TURBINE ENGINE SHUTDOWN TEMPERATURE CONTROL SYSTEM

Abstract

A turbine engine shutdown temperature control system configured to foster consistent air temperature within cavities surrounding 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 shutdown temperature control system may include one or more air amplifiers positioned in a turbine case. An exhaust outlet of the air amplifier may extend into a cavity created by a turbine case and may be configured to exhaust air in a generally circumferential direction to entrain air within the cavity to flow circumferentially to establish a consistent air temperature within the cavity thereby preventing uneven cooling of turbine engine components after shutdown and prevent damage to turbine components during a warm restart.

Description

FIELD OF THE INVENTION

[0001] 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

[0002] 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 clearance between turbine blade tips and blade rings positioned immediately radially outward of the turbine blades is such a configuration in which an interference often develops. More specifically, the turbine vane carriers with blade rings typically cool faster than the turbine rotor assembly including the turbine blades. As a result, the turbine vane carriers reduce in diameter more than the turbine rotor assembly. Thus, if it is desired to startup the gas turbine before it 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 caused by the blade rings and turbine vane carriers cooling and shrinking faster than the turbine rotor assembly.

[0003] Furthermore, hot gases in cavities surrounding compressor and turbine airfoil assemblies rise within those cavities and collect near the top of the cavities. As such, the bottom portion of the casing surrounding the compressor and turbine assemblies cools faster than the top of the casing and thus creates thermal gradients and stress within the casing. The uneven cooling causes bowing to occur within the outer casing. Thus, a need exists for reducing turbine vane carrier and blade ring cooling after shutdown and to reduce thermal gradients within the outer casing.

SUMMARY OF THE INVENTION

[0004] This invention relates to a turbine engine shutdown temperature control system configured to foster consistent air temperature within cavities surrounding compressor and turbine blade assemblies to eliminate turbine and compressor blade tip rub during warm restarts of gas turbine engines. The turbine engine shutdown temperature control system may include one or more air amplifiers positioned in a turbine engine component. An exhaust outlet of the air amplifier may extend into a cavity created by a turbine case and may be configured to exhaust air in a generally circumferential direction to entrain air within the cavity to flow circumferentially to establish a consistent air temperature within the cavity thereby preventing uneven cooling of turbine engine components after shutdown and prevent damage to turbine components during a warm restart.

[0005] The turbine engine shutdown temperature control system may include a turbine engine component positioned within a turbine case such that a cavity is positioned therebetween and at least one air amplifier. The air amplifier may include a hollow chamber, wherein the air amplifier may extend into the cavity and may have a longitudinal axis that is nonparallel with a longitudinal axis of the turbine case. An exhaust outlet of the air amplifier may be directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case. The air amplifier may be in fluid communication with an air supply source enabling the air amplifier to exhaust air into the cavity. The air amplifier may be positioned in a turbine case that may be, but is not limited to being, a turbine exhaust casing forward outer diameter cavity or a turbine combustion casing midframe cavity. The turbine engine component positioned concentrically within the turbine case may be, but is not limited to being, a turbine vane carrier.

[0006] The air amplifier may be offset in the cavity such that the air amplifier is positioned radially outward from the longitudinal axis of the turbine case. In such a configuration, the air exhausted from the exhaust outlet of the air amplifier is able to create a circumferential flow within the cavity. The exhaust outlet of the air amplifier may be positioned no further than a distance from an inner surface of an outer wall equating to 20 percent of a radially extending distance from the inner surface of the turbine case forming the outer wall of the cavity to an inner surface forming an inner wall of the cavity. In one embodiment, the exhaust outlet of the air amplifier, when viewed axially downstream, may be offset circumferentially from top dead center, bottom dead center, left side center and right side center.

