WO2019168501A1

WO2019168501A1 - Turbine cooling air delivery system

Info

Publication number: WO2019168501A1
Application number: PCT/US2018/019943
Authority: WO
Inventors: David May; Constant CHARRETON
Original assignee: Siemens Aktiengesellschaft
Priority date: 2018-02-27
Filing date: 2018-02-27
Publication date: 2019-09-06
Also published as: WO2019168590A1

Abstract

A gas turbine engine includes a pre-swirl cavity. There is a first passage and a second passage within the gas turbine engine. The gas turbine engine has a first self-adjusting seal disposed within the pre-swirl cavity and a second self-adjusting seal located between an outer rotating arm and an inner wall of the gas turbine engine. A bypass channel maybe connected to the pre-swirl cavity.

Description

TURBINE COOLING AIR DELIVERY SYSTEM

BACKGROUND

[0001] 1. Field

[0002] Disclosed embodiments are generally related to turbine engines, and in particular to cooling systems of the turbine engine.

[0003] 2. Description of the Related Art

[0004] A high pressure turbine (HPT) cooling air delivery system traditionally includes a pre-swirl system. The system takes air from the high pressure compressor and injects it in front of the HPT disc through angled holes or nozzles (pre-swirl ers). The angle is set so that the air tangential velocity ejected through the pre-swirls matches that of the disc speed. This yields minimum air temperature rise when washing the surface of the disc with incoming air. The air also feeds the HPT blade internal passage. For the same reason as the disc, it is desirable to feed air at the same tangential velocity as the blade/disc so the blade is cooled using the lowest possible feed air temperature.

[0005] The static and rotating surfaces that contain the swirled cooling air, i.e. the pre-swirl cavity, are traditionally sealed by labyrinth seals. There is a certain amount of leakage (around 15% of total pre-swirl flow) into the pre-swirl cavity through the lower seal. This leakage is hotter than the pre-swirled air for at least two reasons. First, windage heating of the leakage, due to friction on the multiple teeth. Second, the leakage swirls at a lower tangential velocity (around half) of that of the pre-swirled air which creates an offset between the mixed air swirl and the disc speed.

[0006] Another variation of arrangement of the gas turbine engine comprises dropping the pressure upstream of the lower labyrinth seal by means of another sealing element so as to reverse the flow direction. The result is that higher temperature air is no longer leaking into the pre-swirl cavity, i.e. only pre-swirled air is feeding the disc and the blade internal passages. This reversed air flow is directed to the rim cavity through a bypass in the pre-swirlers support structure.

SUMMARY

[0007] Briefly described, aspects of the present disclosure relate to gas turbine engines and more particularly to sealing portions of the gas turbine engine. [0008] An aspect of the present disclosure may be a gas turbine engine having a first self-adjusting seal disposed within the pre-swirl cavity. The gas turbine engine may also have a second self-adjusting seal located between an inner wall and a rotating arm of the gas turbine engine.

[0009] Another aspect of the present invention may be a gas turbine engine having a first passage formed by an exterior wall of a combustor and an inner wall within the gas turbine engine. The gas turbine engine may have a second passage formed by the inner wall and a rotating arm; a pre-swirl cavity located at distal ends of the first passage and the second passage; a first self-adjusting seal located in the first passage; and a second self-adjusting seal located in the pre-swirl cavity.

[0010] Still yet another aspect of the present invention may be a gas turbine engine having a first passage formed by an exterior wall of a combustor and an inner wall within the gas turbine engine. The gas turbine engine may have a second passage formed by the inner wall and a rotating arm; pre-swirl cavity located at distal ends of the first passage and the second passage; a bypass channel connected to a pre-swirl cavity; a first self-adjusting seal located in the first passage; and a second self-adjusting seal located in the pre-swirl cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Fig. 1 is diagrammatic view of a gas turbine engine.

[0012] Fig. 2 is a cut-away view of a self-adjusting seal.

[0013] Fig. 3 is a diagrammatic view of a gas turbine engine with self-adjusting seals.

