Claims:1. A labyrinth seal system comprising:
a stationary component;
a rotatable component, wherein one of the stationary and rotatable components comprises teeth facing the other of the stationary and rotatable components; and
an abradable component coupled to a surface of the other of the stationary and rotatable components, wherein the abradable component is disposed facing the teeth and comprises a plurality of grooves spaced apart from each other along an axial direction of the labyrinth seal system and extending along a circumferential direction of the abradable component.

2. The labyrinth seal system of claim 1, wherein the rotatable component further comprises a plurality of labyrinth seal pockets, each labyrinth seal pocket formed between two adjacent teeth, wherein each groove of the plurality of grooves is disposed facing a corresponding labyrinth seal pocket from the plurality of labyrinth seal pockets.

3. The labyrinth seal system of claim 2, wherein the abradable component further comprises a projection disposed downstream relative to at least one groove of the plurality of grooves, wherein the projection protrudes towards the corresponding labyrinth seal pocket from the plurality of labyrinth seal pockets.

4. The labyrinth seal system of claim 1, wherein the stationary component further comprises a plurality of labyrinth seal pockets, each labyrinth seal pocket formed between two adjacent teeth, wherein each groove of the plurality of grooves is disposed facing a corresponding labyrinth seal pocket from the plurality of labyrinth seal pockets.

5. The labyrinth seal system of claim 4, wherein the abradable component further comprises a projection disposed downstream relative to at least one groove of the plurality of grooves, wherein the projection protrudes towards the corresponding labyrinth seal pocket from the plurality of labyrinth seal pockets.

6. The labyrinth seal system of claim 1, wherein the plurality of grooves comprises at least one of a rectangular groove, a triangular groove, a triangular-rectangular groove, and a convex-rectangular groove.

7. The labyrinth seal system of claim 1, wherein the abradable component comprises a honeycomb component.

8. A gas turbine engine comprising:
a compressor;
a combustor coupled to the compressor;
a turbine coupled to the combustor and the compressor; and
a labyrinth seal system disposed at a pre-defined location in the gas turbine engine, wherein the labyrinth seal system comprises:
a stationary component;
a rotatable component, wherein one of the stationary and rotatable components comprises teeth facing the other of the stationary and rotatable components; and
an abradable component coupled to a surface of the other of the stationary and rotatable components, wherein the abradable component is disposed facing the teeth and comprises a plurality of grooves spaced apart from each other along an axial direction of the labyrinth seal system and extending along a circumferential direction of the abradable component.

9. The gas turbine engine of claim 8, wherein the rotatable component further comprises a plurality of labyrinth seal pockets, each labyrinth seal pocket formed between two adjacent teeth, wherein each groove of the plurality of grooves is disposed facing a corresponding labyrinth seal pocket from the plurality of labyrinth seal pockets.

10. The gas turbine engine of claim 9, wherein the abradable component further comprises a projection disposed downstream relative to at least one groove of the plurality of grooves, wherein the projection protrudes towards the corresponding labyrinth seal pocket from the plurality of labyrinth seal pockets.

11. The gas turbine engine of claim 8, wherein the stationary component further comprises a plurality of labyrinth seal pockets, each labyrinth seal pocket formed between two adjacent teeth, wherein each groove of the plurality of grooves is disposed facing a corresponding labyrinth seal pocket from the plurality of labyrinth seal pockets.

12. The gas turbine engine of claim 11, wherein the abradable component further comprises a projection disposed downstream relative to at least one groove of the plurality of grooves, wherein the projection protrudes towards the corresponding labyrinth seal pocket from the plurality of labyrinth seal pockets.

13. The gas turbine engine of claim 8, wherein the plurality of grooves comprises at least one of a rectangular groove, a triangular groove, a triangular-rectangular groove, and a convex-rectangular groove.

14. The gas turbine engine of claim 8, wherein the pre-defined location comprises at least one of a first leakage flow path extending from the compressor to the turbine bypassing the combustor, a second leakage flow path extending between a tip of a rotor blade and a casing of the turbine, a third leakage flow path extending between a tip of a stator blade and a spacer wheel of the turbine, and a fourth leakage flow path extending between a bearing housing and the rotatable component.

