Sealing against corner leaks in a gas turbine

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention is directed to a gas turbine engine with a seal located in the space between circumferentially adjacent arc segments and to a method of assembling a seal in a gas turbine engine. BACKGROUND OF THE INVENTION

[0002] The main gas-flow path in a gas turbine commonly includes the operational components of a compressor inlet, a compressor, a turbine and a gas outflow. There are also secondary flows that are used to cool the various heated components of the turbine. Mixing of these flows and gas leakage in general, from or into the gas-flow path, is detrimental to turbine performance.

[0003] The operational components of a gas turbine are contained in a casing. The turbine is commonly surrounded annularly by adjacent arc segments. As used herein, the term "arcuate" may refer to a member, component, part, etc. having a curved or partially curved shape. The adjacent arc segments include outer shrouds, inner shrouds, nozzle blocks, and diaphragms. Arc segments may provide a container for the gas-flow path in addition to the casing alone. Arc segments may secure other components of the turbine and may define spaces within the turbine. Between each adjacent pair of arc segments is a space that permits the arc segments to expand as the operation of the gas turbine forces the arc segments to expand.

[0004] Slots are defined on the sides of each arc segment for receiving a seal in cooperation with an adjacent slot of an adjacent arc segment. The seal is placed in the slot to prevent leakage between the areas of the turbine on either side of the seal. These areas may include the main gas-flow path and secondary cooling flows.

[0005] The slots within the end of a particular arc segment may be angled in orientation to each other and the slots may connect. When a planar seal is received in each of the two slots that are connected, a gap is left between the two seals. This gap permits leakage between the internal and external areas of the gas turbine. Reducing this gap improves gas turbine performance.

[0006] US 2015 / 118042 A1 discloses a gas turbine having a multi-layer seal received in slots formed in opposite side surfaces of adjacent shroud segments. The seal includes a layer having seal end portions which are temporarily deflected and temporarily secured in position via a temperature-sensitive adhesive, such that the seal has an initial overall length that is shorter than a length of the slot, to facilitate insertion of the seal into the slot. During gas turbine operation, the adhesive is exposed to elevated temperatures that cause the adhesive to melt, enabling deployment of the seal end portions to their extended positions in contact with the slot end walls to prevent leakage around ends of the seal.

[0007] EP 2 236 766 A2 discloses a gas turbine having pairs of interconnected slots extending in axial and in radial direction and formed in opposite side surfaces of adjacent shroud segments. These slots are sealed by two seal members coupled to each other by a connector to cover the gap between the seal members and thus avoid leakage between the seal members.BRIEF DESCRIPTION OF THE INVENTION

[0008] The invention is directed to a gas turbine as defined in claim 1 and to a method of assembling a seal as defined in claim 7. Further aspects of the invention are set out in the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings that depict various embodiments of the disclosure, in which: FIG. 1 shows a perspective partial cut-away view of a known gas turbine. FIG. 2 shows a perspective view of known arc segments in an annular arrangement. FIG. 3 shows a cross-sectional longitudinal view of a known turbine of a gas turbine. FIG. 4 shows a schematic cross-sectional side view of a section of a turbine according to various embodiments of the invention. FIG. 5 shows a schematic cross-sectional side view of a section of a turbine not falling within the scope of the claims. FIG. 6 shows a flow diagram illustrating a method according to various embodiments of the invention.

[0010] It is noted that the drawings of the invention are not necessarily to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings.DETAILED DESCRIPTION OF THE INVENTION

[0011] As noted herein, the subject matter disclosed relates to turbines. Specifically, the subject matter disclosed herein relates to cooling fluid flow in gas turbines.

[0012] In contrast to conventional approaches, various embodiments of the disclosure include gas turbomachine (or, turbine) buckets having a shroud including an outlet path. The outlet path can be fluidly connected with a plurality of radially extending cooling passageways in the blade, and can direct outlet of cooling fluid from a set (e.g., two or more) of those cooling passageways to a location radially adjacent the shroud, and proximate the trailing edge of the bucket.

