WO2014068355A1

WO2014068355A1 - Gas turbine engine exhaust system and corresponding method for accessing turbine buckets

Info

Publication number: WO2014068355A1
Application number: PCT/IB2012/002841
Authority: WO
Inventors: Robert JAMIOLKOWSKI; Piotr Edward KOBEK; Przemyslaw JAKUBCZAK
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 2012-10-30
Filing date: 2012-10-30
Publication date: 2014-05-08
Anticipated expiration: 2015-04-30
Also published as: CN104769235A

Abstract

According to one embodiment, there is disclosed an exhaust system for a gas turbine engine. The system may include an inner diffuser section having a forward portion and an aft portion. The system may also include a circumferential groove disposed in the aft portion. Moreover, the system may include a boss disposed in the forward portion. In this manner, the boss may be configured to mate with the circumferential groove to attach the forward portion to the aft portion in a removable configuration. A corresponding method for accessing turbine buckets is also provided.

Description

GAS TURBINE ENGINE EXHAUST SYSTEM AND CORRESPONDING METHOD FOR ACCESSING TURBINE BUCKETS

FIELD OF THE DISCLOSURE

[0001] Embodiments of the present disclosure relate generally to gas turbine engines and more particularly to exhaust systems and methods for facilitating access to one or more turbine buckets.

BACKGROUND OF THE DISCLOSURE

[0002] Gas turbine engines are widely utilized in fields such as power generation. A conventional gas turbine engine may include a compressor, a combustor, and a turbine. The compressor may supply compressed air to the combustor, where the compressed air may be mixed with fuel and burned to generate a hot gas. This hot gas may be supplied to the turbine, where energy may be extracted from the hot gas to produce work. In particular, the turbine may include one or more turbine buckets which rotate as the hot gas passes therethrough. The hot gas may exit the turbine via an exhaust system.

[0003] Typical exhaust system configurations, however, substantially impede access to the turbine buckets for repair and/or replacement. Accordingly, it continues to be a priority to provide access to the turbine buckets without jeopardizing performance of the gas turbine engine.

BRIEF DESCRIPTION OF THE DISCLOSURE

[0004] Some or all of the above needs and/or problems may be addressed by certain embodiments of the present disclosure. According to one embodiment, there is disclosed an exhaust system for a gas turbine engine. The system may include an inner diffuser section having a forward portion and an aft portion. The system may also include a circumferential groove disposed in the aft portion. Moreover, the system may include a boss disposed in the forward portion. In this manner, the boss may be configured to mate with the circumferential groove to attach the forward portion to the aft portion in a removable configuration.

[0005] According to another embodiment, there is disclosed an exhaust system for a gas turbine engine. The system may include an inner diffuser section having a forward portion and an aft portion. The system may also include a rabbet joint configured to attach the forward portion to the aft portion.

[0006] Further, according to another embodiment, there is disclosed a method for accessing one or more turbine buckets. The method may include removing an exhaust frame forward casing. The method may also include removing a forward portion of an outer diffuser section. Moreover, the method may include removing a forward portion of an inner diffuser section.

[0007] Other embodiments, aspects, and features of the invention will become apparent to those skilled in the art from the following detailed description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0009] FIG. 1 is a schematic of an example diagram of a gas turbine engine with a compressor, a combustor, and a turbine, according to an embodiment of the disclosure.

[0010] FIG. 2 is a cross sectional view of a portion of an exhaust system, according to an embodiment of the disclosure.

[0011] FIG. 3 is a cross sectional view of a portion of an exhaust system, according to an embodiment of the disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0012] Illustrative embodiments of the disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the disclosure are shown. The disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

[0013] Illustrative embodiments are directed to, among other things, gas turbine engines including exhaust systems and methods for facilitating access to one or more turbine buckets. In this manner, certain embodiments of the disclosure may facilitate accessing one or more turbine buckets, particularly the last stage turbine buckets, via the exhaust system. For instance, the various components described herein may be detachable and/or removable from the exhaust system. That is, in one embodiment, an exhaust frame forward casing, a forward portion of the outer diffuser section, and a forward portion of the inner diffuser section may be removed in order to provide access to (or removal of) the last stage turbine buckets.

[0014] In one example embodiment, the exhaust system may include an inner diffuser section having a forward portion and an aft portion. In some instances, the forward portion of the inner diffuser section and the aft portion of the inner diffuser section may be removeably attached to each other via a rabbet joint. For example, the rabbet joint may include a circumferential groove disposed in the aft portion of the inner diffuser section and a boss disposed in the forward portion of the inner diffuser section. In this manner, the boss may be configured to mate with the circumferential groove. In certain embodiments, a retaining ring may be positioned adjacent to the circumferential groove to secure the boss within the circumferential groove.

