US20130084160A1

US20130084160A1 - Turbine Shroud Impingement System with Bellows

Info

Publication number: US20130084160A1
Application number: US13/249,554
Authority: US
Inventors: Georgia Leigh Fleming; Robert W. Coign; Christopher L. Golden
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 2011-09-30
Filing date: 2011-09-30
Publication date: 2013-04-04
Also published as: EP2574730A2; CN103032114A; EP2574730A3

Abstract

The present application provides a turbine shroud impingement system. The turbine shroud impingement system may include a turbine shroud segment, an impingement box positioned within the turbine shroud segment, a feed tube in communication with the impingement box, and a bellows positioned about the feed tube.

Description

TECHNICAL FIELD

The present application and the resultant patent relate generally to gas turbine engines and more particularly relate to a turbine shroud impingement system with an impingement box in communication with a feed tube and a bellows for effective sealing, low leakage, and improved production.

BACKGROUND OF THE INVENTION

Generally described, a gas turbine includes a number of turbine blades rotating in a hot gas pathway. This hot gas pathway may be enclosed and defined in part by a turbine shroud. Specifically, a number of turbine shroud segments may be fixed in an annular array adjacent to the turbine blades. The turbine shroud thus protects an outer turbine casing and inhibits leakage of the hot combustion gases past the turbine blades without producing useful work therein.
Because the turbine shroud defines the hot gas pathway in part, the turbine shroud may be cooled with a cooling air flow from the compressor or other source. This cooling air flow is required to maintain the structural integrity of the turbine shroud and maintain the clearances in the hot gas pathway. Because this cooling air flow is a parasitic loss on the overall gas turbine engine, reducing the leakage of such cooling air flow about the turbine shroud and elsewhere should promote overall gas turbine efficiency and performance.
There is thus a desire for an improved turbine shroud cooling system. Preferably, such an improved turbine shroud cooling system should provide a cooling air flow to the turbine shroud for sufficient cooling therein while limiting overall leakage losses and the like.

SUMMARY OF THE INVENTION

The present application and the resultant patent thus provide a turbine shroud impingement system. The turbine shroud impingement system may include a turbine shroud segment, an impingement box positioned within the turbine shroud. segment, a feed tube in communication with the impingement box, and a bellows positioned about the feed tube.
The present application and the resultant patent further provide a method of cooling a shroud segment. The method may include the steps of positioning an impingement box within the shroud segment, positioning a feed tube with a bellows within an inlet of the impingement box, maintaining the feed tube within the inlet of the impingement box by the axial compression of the bellows, and delivering a flow of air through the feed tube to the impingement box to cool the shroud segment.
The present application and the resultant patent further provide a turbine shroud impingement system. The turbine shroud impingement system may include a turbine shroud segment, an impingement box with a number of impingement holes positioned within the turbine shroud segment, a feed tube in communication with the impingement box, and a bellows with a number of convolutions positioned about feed tube.
These and other features and improvements of the present application and the resultant patent will become apparent to one of ordinary skill in the art upon review of the following detailed description when taken in conjunction with the several drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a gas turbine engine with a compressor, a combustor, and a turbine.

FIG. 2 is a schematic diagram of portions of a number of stages of the turbine.

FIG. 3 is a side view of a turbine shroud impingement system as may be described herein.

FIG. 4 is a side view of an alternative embodiment of a turbine shroud impingement system as may be described herein.

