WO2018089014A1

WO2018089014A1 - Seal assembly between a transition duct and a stage one turbine vane structure

Info

Publication number: WO2018089014A1
Application number: PCT/US2016/061579
Authority: WO
Inventors: Chad W. Heinrich; Stephen A. Camillieri; Christian K. Funk; Jacob Williams HARDES; Daniel CASSAR
Original assignee: Siemens Aktiengesellschaft
Priority date: 2016-11-11
Filing date: 2016-11-11
Publication date: 2018-05-17

Abstract

A seal assembly (10) arranged to seal a gap between a transition duct (12) of a gas turbine engine and a first stage turbine vane structure (14) is provided. A flexible seal element (26), such as cloth seal, extends between opposed sides (18, 24) of the seal assembly in a first zone of the gas turbine engine subject to a first pressure load A biasing assembly (28) is disposed between the opposed sides of the seal assembly in a second zone of the gas turbine engine subject to a second pressure load different than the first pressure load. Biasing assembly (28) is arranged to compliantly accept displacements that occur between the transition duct and the first stage turbine vane structure during operation of the gas turbine engine. Biasing assembly (28) is further arranged to provide mechanical support to flexible seal element (26) so that this flexible seal element can withstand a pressure load differential between the first and the second zones of the gas turbine engine.

Description

SEAL ASSEMBLY BETWEEN A TRANSITION DUCT AND

A STAGE ONE TURBINE VANE STRUCTURE

FIELD OF THE INVENTION

Disclosed embodiments are generally related to a combustion turbine engine, and, more particularly, to a seal assembly between a transition duct and a stage one turbine vane structure.

BACKGROUND OF THE INVENTION

A combustion turbine engine, such as a gas turbine engine, includes for example a compressor section, a combustor section and a turbine section. Intake air is

compressed in the compressor section and then mixed with fuel. The mixture is ignited in the combustor section to produce a high-temperature and high-pressure flow of combustion gases conveyed by a transition duct system to the turbine section of the engine, where thermal energy is converted to mechanical energy. Seals are interposed between respective outlets of the transition ducts and corresponding stage one turbine vane structures to prevent compressed air, as may be fluidly coupled to a transition shell, to leak and mix with the hot flow of combustion gases. A number of factors -such as adjacent component growth, variances due to thermal expansion, mechanical and/or pressure loads, vibrational forces from combustion dynamics, etc.,- can present various challenges regarding durability and performance of such seals. A seal involving a floating cloth seal is described in US patent 6,547,257.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in the following description in view of the drawings that show:

FIG. 1 shows a cross-sectional view of one non-limiting embodiment of a disclosed seal assembly between a transition duct and a stage one turbine vane structure.

FIG. 2 shows a perspective view of one non-limiting embodiment of a disclosed seal assembly. FIG. 3 is a front view of seal segments arranged to form a segmented annular seal assembly.

FIG. 4 shows a perspective view of another non-limiting embodiment of a disclosed seal assembly.

DETAILED DESCRIPTION OF THE INVENTION

The present inventors have recognized certain issues in connection with certain known seals between a transition duct and a first stage turbine vane structure. Often, such seals may involve separate seal structures that can result in a relatively large radial gap between the transition and the vane structure, and such a relatively large gap may not be conducive to reducing leakage of compressed air into the hot flow of combustion gases. This relatively large gap in turn leads to a correspondingly large gap volume, which may not be conducive to reducing the amount of purged air utilized for cooling structures involved in the interface between the transition and the vane structure.

In view of such a recognition, the present inventors propose an innovative seal assembly that is effective for reducing such a radial gap and thus conducive to reducing such leakage. This gap reduction is further effective for reducing the volume of the gap, which in turn reduces the amount of purging air utilized for cooling the structures involved in the interface between the transition and the vane structure. Additionally, the proposed seal assembly is effective to increase the sealing area between the transition and the vane structure. This increase in sealing area in turn reduces the size of possible paths through which leakage could develop, and thus contributing to engine efficiency by reducing total engine leakage.

The proposed seal assembly is also effective to compliantly accept

displacements, such as axial, radial, or circumferential displacements, that can develop between the transition duct and the first stage turbine vane structure during operation of the gas turbine engine. It will be appreciated that combinations of such displacements, if not appropriately accommodated, could result in excessive twisting or bending of the structures subject to such displacements. Compliant acceptance of such displacements permits relatively more relative motion between the transition duct and the first stage turbine vane structure without undesirable mechanical distress, and thus the proposed seal assembly is expected to last longer in operation without malfunctions. Accordingly, in a cost-effective and reliable manner, the proposed seal assembly is expected to result in relatively lower levels of stress to the seal assembly and associated structures, with a concomitant reduction in wear and cracking, which is conducive to a more reliable and longer-lasting seal assembly.

