention is directed generally to turbine engines, and more particularly to systems enabling warm startups of the gas turbine engines without risk of compressor and turbine blade interference with radially outward sealing surfaces.

BACKGROUND

Typically, gas turbine engines include a compressor for compressing air, a combustor for mixing the compressed air with fuel and igniting the mixture, and a turbine blade assembly for producing power. Combustors often operate at high temperatures that may exceed 2,500 degrees Fahrenheit. Typical turbine combustor configurations expose turbine blade assemblies to these high temperatures. Because of the mass of these large gas turbine engines, the engines take a long time to cool down after shutdown. Many of the components cool at different rates and as a result, interferences develop between various components. The casing component cools at different rates from top to bottom due to natural convection. As a result, the casings cooling faster at the bottom versus the top, and the casings take on a deformed shape during shutdown prior to being fully cooled. The hotter upper surface of the casing versus the cooler bottom surface causes the casing to thermally bend or bow upwards. If the engine undergoes a re-start during the time the casing is distorted, the blade tips will have a tendency to interfere at the bottom location due to the upward bow. Thus, if it is desired to startup the gas turbine before is has completely cooled, there exists a significant risk of damage to the turbine blades due to turbine blade tip rub from the interference between the turbine blade tips and the blade rings at the bottom of the engine due to the deformed shape of the outer casing. Thus, a need exists for reducing turbine vane carrier and blade ring cooling after shutdown.

SUMMARY OF THE INVENTION

This invention relates to a turbine engine heating system configured to heat compressor and turbine blade assemblies to eliminate turbine and compressor blade tip rub during warm restarts of the gas turbine engine. The turbine engine heating system may include a heating air extraction system configured to withdraw air from the turbine engine and to pass that air thru a heating element configured to increase a temperature of the air supplied by the heating air extraction system. The air may then be passed to a heating air supply system via an air movement device. The heating air supply system may be in communication with a turbine cylinder cavity of the turbine engine positioned radially outward from at least one turbine assembly. The heated air may be passed into the turbine cylinder cavity to reduce the cooling rate of the turbine vane carriers after shutdown and before a warm restart to limit tip rubbing by heating the turbine vane carrier. Similarly, heated air may be passed via a compressor heating system to the compressor shell cavity to heat compressor vane carrier to prevent the compressor vane carrier from developing an oval cross-section due to material growth because of thermal gradients between the top and midsections of the compressor vane carrier.

The turbine engine with a turbine engine heating system may be configured for controlling turbine vane carrier temperatures after engine shutdown and before a warm restart and may include a heating air extraction system configured to withdraw air from the turbine engine and a heating element configured to increase a temperature of the air supplied by the heating air extraction system. The turbine engine heating system may also include a heating air supply system having an inlet in communication with the heating element and including one or more outlets in communication with a turbine cylinder cavity of the turbine engine positioned radially outward from one or more turbine assemblies.

The outlet of the heating air supply system may be formed from a first outlet positioned within 30 degrees of a first horizontal joint joining first and second sections of a housing forming at least a portion of the turbine cylinder cavity, wherein the first outlet may be positioned on a first side of the housing. A second outlet may be positioned within 30 degrees of a second horizontal joint between the first and second sections of the housing forming at least a portion of the turbine cylinder cavity, wherein the second outlet may be positioned on a second side of the housing. In another embodiment, a third outlet may be positioned on the first side of the housing within 30 degrees of the first horizontal joint and on an opposite side of the first horizontal joint from the first outlet and a fourth outlet positioned on the second side of the housing within 30 degrees of the second horizontal joint and on an opposite side of the second horizontal joint from the second outlet.

The heating air extraction system may be configured to withdraw air from a turbine engine combustor shell of the turbine engine. The heating air extraction system may also include one or more inlets in communication with the turbine engine combustor shell. The inlet may include a bell mouth to minimize the pressure loss.

The turbine engine heating system may also include an air movement device in fluid communication with the heating element. In one embodiment, the air movement device may be, but is not limited to being, a blower. The blower may be positioned upstream of the heating element. The blower may be configured to run at least as high as 2,500 rpm.

