Seal assembly for gas turbine engine

Abstract

A seal assembly includes a seal holder, a first seal having a first end fixedly attached to a first component and a second end movably attached to the seal holder, and a second seal having a third end movably attached to a second component and a fourth end fixedly attached to the seal holder, the first component and the second component movable relative to each other.

Description

SEAE ASSEMBLY FOR GAS TURBINE ENGINEBACKGROUND

[0001] A gas turbine engine typically includes a compressor section, a turbine section, and a combustion section disposed therebetween. The compressor section typically includes multiple stages of rotating compressor blades and stationary compressor vanes to produce compressed air. The combustion section typically includes a plurality of combustor to produce hot working fluid by combusting mixture of the compressed air and fuel. The turbine section typically includes multiple stages of rotating turbine blades and stationary turbine vanes to expand the hot working fluid and to convert fluid energy to mechanical energy. The rotating turbine blades and stationary turbine vanes often operate in a high temperature environment and are internally cooled.

[0002] Each combustor may include a head section, a combustion chamber, and a transition duct. The head section includes fuel injectors for providing a fuel. The fuel and the compressed air are mixed and combusted in the combustion chamber to generate the combustion gas. The combustion gas exits the combustor through the transition duct and flows into the turbine section. A seal is typically arranged between the combustor and turbine section, specifically, between the transition duct and the first stage stationary turbine vane. The seal may restrict the transition duct and the first stage stationary turbine vane to move independently in different directions during operation of the gas turbine engine.BRIEF SUMMARY

[0003] In one aspect, a seal assembly is provided. The seal assembly includes a seal holder, a first seal having a first end fixedly attached to a first component and a second endmovably attached to the seal holder, and a second seal having a third end movably attached to a second component and a fourth end fixedly attached to the seal holder, the first component and the second component movable relative to each other.

[0004] In one aspect, a gas turbine engine is provided. The gas turbine engine includes a transition duct for passing combustion gas, the transition duct includes an inner exit frame disposed at a downstream end of the transition duct with respect to a flow direction of the combustion gas. The gas turbine engine also includes a vane disposed downstream of the transition duct to receive the combustion gas, the vane includes an inner platform and an inner rail disposed at an upstream edge of the inner platform with respect to the flow direction of the combustion gas. The gas turbine engine also includes a shaft cover disposed radially inward from the vane. The gas turbine engine also includes a seal assembly disposed between the transition duct and the vane, the seal assembly includes a first seal having a first outer diameter end and a first inner diameter end, the first outer diameter end fixedly attached to the inner exit frame, a second seal having a second outer diameter end and a second inner diameter end, the second outer diameter end movably attached to the inner rail, and a seal holder fixedly attached to the shaft cover, the seal holder defining a first groove to movably receive the first inner diameter end and a second groove to fixedly receive the second inner diameter end.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0006] FIG. 1 is a longitudinal cross-sectional view of a gas turbine engine taken along a plane that contains a longitudinal axis or central axis.

[0007] FIG. 2 is an enlarged view of a portion of the gas turbine engine of FIG. 1 in an assembled condition.

[0008] FIG. 3 is a view of FIG. 2 in an operation condition.

[0009] FIG. 4 is a partial perspective view of a seal assembly of FIG. 2 and FIG. 3.DETAILED DESCRIPTION

[0010] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in this description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0011] Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0012] It should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms “including”, “having”, and “comprising”, as well as derivatives thereof, mean inclusion without limitation. The singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the term “and / or” as usedherein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term “or” is inclusive, meaning and / or, unless the context clearly indicates otherwise. The phrases “associated with” and “associated therewith” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Furthermore, while multiple embodiments or constructions may be described herein, any features, methods, steps, components, etc. described with regard to one embodiment are equally applicable to other embodiments absent a specific statement to the contrary.

[0013] Although the terms “first”, “second”, “third” and so forth may be used herein to refer to various elements, information, functions, or acts, these elements, information, functions, or acts should not be limited by these terms. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

[0014] In the description, the terms “axial” or “axially” refer to a direction along a longitudinal axis of a gas turbine engine. The terms “radial” or “radially” refer to a direction perpendicular to the longitudinal axis of the gas turbine engine. The terms “downstream” or “aft” refer to a direction along a flow direction. The terms “upstream” or “forward” refer to a direction against the flow direction.