DETAILED DESCRIPTION

Referring now to the drawings, in which like numerals refer to like elements throughout the several views, FIG. 1 shows a schematic view of gas turbine engine 10 as may be used herein. The gas turbine engine 10 may include a compressor 15. The compressor 15 compresses an incoming flow of air 20. The compressor 15 delivers the compressed flow of air 20 to a combustor 25. The combustor 25 mixes the compressed flow of air 20 with a pressurized flow of fuel 30 and ignites the mixture to create a flow of combustion gases 35. Although only a single combustor 25 is shown, the gas turbine engine 10 may include any number of combustors 25. The flow of combustion gases 35 is in turn delivered to a turbine 40. The flow of combustion gases 35 drives the turbine 40 so as to produce mechanical work. The mechanical work produced in the turbine 40 drives the compressor 15 via a shaft 45 and an external load 50 such as an electrical generator and the like.
The gas turbine engine 10 may use natural gas, various types of syngas, and/or other types of fuels. The gas turbine engine 10 may be any one of a number of different gas turbine engines offered by General Electric Company of Schenectady, N.Y., including, but not limited to, those such as a 7 or a 9 series heavy duty gas turbine engine and the like. The gas turbine engine 10 may have different configurations and may use other types of components. Other types of gas turbine engines also may be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment also may be used herein together.
FIG. 2 shows a number of the components of the turbine 40. Specifically, a stage one bucket 55 and a stage two nozzle 60 are shown. The stage one bucket 55 may be surrounded by a stage one shroud 65. The stage one shroud 65 may be in communication with a flow of air 20 from the compressor 15 or other source. Known systems for delivering this flow of air 20 to the shroud 65 may include metered holes, spoolie systems, and the like. (Cooling systems are not limited to stage one use.) As described above, such known shroud cooling systems, however, may be subject to leakage therein.
FIG. 3 shows a shroud 100 as may be described herein. Specifically, FIG. 3 shows a shroud segment 110. Any number of shroud segments 110 may be used in the overall shroud 100 in a circumferential array. As described above, the shroud segments 110 surround the buckets 55 and define the hot gas pathway therethrough. A lower surface 120 of the shroud segment 110 may thee the buckets 55 and the flow of combustion gases 35 therein. Other components and other configurations may be used herein.
Each shroud segment 110 may include a shroud impingement system 130 positioned therein. The shroud impingement system 130 may include an impingement box 140. A bottom surface 150 of impingement box 140 may have a number of impingement holes 160 therein. The impingement holes 160 may have any desired size, shape, or configuration. Any number of impingement holes 160 may be used herein. The impingement holes 160 face the lower surface 120 of the shroud segment 110 for cooling purposes. The impingement box 140 also may include an offset inlet 170. The offset inlet 170 may be positioned about a conical or an axial load face 180. The offset inlet 170 may have a substantial tube like shape 190. The offset inlet 170 may extend. about the axial load face 180 into an interior 200 of the impingement box 140. Other components and other configurations may be used herein.
The shroud impingement system 130 also may include a feed tube 220. The feed tube 220 may be in communication with the flow of air 20 from the compressor 15 or elsewhere and with the impingement box 140. The feed tube 220 may have any desired size, shape, or configuration. The shroud impingement system 130 also may include a bellows 230. In this example, the bellows 230 may be part of the feed tube 220. The bellows 230 may include a number of convolutions 240 and the like. The bellows 230 as a whole and the convolutions 240 may have any size, shape, or configuration. The bellows 230 acts as a type of expansion joint. Other types of deflection and sealing means may be used herein. The bellows 230 can withstand the internal pressure of the flow of air 20 within the feed tube 220 while also being flexible enough to accept axial, lateral, and/or angular deflections. Likewise, the bellows 230 may compensate for thermal movement, manufacturing and assembly variations, and the like. The configuration of the bellows 230 may vary with the configuration of the stages and the overall gas turbine engine and the output thereof. The feed tube 220 and the bellows 230 may be made out of any type of high temperature resistant materials and alloys. Other components and other configurations also may be used herein.
The bellows 230 may be positioned between a first section 250 and a second section 260 of the feed tube 220 or otherwise. The second section 260 may have any type of geometry and may be sized to accommodate the offset inlet 170 of the impingement box 140. For example, the second tube 260 may have an expanded spherical shape to accommodate the offset inlet 170. The feed tube 220 and the sections 250, 260 thereof may be sized with a predetermined diameter depending upon the desired flow rate of the flow of air 20 therein. The respective lengths of the sections 250, 260 and the bellows 230 may vary. Other components and other configurations also may be used herein.
The shroud impingement system 130 may be positioned within an impingement box aperture 270 of the shroud segment 110. The impingement box. aperture 270 may be sized and shaped to accommodate the intended impingement box 140. Standoffs tend to maintain a certain distance between the impingement box 140 and the shroud segment 110. Likewise, the lower surface 120 of the shroud segment 110 may face the bottom surface 150 and the impingement holes 160 of the impingement box 140 for impingement cooling therein. A feed tube aperture 290 also may extend through the shroud segment 110. The feed tube aperture 290 may be sized and shaped to accommodate the feed tube 220 and the bellows 230 securely therein. Other components and other configurations also may be used herein.
FIG. 4 shows an alternative embodiment of a shroud impingement system 300 as may be described herein. In this example, the bellows 230 may be attached directly to the offset inlet 170 of the impingement box 140 instead of the feed tube 220 described above. The bellow 230 extends directly to the first section 250 of the feed tube 220 without the use of the second section 260. A flange 310 and the like also may be attached to the bellows 230. Other components and other configurations also may be used herein.
In use, the feed tube 220 of the shroud impingement system 130 extends through the feed tube aperture 290 of the shroud segment 110. The second section 260 of the feed tube 220 may be positioned within the offset inlet 170 about the axial load face 180 of the impingement box 140. The connection between the feed tube 220 and the impingement box 140 may be maintained by the axial compression of the bellows 230. The bellows 230 thus reduces the leakage in the flow of air 20 by maintaining a sealing surface in spite of relative movement between the feed tube 220 and the impingement box 140. The sealing surface may be maintained regardless of slight relative movement therein. Additional sealing means also may be used herein. The shroud impingement system 130 thus delivers the flow of air 20 to the impingement box 140 so as to cool the lower surface 120 of the shroud segment 110 in an efficient manner. Alternatively, the bellows 230 may be attached to the offset inlet 170 of the impingement box 140 or elsewhere and may receive the feed tube 220 therein.
The bellows 230 of the shroud impingement system 130 thus may reduce the need for tight machining tolerances that otherwise would he required for a rigid connection between the impingement box 140 and the feed tube 220. The bellows 230 therefore provides a constant sealing surface in a low cost, efficient sealing system with high reliability.
It should be apparent that the foregoing relates only to certain embodiments of the present application and the resultant patent. Numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.