[0007] The air amplifier may be formed from a support engaging extension and an exhaust region housing the exhaust outlet. The support engaging extension may extend through the turbine case and the exhaust region may be positioned in the cavity. The exhaust region may be nonparallel and nonorthogonal with the support engaging extension. The exhaust region may be aligned tangentially with an inner surface of the turbine case forming the cavity. In another embodiment, the exhaust region may be orthogonal with the support engaging extension.

[0008] In one embodiment, the turbine engine shutdown temperature control system may include first and second air amplifiers. In particular, the turbine engine shutdown temperature control system may include a first air amplifier extending into the cavity and having a longitudinal axis that is nonparallel with the longitudinal axis of the turbine case. An exhaust outlet of the first air amplifier may be directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case. The second air amplifier may extend into the cavity and having a longitudinal axis that is nonparallel with the longitudinal axis of the turbine case. An exhaust outlet of the second air amplifier may be directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case and in a same circumferential direction as air exhausted from the exhaust outlet of the first air amplifier. In one embodiment, the first and second air amplifiers may be positioned on opposite sides of the cavity from each other to entrain a circumferential airflow and maintain a consistent airflow temperature throughout the cavity.

[0009] An advantage of this invention is that the turbine engine shutdown temperature control system creates consistent air temperature within cavities surrounding compressor and turbine blade assemblies to eliminate turbine and compressor blade tip rub during warm restarts of gas turbine engines.

[0010] Another advantage is that the turbine engine shutdown temperature control system creates a circumferential airflow within the cavity formed by the turbine case by entraining the air already within the turbine case in the cavity, thereby creating an air mass within the cavity having a generally consistent temperature without having to inject large quantities of air into cavity.

[0011] Still another advantage of this invention is that the turbine engine shutdown temperature control system reduces the temperature gradient between the top dead center and other aspects of the turbine case.

[0012] Another advantage of this invention is that the turbine engine shutdown temperature control system reduces the temperature gradient between the top dead center and other aspects of the blade ring to eliminate turbine airfoil rubbing.

[0013] Yet another advantage of this invention is that due to a large amplification ratio of the turbine engine shutdown temperature control system, there is no need for large conduits, such as four inches to six inches. Rather, an air supply source may be coupled to one or more air amplifiers with 3/8 inch diameter tubing.

[0014] Another advantage of this invention is that only a very small amount of compressed air is needed to entrain air within the cavity in the turbine case.

[0015] Still another advantage of this invention is that the air exhausted by one or more air amplifiers has a temperature nearly equal to a temperature of the air within the cavity, thereby eliminating the possibility of thermal shock to the system.

[0016] Another advantage of this invention is that the turbine engine shutdown temperature control system operates during turning gear operation and thus, there is no impact to normal gas turbine engine operation.

[0017] These and other embodiments are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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.

[0019] FIG. 1 is a cross-sectional side view of a gas turbine engine.

[0020] FIG. 2 is a cross-sectional side view of a gas turbine engine including a turbine engine shutdown temperature control system of this invention.

[0021] FIG. 3 is a schematic diagram of a gas turbine engine including the turbine engine shutdown temperature control system taken at section line 3-3 in FIG. 2.

[0022] FIG. 4 is a perspective view of the turbine engine shutdown temperature control system positioned in a turbine exhaust casing.

[0023] FIG. 5 is a detailed view of an air amplifier installed in a turbine exhaust casing.

[0024] FIG. 6 is another detailed view of an air amplifier installed in a turbine exhaust casing.

[0025] FIG. 7 is a partial perspective view of the turbine engine shutdown temperature control system positioned in a turbine combustion casing.

[0026] FIG. 8 is a detailed view of the turbine engine shutdown temperature control system positioned in the turbine combustion casing.

[0027] FIG. 9 is a partial perspective view of the turbine engine shutdown temperature control system positioned in a turbine vane carrier.

[0028] FIG. 10 is a partial cross-sectional view of the turbine engine shutdown temperature control system positioned a horizontal joint of the turbine vane carrier.

[0029] FIG. 11 is a top view of a portion of a turbine case in which an air amplifier is mounted.