15. A method for controlling flow of a fluid through a labyrinth seal system, the method comprising:
receiving the fluid through a clearance defined between an abradable component and one of a stationary component and a rotatable component comprising teeth facing the other of the stationary and rotatable components, wherein the abradable component is coupled to a surface of the other of the stationary and rotatable components, wherein the abradable component is disposed facing the teeth and comprises a plurality of grooves spaced apart from each other along an axial direction of the labyrinth seal system and extending along a circumferential direction of the abradable component;
regulating the flow of the fluid, using the plurality of grooves and the teeth; and
reducing an amount of the fluid flowing through the clearance.

16. The method of claim 15, wherein regulating the flow of the fluid comprises recirculating a portion of the fluid within each groove of the plurality of grooves and deflecting the portion of the fluid, using each groove of the plurality of grooves.

17. The method of claim 16, further comprising recirculating the portion of the fluid at a region formed downstream relative to each groove and upstream relative to a tip of a corresponding proximate tooth.

18. The method of claim 17, further comprising impinging the portion of the fluid against the tip of the corresponding proximate tooth.
19. The method of claim 16, further comprising deflecting the portion of the fluid, using a projection disposed downstream relative to at least one groove of the plurality of grooves, wherein the projection protrudes towards a labyrinth seal pocket from a plurality of labyrinth seal pockets formed in one of the stationary and rotatable components, wherein each seal pocket is formed between two adjacent teeth, wherein each groove of the plurality of grooves is disposed facing the labyrinth seal pocket from the plurality of labyrinth seal pockets.

20. The method of claim 19, further comprising recirculating the portion of the fluid at a region formed downstream relative to each groove and upstream relative to a tip of a corresponding proximate tooth.

21. The method of claim 20, further comprising impinging the portion of the fluid against the tip of the corresponding proximate tooth.

22. The method of claim 16, wherein regulating the flow of the fluid further comprises recirculating another portion of the fluid, using a labyrinth seal pocket from a plurality of labyrinth seal pockets formed in the rotatable component, wherein each seal pocket is formed between two adjacent teeth, wherein each groove of the plurality of grooves is disposed facing the labyrinth seal pocket from the plurality of labyrinth seal pockets.