The turbine engine heating system may also include a compressor heating system extending from the turbine cylinder cavity and terminating in a compressor air feed supply. In one embodiment, the compressor air feed supply may be a compressor shell cavity. The compressor heating system may also include further comprising a first inlet in communication with the turbine cylinder cavity within 30 degrees of top dead center. The compressor heating system may also include a second inlet in communication with the turbine cylinder cavity within 30 degrees of bottom dead center. In another embodiment, the compressor heating system may include an inlet in communication with the turbine cylinder cavity within 30 degrees of bottom dead center without an inlet at top dead center. The turbine engine heating system may include one or more valves for isolating the heating air extraction system to prevent air from being exchanged with the turbine engine and at least one valve for isolating the heating air supply system from the turbine cylinder cavity of the turbine engine.

An advantage of this invention is that the heated air delivered to the turbine cylinder cavity reduces the rate of cooling of the turbine vane carrier after shutdown, thereby preventing the turbine vane carrier from developing an oval cross-section and creating turbine blade tip rub during a warm startup of the gas turbine engine.

Another advantage of this invention is that the heated air delivered to the compressor shell cavity reduces the rate of cooling of the compressor vane carrier after shutdown, thereby preventing the compressor vane carrier from developing an oval cross-section and creating compressor blade tip rub during a warm startup of the gas turbine engine.

Yet another advantage of this invention is that the turbine engine heating system may be installed in currently existing gas turbine engines, thereby making gas turbine engines that are currently in use more efficient by enabling warm startups to occur rather than waiting days for the gas turbine engines to cool enough for a safe startup.

Another advantage of this invention is that the uniform temperature distribution of heated air by the turbine engine heating system in the turbine cylinder cavity and in the compressor shell cavity overcomes any buoyancy effects from forming, thus preventing ovalization of the annular shaped turbine cylinder cavity and the compressor shell cavity due to vertical temperature gradients.

Still another advantage of this invention is that the uniform cavity air in the turbine cylinder cavity and the compressor shell cavity help to mitigate vertical gradients within the housing forming the turbine cylinder cavity and the compressor shell.

Another advantage of this invention is that injecting heated air at about 350 degrees Celsius into a turbine cylinder cavity causes turbine vane carriers number 1 and 2 to remain thermally expanded, thereby increasing the blade ring diameter in row 1 by about 0.40 mm and in row 2 by about 0.65 mm.

Yet another advantage of this invention is that the turbine engine heating system reduces case bowing by reducing the top to bottom temperature gradient.

Another advantage of this invention is that use of the turbine engine heating system is also beneficial in a cold start up condition of a gas turbine engine, whereby two hours of preheating may increase the cold start pinch point gap by 1 mm and four hours of preheating may increase the cold start pinch point gap by 1.2 mm.

These and other embodiments are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, disclose the principles of the invention.

FIG. 1 is a cross-sectional side view of a gas turbine engine including a turbine engine heating system of this invention.

FIG. 2 is a detail view of a portion of the gas turbine engine showing a turbine rotor assembly with adjacent turbine vane carriers taken at detail 2 in FIG. 1.

FIG. 3 is a detail view of a gap between a row 1 turbine blade and an adjacent blade ring taken at detail 3 in FIG. 2.

FIG. 4 is a detail view of a gap between a row 2 turbine blade and an adjacent blade ring taken at detail 4 in FIG. 2.

FIG. 5 is a partial cross-sectional side view diagram of the gas turbine engine with a portion of the turbine engine heating system taken a detail 5.

FIG. 6 is a schematic diagram of a turbine cylinder cavity of the turbine engine shown in FIG. 1 with aspects of the turbine engine heating system taken from the view point at section line 6-6 in FIG. 1.

FIG. 7 is a side view of a housing forming the turbine cylinder and partially forming the turbine cylinder cavity.

FIG. 8 is a cross-sectional view of the turbine cylinder taken along section line 8-8 in FIG. 7.

FIG. 9 is a detail view of casing ports in the turbine cavity taken at detail 9 in FIG. 8.

FIG. 10 is a right side view of a housing forming the combustor shell and partially forming the combustor shell cavity.

FIG. 11 is a front view of the combustor shell.