DETAILED DESCRIPTION OF THE INVENTION

[0030] As shown in FIGS. 1-11, this invention is directed to a turbine engine shutdown temperature control system 10 configured to foster consistent air temperature within cavities 12 surrounding compressor and turbine blade assemblies 14, 16 to eliminate turbine and compressor blade 18, 20 tip rub during warm restarts of gas turbine engines 22. The turbine engine shutdown temperature control system 10 may include one or more air amplifiers 24 positioned in a turbine engine component. An exhaust outlet 26 of the air amplifier 24 may extend into a cavity 12 created by a turbine case 34 and may be configured to exhaust air in a generally circumferential direction to entrain air within the cavity 12 to flow circumferentially to establish a consistent air temperature within the cavity 12 thereby preventing uneven cooling of turbine engine components after shutdown and prevent damage to turbine components during a warm restart.

[0031] The turbine engine shutdown temperature control system 10 may include one or more air amplifiers 24 configured to exhaust air into the cavity 12. The air amplifier 24 may include one or more hollow chambers 28. The air amplifier 24 may extend into the cavity 12 and may have a longitudinal axis 30 that is nonparallel with a longitudinal axis 32 of the turbine case 34. The air amplifier 24 may be positioned such that an exhaust outlet 26 of the air amplifier 24 may be directed to exhaust air in a direction that is nonparallel with the longitudinal axis 32 of the turbine case 34. The air amplifier 24 may be in fluid communication with an air supply source 36 enabling the air amplifier 24 to exhaust air into the air amplifier 24.

[0032] The turbine engine shutdown temperature control system 10 may include a turbine engine component 38 positioned concentrically within a turbine case 34 such that a cavity 12 is positioned therebetween. The cavity 12 may be a cylindrically shaped cavity 12 defined outwardly by the turbine case 34 and inwardly by the turbine component 38. The turbine component 38 may be, but is not limited to being, a compressor blade assembly 14, a turbine blade assembly 16 and combustor 40. In one embodiment, as shown in FIGS. 4-6, the turbine case 34 may be a turbine exhaust casing 42 forming a forward outer diameter cavity 44. In yet another embodiment, as shown in FIGS. 7-8, the turbine case 34 may be a turbine combustion casing 46 forming a turbine combustion casing midframe cavity 48. The cavity may also be defined inwardly by outer surfaces of a turbine component 38. In at least one embodiment, as shown in FIGS. 9-10 the turbine component 38 may be a turbine vane carrier 50 positioned concentrically within a turbine case 34.

[0033] The air amplifier 24 positioned within the cavity 12 such that the air amplifier 24 is offset within the cavity 12. In particular, the air amplifier 24 may be offset in the cavity 12 such that the air amplifier 24 may be positioned radially outward from the longitudinal axis 32 of the turbine case 34. The exhaust outlet 26 of the air amplifier 24, when viewed axially downstream, may be offset circumferentially from top dead center 52, bottom dead center 54, left side center 56 and right side center 58. The exhaust outlet 26 of the air amplifier 24, when viewed from above the turbine engine 22, may be directed orthogonal to the longitudinal axis 32 of the engine 22 and the turbine case 34. Alternatively, the exhaust outlet 26 of the air amplifier 24, when viewed from above the turbine engine 22, may be directed nonorthogonal to the longitudinal axis 32 of the engine 22 and the turbine case 34. As such, air exhausted out of the exhaust outlet 26 may flow torodially within the cavity 12 such that it flows nonorthogonally relative to the longitudinal axis 32 of the engine 22 and the turbine case 34.