In the following detailed description, various specific details are set forth in order to provide a thorough understanding of such embodiments. However, those skilled in the art will understand that embodiments of the present invention may be practiced without these specific details, that the present invention is not limited to the depicted embodiments, and that the present invention may be practiced in a variety of alternative embodiments. In other instances, methods, procedures, and components, which would be well-understood by one skilled in the art have not been described in detail to avoid unnecessary and burdensome explanation.

Furthermore, various operations may be described as multiple discrete steps performed in a manner that is helpful for understanding embodiments of the present invention. However, the order of description should not be construed as to imply that these operations need be performed in the order they are presented, nor that they are even order dependent, unless otherwise indicated. Moreover, repeated usage of the phrase "in one embodiment" does not necessarily refer to the same embodiment, although it may. It is noted that disclosed embodiments need not be construed as mutually exclusive embodiments, since aspects of such disclosed embodiments may be appropriately combined by one skilled in the art depending on the needs of a given application.

The terms "comprising", "including", "having", and the like, as used in the present application, are intended to be synonymous unless otherwise indicated. Lastly, as used herein, the phrases "configured to" or "arranged to" embrace the concept that the feature preceding the phrases "configured to" or "arranged to" is intentionally and specifically designed or made to act or function in a specific way and should not be construed to mean that the feature just has a capability or suitability to act or function in the specified way, unless so indicated. FIG. 1 shows a cross-sectional view of one non-limiting embodiment of a disclosed seal assembly 10 between a transition duct 12 and a stage one turbine vane structure 14. Seal assembly 10 is arranged to seal a gap between transition duct 12 extending between a combustor (not shown) of a gas turbine engine and first stage turbine vane structure 14.

In one non-limiting embodiment a connection member 16 may be arranged at a first side 18 of seal assembly 10 for connecting, for example, to a transition outlet ring 20 of transition duct 12. A connection member 22 may be arranged at a second side 24 of seal assembly 10 opposed to first side 18 of the seal assembly for connecting to the first stage turbine vane structure 14, such as a vane shroud. In one non-limiting embodiment, connection members 16, 22 may comprise protrusions, which are respectively insertable into appropriately configured cutouts in transition outlet ring 20 and first stage turbine vane structure 14. Respective retainers 19 may be used to secure connection members 16, 22 into the respective receiving cutouts constructed in transition outlet ring 20 and first stage turbine vane structure 14.

In one non-limiting embodiment, a flexible seal element 26 extends between opposed sides 18, 24 of seal assembly 10 in a first zone of the gas turbine engine subject to a first pressure load, schematically represented by arrows 33 in FIG. 1 . For example, this zone may comprise air compressed in the compressor section of the engine that may be conveyed to an air plenum fluidly coupled to the transition system for cooling/purging purposes. To facility spatial orientation of disclosed embodiments, FIG. 1 indicates a coordinate system comprising an axis 23, which corresponds to a longitudinal axis of the seal assembly, an axis 25 which corresponds to a radial axis relative to a circumferential axis 27 of the seal assembly.

Flexible seal element 26 may be a cloth seal, such as without limitation may comprise a high temperature-resistant material, such as metal, ceramic or polymer fibers which may be woven, knitted or otherwise pressed into a layer of fabric. If the seal cloth involves two or more layers of cloth, depending on the needs of a given application, the multiple doth layers may be appropriately tailored. For example, different materials may be chosen for the multiple layers, the construction may be different for the multiple layers or different thicknesses may be chosen for the multiple layers. In one non-limiting embodiment, the cloth seal may involve a Dutch twill weave cloth assembly, as may be formed of a high temperature cobalt-based superalloy, such as without limitation Haynes 188 alloy.

In one non-limiting embodiment, a biasing assembly 28 is disposed between opposed sides 18, 24 of seal assembly 10 in a second zone of the gas turbine engine subject to a second pressure load different than the first pressure load. For example, this zone may allow passage to the hot flow of combustion gases, schematically represented by arrows 35 in FIG. 1 and would be at a relatively lower pressure than the first zone of the gas turbine engine subject to the first pressure load. Biasing assembly 28 is arranged to compliantly accept the various displacements that can occur between transition duct 12 and first stage turbine vane structure 14 during operation of the gas turbine engine. Biasing assembly 28 is further arranged to provide mechanical support to flexible seal element 26 so that flexible seal element 26 can withstand the pressure load differential between the first and the second zones of the gas turbine engine.

