WO2017058155A1

WO2017058155A1 - Impingement cooling arrangement for gas turbine transition ducts

Info

Publication number: WO2017058155A1
Application number: PCT/US2015/052848
Authority: WO
Inventors: Manish Kumar; Rex Smith; Andrew Carlson
Original assignee: Siemens AG; Siemens Corp; Siemens Energy Inc
Current assignee: Siemens AG; Siemens Corp; Siemens Energy Inc
Priority date: 2015-09-29
Filing date: 2015-09-29
Publication date: 2017-04-06
Anticipated expiration: 2018-03-29

Abstract

Provided is a way of implementing impingement cooling for a gas turbine engine. Instead of welding the impingement sheets (10a-10i) to an integrated exit piece (15), the impingement sheets (10a-10i) are attached in a way that takes advantage of the pressure loads in the system. The impingement sheets (10a-10i) surround posts (16) located in the integrated exit piece (15) and strips (18a, 18b) are installed on the interfaces (13) and secured to the post (16).

Description

IMPINGEMENT SHEETS FOR GAS TURBINE COMBUSTORS

BACKGROUND

[0001] 1. Field [0002] Disclosed embodiments are generally related to gas turbine combustors and, more particularly to the structural components for the gas turbine combustors.

[0003] 2. Description of the Related Art

[0004] Gas turbine engines with can annular combustors have transition ducts to conduct and direct the gasses from the combustors to rows of turbine blades. The transition ducts as well as vanes orient the combustion gas flow streams to contact the turbine blades at preferred angles for rotation of the blades.

[0005] In the gas turbine engines an impingement cooling method may be employed to cool the transition ducts. The impingement cooling method depends on two closely spaced enclosures, both at different pressures. By feeding coolant from higher pressure enclosures onto the hot surface, which is at a relatively lower pressure, cooling can occur. In gas turbine combustion and with a hot gas flow path it is preferable to use the impingement cooling scheme because of the high heat transfer that occurs. However, due to emissions that may occur and the associated implications for the gas turbine engines, it is not desirable for leakage to occur. [0006] When using the impingement cooling method of transition ducts in current gas turbine systems, in order to minimize leakage, impingement sheets are welded along their perimeters. While this design helps to prevent leakage, it creates some structural issues associated with dissimilar thermal expansion, weld and heat induced stress and crack initiation. Additionally excessive welding of the impingement sheets to the integrated exit piece and the subsequent heat treatment cause undesirable deformation of the transition duct. A high fatigue safety reduction factor also results in a very low predicted life of the component. Therefore, being able to retain the impingement sheets by permitting them to respond favourably to heat different can improve upon the issues that may occur due to welding the impingement sheets.

SUMMARY

[0007] Briefly described, aspects of the present disclosure relate to a cooling system for a gas engine turbine.

[0008] An aspect of the disclosure is a cooling system for a gas turbine engine comprising: an integrated exit piece and a first impingement sheet are located proximate to a second impingement sheet on the integrated exit piece. An interface is formed between the first impingement sheet and the second impingement sheet. The system also has a post located within the integrated exit piece, wherein the first impingement sheet and second impingement sheet are adapted to surround the post. The system further has a strip that covers the interface, wherein the strip retains the first impingement sheet and the second impingement sheet.

[0009] Another aspect of the disclosure may be a method for cooling integrated exit pieces in a gas turbine engine. The method involves placing a first impingement sheet proximate to a second impingement sheet on an integrated exit piece. The first impingement sheet and the second impingement sheet surround a post located on the integrated exit piece. An interface is formed between the first impingement sheet and the second impingement sheet and the interface is covered with a strip, wherein the strip retains the first impingement sheet and the second impingement sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Fig. 1 shows a view of impingement sheets prior to being attached to the body of a transition duct.

[0011] Fig. 2 shows the impingement sheets attached to the integrated exit piece forming the transition duct.

[0012] Fig. 3 is a top down view of the body of the transition duct prior to attachment of the impingement sheets. [0013] Fig. 4 is a top down view showing attachment of impingement sheets to the transition duct.

[0014] Fig. 5 is a top down view showing attachment of the impingement sheets using a contoured strip. [0015] Fig. 6 is a top down view showing attachment of the impingement sheets using a uniform strip.

[0016] Fig. 7 shows a schematic side view of attachment of an impingement sheet to an transition duct in accordance with an embodiment of the preset invention.

[0017] Fig. 8 is a schematic diagram of an alternative embodiment for retaining impingement sheets.

[0018] Fig. 9 is a schematic side view of attachment of an impingement sheet to an transition duct using a riffle seal.

[0019] Fig. 10 is a schematic side view of attachment of an impingement sheet to an transition duct using a spring.

DETAILED DESCRIPTION

[0020] To facilitate an understanding of embodiments, principles, and features of the present disclosure, they are explained 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. [0021] The components and materials described hereinafter as making up the various embodiments are intended to be illustrative and not restrictive. Many suitable components and materials that would perform the same or a similar function as the materials described herein are intended to be embraced within the scope of embodiments of the present disclosure.