FIG. 12 is a detail view of casing ports in the combustor shell taken at detail 12A in FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1-12, this invention is directed to a turbine engine heating system 10 configured to heat compressor and turbine blade assemblies 12, 14 to eliminate turbine and compressor blade tip rub during warm restarts of the gas turbine engine 16. The turbine engine heating system 10 may include a heating air extraction system 18 configured to withdraw air from the turbine engine 16 and to pass that air thru a heating element 20 configured to increase a temperature of the air supplied by the heating air extraction system 18. The air may then be passed to a heating air supply system 22 via an air movement device 24. The heating air supply system 22 may be in communication with a turbine cylinder cavity 26 of the turbine engine 16 positioned radially outward from at least one turbine assembly 14. The heated air may be passed into the turbine cylinder cavity 26 to reduce the cooling rate of the turbine vane carriers 28 after shutdown and before a warm restart to limit tip rubbing.

As shown in FIGS. 2, 6 and 8, the heating air supply system 22 may be configured for controlling turbine vane carrier temperatures after engine shutdown and before a warm restart by passing heated air to the turbine cylinder cavity 26 at a location proximate to horizontal joints 36, 48 that are generally positioned between top dead center 56 and bottom dead center 58 of the turbine cylinder cavity 26. Such configurations enable heated air to be passed into the turbine cylinder cavity 26 and to limit the rate of cooling of the turbine blade assembly 14. In one embodiment, as shown in FIG. 6, the heating air supply system 22 may include an inlet 30 in communication with the heating element 20 and may include at least one outlet 32 in communication with a turbine cylinder cavity 26 of the turbine engine 16 positioned radially outward from one or more turbine assemblies 14, as shown in FIGS. 7-9. The outlet 32 of the heating air supply system may be formed from a first outlet 34 positioned within 30 degrees of a first horizontal joint 36 joining first and second sections 38, 40 of a housing 42 forming at least a portion of the turbine cylinder cavity 26 and wherein the first outlet 34 is on a first side 44 of the housing 42. In another embodiment, the outlet 32 may be positioned within 10 degrees of the first horizontal joint 36. The heating air supply system 22 may also include a second outlet 46 positioned within 30 degrees of a second horizontal joint 48 between the first and second sections 38, 40 of the housing 42 forming at least a portion of the turbine cylinder cavity 26 and wherein the second outlet 46 is on a second side 50 of the housing 42. The second side 50 of the housing 42 may be positioned on an opposite side from the first side 44. In another embodiment, the second outlet 46 may be positioned within 10 degrees of the second horizontal joint 48.

In yet another embodiment, as shown in FIG. 6, the heating air supply system 22 may include a third outlet 52 positioned on the first side 44 of the housing 42 within 30 degrees of the first horizontal joint 36 and on an opposite side of the first horizontal joint 36 from the first outlet 34. In another embodiment, the third outlet 52 may be positioned within 10 degrees of the first horizontal joint 36. The heating air supply system 22 may further include a fourth outlet 54 positioned on the second side 50 of the housing 42 within 30 degrees of the second horizontal joint 48 and on an opposite side of the second horizontal joint 48 from the second outlet 46. In another embodiment, the fourth outlet 54 may be positioned within 10 degrees of the second horizontal joint 48.

The turbine engine heating system 10, as shown in FIGS. 1 and 5, may also include a heating air extraction system 18 configured to withdraw air from the turbine engine 16. In at least one embodiment, the heating air extraction system 18 may be configured to withdraw air from a midframe cavity 60 of the turbine engine 16. In at least one embodiment, the midframe cavity 60 may be a turbine engine combustor shell 62. Thus, the heating air extraction system 18 may be configured to withdraw air from a turbine engine combustor shell 62 of the turbine engine 16. The heating air extraction system 18 may also include one or more inlets 64 in communication with the turbine engine combustor shell 62. The inlet 64 of the heating air extraction system 18 may also include a bell mouth 66, as shown in FIG. 12, to minimize the pressure loss. The turbine engine heating system 10 may also include one or more valves 80 for isolating the heating air extraction system 18 to prevent air from being exchanged with the turbine engine 16. The turbine engine heating system 10 may also include one or more valves 80 for isolating the heating air supply system 10 from the turbine cylinder cavity 26 of the turbine engine 16.

The turbine engine heating system 10 may also include a heating element 20 configured to increase a temperature of the air supplied by the heating air extraction system 18. The heating element 20 may be configured to heat air to between 300 degrees Celsius and 500 degrees Celsius. In at least one embodiment, the heating element 20 may be configured to heat air to between 335 degrees Celsius and 365 degrees Celsius. In yet another embodiment, the heating element 20 may be configured to heat air to 350 degrees Celsius.