In one non-limiting embodiment, biasing assembly 28 may include a first biasing element 32 including a first portion 34 (e.g., a straight portion), disposed onto a corresponding portion of a radially inwardly surface 36 of flexible seal element 26 and extending axially from first side 18 of seal assembly 10 to a first location 38 between opposed sides 18, 24 of the seal assembly, and further includes a second portion 40 extending from first portion 34 of first biasing element 32 to define a biasing segment 42 of first biasing element 32.

Biasing assembly 28 may further include a second biasing element 44

(structurally similar to first biasing element 32, such as forming respective spring clips) including a first portion 46 ( e.g., a straight portion) disposed onto a corresponding portion of radially inwardly surface 36 of flexible seal element 26 and extending axially from second side 24 of seal assembly 10 to a second location 48 between opposed sides 18, 24 of seal assembly 10, and further includes a second portion 50 extending from first portion 46 of second biasing element 44 to define a biasing segment 52 of second biasing element 44. Respective biasing segments 42, 52 of first and second biasing elements 32, 44 are arranged to mutually engage one another at a location radially away (e.g., radially inwardly) from flexible seal element 26. Without being limiting, embodiments of biasing elements 32, 44 may be made of a multi-ply construction, such as IN X-750 sheet metal, which may be heat treated to meet any desired spring properties. This and other materials that have suitable spring and thermal resistance qualities may be used in various embodiments of biasing elements 32, 44. It will be appreciated that respective first and second portions 34, 40 of first biasing element 32 may (but need not) comprise a respective unitary construction.

Similarly, respective first and second portions 46, 50 of second biasing element 44 may also (but need not) comprise a respective unitary construction.

In one non-limiting embodiment, a radially outer surface 60 of a respective one of biasing segments (e.g., second biasing element 44 in FIG. 1 ) engages a corresponding radially inner surface 62 of the other respective one of the biasing segments (e.g., first biasing element 32 in FIG. 1 ) to establish a mutually opposed urging interface between the engaging surfaces of respective biasing elements 32, 44. In one non-limiting embodiment, the respective biasing segments 42, 52 of first and second biasing elements 32, 44 comprise respective curvilinear segments relative to longitudinal axis 23.

FIG. 2 shows a perspective view of one non-limiting embodiment of a disclosed seal assembly illustrating affixing means 21 (such as spot welds, etc) for connecting flexible seal element 26 to biasing assembly 28.

FIG. 3 is a front view of arcuate seal segments 10A through 10F arranged to form a segmented annular seal assembly 69. It will be appreciated that the number of seal segments illustrated in FIG. 3 should be construed in an example sense and not in a limiting sense since annular seal assembly 69 may be formed by any number of seal assembly segments, such as one or more seal segments circumferentially

interconnected to one another other. In one non-limiting embodiment, as may be appreciated in FIG. 4, respective edges 72, 74 of the respective first portions of the first and second biasing elements are configured to provide an overlapping joint (shiplap joint) between respective adjacent seal assembly segments of the plurality of

circumferentially interconnected seal assembly segments.

In operation, disclosed embodiments are expected to provide in a cost-effective manner a compliant and robust seal assembly that should provide extended life to associated transition ducts and row 1 vane structures, while also providing more consistent sealing performance.

While various embodiments of the present invention have been shown and described herein, it will be apparent that such embodiments are provided by way of example only. Numerous variations, changes and substitutions may be made without departing from the invention herein. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.

Claims

The invention claimed is: 1 . A seal assembly arranged (10) to seal a gap between a transition duct

(12) extending between a combustor of a gas turbine engine and a first stage turbine vane structure (14), the seal assembly comprising:

a connection member (16) arranged at a first side (18) of the seal assembly for connecting to the transition duct (12);

a connection member (22) arranged at a second side (24) of the seal assembly opposed to the first side of the seal assembly for connecting to the first stage turbine vane structure;

a flexible seal element (26) extending between the opposed sides of the seal assembly in a first zone of the gas turbine engine subject to a first pressure load; and a biasing assembly (28) disposed between the opposed sides of the seal assembly in a second zone of the gas turbine engine subject to a second pressure load different than the first pressure load, the biasing assembly arranged to compliantly accept displacements that occur between the transition duct and the first stage turbine vane structure during operation of the gas turbine engine, the biasing assembly further arranged to provide mechanical support to the flexible seal element so that the flexible seal element can withstand a pressure load differential between the first and the second zones of the gas turbine engine.

2. The seal assembly of claim 1 , wherein the biasing assembly (28) comprises a first biasing element (32) comprising a first portion (34) disposed onto a radially inwardly surface (36) of the flexible seal element and extending axially from the first side of the seal assembly to a first location (38) between the opposed sides of the seal assembly, and further comprises a second portion (40) extending from the first portion of the first biasing element to define a biasing segment (42) of the first biasing element.