[0015] In some instances, the exhaust system may also include a primary seal positioned adjacent to the circumferential groove to form a seal between an exhaust frame and the inner diffuser section. For example, a slot may be associated with the aft portion of the inner diffuser section such that at least a portion of the primary seal may be disposed within the slot. In other instances, the exhaust system may include a secondary seal positioned adjacent to a forward end of the forward portion of the inner diffuser section. The secondary sea! may form a seal between the exhaust frame and the inner diffuser section. For example, a slot may be associated with the forward portion of the inner diffuser section such that at least a portion of the secondary seal is disposed within the slot.

[0016] In certain embodiments, the exhaust system may include an outer diffuser section having a forward portion attached to an aft portion. In other embodiments, the exhaust system may include an exhaust frame forward casing disposed about the inner diffuser section and the outer diffuser section. For example, the exhaust frame forward casing may include a shell that is attached (e.g., bolted) to a turbine shell at one end and to the exhaust frame at the other end. In yet other embodiments, the exhaust system may include an outer forward seal positioned adjacent to a forward end of the forward portion of the outer diffuser section to form a seal between the exhaust frame forward casing and the outer diffuser section.

[0017] Turning now to FIG. 1, which depicts a schematic view of an example embodiment of a gas turbine engine 10 as may be used herein. For example, the gas turbine engine 10 may include a compressor 15. The compressor 15 may compress an incoming flow of air 20. The compressor 15 may deliver the compressed flow of air 20 to a combustor 25. The combustor 25 may mix the compressed flow of air 20 with a pressurized flow of fuel 30 and ignite 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 in turn may be delivered to a turbine 40. The flow of combustion gases 35 may drive the turbine 40 so as to produce mechanical work. The mechanical work produced in the turbine 40 may drive the compressor 15 via a shaft 45 and an external load 50 such as an electrical generator or the like.

[0018] 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, New York, including, but not limited to, those such as a 7 or a 9 series heavy duty gas turbine engine or the like. The gas turbine engine 10 may have different configurations and may use other types of components. Moreover, 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.

[0019] Referring to FIG. 2, there is depicted a partial view of an example embodiment of the gas turbine engine 10. In one embodiment, the gas turbine engine 10 may include an exhaust system 100. The exhaust system 100 may include an exhaust frame 102. For example, the exhaust frame 102 may support (directly or indirectly) various components of the exhaust system 100. The exhaust system 100 may also include an exhaust frame forward casing 104. In some instances, the exhaust frame forward casing 104 may be attached (e.g., by bolts 106) to a turbine shell 108 at one end and to the exhaust frame 102 at the other end. In one embodiment, the exhaust frame forward casing 104 may be formed of several components, such as two 180 degree shells secured together. In other embodiments, however, the exhaust frame forward casing 104 may be a single component or multiple components. In this manner, the exhaust frame forward casing 104 may be detached from the turbine shell 108 and the exhaust frame 102 to provide access to internal portions of the exhaust system 100.

[0020] The exhaust system 100 may also include an outer diffuser section 110. The outer diffuser section 110 may include an aft portion 112 and a forward portion 114. In some instances, the aft portion 112 of the outer diffuser section 110 and the forward portion 114 of the outer diffuser section 110 may be secured together (e.g., by bolt 116) so as to form a continuous flow path for the combustion hot gasses when assembled. In addition, the exhaust system 100 may include an outer forward seal 118 positioned between the forward portion 114 of the outer diffuser section 110 and the exhaust frame forward casing 104. The outer forward seal 118 may be held in place by a radial slot 120 associated with the forward portion 114 of the outer diffuser section 110 and a radial slot 122 associated with the exhaust frame forward casing 104. Any securing means may be used to fasten the outer forward seal 118 in place.

[0021] In certain instances, in order to provide access to internal portions of the exhaust system 100, the outer forward seal 118 may be removed from radial slots 120 and 122. In addition, the forward portion 114 of the outer diffuser section 110 may be detached from the aft portion 112 of the outer diffuser section 110 and removed.

[0022] In one embodiment, the exhaust system 100 may include an inner diffuser section 124. The inner diffuser section 124 may include an aft portion 126 and a forward portion 128. In some instances, the aft portion 126 of the inner diffuser section 124 and the forward portion 128 of the inner diffuser section 124 may be secured together by a rabbet joint 130 so as to from a continuous flow path for the combustion hot gasses when assembled. As depicted in FIGS. 2 and 3, in one embodiment, the rabbet joint 130 may include a circumferential groove 132 disposed in the aft portion 128 of the inner diffuser section 124. Moreover, the rabbet joint 130 may include a boss 134 disposed in the forward portion 126 of the inner diffuser section 124. In this manner, the boss 134 may be configured to mate with the circumferential groove 132, for example, in a hooking manner. In certain embodiments, the exhaust system 100 may also include a retaining ring 136 positioned adjacent to the circumferential groove 132 and boss 134 to secure the boss 134 within the circumferential groove 132.