[0034] The exhaust outlet 26 of the air amplifier 24 may be positioned to entrain air within the cavity 12 while maintaining no more than a limited profile to limit disruption of the air flow in the cavity 12. In at least one embodiment, the exhaust outlet 26 of the air amplifier 24 may be positioned no further than a distance 60 from an inner surface 62 of an outer wall 64 equating to 20 percent of a radially extending distance 60 from the inner surface 62 of the turbine case 34 forming the outer wall 64 of the cavity 12 to an inner surface 66 forming an inner wall 68 of the cavity 12. The air amplifier 24 may be formed from a support engaging extension 70 and an exhaust region 72 housing the exhaust outlet 26. The support engaging extension 70 may extend through the turbine case 34, and the exhaust region 72 may be positioned in the cavity 12. The exhaust region 72 may be nonparallel and nonorthogonal with the support engaging extension 70. In another embodiment, the exhaust region 72 may be orthogonal with the support engaging extension 70. The exhaust region 72 may be aligned tangentially with the inner surface 62 of the turbine case 34 forming the cavity 12. In such a position, the air exhausted from the exhaust outlet 26 causes minimal disruption with the air flow within the cavity 12 and continues to keep the air flowing in a circumferential direction within the cavity 12.

[0035] One or more air amplifiers 24 may be positioned within the turbine case 34 in varying configurations to entrain the air within the cavity 12 via air exhausted from the air amplifiers 24. In one embodiment, the turbine engine shutdown temperature control system 10 may be formed from a first air amplifier 74 extending into the cavity 12 and having a longitudinal axis 30 that is nonparallel with the longitudinal axis 32 of the turbine case 34. The exhaust outlet 26 of the first air amplifier 74 may be directed to exhaust air in a direction that is nonparallel with the longitudinal axis 32 of the turbine case 34. The turbine engine shutdown temperature control system 10 may also include a second air amplifier 76 extending into the cavity 12 and having a longitudinal axis 30 that is nonparallel with the longitudinal axis 32 of the turbine case 34. The exhaust outlet 26 of the second air amplifier 76 may be directed to exhaust air in a direction that is nonparallel with the longitudinal axis 32 of the turbine case 34 and in a same circumferential direction as air exhausted from the exhaust outlet 26 of the first air amplifier 74. The first and second air amplifiers 74, 76 may be positioned on opposite sides of the cavity 12 from each other to entrain a circumferential airflow and maintain a consistent airflow temperature throughout the cavity 12.

[0036] The exhaust regions 72 of the first and second air amplifiers 74, 76 may be aligned tangentially with an inner surface 62 of the turbine case 34 forming the cavity 12. The exhaust outlets 26 of the first and second air amplifiers 74,76 may be positioned no further than a distance from the inner surface 62 of the outer wall 64 equating to 20 percent of a radially extending distance 20 from the inner surface 62 of the turbine engine component forming the outer wall 62 of the cavity 12 to an inner surface 66 forming an inner wall 68 of the cavity 12.

[0037] In yet another embodiment, the air amplifiers 24 may be positioned in close proximity to horizontal extending joints 78 of the turbine case 34. One or more first air amplifiers 74 may be positioned proximate to a first horizontal extending joint 78 on a first side of the turbine case 34, and one or more second air amplifiers 76 may be positioned proximate to a second horizontal extending joint 78 positioned on a second side of the turbine case 34 whereby the second side is on an opposite side of the turbine case 34 from the first side.

[0038] The turbine engine shutdown temperature control system 10 may be used to foster consistent air temperature within cavities 12 surrounding compressor and turbine blade assemblies 14, 16 to eliminate turbine and compressor blade 18, 20 tip rub during warm restarts of gas turbine engines 22. The turbine engine shutdown temperature control system 10 creates a consistent air temperature within the air cavity 12 by exhausting air from the exhaust outlet 26 of the air amplifiers 24 into the cavity 12. In addition, the exhaust air is exhausted in a circumferential direction to create a circumferential flow of air within the cavity 12 and thereby prevent the hottest gases within the cavity 12 from collecting at the top dead center 52 and causing unequal cooling and unequal thermal contraction while the turbine engine 22 cools after shutdown. The turbine engine shutdown temperature control system 10 operates during turning gear operation and thus, there is no impact to normal gas turbine engine operation.