[0014] Fig. 4 is a close up view of the pre-swirl cavity shown in Fig. 3.

[0015] Fig. 5 is a close up view of the pre-swirl support structure shown in Fig. 3.

DETAILED DESCRIPTION

[0016] To facilitate an understanding of embodiments, principles, and features of the present disclosure, they are disclosed hereinafter with reference to implementation in illustrative embodiments. Embodiments of the present disclosure, however, are not limited to use in the described systems or methods and may be utilized in other systems and methods as will be understood by those skilled in the art.

[0017] The components described hereinafter as making up the view of various embodiments are intended to be illustrative and not restrictive. Many suitable components that would perform the same or a similar function as the components described herein are intended to be embraced within the scope of embodiments of the present disclosure.

[0018] Through use of self-adjusting seals, the leakage into a pre-swirl cavity can be reduced or stopped. Referring now to Fig. 1, a gas turbine engine 10 is shown. The gas turbine engine 10 may include a compressor section 11 for compressing air. The compressed air from the compressor section 11 is conveyed to a combustion section 12, which produces hot combustion gases by burning fuel in the presence of the compressed air from the compressor section 11. The combustion gases are conveyed through a plurality of transition ducts 13 to a turbine section 14 of the engine 10. The turbine section 14 comprises alternating rows of rotating blades and stationary vanes.

[0019] In the turbine section 14, blade disc structures 15 are positioned adjacent to one another in an axial direction. The blade disc structures 15 define a rotor. Each of the blade disc structures 15 supports circumferentially spaced apart blades and each of a plurality of lower stator support structures support a plurality of circumferentially spaced apart vanes. The vanes direct the combustion gases from the transition ducts 13 along a hot gas flow path to the blades such that the combustion gases cause rotation of the blades, which in turn causes corresponding rotation of the rotor.

[0020] A supply of fluid, can supply fluid within the gas turbine engine 10. The fluid may have a temperature of, for example, between about 1000-1200° F.

[0021] The fluid flows through passages formed between an inner wall 17 and an outer combustor wall 18. The fluid also flows between a rotating arm 16 and inner wall 17. The rotating arm 16 may be connected to the compressor section 11 and the turbine section 14. The rotating arm 16 may also be referred to as a“drive cone” or“shaft.”

[0022] The first passage 19 is formed between the outer combustor wall 18 and the inner wall 17. The second passage 20 is formed between the rotating arm 16 and the inner wall 17. The fluid flow enters the pre-swirl cavity 30 from the first passage 19 and from the second passage 20. In Fig. 1, the area of leakage is shown at position 31. This is where fluid from the pre-swirl cavity 30 may leak into the second passage 20.

[0023] Improving or stopping the leakage that occurs within the pre-swirl cavity 30 can help improve the efficiency of the gas turbine engine 10. This can be accomplished by using a self-adjusting seal 40, such as shown in Fig. 2. Self-adjusting seals 40 of the type that may be employed in the instant invention may be found in U.S. Patent nos. 8,002,285; 8,172,232 and 8,919,781, the contents of which are hereby incorporated by reference.

[0024] The self-adjusting seal 40 shown in Fig. 2 has beams 42 and shoes 43. Each self-adjusting seal 40 comprises a plurality of shoes 43, with each shoe 43 being supported by two beams 42. The beams 42 permit the self-adjusting seal 40 to adjust by being responsive to the pressures in the surrounding environment. In order to be adjustable, the beams 42 can be made of a material that is both durable and flexible. For example the beams 42 may be made of stainless steel. The beams 42 may also be made of inconel for high temperature application.

[0025] The pressure at the location of the self-adjusting seal 40 determines the movement of the self-adjusting seal 40. Too little leakage will result is a small pressure drop which may not be sufficient to activate the self-adjusting seal 40, so the beams 42 will stay at their cold build position. Too much leakage and pressure drop across the self-adjusting seal 40 may result in unpredictable shoe 43 movement due to high-Mach flow prediction uncertainty.

[0026] Referring now to Figs. 3 and 4, self-adjusting seals 40 and 41 are shown implemented in the gas turbine engine 10. The first self-adjusting seal 40 is located in the pre-swirl cavity 30.