23. The method of claim 16, wherein regulating the flow of the fluid further comprises recirculating another portion of the fluid, using a labyrinth seal pocket from a plurality of labyrinth seal pockets formed in the stationary component, wherein each seal pocket is formed between two adjacent teeth, wherein each groove of the plurality of grooves is disposed facing the labyrinth seal pocket from the plurality of labyrinth seal pockets.
, Description:BACKGROUND
[0001] Embodiments of the present invention relate to a seal system for turbomachines, and more specifically, to a labyrinth seal system having grooves disposed in an abradable component of such turbomachines.
[0002] A labyrinth seal is often used to minimize leakage of a fluid in a clearance defined between a stationary component and a rotatable component of a turbomachine. The labyrinth seal includes teeth formed on the stationary or rotatable components, thereby obstructing the flow and minimizing the leakage of the fluid. However, certain operational transient conditions of the turbomachines, such as startup, shutdown, or load variations, often result in an axial movement of the rotatable component in relation to the stationary component. Such movement may cause the teeth of the rotatable component to slide or rub against the stationary component, resulting in damage of the teeth. The damage of the teeth may affect the seal performance causing increased leakage of the fluid.
[0003] Other labyrinth seals may include modified geometry of teeth in the rotatable component so as to minimize the contact with the stationary component. However, such modification may cause higher frictional heating in the turbomachines. Alternatively, some other conventional labyrinth seals may include a wide clearance. However, such a wide clearance results in increased leakage of the fluid through the clearance.
[0004] Accordingly, there is a need for an enhanced labyrinth seal system and an associated method.
BRIEF DESCRIPTION
[0005] In accordance with one exemplary embodiment, a labyrinth seal system is disclosed. The labyrinth seal system includes a stationary component and a rotatable component, where one of the stationary component and rotatable components includes teeth facing the other of the stationary and rotatable components. The labyrinth seal system further includes an abradable component coupled to a surface of the other of the stationary and rotatable components. The abradable component is disposed facing the teeth and includes a plurality of grooves spaced apart from each other along an axial direction of the labyrinth seal system and extending along a circumferential direction of the abradable component.
[0006] In accordance with another exemplary embodiment, a gas turbine engine is disclosed. The gas turbine engine includes a compressor, a combustor, a turbine, and a labyrinth seal system. The combustor is coupled to the compressor. The turbine is coupled to the combustor and the compressor. The labyrinth seal system is disposed at a pre-defined location in the gas turbine engine. The labyrinth seal system includes a stationary component and a rotatable component, where one of the stationary and rotatable components includes teeth facing the other of the stationary and rotatable components. The labyrinth seal system further includes an abradable component coupled to a surface of the other of the stationary and rotatable components. The abradable component is disposed facing the teeth and includes a plurality of grooves spaced apart from each other along an axial direction of the labyrinth seal system and extending along a circumferential direction of the abradable component.
[0007] In accordance with another exemplary embodiment, a method for controlling flow of a fluid through a labyrinth seal system is disclosed. The method involves receiving the fluid through a clearance defined between an abradable component and one of a stationary component and a rotatable component including teeth facing the other of the stationary and rotatable components. The abradable component is coupled to a surface of the other of the stationary and rotatable components. The abradable component is disposed facing the teeth and includes a plurality of grooves spaced apart from each other along an axial direction of the labyrinth seal system and extending along a circumferential direction of the abradable component. The method further involves regulating the flow of the fluid, using the plurality of grooves and the teeth and thereby reducing an amount of the fluid flowing through the clearance.
DRAWINGS
[0008] These and other features and aspects of embodiments of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
[0009] FIG. 1 is a cross-sectional view of a portion of a gas turbine engine in accordance with one exemplary embodiment;
[0010] FIG. 2 is a schematic view of another portion of the gas turbine engine in accordance with the exemplary embodiment of FIG.1;
[0011] FIG. 3A is a schematic diagram of a conventional labyrinth seal system;
[0012] FIG. 3B is a schematic diagram of another conventional labyrinth seal system;