[0039] 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 shutdown temperature control system, comprising: a turbine engine component positioned within a turbine case such that a cavity is positioned therebetween; at least one air amplifier having a hollow chamber, wherein the at least one air amplifier extends into the cavity and has a longitudinal axis that is nonparallel with a longitudinal axis of the turbine case, wherein an exhaust outlet of the at least one air amplifier is directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case; and wherein the at least one air amplifier is in fluid communication with an air supply source enabling the at least one air amplifier to exhaust air into the at least one air amplifier.

2. The turbine engine shutdown temperature control system of claim 1, wherein the turbine case is a turbine exhaust casing forming a forward outer diameter cavity.

3. The turbine engine shutdown temperature control system of claim 1, wherein the turbine case is a turbine combustion casing forming a turbine combustion casing midframe cavity.

4. The turbine engine shutdown temperature control system of claim 1, wherein the turbine engine component positioned concentrically within the turbine case is a turbine vane carrier.

5. The turbine engine shutdown temperature control system of claim 1, wherein the at least one air amplifier is offset in the cavity such that the at least one air amplifier is positioned radially outward from the longitudinal axis of the turbine case.

6. The turbine engine shutdown temperature control system of claim 1, wherein the at least one air amplifier comprises a first air amplifier extending into the cavity and having a longitudinal axis that is nonparallel with the longitudinal axis of the turbine case, wherein an exhaust outlet of the first air amplifier is directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case and a second air amplifier extending into the cavity and having a longitudinal axis that is nonparallel with the longitudinal axis of the turbine case, wherein an exhaust outlet of the second air amplifier is directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case and in a same circumferential direction as air exhausted from the exhaust outlet of the first air amplifier.

7. The turbine engine shutdown temperature control system of claim 6, wherein the first and second air amplifiers are positioned on opposite sides of the cavity from each other to entrain a circumferential airflow and maintain a consistent airflow temperature throughout the cavity.

8. The turbine engine shutdown temperature control system of claim 1, wherein the at least one air amplifier is formed from a support engaging extension and an exhaust region housing the exhaust outlet, wherein the support engaging extension extends through the turbine case and the exhaust region is positioned in the cavity, wherein the exhaust region is nonparallel and nonorthogonal with the support engaging extension.

9. The turbine engine shutdown temperature control system of claim 8, wherein the exhaust region is aligned tangentially with an inner surface of the turbine case forming the cavity.

10. The turbine engine shutdown temperature control system of claim 1, wherein the at least one air amplifier is formed from a support engaging extension and an exhaust region housing the exhaust outlet, wherein the support engaging extension extends through the turbine case and the exhaust region is positioned in the cavity, wherein the exhaust region is orthogonal with the support engaging extension.

11. The turbine engine shutdown temperature control system of claim 1, wherein the exhaust outlet of the at least one air amplifier is positioned no further than a distance from an inner surface of an outer wall equating to 20 percent of a radially extending distance from the inner surface of the turbine case forming the outer wall of the cavity to an inner surface forming an inner wall of the cavity.

12. The turbine engine shutdown temperature control system of claim 1, wherein the exhaust outlet of the at least one air amplifier, when viewed axially downstream, is offset circumferentially from top dead center, bottom dead center, left side center and right side center.