[0013] As denoted in these Figures, the "A" axis represents axial orientation (along the axis of the turbine rotor, omitted for clarity). As used herein, the terms "axial" and / or "axially" refer to the relative position / direction of objects along axis A, which is substantially parallel with the axis of rotation of the turbomachine (in particular, the rotor section). As further used herein, the terms "radial" and / or "radially" refer to the relative position / direction of objects along axis (r), which is substantially perpendicular with axis A and intersects axis A at only one location. Additionally, the terms "circumferential" and / or "circumferentially" refer to the relative position / direction of objects along a circumference (c) which surrounds axis A but does not intersect the axis A at any location. It is further understood that common numbering between FIGURES can denote substantially identical components in the FIGURES.

[0014] Referring to FIG. 1, a perspective view of one embodiment of a gas turbine 2 is shown. In this embodiment, gas turbine 2 includes a compressor inlet 4, a compressor 6, a plurality of combustors 8, a compressor discharge (not shown), a turbine 12 including a plurality of turbine blades 14, a rotor 16 and a gas outflow 18. Compressor inlet 4 supplies air to compressor 6. Compressor 6 supplies compressed air to combustors 8 where it mixes with fuel. Combustion gases from combustors 8 propels turbine blades 12. Propelled turbine blades 12 rotate rotor 16. A casing 20 forms an outer enclosure that encloses compressor inlet 4, compressor 6, plurality of combustors 8, compressor discharge (not shown), turbine 12, turbine blades 14, rotor 16 and gas outflow 18. Gas turbine 2 is only illustrative; teachings of the invention may be applied to a variety of gas turbines.

[0015] Referring to FIG. 2, a perspective view of one embodiment of an annular arrangement 22 of arc segments 24 of turbine 12 of gas turbine 2 is shown. This view shows seven arc segments 24 with one arc segment removed for illustrative purposes. The end of each arc segment 24 has slots 26. Between each arc segment 24 is a space 28. A person skilled in the art will readily recognize that annular arrangement 22 may have any number of arc segments 24; that arc segments 24 may be of varying shapes and sizes; and that arc segments 24 may serve different functions in gas turbine 2. For example, arc segments in a turbine may include, but not be limited to, outer shrouds, inner shrouds, nozzle blocks, and diaphragms as discussed below.

[0016] Referring to FIG. 3, a cross-sectional view of one embodiment of turbine 12 of gas turbine 2 (FIG. 1) is shown. In this embodiment, casing 20 encloses a plurality of outer shrouds 30, an inner shroud 32, a plurality of nozzle blocks 34, a plurality of diaphragms 36, and turbine blades 14. Each of the outer shrouds 30, inner shroud 32, nozzle blocks 34 and diaphragms 36 are arc segments 24. Each of the outer shrouds 30, inner shrouds 32, nozzle blocks 34 and diaphragms 36 have slots 26 in a side thereof. In this embodiment, outer shrouds 30 connect to casing 20; inner shroud 32 connects to outer shrouds 30; nozzle blocks 34 connect to outer shrouds 30; and diaphragms 36 connect to nozzle blocks 34. A person skilled in the art will readily recognize that many different arrangements and geometries of arc segments are possible. Alternative embodiments, may include different arc segments, more arc segments, or less arc segments.

[0017] Turning to FIG. 4, a section of a gas turbine 102 is shown according to various embodiments, the gas turbine 102 including a first arc segment 104 circumferentially adjacent a second arc segment 106, each arc segment 104, 106 including an end surface 108 and radially facing surfaces 110 extending from opposite ends of the end surface 108. Turbine 102 also includes slot 112 located between end surfaces 108 of first arc segment 104 and second arc segment 106. turbine 102 also includes a first seal 114 disposed in slot 112, where first seal 114 contacts first arc segment 104 at its end surface 108, and extends over radially facing surfaces 110 of first arc segment 104. The first seal 114 includes: a shim 116 contacting first arc segment 104, a laminate material 118 over shim 116 and covering shim 116, and a conforming material 120 coupling the laminate material 118 to the shim 116. It is understood that according to various embodiments, laminate material 118 can include a plurality of individual layers (e.g., shims) which can be bonded, welded or otherwise joined to form a material. In some cases, the individual layers of the laminate material 118 can include one or more metal layers, and in some cases, the individual layers are welded (e.g., spot welded) to one another, allowing for flexibility of the laminate material 118 (e.g., torsional movement).

[0018] The conforming material 120 has a melting temperature causing the conforming material 120 to substantially disintegrate during operation of the turbine 102, for example, a melting temperature of approximately 65 degrees Celsius (approximately 150 degrees Fahrenheit) to approximately 485 degrees Celsius (approximately 900 degrees Fahrenheit. In various embodiments, conforming material 120 includes at least one of: rubber, silicone, plastic, wax, related low-melting temperature materials, or composites thereof.