[0013] FIG. 4 is a perspective view of a portion of a labyrinth seal system in accordance with the exemplary embodiment of FIG.1;
[0014] FIG. 5 is a schematic diagram of a labyrinth seal system including a plurality of rectangular grooves in accordance with one exemplary embodiment;
[0015] FIG. 6 is a schematic diagram depicting a fluid flow pattern for the labyrinth seal system in accordance with the exemplary embodiment of FIG. 5;
[0016] FIG. 7 is a schematic diagram of a labyrinth seal system including a plurality of triangular grooves in accordance with another exemplary embodiment;
[0017] FIG. 8 is a schematic diagram depicting a fluid flow pattern for the labyrinth seal system in accordance with the exemplary embodiment of FIG. 7;
[0018] FIG. 9 is a schematic diagram of a labyrinth seal system including a plurality of triangular-rectangular grooves in accordance with another exemplary embodiment;
[0019] FIG. 10 is a schematic diagram depicting a fluid flow pattern for the labyrinth seal system in accordance with the exemplary embodiment of FIG. 9;
[0020] FIG. 11 is a schematic diagram of a labyrinth seal system including a plurality of projections disposed downstream relative to a plurality of triangular-rectangular grooves in accordance with another exemplary embodiment;
[0021] FIG. 12 is a schematic diagram depicting a fluid flow pattern for the labyrinth seal system in accordance with the exemplary embodiment of FIG. 11;
[0022] FIG. 13 is a schematic diagram of a labyrinth seal system including a plurality of convex-rectangular grooves in accordance with another exemplary embodiment;
[0023] FIG. 14 is a schematic diagram of a labyrinth seal system including a plurality of grooves in accordance with another exemplary embodiment;
[0024] FIG. 15 is a schematic diagram of a labyrinth seal system in accordance with another exemplary embodiment; and
[0025] FIG. 16 is a flow diagram of an exemplary method for controlling flow of a fluid through a labyrinth seal system in accordance with one exemplary embodiment.
DETAILED DESCRIPTION
[0026] Embodiments of the present invention discussed herein relate to a labyrinth seal system for turbomachines, such as a gas turbine engine. The labyrinth seal system is configured to control leakage of a fluid through a clearance defined between an abradable component and one of a stationary component and a rotatable component including teeth facing the other of the stationary and rotatable components. In one embodiment, a plurality of grooves is formed in the abradable component. The abradable component is coupled to a surface of the other of the stationary and rotatable components. The abradable component is disposed facing teeth. The abradable component may be a honeycomb component. In certain embodiments, the plurality of grooves may include a rectangular groove, a triangular groove, a triangular-rectangular groove, and/or a convex-rectangular groove. The usage of the abradable component minimizes damage caused to the rotatable and/or stationary component due to contact of the teeth with the rotatable and/or stationary component. In certain embodiments, a labyrinth seal system includes a stationary component and a rotatable component, where one of the stationary and rotatable components includes teeth facing the other of the stationary and rotatable components. The labyrinth seal system further includes an abradable component coupled to a surface of the other of the stationary and rotatable components. The abradable component is disposed facing the teeth and includes a plurality of grooves spaced apart from each other along an axial direction of the labyrinth seal system and extending along a circumferential direction of the abradable component.
[0027] FIG. 1 illustrates a cross-sectional view of a portion 11 of a gas turbine engine 10 in accordance with one exemplary embodiment of the present invention. The gas turbine engine 10 includes a compressor 12, a combustor 14, and a turbine 16. In the illustrated embodiment, the compressor 12 is a multistage compressor and the turbine 16 is a multistage turbine. The compressor 12 is coupled to the combustor 14. The turbine 16 is coupled to the combustor 14 and the compressor 12. A first leakage flow path 26 extends from the compressor 12 to the turbine 16 bypassing the combustor 14. During operation, the compressor 12 is configured to receive a fluid, such as air and compress the received fluid to generate a compressed fluid. The combustor 14 is configured to receive the compressed fluid from the compressor 12 and a fuel, such as natural gas from a plurality of fuel injectors 18 and burn the fuel and the compressed fluid within a combustion zone 22 to generate exhaust gases. The turbine 16 is configured to receive the exhaust gases from the combustor 14 and expand the exhaust gases to convert energy of the exhaust gases to work. The turbine 16 is configured to drive the compressor 12 through a rotatable component 82.