[0022] Now turning to the invention, impingement sheets are attached to the transition ducts in the gas turbine engines. The impingement sheets are formed and assembled to avoid having to weld them together. Retention of the impingement sheets is avoided by employing the pressure differences impacting the integrated exit piece and the impingement sheets. The pressure differences provide sufficient loads to keep the impingement sheets attached to the body of the integrated exit piece during operation thus minimizing leakage.

[0023] Fig. 1 shows an arrangement of impingement sheets 10a- lOi prior to their assembly and attachment. As shown in Fig. 1 the impingement sheets 10a- lOi are formed and shaped to conform to the shape of the transition duct 15, shown in Fig. 2, transition duct 15 is a transition duct used in a gas turbine engine. Each of the impingement sheets 10a- lOi have recesses 12 formed on the surface that facilitate circulation of the air and cooling of the transition duct 15. In Figs. 1 and 2, the recesses 12 formed are rectangular and arranged in rows. While the recesses 12 are shown as being rectangular in shape it should be understood that other geometric configurations are possible and may take any polygonal shape, circular or amorphous form in shape provided that it facilitates the flow of air.

[0024] Fig. 2 shows the impingement sheets 10a- lOi attached to the transition duct 15. It should be understood that the transition duct 15 may have other shapes than that which is shown depending on the gas turbine engine in which it is used. Generally, the invention disclosed herein is applicable to those impingement sheets that are located adjacent each other.

[0025] Fig. 3 shows an up close top down view of the body 17 of the transition duct 15 before any of the impingement sheets 10a- lOi are installed. Shown in the center of the transition duct 15 is the top of post 16. Post 16 may be inserted into the body 17 of the transition duct 15 and welded in place. The post 16 may be a structure such as bolt, bar, threaded stud, nut, rivet, etc. There are more than one posts 16 located on the transition duct 15 and many posts 16 may be placed between adjacent impingement sheets 10a- lOi. The posts 16 are used in the securing of the impingement sheets 10a- lOi. [0026] Fig. 4 shows the placement of two impingement sheets 10a and 10b proximate to each other. In Fig. 4 the impingement sheets 10a and 10b are adjacent to each other and form an interface 13 with their respective peripheral edges 1 1a and l ib. Additionally, impingement sheets 10a and 10b have cut outs 14a and 14b. The cut outs 14a and 14b are formed so that they surround the top of post 16. Cut outs 14a and 14b each form half of a circle in order to conform to the shape of the post 16. Other shapes may be formed depending on the shape of the post 16, such as rectangular, polygonal, etc.

[0027] In Fig. 5 strip 18a is shown attached to the impingement sheets 10a and 10b and covering the interface 13. Fig. 5 shows a strip 18a that is shaped to conform to the contour of the impingement sheets 10a and 10b. Having the shape of the strip 18a conform to the shape of the impingement sheets 10a and 10b along the interface 13 helps retain the impingement sheets 10a and 10b to the body 17 of the transition duct 15. Fig. 6 shows an alternative embodiment where a strip 18b is formed to be flat. Strip 18b may be easier to manufacture and still be able to retain the impingement sheets 10a and 10b. Both strips 18a and 18b may be metallic. Both strips 18a and 18b assist in retaining adjacent impingement sheets lOa-lOi to the transition duct 15 while additionally preventing leakage from the interface 13. Strips 18a and 18b may be elongated belts or pieces of material that overlap the interfaces 13. Further, for those portions of impingement sheets lOa-lOi that are not adjacent to one of the other impingement sheets lOa-lOi, those portions are able to remain thermally free. "Thermally free" means that the sheets are able to move in response to the temperature differentials that occur during operation.

[0028] It should be understood that Figs. 3-6 represent only a portion of the interface 13 formed between adjacent impingement sheets 10a and 10b. The retention of adjacent impingement sheets lOa-lOi shown in Figs. 3-6 is repeated along the length of the interface 13 and any adjacent impingement sheets lOa-lOi.

[0029] Now turning to Fig. 7, shown is a schematic side view of attachment of impingement sheets 10a and 10b to the body of the integrated exit piece 15. As shown post 16 extends into transition duct 15. The strip 18a is connected and secured to the post 16. The strip 18a may be secured via welding, the use of bolts, or any other suitable mechanism for securing the strip such as threaded studs with bolts, post with pin, rivet, bolts threaded into base component. The strip 18a covers the interface 13 formed by the adjacent impingement sheets 10a and 10b formed by adjacent peripheral edges 1 1a and l ib (shown in Fig. 4). This connection allows the impingement sheet 10a to be thermally free at the one end while still being retained by the strip 18a for some length.