[0019] As shown in FIG. 4, laminate material 118 includes a plurality of segments 118A, 118B, 118C, where each segment is separated from its neighboring segment (e.g., 118A and 118B). Each segment 118A, 118B, 118C of laminate material 118 corresponds with a distinct surface of first arc segment 104, whereby segment 118A corresponds with a first radially facing surface 110, segment 118B corresponds with end surface 108 and segment 118C corresponds with a second radially facing surface 110.

[0020] As noted herein, the conforming material 120 has a melting temperature causing it to substantially disintegrate during operation of the turbine 102. According to various embodiments, the shim 116 and laminate material 118 (including segments 118A, 118B, 118C) are adapted to move independently of one another when the conforming material 120 (between shim 116 and segments of laminate material 118) has substantially disintegrated. Shim 116 may be a single, continuous piece of metal, and substantially seals corner regions 122 spanning between end surface 108 and each of radially facing surfaces 110. In some particular embodiments, shim 116 has a thickness of approximately 0.0025 millimeters to approximately 1.3 millimeters.

[0021] FIG. 5 shows an alternative view of a section of a gas turbine 202 not falling within the scope of the claims. It is understood that commonly labeled components between the FIGURES can represent substantially identical components (e.g., first arc segment 104 adjacent a second arc segment 106, each arc segment 104, 106 including an end surface 108 and radially facing surfaces 110 extending from opposite ends of the end surface 108, and slot 112 located between end surfaces 108 of first arc segment 104 and second arc segment 106). In various embodiments, turbine 202 can include a second seal 214 disposed in slot 112, where second seal 114 contacts first arc segment 104 at its end surface 108, and extends over radially facing surfaces 110 of first arc segment 104. The second seal 114 can include: a laminate material 118 contacting first arc segment 104, and a conforming material 120 sealing the end surface 108 and radially facing surfaces 110 of the first arc segment 104.

[0022] In various embodiments, conforming material 120 has a melting temperature causing the conforming material 120 to substantially disintegrate during operation of the turbine 102, for example, a melting temperature of approximately 65 degrees Celsius (approximately 150 degrees Fahrenheit) to approximately 485 degrees Celsius (approximately 900 degrees Fahrenheit. In various embodiments, conforming material 120 includes at least one of: rubber, silicone, plastic, wax, related low-melting temperature materials, or composites thereof.

[0023] In some cases, as shown in FIG. 4, laminate material 118 includes a plurality of segments 118A, 118B, 118C, where each segment is separated from its neighboring segment (e.g., 118A and 118B). Each segment 118A, 118B, 118C of laminate material 118 can correspond with a distinct surface of first arc segment 104, e.g., segment 118A corresponds with a first radially facing surface 110, segment 118B corresponds with end surface 108 and segment 118C corresponds with a second radially facing surface 110.

[0024] As noted herein, the conforming material 120 can have a melting temperature causing it to substantially disintegrate during operation of the turbine 102. According to various embodiments, the laminate material 118 (including segments 118A, 118B, 118C) are adapted to move when the conforming material 120 has substantially disintegrated, for example, moving closer to radially facing surfaces 110 as the conforming material 120 disintegrates, thereby contacting each other (e.g., segment 118A and segment 118C each contact 118B as conforming material disintegrates and close gaps at corner regions 122.

[0025] FIG. 6 is a flow diagram illustrating a method of forming a seal according to various embodiments of the invention. Reference is also made simultaneously to the remaining FIGURES. The method includes the following processes: Process P1: forming a seal 114, the forming including coupling laminate material segments 118A, 118B, 118C to a first side 600 of shim 116 using conforming material 120 (FIG. 4). In various embodiments, coupling laminate material 118 to first side 600 of shim 116 includes sliding the conforming material 120 over the laminate material 118 and the shim 116. Process P2: applying the seal 114 to a gas turbine 102, FIG. 4, where applying includes inserting the seal 114 in the slot 112 such that a second side 602 of the shim 116 of the seal contacts the first arc segment 104 at the end surface 108 and extends over the radially facing surfaces 110 of the first arc segment 104, where the second side 602 of the shim 116 opposes the first side 600 of the shim 116.