[0028] In the illustrated embodiment, the turbine 16 includes four-stages represented by four rotors 38, 40, 42, 44 connected to the rotatable component 82 for rotation therewith. Each rotor 38, 40, 42, 44 includes airfoils (rotor blades) 46, 48, 50, 52, which are arranged alternately between stator blades 54, 56, 58, 60 (nozzles) respectively. The stator blades 54, 56, 58, 60 are fixed to a casing 70 of the turbine 16. The turbine 16 further includes three spacer wheels 62, 64, 66 coupled to and disposed alternately between rotors 38, 40, 42, 44. Specifically, the turbine 16 includes a first stage having the stator blade 54 and the rotor blade 46, a second stage having the stator blade 56, the spacer wheel 62, and the rotor blade 48, a third stage having the stator blade 58, the spacer wheel 64, and the rotor blade 50, and a fourth stage having the stator blade 60, the spacer wheel 66, and the rotor blade 52.
[0029] The gas turbine engine 10 further includes a labyrinth seal system 68 disposed at a pre-defined location in the turbine 16. In one embodiment, the pre-defined location is a first leakage flow path 26 extending from the compressor 12 to the turbine 16, bypassing the combustor 14. The labyrinth seal system 68 includes a stationary component 80, a rotatable component 82 having teeth 84, and an abradable component 86 coupled to the stationary component 80, facing the teeth 84. The abradable component 86 includes a plurality of grooves (not shown in FIG. 1) spaced apart from each other along an axial direction 90 of the labyrinth seal system 68. Further, each groove extends along a circumferential direction 92 of the abradable component 86, facing the rotatable component 82. In the illustrated embodiment, the stationary component 80 is a barrel disposed below the combustor 14 and extends from the compressor 12 to the turbine 16. The rotatable component 82 is a mid-shaft, which connects the turbine 16 to the compressor 12.
[0030] The labyrinth seal system 68 is configured to control leakage of the compressed fluid flowing through a clearance (not labeled in FIG. 1) defined between the abradable component 86 and the rotatable component 82. The labyrinth seal system 68 is discussed in greater detail below with reference to subsequent figures.
[0031] A labyrinth seal system 94 may additionally be disposed in another pre-defined location, such as a second leakage flow path 28 extending between a tip 96 of the rotor blade 50 and the casing 70. The labyrinth seal system 94 may be similar to the labyrinth seal system 68, except that the casing 70 is a stationary component and the rotor blade 50 is a rotatable component. In such embodiments, the labyrinth seal system 94 is configured to control leakage of the exhaust gases through a tip clearance, bypassing the rotor blade 50. The tip clearance may be defined between the rotor blade 50 and the abradable component 86 coupled to the casing 70. In certain embodiments, the labyrinth seal system 94 may be disposed between a tip (not labeled in FIG. 1) of the respective rotor blades 46, 48, 52 and the abradable component 86 coupled to the casing 70.
[0032] A labyrinth seal system 98 may be disposed in yet another pre-defined location, such as a third leakage flow path 30 extending between a tip 100 of the stator blade 56 and the spacer wheel 62. The labyrinth seal system 98 may be similar to the labyrinth seal system 68, except that the stator blade 56 is a stationary component and the spacer wheel 62 is a rotatable component. The labyrinth seal system 98 is configured to control leakage of the exhaust gases through a clearance (not labeled in FIG. 1) defined between the abradable component 86 coupled to the stator blade 56 and the spacer wheel 62. The labyrinth seal system 98 is disposed between a tip (not labeled in FIG. 1) of the respective stator blades 58, 60 and the respective spacer wheels 64, 66.
[0033] FIG. 2 illustrates a cross-sectional view of another portion 13 of the gas turbine engine 10 in accordance with the exemplary embodiment of FIG. 1. In the illustrated embodiment, the turbine 16 includes the rotor blade 52 mounted on the rotor 44 of the last stage. The rotor 44 is coupled to rotatable component such as an aft-shaft 24 via a connecting element 106. The aft-shaft 24 is supported by a bearing 110 disposed within a stationary component such as a bearing housing 112. The gas turbine engine 10 includes a labyrinth seal system 108 disposed in yet another pre-defined location, such as a fourth leakage flow path 32 extending between the bearing housing 112 and the aft-shaft 24. The labyrinth seal system 108 includes the aft-shaft 24, the bearing housing 112 having teeth 114, and an abradable component 116 coupled to the aft-shaft 24, facing the teeth 114. The abradable component 116 includes a plurality of grooves (not shown in FIG. 2) spaced apart from each other along an axial direction 90 of the labyrinth seal system 108. Further, each groove extends along a circumferential direction 92 of the abradable component 86, facing the bearing housing 112.
[0034] The labyrinth seal system 108 is configured to control leakage of a portion of the exhaust gases through a clearance (not labeled in FIG. 2) defined between the abradable component 116 and the aft-shaft 24. The labyrinth seal system 108 is discussed in greater detail below with reference to the embodiment of FIG. 15.