The turbine engine heating system 10 may also include one or more air movement devices 24 in fluid communication with the heating element 20. In one embodiment, the air movement device 24 may be a blower 68. The blower 68 may be positioned upstream of the heating element 20. The blower 68 may be coupled to the heating element 20 via one or more plenums or other appropriate structure. The blower 68 may be configured to run at least as high as 2,500 revolutions per minute (rpm).

The turbine engine heating system 10 may also include one or more compressor heating systems 70 for heating the compressor blade assembly 12 after shutdown and before a warm restart to eliminate compressor blade tip rub during warm restarts of the gas turbine engine 16. The compressor heating system 70 may extend from the turbine cylinder cavity 26 and may terminate in a compressor air feed supply 72. In at least one embodiment, the compressor air feed supply 72 may be a compressor shell cavity 74. The compressor heating system 70 may also include a first inlet 76 in communication with the turbine cylinder cavity 26 within 30 degrees of top dead center 56, as shown in FIGS. 10-12. In another embodiment, the first inlet 76 may be positioned within 10 degrees of top dead center 56. The compressor heating system 70 may also include an inlet, which may be a second inlet 78 in addition to the first inlet 76 or without the first inlet 76, in communication with the turbine cylinder cavity 26. The second inlet 78 may be positioned within 30 degrees of bottom dead center 58. In another embodiment, the second inlet 78 may be positioned within 10 degrees of bottom dead center 58.

The turbine engine heating system 10 may be used most often to eliminate turbine and compressor blade tip rub during warm restarts of the gas turbine engine 16 that can occur at the tip 88 of the turbine blade 90 and the blade ring 92, as shown in FIGS. 3 and 4. The turbine engine heating system 10 may be used to heat air to reduce the cooling rate of the turbine vane carriers 28 after shutdown and before a warm restart to limit tip rubbing. During use, air may be sent to the heating element 20 to be heated. The air may be supplied by the heating air extraction system 18. The heating air extraction system 18 may receive air from the midframe cavity 60, and in at least one embodiment, from the turbine engine combustor shell 62. An air movement device 24 may draw or push the air into the heating element 20. The air is heated within the heating element 20. The heated air is then sent into the turbine cylinder cavity 26. In at least one embodiment, the heated air may be sent to a turbine vane carrier number 2 spaced radially outward from a set of row 2 turbine vanes. In other embodiments, the turbine engine heating system 10 may be in fluid communication with other turbine vane cavities.

The air may be passed into the turbine cylinder cavity 26 to reduce the rate of cooling. The air may be passed into the turbine cylinder cavity 26 via one or more of outlets 34, 46, 52, 54 of the turbine engine heating system 10. The air may heat the turbine cylinder cavity 26 and heat turbine vane carriers 28, thereby limiting the cooling rate and preventing the turbine vane carrier 28 from developing an oval-shaped cross-section. As least a portion of the air may flow through the blade ring and the remaining heated air may flow into the compressor heating system 70 from the turbine cylinder cavity 26. The air may flow into one or more inlets, such as, but not limited to, first and second inlets 76, 78 of the compressor heating system 70. The air may flow into the compressor shell cavity 74 where the air is used to reduce the rate of cooling of the compressor vane carriers 84.

By slowing the cooling rate of the compressor vane carriers 84 and the turbine vane carriers 28, the housing 42 undergoes less thermal shrinkage. The turbine engine heating system 10 may be typically operated during a turbine engine shutdown sequence when the turbine engine 16 is on turning gear operation and has depressurized.

The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention.

Claims

1. A turbine engine with a turbine engine heating system for controlling turbine vane carrier temperatures after engine shutdown and before a warm restart, comprising:

a heating air extraction system configured to withdraw air from the turbine engine;

a heating element configured to increase a temperature of the air supplied by the heating air extraction system; and

a heating air supply system having an inlet in communication with the heating element and including at least one outlet in communication with a turbine cylinder cavity of the turbine engine positioned radially outward from at least one turbine assembly.

2. The turbine engine with a turbine engine heating system of claim 1, wherein the outlet of the heating air supply system is formed from a first outlet positioned within 30 degrees of a first horizontal joint joining first and second sections of a housing forming at least a portion of the turbine cylinder cavity and wherein the first outlet is on a first side of the housing.

3. The turbine engine with a turbine engine heating system of claim 2, further comprising a second outlet positioned within 30 degrees of a second horizontal joint between the first and second sections of the housing forming at least a portion of the turbine cylinder cavity and wherein the second outlet is on a second side of the housing.