[0027] The pre-swirl cavity 30 may define a flow passage in which a pre-swirl structure 33 exists. The pre-swirl structure 33 may have swirl members 34. The swirl members 34 may include a leading edge and a circumferentially offset trailing edge. The movement of the pre-swirl members 34 moves the cooling fluid. Cooling fluid exits the pre-swirl cavity 30 with a velocity component in a direction tangential to the circumferential direction of the gas turbine engine 10. A swirl ratio is defined as the velocity component in the direction tangential to the circumferential direction of the cooling fluid as compared to a velocity component of a rotating shaft in the direction tangential to the circumferential direction. [0028] The first self-adjusting seal 40 is oriented so that the shoe 43 is located proximate to the transition duct 13 and the first passage 19 within the pre-swirl cavity 30. The beams 42 of the first self-adjusting seal 40 move in response to the pressures within the pre-swirl cavity 30 and surrounding environment. The self-adjusting seal 40 is located at the top of the pre-swirl cavity 30 and above the lower seal 35. The first self-adjusting seal 40 may be secured to the inner wall 17 using a bolt 3.

[0029] The fist self-adjusting seal 40 causes fluid to move from the pre-swirl cavity 30 into a bypass channel chamber 21 that then enters the bypass channel 22. The bypass channel flow 23 moves through the bypass channel 22. Prior to entering the bypass channel 22 the bypass channel flow 23 may pass through lower seal 35. The bypass channel 22 allows evacuating the mix of air from the second passage20 and the lower labyrinth seal 35, without contaminating the pre-swirl cavity 30. The bypass channel flow 23 is dumped in the rim cavity (not shown) and it contributes to purging and cooling of the rim cavity.

[0030] Referring to Fig. 5, the bypass channel 22 may be composed of drillings and pockets in the pre-swirl support structure 27. Fluid from the first passage 19 enters through the pockets 28 into the pre-swirl cavity 30. The bypass air flow 23 enters through the pockets 29 in the pre-swirl support structure 27.

[0031] Additionally located in the pre-swirl cavity 30 and forming part of the bypass channel 22 is a diaphragm 48. The diaphragm 48 isolates the bypass air flow 23 from the leakage flow 47 through the self-adjusting seal 40 that comes from pre-swirl cavity 30.

[0032] Also located in the pre-swirl cavity 30 is a blade cooling flow passage 50. The first self-adjusting seal 40 causes the blade fluid flow 51 to move from the pre- swirl structure 33 through the blade cooling flow passage 50 into the turbine section 14 in order to provide cooling for the turbine discs 15.

[0033] The second self-adjusting seal 41 is located within the second passage 20. The second self-adjusting seal 41 is located between the inner wall 17 and the rotating arm 16. The beams 42 of the second self-adjusting seal 41 are located proximate to the inner wall 17. The shoe 43 is located proximate to the rotating arm 16. The second self-adjusting seal 41 helps seal the bypass channel chamber 21 and allows dropping the pressure in the bypass channel chamber 21 to reverse the flow through labyrinth seal 35. The second adjusting seal 41 is secured to the inner wall 17 using bolt 4.

[0034] As discussed above, the first self-adjusting seal 40 causes the fluid flow to reverse through the lower seal 35 that is located in the pre-swirl cavity 30. This causes reverse flow 37 The lower seal 35 may be a labyrinth seal, or a brush seal. The first self-adjusting seals 40 and the second self-adjusting seal 41 reacts to the pressure drop across them to maintain a tight running clearance over a wide range of conditions. Unlike labyrinth seals, the first self-adjusting seal 40 and the second self-adjusting seal 41 are effectively insensitive to thermal movements and instead respond to changes in pressure.