[0023] In some instances, the exhaust system 100 may include a primary seal 138 positioned adjacent to the circumferential groove 132 to form a seal between the exhaust frame 102 and the inner diffuser section 124. For example, the primary seal 138 may be secured in place by a radial slot 140 associated with the aft portion 126 of the inner diffuser 124 and a bolt 142 associated with the exhaust frame 102. Any securing means, however, may be used to fasten the primary seal 138 in place. In other instances, the exhaust system 100 may include a secondary seal 144 positioned adjacent to a forward end of the forward portion 128 of the inner diffuser section 124 to form a seal between the exhaust frame 102 and the inner diffuser section 124. In one example embodiment, the secondary seal may be secured in place by an axial slot 146 associated with the forward portion 128 of the inner diffuser section 124 and a radial slot 148 associated with a removable ring 150.

[0024] The forward portion 128 of the inner diffuser section 124 may be removed from the exhaust system 100 by removing the retaining ring 136 and then disengaging the forward portion 128 of the inner diffuser section 124 from the primary seal 138 and the secondary seal 144. Moreover, the removable ring 150 may be removed to provide access to a cavity 152 for turbine bucket 154 removal. For example, the removable of the exhaust frame forward casing 104, the forward portion 114 of the outer diffuser section 11, the forward portion 128 of the inner diffuser section 124, and the removable ring 150 may provide a space to allow the last stage turbine buckets 154 to be pulled out of the rotor wheel from the aft side of the turbine casing for maintenance and/or replacement.

[0025] Although embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the embodiments.

Claims

CLAIMS THAT WHICH IS CLAIMED:

1. An exhaust system for a gas turbine engine, comprising:

an inner diffuser section comprising a forward portion and an aft portion;

a circumferential groove disposed in the aft portion; and

a boss disposed in the forward portion that is configured to mate with the circumferential groove to attach the forward portion to the aft portion in a removable configuration.

2. The exhaust system of claim 1> further comprising a retaining ring positioned adjacent to the circumferential groove to secure the boss within the circumferential groove.

3. The exhaust system of claim 1, further comprising a primary seal positioned adjacent to the circumferential groove to form a seal between an exhaust frame and the inner diffuser section.

4. The exhaust system of claim 3, further comprising a slot associated with the aft portion, wherein at least a portion of the primary seal is disposed within the slot.

5. The exhaust system of claim 1, further comprising a secondary seal positioned adjacent to a forward end of the forward portion to form a seal between an exhaust frame and the inner diffuser section.

6. The exhaust system of claim 5, further comprising a slot associated with the forward end of the forward portion, wherein at least a portion of the secondary seal is disposed within the slot.

7. The exhaust system of claim 1, further comprising an outer diffuser section comprising a forward portion and an aft portion.

8. The exhaust system of claim 7, further comprising an exhaust frame forward casing disposed about the inner diffuser section and the outer diffuser section.

9. The exhaust system of claim 8, further comprising an outer forward seal positioned adjacent to a forward end of the forward portion of the outer diffuser section to form a seal between the exhaust frame forward casing and the outer diffuser section.

10. An exhaust system for a gas turbine engine, comprising:

an inner diffuser section comprising a forward portion and an aft portion; and a rabbet joint configured to attach the forward portion to the aft portion.

1 1. The exhaust system of claim 10, wherein the rabbet joint comprises:

a circumferential groove disposed in the aft portion; and

a boss disposed in the forward portion that is configured to mate with the circumferential groove to attach the forward portion to the aft portion.

12. The exhaust system of claim 11, further comprising a retaining ring positioned adjacent to the circumferential groove to secure the boss within the circumferential groove.

13. The exhaust system of claim 1 1, further comprising a primary seal positioned adjacent to the circumferential groove to form a seal between an exhaust frame and the inner diffuser section.

14. The exhaust system of claim 13, further comprising a slot associated with the aft portion, wherein at least a portion of the primary seal is disposed within the slot.

15. The exhaust system of claim 10, further comprising a secondary seal positioned adjacent to a forward end of the forward portion to form a seal between an exhaust frame and the inner diffuser section.

16. The exhaust system of claim 15, further comprising a slot associated with the forward end of the forward portion, wherein at least a portion of the secondary seal is disposed within the slot.

17. The exhaust system of claim 10, further comprising an outer diffuser section comprising a forward portion and an aft portion.

18. The exhaust system of claim 17, further comprising an exhaust frame forward casing disposed about the inner diffuser section and the outer diffuser section.

19. The exhaust system of claim 18, further comprising an outer forward seal positioned adjacent to a forward end of the forward portion of the outer diffuser section to form a seal between the exhaust frame forward casing and the outer diffuser section.

20. A method for accessing one or more turbine buckets, comprising:

removing an exhaust frame forward casing;

removing a forward portion of an outer diffuser section; and

removing a forward portion of an inner diffuser section.