[0030] Fig. 8 is a schematic diagram of an alternative embodiment for retaining impingement sheets lOa-lOi. In the embodiment shown in Fig. 8 impingement sheets 10a and 10b overlap in order to form the interface 13. This creates a difficult path for gases that reduce the potential for leakage. [0031] Fig. 9 shows an alternative embodiment of the present invention where a riffle seal 19 is placed under the strip 18a. The riffle seal 19 is formed with a roughened surface that further assists in retaining the strip 18a and preventing leakage. The riffle seal 19 is an optional feature which may be added.

[0032] Fig. 10 shows an alternative embodiment of the present invention that uses a spring 20 to further bias the strip 18a to the impingement sheets 10a and 10b and the body 17 of the transition duct 15. Additionally, in the embodiment shown in Fig. 9 a riffle seal 19 is used as well to assist in the securing of the impingement sheets 10a- lOi to the transition duct 15. The spring 20 may be attached to the post 16 using a screw and nut, or other attachment mechanism. [0033] During operation of the gas turbine engine the pressure loads hold down the impingement sheets lOa- lOi. During shutdown the posts 16 and strips 18a or 18b hold the impingement sheets 10a- lOi in place. The sliding contact between the impingement plates lOa-lOi and the transition duct 15 eliminates thermal stress.

[0034] 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

What is claimed is:

1. A cooling system for a gas turbine engine comprising:

an integrated exit piece (15);

a first impingement sheet(lOa) located proximate to a second impingement sheet (10b) on the integrated exit piece (15), wherein an interface (13) is formed between the first impingement sheet (10a) and the second impingement sheet (10b);

a post (16) located within the integrated exit piece (15), wherein the first impingement sheet (10a) and second impingement sheet (10b) are adapted to surround the post (16); and

a strip (18a, 18b) covering the interface (13), wherein the strip (18a, 18b) retains the first impingement sheet (10a) and the second impingement sheet (10b).

2. The cooling system of claim 1, wherein the strip (18a, 18b) is secured to the post (16).

3. The cooling system of claims 1 or 2, wherein the strip (18a) conforms to the shape of the interface (13).

4. The cooling system of any one of claims 1-3, wherein the first impingement sheet (10a) is adjacent the second impingement sheet (10b).

5. The cooling system of any of claims 1-4, wherein the first impingement sheet (10a) has a first cut-out (14a) and the second impingement sheet (10b) has a second cut out (14b), wherein the first cut out (14a) and the second cut out (14b) permit the first impingement sheet (10a) and the second impingement sheet (10b) to surround the post (16).

6. The cooling system of any one of claims 1-5, further comprising a riffle seal (19) located under the strip (18a, 18b).

7. The cooling system of any one of claims 1 -3 or 5-6, wherein the first impingement sheet (10a) overlaps the second impingement sheet (10b).

8. The cooling system of any one of claims 1-7, wherein the first impingement sheet (10a) has a surface, wherein recesses (12) are formed on the surface for cooling.

9. The cooling system of any one of claims 1-8, further comprising a spring (20) attached to the post (16), wherein the spring (20) biases the first impingement sheet (10a) and the second impingement sheet (10b) towards the integrated exit piece (15).

10. The cooling system of any one of claims 1-9, wherein the first impingement sheet (10a) and the second impingement sheet (10b) are not welded together.

11. A method for cooling transition ducts in a gas turbine engine comprising; placing a first impingement sheet (10a) proximate to a second impingement sheet (10b) on an integrated exit piece (15), wherein the first impingement sheet (10a) and the second impingement sheet (10b) surround a post (16) located on the integrated exit piece (15);

forming an interface (13) between the first impingement sheet (10a) and the second impingement sheet (10b); and

covering the interface (13) with a strip (18a, 18b).

12. The method of claim 11, wherein the strip (18a, 18b)is secured to the post (16).

13. The method of claims 1 1 or 12, wherein the strip (18a) conforms to the shape of the interface (13).

14. The method of any one of claims 1 1-13, wherein the first impingement sheet (10a) is adjacent the second impingement sheet (10b).

15. The method of any one of claims 1 1-13, wherein the first impingement sheet (10a) overlaps the second impingement sheet (10b).

16. The method of any one of claims 1 1-15, wherein the first impingement sheet (10a) has a first cut-out (14a) and the second impingement sheet (10b) has a second cut out (14b), wherein the first cut out (14a) and the second cut out (14b) permit the first impingement sheet (10a) and the second impingement sheet (10b) to surround the post (16).

17. The method of any one of claims 1 1-16, further comprising a riffle seal (19) located under the strip (18a, 18b).

18. The method of any one of claims 1 1-17, wherein the first impingement sheet (10a) has a surface, wherein recesses (12) are formed on the surface for cooling.

19. The method of any one of claims 1 1-18, further comprising biasing the first impingement sheet (10a) and the second impingement sheet (10b) towards the integrated exit piece (15) using a spring (20).

20. The method of any one of claims 1 1-19, wherein the first impingement sheet (10a) and the second impingement sheet (10b) are not welded together.