[0026] It is understood that in the flow diagrams shown and described herein, other processes may be performed while not being shown, and the order of processes can be rearranged according to various embodiments. Additionally, intermediate processes may be performed between one or more described processes. The flow of processes shown and described herein is not to be construed as limiting of the various embodiments.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0028] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims.

Claims

1. A gas turbine (102) comprising: a first arc segment (104) circumferentially adjacent to a second arc segment (106), each arc segment (24, 104, 106) including an end surface (108) and radially facing surfaces (110) extending from opposite ends of the end surface (108); a slot (112) located between the end surfaces (108) of the first arc segment (104) and the second arc segment (106); and a seal (114) disposed in the slot (112), the seal (114) contacting the first arc segment (104) at the end surface (108) and extending over the radially facing surfaces (110) of the first arc segment (104), the seal (114) including: a shim (116) contacting the first arc segment (104); a laminate material (118) over the shim (116) and covering the shim (116), wherein the laminate material (118) is coupled to a first side (600) of the shim (116); and a conforming material (120) coupling the laminate material (118) to the shim (116); the shim (116) having a second side (602) opposing the first side (600), the second side (602) of the shim (116) contacting the first arc segment (104) at the end surface (108) and extending over the radially facing surfaces (110) of the first arc segment (104) to substantially seal corner regions (122) spanning between the end surface (108) and each of the radially facing surfaces (110), the laminate material (118) including a plurality of segments (118A, 118B, 118C) each corresponding with the end surface (108) and the radially facing surfaces (110), respectively, of the first arc segment (104), and the conforming material (120) having a melting temperature causing the conforming material (120) to substantially disintegrate during operation of the gas turbine (2, 102, 202).

2. The gas turbine (102) of claim 1, wherein the conforming material (120) includes at least one of: rubber, silicone, plastic, wax, a low-melting temperature material, or composites thereof.

3. The gas turbine (102) of claim 1, wherein the shim (116) and the laminate material (118) are adapted to move independently of one another when the conforming material (120) has substantially disintegrated.

4. The gas turbine of any preceding claim, wherein the end surfaces (108) face one another and are substantially coincident.

5. The gas turbine (102) of claim 4, wherein the plurality of segments (118A, 118B, 118C) of the laminate material (118) include three segments (118A, 118B, 118C) each corresponding with the end surface (108) and the radially facing surfaces (110), respectively, of the first arc segment (104).

6. The gas turbine of any preceding claim, wherein the shim has a thickness of approximately 0.0025 millimeters to approximately 1.3 millimeters.

7. A method of assembling a seal (114) in a gas turbine (102), the method comprising: forming a seal (114), the forming including: coupling a laminate material (118) to a first side (600) of a shim (116) using a conforming material (120); and applying the seal (114) to the gas turbine (102), the gas turbine (102) having: a first arc segment (104) circumferentially adjacent to a second arc segment (106), each arc segment (104, 106) including an end surface (108) and radially facing surfaces (110) extending from opposite ends of the end surface (108); and a slot (112) located between the end surfaces (108) of the first arc segment (104) and the second arc segment (106), the applying including inserting the seal (114) in the slot speee (112) such that a second side (602) of the shim (116) of the seal (114) contacts the first arc segment (104) at the end surface (108) and extends over the radially facing surfaces (110) of the first arc segment (104) to substantially seal corner regions (122) spanning between the end surface (108) and each of the radially facing surfaces (110), the second side (602) of the shim (116) opposing the first side (600) of the shim (116), the laminate material (118) having a plurality of segments (118A,118B,118C) each corresponding with the end surface (108) and the radially facing surfaces (110), respectively, of the first arc segment (104), and the conforming material (120) having a melting temperature causing the conforming material (120) to substantially disintegrate during operation of the gas turbine (102).

8. The method of claim 7, wherein the conforming material (120) includes at least one of: rubber, silicone, plastic, wax, a low-melting temperature material, or composites thereof.

9. The method of claim 7 or 8, wherein the coupling of the laminate material (118) to the first side (600) of the shim (116) includes sliding the conforming material (120) over the laminate material (118) and the shim (116).

10. The method of any of claims 7 to 9, wherein the plurality of segments includes three segments (118A,118B,118C).

11. The method of claim 7, wherein the shim (116) and the laminate material (118) are adapted to move independently of one another when the conforming material (120) has substantially disintegrated.