[0035] FIG. 3A is a schematic diagram of a conventional labyrinth seal system 118. The conventional labyrinth seal system 118 includes a stationary component 120, a stator 122 coupled to a surface 124 of the stationary component 120, and a rotatable component 126 having teeth 128 spaced apart from each other and facing the stator 122. The conventional labyrinth seal system 118 is configured to regulate leakage of a fluid 130 (also referred as a “leakage flow”) through a clearance 132 defined between the stator 122 and the teeth 128. During operation, the rotatable component 126 is configured to rotate along a circumferential direction 134. The leakage flow is along an axial direction 136 of the conventional labyrinth seal system 118. The stator 122 and the teeth 128 are configured to regulate the leakage of the fluid 130. In the embodiment of FIG. 3A, the stator 122 and the teeth 128 of the conventional labyrinth seal system 118 do not define a tortuous flow path for the leakage flow through the clearance 132.
[0036] FIG. 3B is a schematic diagram of another conventional labyrinth seal system 168. The conventional labyrinth seal system 168 includes a stationary component 170, a stator 172 coupled to a stepped surface 174 of the stationary component 170, and a rotatable component 176 having teeth 178 spaced apart from each other and facing the stator 172. The conventional labyrinth seal system 168 is configured to control leakage of a fluid 180 (also referred as a “leakage flow”) through a clearance 182 defined between the stator 172 and the teeth 178. The stator 172 and the teeth 178 are configured to regulate the leakage flow through the clearance 182 by recirculating a portion of the leakage flow. An axial movement 186 of the rotatable component 176 during transient operation conditions may result in teeth 178 contacting the stator 172, thereby resulting in damage to the stator 172 and the teeth 178.
[0037] FIG. 4 is a perspective view of a portion of a labyrinth seal system 68 in accordance with the exemplary embodiment of FIG. 1. The portion illustrates a strip of the labyrinth seal system 68. In one embodiment, a plurality of such strips may be positioned side by side extending along a circumferential direction 92. The labyrinth seal system 68 includes the stationary component 80, the rotatable component 82 including the teeth 84, and the abradable component 86. In the illustrated embodiment, the teeth 84 extend substantially perpendicular from a base 158 of the rotatable component 82. Further, each tooth 84 may be coupled to the base 158 through a crack arrestor edge portion 160. In certain other embodiments, each of the teeth 84 may be oriented at a predefined tilt angle relative to the base 158, along an axial direction 90 depending on the application and design criteria.
[0038] In the illustrated embodiment, the abradable component 86 includes a honeycomb component having a plurality of honeycomb cells 140. In certain embodiments, the abradable component 86 may include a porous component. The abradable component 86 includes a plurality of grooves 142 spaced apart from each other along the axial direction 90 of the labyrinth seal system 68. Each groove 142 extends along the circumferential direction 92 of the abradable component 86, facing the rotatable component 82. Each groove 142 may be formed, for example, by machining the abradable component 86, using a milling, a lathe, a boring machine, and the like. In the illustrated embodiment, each groove 142 is a triangular-rectangular groove. In other words, each groove 142 includes a triangular portion 143 and a rectangular portion 145 separated by an imaginary line 190.
[0039] The abradable component 86 is coupled to a surface 88 of the stationary component 80, facing the teeth 84 of the rotatable component 82. In one embodiment, the abradable component 86 may be brazed to the surface 88 of the stationary component 80. The surface 88 is a flat surface compared to the stepped surface 174 of the stationary component 170 (shown in FIG. 3B). The abradable component 86 is coupled to the stationary component 80 such that each groove 142 faces a labyrinth seal pocket of a plurality of labyrinth seal pockets 154, formed between two adjacent teeth 84 of the rotatable component 82.
[0040] In one embodiment, the abradable component 86 may include a first material and the stationary component 80 may include a second material different from the first material. In another embodiment, the abradable component 86 and the stationary component 80 may include the same material.