[0015] In addition, the term “adjacent to" may mean that an element is relatively near to but not in contact with a further element or that the element is in contact with the further portion, unless the context clearly indicates otherwise. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Terms “about” or “substantially” or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standardis available, a variation of twenty percent would fall within the meaning of these terms unless otherwise stated.

[0016] FIG. 1 illustrates an example of a gas turbine engine 100 including a compressor section 102, a combustion section 104, and a turbine section 106 arranged along a central axis 108. The compressor section 102 includes a plurality of compressor stages 110 with each compressor stage 110 including a set of stationary compressor vanes 112 or adjustable guide vanes and a set of rotating compressor blades 114. A rotor 116 supports the rotating compressor blades 114 for rotation about the central axis 108 during operation. In some constructions, a single one-piece rotor 116 extends the length of the gas turbine engine 100 and is supported for rotation by a bearing at either end. In other constructions, the rotor 116 is assembled from several separate spools that are attached to one another or may include multiple disk sections that are attached via a bolt or plurality of bolts.

[0017] The compressor section 102 is in fluid communication with an inlet section 118 to allow the gas turbine engine 100 to draw atmospheric air into the compressor section 102. During operation of the gas turbine engine 100, the compressor section 102 draws in atmospheric air and compresses that air for delivery to the combustion section 104. The illustrated compressor section 102 is an example of one compressor section 102 with other arrangements and designs being possible.

[0018] In the illustrated construction, the combustion section 104 includes a plurality of separate combustor 120 that each operate to mix a flow of fuel with the compressed air from the compressor section 102 and to combust that air-fuel mixture to produce a flow of high temperature, high pressure combustion gas 122. Of course, many other arrangements of the combustion section 104 are possible.

[0019] The turbine section 106 includes a plurality of turbine stages 124 with each turbine stage 124 including a number of stationary turbine vanes 126 and a number of rotating turbine blades 128. The turbine stages 124 are arranged to receive the combustion gas 122 from the combustion section 104 at a turbine inlet 130 and expand that gas to convert thermal and pressure energy into rotating or mechanical work. The turbine section 106 is connected to the compressor section 102 to drive the compressor section 102. For gasturbine engines 100 used for power generation or as prime movers, the turbine section 106 is also connected to a generator, pump, or other device to be driven. As with the compressor section 102, other designs and arrangements of the turbine section 106 are possible.

[0020] An exhaust portion 132 is positioned downstream of the turbine section 106 and is arranged to receive the expanded flow of combustion gas 122 from the final turbine stage 124 in the turbine section 106. The exhaust portion 132 is arranged to efficiently direct the combustion gas 122 away from the turbine section 106 to assure efficient operation of the turbine section 106. Many variations and design differences are possible in the exhaust portion 132. As such, the illustrated exhaust portion 132 is but one example of those variations.

[0021] A control system 134 is coupled to the gas turbine engine 100 and operates to monitor various operating parameters and to control various operations of the gas turbine engine 100. In preferred constructions the control system 134 is typically micro-processor based and includes memory devices and data storage devices for collecting, analyzing, and storing data. In addition, the control system 134 provides output data to various devices including monitors, printers, indicators, and the like that allow users to interface with the control system 134 to provide inputs or adjustments. In the example of a power generation system, a user may input a power output set point and the control system 134 may adjust the various control inputs to achieve that power output in an efficient manner.

[0022] The control system 134 can control various operating parameters including, but not limited to variable inlet guide vane positions, fuel flow rates and pressures, engine speed, valve positions, generator load, and generator excitation. Of course, other applications may have fewer or more controllable devices. The control system 134 also monitors various parameters to assure that the gas turbine engine 100 is operating properly. Some parameters that are monitored may include inlet air temperature, compressor outlet temperature and pressure, combustor outlet temperature, fuel flow rate, generator power output, bearing temperature, and the like. Many of these measurements are displayed for the user and are logged for later review should such a review be necessary.