13. A turbine engine shutdown temperature control system, comprising: a turbine engine component positioned concentrically within a turbine case such that a cavity is positioned therebetween; at least one air amplifier having a hollow chamber, wherein the at least one air amplifier extends into the cavity and has a longitudinal axis that is nonparallel with a longitudinal axis of the turbine case, wherein an exhaust outlet of the at least one air amplifier is directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case; wherein the at least one air amplifier is in fluid communication with an air supply source enabling the at least one air amplifier to exhaust air into the at least one air amplifier; wherein the at least one air amplifier comprises a first air amplifier extending into the cavity and having a longitudinal axis that is nonparallel with the longitudinal axis of the turbine case, wherein an exhaust outlet of the first air amplifier is directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case, and a second air amplifier extending into the cavity and having a longitudinal axis that is nonparallel with the longitudinal axis of the turbine case, wherein an exhaust outlet of the second air amplifier is directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case and in a same circumferential direction as air exhausted from the exhaust outlet of the first air amplifier; and wherein at least one of the first and second amplifiers are formed from a support engaging extension and an exhaust region housing the exhaust outlet, wherein the support engaging extension extends through the turbine case and the exhaust region is positioned in the cavity, wherein the exhaust region is nonparallel and nonorthogonal with the support engaging extension.

14. The turbine engine shutdown temperature control system of claim 13, wherein the turbine case is selected from the group consisting of a turbine exhaust casing forward outer diameter cavity and a turbine combustion casing forming a turbine combustion casing midframe cavity.

15. The turbine engine shutdown temperature control system of claim 13, wherein the first and second air amplifiers are positioned on opposite sides of the cavity from each other to entrain a circumferential airflow and maintain a consistent airflow temperature throughout the cavity.

16. The turbine engine shutdown temperature control system of claim 13, wherein the exhaust regions of the first and second air amplifiers are aligned tangentially with an inner surface of the turbine case forming the cavity.

17. The turbine engine shutdown temperature control system of claim 13, wherein the exhaust outlets of the first and second air amplifiers are positioned no further than a distance from an inner surface of an outer wall equating to 20 percent of a radially extending distance from the inner surface of the turbine case forming the outer wall of the cavity to an inner surface forming an inner wall of the cavity.

18. The turbine engine shutdown temperature control system of claim 13, wherein the exhaust outlet at least one of the first and second air amplifiers, when viewed axially downstream, is offset circumferentially from top dead center, bottom dead center, left side center and right side center.

19. A turbine engine shutdown temperature control system, comprising: a turbine engine component positioned concentrically within a turbine case such that a cavity is positioned therebetween; at least one air amplifier having a hollow chamber, wherein the at least one air amplifier extends into the cavity and has a longitudinal axis that is nonparallel with a longitudinal axis of the turbine case, wherein an exhaust outlet of the at least one air amplifier is directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case; wherein the at least one air amplifier is in fluid communication with an air supply source enabling the at least one air amplifier to exhaust air into the at least one air amplifier; wherein the at least one air amplifier comprises a first air amplifier extending into the cavity and having a longitudinal axis that is nonparallel with the longitudinal axis of the turbine case, wherein an exhaust outlet of the first air amplifier is directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case, and a second air amplifier extending into the cavity and having a longitudinal axis that is nonparallel with the longitudinal axis of the turbine case, wherein an exhaust outlet of the second air amplifier is directed to exhaust air in a direction that is nonparallel with the longitudinal axis of the turbine case and in a same circumferential direction as air exhausted from the exhaust outlet of the first air amplifier; wherein at least one of the first and second amplifiers are formed from a support engaging extension and an exhaust region housing the exhaust outlet, wherein the support engaging extension extends through the turbine case and the exhaust region is positioned in the cavity, wherein the exhaust region is nonparallel and nonorthogonal with the support engaging extension; and wherein the exhaust regions of the first and second air amplifiers are aligned tangentially with an inner surface of the turbine case forming the cavity.

20. The turbine engine shutdown temperature control system of claim 13, wherein the first and second air amplifiers are positioned on opposite sides of the cavity from each other to entrain a circumferential airflow and maintain a consistent airflow temperature throughout the cavity and wherein the exhaust outlets of the first and second air amplifiers are positioned no further than a distance from an inner surface of an outer wall equating to 20 percent of a radially extending distance from the inner surface of the turbine case forming the outer wall of the cavity to an inner surface forming an inner wall of the cavity.

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