3. The seal assembly of claim 2, wherein the biasing assembly (28) comprises a second biasing element (44) comprising a first portion (46) disposed onto the radially inwardly surface of the flexible seal element and extending axially from the second side of the seal assembly to a second location (48) between the opposed sides of the seal assembly, and further comprises a second portion (50) extending from the first portion of the second biasing element to define a biasing segment (52) of the second biasing element.

4. The seal assembly of claim 3, wherein the respective biasing segments (42,52) of the first and second biasing elements (32,44) are arranged to mutually engage one another at a location radially away from the flexible seal element.

5. The seal assembly of claim 4, wherein a radially outer (60) surface of a respective one of the biasing segments engages a corresponding radially inner (62) surface of the other respective one of the biasing segments to establish a mutually opposed urging interface between the engaging surfaces (60,62) of the respective biasing elements. (34, 44)

6. The seal assembly of claim 5, wherein the respective biasing segments (45, 52) of the first and second biasing elements (32,44) comprise respective curvilinear segments.

7. The seal assembly of claim 1 , wherein the flexible seal element comprises a cloth seal.

8. The seal assembly of claim 4, comprising an annular seal assembly (69).

9. The seal assembly of claim 8, wherein the annular seal assembly comprises a plurality of seal assembly segments (10A-10F) circumferentially

interconnected to one another other.

10. The seal assembly of claim 9, wherein respective edges (72,74) of the respective first portions of the first and second biasing elements (32,44) are configured to provide an overlapping joint between respective adjacent seal assembly segments of the plurality of circumferentially interconnected seal assembly segments.

1 1 . The seal assembly of claim 10, wherein the respective first and second (34,40) portions of the first biasing element (32) comprise a respective unitary construction, and the respective first and second portions (46,50) of the second biasing element (44) comprise a respective unitary construction.

12. A gas turbine engine including a transition duct (12) extending between a combustor of a gas turbine engine and a first stage turbine vane structure (14), the gas turbine engine comprising:

an annular seal assembly (69) to seal a gap between the transition duct and the first stage turbine vane structure, the annular seal assembly comprising at least one seal segment (10) comprising:

a connection member (16) arranged at a first side (24) of the annular seal assembly for connecting to the transition duct;

a connection member (22) arranged at a second side (24) of the annular seal assembly opposed to the first side of the seal assembly for connecting to the first stage turbine vane structure;

a flexible cloth seal (26) extending between the opposed sides of the annular seal assembly; and

a biasing assembly(28) disposed between the opposed sides of the annular seal assembly, the biasing assembly arranged to compliantly accept displacements that occur between the transition duct and the first stage turbine vane during operation of the gas turbine engine, the biasing assembly further arranged to provide structural support to the flexible cloth seal relative to a pressure load.

13. The gas turbine engine of claim 12, wherein the biasing assembly comprises a first biasing element (32) comprising a first portion (34) disposed onto a radially inwardly surface (36) of the flexible cloth seal and extending axially from the first side of the seal assembly to a first location (38) between the opposed sides (18,24) of the seal assembly, and further comprises a second portion (40) extending from the first portion of the first biasing element to define a biasing segment (42) of the first biasing element.

14. The gas turbine engine of claim 13, wherein the biasing assembly (28) comprises a second biasing element (44) comprising a first portion (46) disposed onto the radially inwardly surface of the flexible cloth seal and extending axially from the second side of the seal assembly to a second location (48) between the opposed sides (18,24) of the seal assembly, and further comprises a second portion (50) extending from the first portion of the second biasing element to define a biasing segment (52) of the second biasing element.

15. The gas turbine engine of claim 14, wherein the respective biasing segments (42, 52) of the first and second biasing elements are arranged to mutually engage one another at a location radially away from the flexible seal element.

16. The gas turbine engine of claim 15, wherein a radially outer surface (60) of a respective one of the biasing segments engages a corresponding radially inner surface (62) of the other respective one of the biasing segments to establish a mutually opposed urging interface between the engaging surfaces of the respective biasing elements (32, 44).

17. The seal assembly of claim 15, wherein the respective biasing segments (42, 52) of the first and second biasing elements comprise respective curvilinear segments.

18. The gas turbine engine of claim 16, wherein the annular seal assembly comprises a plurality of seal assembly segments (10A-10F) circumferentially interconnected to each other.

19. The gas turbine engine of claim 18, wherein respective edges (72,74) of the respective first portions of the first and second biasing elements (32,44) are configured to provide an overlapping joint between respective adjacent seal assembly segments of the plurality of circumferentially interconnected seal assembly segments.