[0023] FIG. 2 is an enlarged view of a portion of the gas turbine engine 100 in an assembled condition. A seal assembly 202 is arranged in the portion between a first component, a second component, and a third component. In the embodiment as illustrated in FIG. 2, the portion is an interface area between the compressor section 102 and the turbine section 106. The first component is a transition duct 204 of the combustor 120. The second component is a vane 206. The vane 206 is the stationary turbine vane 126 of the first turbine stage 124. The third component is a shaft cover 208 of the gas turbine engine 100. In other embodiments, the seal assembly 202 can be arranged between other components of the gas turbine engine 100 or arranged between components in a device other than the gas turbine engine 100.

[0024] The transition duct 204 guides the combustion gas 122 flowing from the combustor 120 to the turbine section 106. An inner exit frame 210 is attached at a downstream edge of the transition duct 204 with respect to the flow direction of the combustion gas 122. The inner exit frame 210 extends radially inward to the rotor 116. The vane 206 includes an inner platform 212 and an inner rail 214 that is attached at an upstream edge of the inner platform 212 with respect to the flow direction of the combustion gas 122. The inner rail 214 extends radially inward to the rotor 116. The inner exit frame 210 interfaces the inner rail 214 with a gap 216 in between.

[0025] The seal assembly 202 is arranged between the transition duct 204 and the vane 206 to seal the combustion gas 122 from leaking through the gap 216. The seal assembly 202 includes a first seal 218, a second seal 220, a seal holder 222, and a seal retainer 224. The seal retainer 224 is fixedly attached to the inner exit frame 210 by for example, a stud. The first seal 218 includes a first end 226 that is arranged between the seal retainer 224 and the inner exit frame 210. A pin 228 is inserted through the seal retainer 224 and into the first end 226 to fixedly attach the first end 226 to the inner exit frame 210. The first seal 218 includes a second end 230 that is movably inserted into a first groove 232 of the seal holder 222. A clearance is arranged between the second end 230 and an end surface of the first groove 232 to allow a radial movement of the first seal 218. A first tab 234 is arranged between the seal retainer 224 and the first end 226. The pin 228 passes through the first tab234. A radial height of the first tab 234 is less than a radial height of the first seal 218. In other embodiments, the seal assembly 202 may not include the first tab 234.

[0026] The second seal 220 includes a third end 236 that is movably inserted into a slot 238 of the inner rail 214. A clearance is arranged between the third end 236 and an end surface of the slot 238 to allow a radial movement of the third end 236. The second seal 220 includes a fourth end 240 that is fixedly inserted into a second groove 242 of the seal holder 222. The fourth end 240 is fixedly inserted into the second groove 242 by any suitable attachment techniques, such as welding. A second tab 244 is inserted into the second groove 242 and arranged between the fourth end 240 and the second seal 220. The second tab 244 is fixedly attached to the second groove 242, for example, by welding. A radial height of the second tab 244 is less than a radial height of the second seal 220. In other embodiments, the seal assembly 202 may not include the second tab 244.

[0027] The seal holder 222 is fixedly attached to the shaft cover 208. In the embodiment illustrated in FIG. 2, the seal holder 222 is fixedly attached to the shaft cover 208 by a stud 246 passing through the shaft cover 208 and inserted into the seal holder 222. In other embodiments, the seal holder 222 may be fixedly attached to the shaft cover 208 by any suitable attachment techniques, such as welding.

[0028] Each of the first seal 218 and the second seal 220 includes a first layer 248 and a second layer 250 that are attached and overlap to each other to form a two layer ply seal. Each of the first layer 248 and the second layer 250 includes a shim wrapped by metal cloth. The first seal 218 and the second seal 220 are flat and flexible.

[0029] In the assembled condition, the first seal 218 is preloaded to a preload shape in which the first end 226 and the second end 230 are positioned axially offset from each other. The preload shape is calculated to split a relative axial movement between the transition duct 204 and the shaft cover 208 during operation of the gas turbine engine 100.

[0030] In the embodiment illustrated in FIG. 2, the first end 226 is the first outer diameter end of the first seal 218 that is fixedly attached to the inner exit frame 210, the second end 230 is the first inner diameter end of the first seal 218 that is moveably attached to the sealholder 222, the third end 236 is the second outer diameter end of the second seal 220 that is movably attached to the vane 206, and the fourth ends 240 is the second inner diameter end of the second seal 220 that is fixedly attached to the seal holder 222. In other embodiments, the first outer diameter end of the first seal 218 may be moveably attached to the inner exit frame 210, the first inner diameter end of the first seal 218 may be fixedly attached to the seal holder 222, the second outer diameter end of the second seal 220 may be fixedly attached to the inner rail 214, and the second inner diameter end of the second seal 220 may be movably attached to the seal holder 222.