[0041] The rotatable component 82 is disposed proximate to the stationary component 80 to define a clearance 144 between the abradable component 86 and the teeth 84. During operation of the gas turbine engine, the rotatable component 82 is configured to rotate along the circumferential direction 92 and a fluid 156 (also referred as “a leakage flow”) flows along the axial direction 90. The honeycomb cells 140 provide a diffusion effect to the fluid 156 flowing through the clearance 144. Further, the labyrinth seal system 68 is configured to regulate a flow of the fluid 156 through the clearance 144, using the plurality of grooves 142 and the teeth 84 and thereby reduce an amount of the fluid 156 flowing through the clearance 144. In one embodiment, the fluid 156 is a compressed air received from the compressor. In another embodiment, the fluid 156 may include an exhaust gas received from the combustor or the turbine.
[0042] As discussed previously, each groove 142 is disposed facing the corresponding labyrinth seal pocket 154 formed between adjacent teeth 84. However, during certain transient operating conditions, the teeth 84 may contact certain portions of the abradable component 86, thereby damaging such portions of the abradable component 86. During such conditions, the damaged abradable component 86 may be easily removed from the stationary component 80 and replaced with another abradable component.
[0043] FIG. 5 is a schematic diagram of a portion of a labyrinth seal system 200 in accordance with another exemplary embodiment of the present invention. The labyrinth seal system 200 includes a stationary component 202, a rotatable component 204, and an abradable component 206. The abradable component 206 includes a plurality of rectangular grooves 208 disposed facing teeth 210 of the rotatable component 204. In certain embodiments, at least one groove 208 of the labyrinth seal system 200 is rectangular groove. The abradable component 206 is coupled to a surface 212 of the stationary component 202 such that each rectangular groove 208 faces a labyrinth seal pocket from a plurality of labyrinth seal pockets 214 formed between adjacent teeth 210 of the rotatable component 204. The stationary component 202 and the rotatable component 204 are disposed such that a clearance 216 is defined between the abradable component 206 and the teeth 210.
[0044] FIG. 6 is a schematic diagram depicting a fluid flow pattern 290 for the labyrinth seal system 200 illustrated in FIG. 5. The labyrinth seal system 200 is configured to control a flow of the fluid 226 through the clearance 216. The flow of the fluid 226 through the clearance 216 is regulated using the plurality of rectangular grooves 208, the teeth 210, and the plurality of labyrinth seal pockets 214. In one embodiment, regulating the fluid 226 involves recirculating a portion 226a of the fluid 226 within each rectangular groove 208 and then deflecting the portion 226a of the fluid 226 using each rectangular groove 208. The portion 226a of the fluid 226 is further recirculated at a region 250 formed downstream relative to each rectangular groove 208 and upstream relative to a tip 252 of a corresponding proximate tooth 210. The portion 226a of the fluid 226 is impinged against the tip 252 of the corresponding proximate tooth 210. In one embodiment, regulating the fluid 226 further involves recirculating another portion 226b of the fluid 226 within each labyrinth seal pocket 214 to regulate the flow of the fluid 226 through the clearance 216.
[0045] The labyrinth seal system 200 defines a tortuous flow path for the flow of the fluid 226 resulting in deflection of the flow of the fluid 226 and subsequent reduction in leakage flow of the fluid 226 through the clearance 216. The labyrinth seal system 200 facilitates to reduce the leakage flow of the fluid 226 through the clearance 216 in a range from about 16 percent to about 30 percent compared to the conventional labyrinth seal system shown in FIG. 3A.
[0046] FIG. 7 is a schematic diagram of a portion of a labyrinth seal system 300 in accordance with another exemplary embodiment. The labyrinth seal system 300 includes a stationary component 302, a rotatable component 304, and an abradable component 306. The abradable component 306 includes a plurality of triangular grooves 308 disposed facing teeth 310 of the rotatable component 304. In certain embodiments, at least one triangular groove 308 of the labyrinth seal system 300 is a triangular groove. The abradable component 306 is coupled to a surface 312 of the stationary component 302 such that each triangular groove 308 faces a labyrinth seal pocket from a plurality of labyrinth seal pockets 314 formed between adjacent teeth 310 of the rotatable component 304. The stationary component 302 and the rotatable component 304 are disposed such that a clearance 316 is defined between the abradable component 306 and the teeth 310.
[0047] FIG. 8 is a schematic diagram depicting a fluid flow pattern 390 for the labyrinth seal system 300 illustrated in FIG. 7. The labyrinth seal system 300 is configured to control a flow of the fluid 326 through the clearance 316. The flow of the fluid 326 through the clearance 316 is regulated using the plurality of triangular grooves 308, the teeth 310, and the plurality of labyrinth seal pockets 314. In one embodiment, regulating the fluid 326 involves recirculating a portion 326a of the fluid 326 within each triangular groove 308 and then deflecting the portion 326a of the fluid 326 using each triangular groove 308. The portion 326a of the fluid 326 is further recirculated and at a region 350 formed downstream relative to each triangular groove 308 and upstream relative to a tip 352 of a corresponding proximate tooth 310. The portion 326a of the fluid 326 is impinged against the tip 352 of the corresponding proximate tooth 310. In one embodiment, regulating the fluid 326 further involves recirculating another portion 326b of the fluid 326 within each labyrinth seal pocket 314 to regulate the flow of the fluid 326 through the clearance 316.