4. The turbine engine with a turbine engine heating system of claim 3, further comprising a third outlet positioned on the first side of the housing within 30 degrees of the first horizontal joint and on an opposite side of the first horizontal joint from the first outlet and a fourth outlet positioned on the second side of the housing within 30 degrees of the second horizontal joint and on an opposite side of the second horizontal joint from the second outlet.

5. The turbine engine with a turbine engine heating system of claim 1, wherein the heating air extraction system is configured to withdraw air from a turbine engine combustor shell of the turbine engine.

6. The turbine engine with a turbine engine heating system of claim 5, wherein the heating air extraction system further comprises at least one inlet in communication with the turbine engine combustor shell, wherein the inlet includes a bell mouth to minimize the pressure loss.

7. The turbine engine with a turbine engine heating system of claim 1, further comprising an air movement device in fluid communication with the heating element.

8. The turbine engine with a turbine engine heating system of claim 7, wherein the air movement device is a blower.

9. The turbine engine with a turbine engine heating system of claim 8, wherein the blower is positioned upstream of the heating element.

10. The turbine engine with a turbine engine heating system of claim 9, wherein the blower is configured to run at least as high as 2,500 rpm.

11. The turbine engine with a turbine engine heating system of claim 1, further comprising a compressor heating system extending from the turbine cylinder cavity and terminating in a compressor air feed supply.

12. The turbine engine with a turbine engine heating system of claim 11, wherein the compressor air feed supply is a compressor shell cavity.

13. The turbine engine with a turbine engine heating system of claim 11, wherein the compressor heating system further comprising a first inlet in communication with the turbine cylinder cavity within 30 degrees of top dead center.

14. The turbine engine with a turbine engine heating system of claim 13, wherein the compressor heating system further comprises a second inlet in communication with the turbine cylinder cavity within 30 degrees of bottom dead center.

15. The turbine engine with a turbine engine heating system of claim 11, wherein the compressor heating system further comprises an inlet in communication with the turbine cylinder cavity within 30 degrees of bottom dead center.

16. The turbine engine with a turbine engine heating system of claim 11, further comprising at least one valve for isolating the heating air extraction system to prevent air from being exchanged with the turbine engine and at least one valve for isolating the heating air supply system from the turbine cylinder cavity of the turbine engine.

17. A turbine engine with a turbine engine heating system for controlling turbine vane carrier temperatures after engine shutdown and before a warm restart, comprising:

a heating air extraction system configured to withdraw air from the turbine engine, wherein the heating air extraction system is configured to withdraw air from a turbine engine combustor shell of the turbine engine;

a heating element configured to increase a temperature of the air supplied by the heating air extraction system;

an air movement device in fluid communication with the heating element;

a heating air supply system having an inlet in communication with the heating element and including at least one outlet in communication with a turbine cylinder cavity of the turbine engine positioned radially outward from at least one turbine assembly;

wherein the outlet of the heating air supply system is formed from a first outlet positioned within 30 degrees of a first horizontal joint joining first and second sections of a housing forming at least a portion of the turbine cylinder cavity and wherein the first outlet is on a first side of the housing;

a second outlet positioned within 30 degrees of a second horizontal joint between the first and second sections of the housing forming at least a portion of the turbine cylinder cavity and wherein the second outlet is on a second side of the housing; and

a compressor heating system extending from the turbine cylinder cavity and terminating in a compressor air feed supply.

18. The turbine engine with a turbine engine heating system of claim 17, wherein the compressor heating system further comprising a first inlet in communication with the turbine cylinder cavity within 30 degrees of top dead center and wherein the compressor heating system further comprises a second inlet in communication with the turbine cylinder cavity within 30 degrees of bottom dead center.

19. The turbine engine with a turbine engine heating system of claim 17, further comprising at least one valve for isolating the heating air extraction system to prevent air from being exchanged with the turbine engine and at least one valve for isolating the heating air supply system from the turbine cylinder cavity of the turbine engine.

20. The turbine engine with a turbine engine heating system of claim 17, further comprising a third outlet positioned on the first side of the housing within 30 degrees of the first horizontal joint and on an opposite side of the first horizontal joint from the first outlet and a fourth outlet positioned on the second side of the housing within 30 degrees of the second horizontal joint and on an opposite side of the second horizontal joint from the second outlet.