[0031] FIG. 3 is a view of FIG. 2 in an operation condition. During operation of the gas turbine engine 100, the shaft cover 208 moves in the axial direction relative as indicated by the dashed arrow line in FIG. 2. The vane 206 moves together with the shaft cover 208 in the axial direction. No relative axial movement exists between the vane 206 and the shaft cover 208. A relative axial movements exists between the shaft cover 208 and the transition duct 204. The relative axial movement between the shaft cover 208 and the transition duct 204 changes the shape of the preloaded flexible first seal 218 from the preload shape to an operation shape in which the first end 226 and the second end 230 of the first seal 218 are positioned axially aligned to each other.

[0032] FIG. 4 is a partial perspective view of the seal assembly 202 showing the seal holder 222 and the second seal 220. The first seal 218 has the same configuration as the second seal 220 and will not be described in detail herewith.

[0033] The first layer 248 and the second layer 250 are attached and overlap to each other to form a complete circle around the central axis 108. The first layer 248 includes a plurality of first layer segments 402 that are arranged circumferentially next to each other. The second layer 250 includes a plurality of second layer segments 404 that are arranged circumferentially next to each other. Each first layer segment 402 and the directly overlapped second layer segment 404 are positioned circumferentially offset from each other to form the complete circle. For illustration purpose, only two first layer segments 402 and two second layer segments 404 are shown in FIG. 4 .

[0034] The seal holder 222 includes a plurality of seal holder segments 406 that are arranged circumferentially next to each other to form a complete circle around the central axis 108. For illustration purpose, only one seal holder segment 406 is shown in FIG. 4. The seal holder segment 406 has at least one hole 408 to receive the stud 246 for fixing the seal holder 222 to the shaft cover 208. Each seal holder segment 406 holds two first layer segments 402 and two second layer segments 404. In other embodiments, each seal holder segment 406 may hold less or more than two first layer segments 402 and two second layer segments 404, for example, one first layer segment 402 and one second layer segment 404, three first layer segments 402 and three second layer segments 404, four first layer segments 402 and four second layer segments 404, etc.

[0035] In operation, the combustion gas 122 exits the combustor 120 through the transition duct 204 and flows to the turbine stages 124. The seal assembly 202 seals the combustion gas 122 from leaking through the gap 216 between the transition duct 204 and the vane 206 of the first turbine stage 124. The first seal 218 and the second seal 220 are two separated seals and seals the transition duct 204 and the vane 206 separately. The separated first seal 218 and second seal 220 allow the transition duct 204 and the vane 206 to move independently in different directions during the operation. The seal assembly 202 reduces the volume of the gap 216 between the transition duct 204 and the vane 206. The purge air that is required to purge the gap 216 is thus reduced. The efficiency of the gas turbine engine 100 is improved. The separated first seal 218 and second seal 220 reduce the risk of potential wear at the seal locations. The life of the gas turbine engine 100 is improved. The seal assembly 202 is retrofittable. The first seal 218 is preloaded to a preload shape to split the relative axial movement between the transition duct 204 and the vane 206.

[0036] Although an exemplary embodiment of the present disclosure has been described in detail, those skilled in the art will understand that various changes, substitutions, variations, and improvements disclosed herein may be made without departing from the spirit and scope of the disclosure in its broadest form.

[0037] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be includedin the claim scope: the scope of patented subject matter is defined only by the allowed claims. Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.LISTING OF DRAWING ELEMENTS100 gas turbine engine102 compressor section104 combustion section106 turbine section108 central axis110 compressor stage112 stationary compressor vane114 rotating compressor blade116 rotor118 inlet section120 combustor122 combustion gas124 turbine stage126 stationary turbine vane128 rotating turbine blade130 turbine inletexhaust portion control system seal assembly transition duct vane shaft cover inner exit frame inner platform inner rail gap first seal second seal seal holder seal retainer first end pin second end first groove first tab third endslot fourth end second groove second tab stud first layer second layer first layer segment second layer segment seal holder segment hole

Claims

CLAIMSWhat is claimed is:

1. A seal assembly comprising: a seal holder; a first seal having a first end fixedly attached to a first component and a second end movably attached to the seal holder; and a second seal having a third end movably attached to a second component and a fourth end fixedly attached to the seal holder, the first component and the second component movable relative to each other.