Claims

We claim:

1. A turbine shroud impingement system, comprising:

a turbine shroud segment;

an impingement box positioned within the turbine shroud segment;

a feed tube in communication with the impingement box; and

a bellows positioned about the feed tube.

2. The turbine shroud impingement system of claim 1, wherein the shroud. segment comprises a lower surface and wherein the impingement box comprises a bottom surface adjacent to the lower surface of the shroud segment.

3. The turbine shroud impingement system of claim 2, wherein the bottom surface of the impingement box comprises a plurality of impingement holes therein.

4. The turbine shroud impingement system of claim 1, wherein the impingement box comprises axial load face thereon.

5. The turbine shroud impingement system of claim 4, wherein the impingement box comprises an offset inlet positioned about the axial load face.

6. The turbine shroud impingement system of claim 5, wherein the offset inlet comprises a tube-like or conical shape.

7. The turbine shroud impingement system of claim 1, wherein the bellows comprises one or more convolutions.

8. The turbine shroud impingement system of claim 1, wherein the feed tube comprises a first section and a second section and wherein the bellows is positioned between the first section and the second section.

9. The turbine shroud impingement system of claim 1, wherein the bellows is attached to the impingement box.

10. The turbine shroud impingement system of claim 1, wherein the shroud segment comprises an impingement box aperture therein.

11. The turbine shroud impingement system of claim 1, wherein the shroud. segment comprises a feed tube aperture therein.

12. The turbine shroud impingement system of claim 1, further comprising a plurality of shroud segments.

13. A method of cooling a shroud segment, comprising:

positioning an impingement box within the shroud segment;

positioning a feed tube with a bellows within an inlet of the impingement box;

maintaining the feed tube within the inlet of the impingement box by axial compression of the bellows; and

delivering a flow of air through the feed tube to the impingement box to cool the shroud segment.

14. A turbine shroud impingement system, comprising:

a turbine shroud segment;

an impingement box with a plurality of impingement holes positioned within the turbine shroud segment;

a feed tube in communication with the impingement box; and

a bellows with a plurality of convolutions positioned about feed tube.

15. The turbine shroud impingement system of claim 14, wherein the shroud segment comprises a lower surface and wherein the impingement box comprises a bottom surface adjacent to the lower surface of the shroud segment.

16. The turbine shroud impingement system of claim 14, wherein the feed tube comprises a first section and a second section and wherein the bellows is positioned between the first section and the second section.

17. The turbine shroud impingement system of claim 14, wherein the bellows is attached to the impingement box.