[0035] A gas turbine engine 10 having an air system architecture with a bypass channel chamber 21, bypass channel 22 combined with the first self-adjusting seals 40 and the second self-adjusting seal 41 has several advantages. The first self-adjusting seal 40 and the second self-adjusting seal 41 provide a uniform performance of the gas turbine engine 10 over a wide range of operating conditions. The first self-adjusting seals 40 and the second self-adjusting seal 41 also enable a robust and consistent reverse flow 37 through the lower seal 35, which results in reduced blade cooling air temperature. The resulting temperature control can provide a potential for power increase and/or gain in the life of the gas turbine components.

[0036] The first self-adjusting seals 40 and the second self-adjusting seal 41 have a tight clearance with respect to traditional labyrinth seals. Wear of the honeycomb or line facing the lower seal 35 can contribute to the deterioration of the system performance. The low leakages and flow through the lower seal 35 improve the aerodynamics in the pre-swirl cavity 30. Better cooling is equivalent to additional power margins to maintain the same blade metal temperature.

[0037] While embodiments of the present disclosure have been disclosed in exemplary forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions can be made therein without departing from the spirit and scope of the invention and its equivalents, as set forth in the following claims.

Claims

CLAIMS What is claimed is:

1. A gas turbine engine:

comprising a first self-adjusting seal disposed within the pre-swirl cavity; and a second self-adjusting seal located between a rotating structure and an inner wall of the gas turbine engine.

2. The gas turbine engine of claim 1, wherein the first self-adjusting seal comprises a first plurality of beams and shoes

3. The gas turbine engine of claim 1, wherein the second self-adjusting seal comprises a second plurality of beams and shoes.

4. The gas turbine engine of claim 1, further comprising a first passage formed by an exterior wall of a combustor and the inner wall within the gas turbine engine; and

a second passage formed by the inner wall and the rotating arm.

5. The gas turbine engine of claim 4, further comprising a bypass channel connected to the pre-swirl cavity.

6. The gas turbine engine of claim 5, wherein the bypass channel is adapted to transmit fluid from the pre-swirl cavity and a second passage.

7. The gas turbine engine of claim 1, further comprising a lower seal located in the pre- swirl cavity.

8. The gas turbine engine of claim 1, wherein the first self-adjusting seal causes a fluid flow through the lower seal into a bypass channel.

9. A gas turbine engine comprising: a first passage formed by an exterior wall of a combustor and an inner wall within the gas turbine engine;

a second passage formed by the inner wall and a rotating arm;

a pre- swirl cavity located at distal ends of the first passage and the second passage;

a first self-adjusting seal located in the first passage; and

a second self-adjusting seal located in the pre-swirl cavity.

10. The gas turbine engine of claim 9, further comprising a bypass channel connected to the pre-swirl cavity.

11. The gas turbine engine of claim 10, wherein the bypass channel is adapted to transmit fluid from the pre-swirl cavity and the second passage.

12. The gas turbine engine of claim 9, wherein the first self-adjusting seal comprises a first plurality of beams and shoes.

13. The gas turbine engine of claim 9, wherein the second self-adjusting seal comprises a second plurality of beams and shoes.

14. The gas turbine engine of claim 9, further comprising a lower seal located in the pre-swirl cavity.

15. The gas turbine engine of claim 14, wherein the first self-adjusting seal causes a fluid flow through the lower seal into a bypass channel.

16. A gas turbine engine comprising:

a first passage formed by an exterior wall of a combustor and an inner wall within the gas turbine engine;

a second passage formed by the inner wall and a rotating arm; a pre- swirl cavity located at distal ends of the first passage and the second passage; a bypass channel connected to the pre- swirl cavity;

a first self-adjusting seal located in the first passage; and

a second self-adjusting seal located in the pre-swirl cavity.

17. The gas turbine engine of claim 16, wherein the bypass channel is adapted to transmit fluid from the pre-swirl cavity and the second passage.

18. The gas turbine engine of claim 16, wherein the first self-adjusting seal comprises a first plurality of beams and shoes.

19. The gas turbine engine of claim 16, wherein the second self-adjusting seal comprises a second plurality of beams and shoes.

20. The gas turbine engine of claim 16, further comprising a lower seal located in the pre-swirl cavity, wherein the first self-adjusting seal causes a fluid flow through the lower seal into a bypass channel.