2. The seal assembly of claim 1, further comprising a seal retainer that is fixedly attached to the first component, and wherein the first end is disposed between the seal retainer and the first component and fixedly attached to the first component by a pin passing through the seal retainer and inserted into the first end.

3. The seal assembly of claim 2, further comprising a first tab that is disposed between the seal retainer and the first end.

4. The seal assembly of claim 1, further comprising a second tab that is fixedly disposed between the fourth end and the seal holder.

5. The seal assembly of claim 1, wherein the seal holder comprises a plurality of seal holder segments that are arranged circumferentially next to each other.

6. The seal assembly of claim 1, wherein the first seal comprises a first layer and a second layer that are attached and overlap to each other.

7. The seal assembly of claim 6, wherein the first layer comprises a plurality of first layer segments that are arranged circumferentially next to each other and the second layer comprises a plurality of second layer segments that are arranged circumferentially next to each other.

8. The seal assembly of claim 7, wherein each first layer segment and the directly overlapped second layer segment are positioned circumferentially offset from each other.

9. The seal assembly of claim 1, wherein a shape of the first seal is changeable from a preload shape to an operation shape, and wherein the first end and the second end are positioned axially offset from each other in the preload shape and positioned axially aligned to each other in the operation shape.

10. The seal assembly of claim 1, wherein the seal holder is fixedly attached to a third component.

11. The seal assembly of claim 1, wherein the seal holder comprises a first groove to moveably receive the second end and a second groove to fixedly receive the fourth end.

12. A gas turbine engine comprising: a transition duct for passing combustion gas, the transition duct comprising an inner exit frame disposed at a downstream end of the transition duct with respect to a flow direction of the combustion gas; a vane disposed downstream of the transition duct to receive the combustion gas, the vane comprising an inner platform and an inner rail disposed at an upstream edge of the inner platform with respect to the flow direction of the combustion gas; a shaft cover disposed radially inward from the vane; and a seal assembly disposed between the transition duct and the vane, the seal assembly comprising: a first seal having a first outer diameter end and a first inner diameter end, the first outer diameter end fixedly attached to the inner exit frame, a second seal having a second outer diameter end and a second inner diameter end, the second outer diameter end movably attached to the inner rail, and a seal holder fixedly attached to the shaft cover, the seal holder defining a first groove to movably receive the first inner diameter end and a second groove to fixedly receive the second inner diameter end.

13. The gas turbine engine of claim 12, wherein the seal assembly further comprises a seal retainer fixedly attached to the inner exit frame, and wherein the first outer diameter end is disposed between the seal retainer and the inner exit frame and fixedly attached to the inner exit frame.

14. The gas turbine engine of claim 13, wherein the seal assembly further comprises a first tab that is disposed between the first outer diameter end and the seal retainer and fixedly attached to the inner exit frame.

15. The gas turbine engine of claim 12, wherein the second outer diameter end is movably inserted into a slot of an inner rail of the vane.

16. The gas turbine engine of claim 12, wherein the seal assembly further comprises a second tab that is disposed between the second inner diameter end and the seal holder and fixedly attached to the seal holder.

17. The gas turbine engine of claim 12, wherein each of the first seal and the second seal comprises a first layer and a second layer that are attached and overlap to each other.

18. The gas turbine engine of claim 17, wherein the first layer comprises a plurality of first layer segments that are arranged circumferentially next to each other and the second layer comprises a plurality of second layer segments that are arranged circumferentially next to each other.

19. The gas turbine engine of claim 18, wherein each first layer segment and the directly overlapped second layer segment are positioned circumferentially offset from each other.

20. The gas turbine engine of claim 12, wherein a shape of the first seal is changeable from a preload shape to an operation shape, and wherein the first outer diameter end and the first inner diameter end are positioned axially offset from each other in the preload shape and positioned axially aligned to each other in the operation shape.

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