[0048] The labyrinth seal system 300 defines a tortuous flow path for the flow of the fluid 326 resulting in deflection of the flow of the fluid 326 and subsequent reduction in leakage flow of the fluid 326 through the clearance 316. The labyrinth seal system 300 facilitates to reduce the leakage flow of the fluid 326 through the clearance 316 in a range from about 11 percent to about 19 percent compared to the conventional labyrinth seal system shown in FIG. 3A.
[0049] FIG. 9 is a schematic diagram of a portion of a labyrinth seal system 400 in accordance with another exemplary embodiment. The labyrinth seal system 400 includes a stationary component 402, a rotatable component 404, and an abradable component 406. The abradable component 406 includes a plurality of triangular-rectangular grooves 408 disposed facing teeth 410 of the rotatable component 404. The abradable component 406 is coupled to a surface 412 of the stationary component 302 such that each triangular-rectangular groove 408 faces a labyrinth seal pocket from a plurality of labyrinth seal pockets 414 formed between adjacent teeth 410 of the rotatable component 404. Each groove 408 includes a triangular portion 422 and a rectangular portion 424 separated by an imaginary line 430. In certain embodiments, at least one groove 408 of the labyrinth seal system 400 is a triangular-rectangular groove.
[0050] FIG. 10 is a schematic diagram depicting a fluid flow pattern 490 for the labyrinth seal system 400 illustrated in FIG. 9. The labyrinth seal system 400 is configured to control a flow of the fluid 426 through the clearance 416. The flow of the fluid 426 through the clearance 416 is regulated using the plurality of triangular-rectangular grooves 408, the teeth 410, and the plurality of labyrinth seal pockets 414. In one embodiment, regulating the fluid 426 involves recirculating a portion 426a of the fluid 426 within each triangular-rectangular groove 408 and then deflecting the portion of the fluid 426 using each triangular-rectangular groove 408. The portion 426a of the fluid 426 is further recirculated at a region 450 formed downstream relative to each triangular-rectangular groove 408 and upstream relative to a tip 452 of a corresponding proximate tooth 410. The portion 426a of the fluid 426 is impinged against the tip 452 of the corresponding proximate tooth 410. In one embodiment, regulating the fluid 426 further involves recirculating another portion 426b of the fluid 426 within each labyrinth seal pocket 414 to restrain the flow of the fluid 426 through the clearance 416.
[0051] The labyrinth seal system 400 defines a tortuous flow path for the flow of the fluid 426 resulting in deflection of the flow of the fluid 426 and subsequent reduction in leakage flow of the fluid 426 through the clearance 416. The labyrinth seal system 400 facilitates to reduce the leakage flow of the fluid 426 through the clearance 416 in a range from about 24 percent to about 32 percent compared to the conventional labyrinth seal system shown in FIG. 3A.
[0052] FIG. 11 is a schematic diagram of a portion of a labyrinth seal system 500 in accordance with another exemplary embodiment. The labyrinth seal system 500 includes a stationary component 502, a rotatable component 504, and an abradable component 506. The abradable component 506 includes a plurality of triangular-rectangular grooves 508 disposed facing teeth 510 of the rotatable component 504. The abradable component 506 is coupled to a surface 512 of the stationary component 502 such that each triangular-rectangular groove 508 faces a labyrinth seal pocket from a plurality of labyrinth seal pockets 514 formed between adjacent teeth 510 of the rotatable component 504. Each groove 508 includes a triangular portion 522 and a rectangular portion 524 separated by an imaginary line 530. In certain embodiments, at least one groove 508 of the labyrinth seal system 500 is a triangular-rectangular groove.
[0053] The labyrinth seal system 500 is similar to the labyrinth seal system 400 shown in the embodiment of FIG. 9 except that the labyrinth seal system 500 includes a plurality of projections 560, where each projection 560 is disposed downstream relative to each triangular-rectangular groove 508. Each projection 560 protrudes towards a labyrinth seal pocket of a plurality of labyrinth seal pockets 514 formed between adjacent teeth 510. In some embodiments, the plurality of projections 560 may be disposed downstream relative to other types of grooves, such as a rectangular groove 208 shown in the embodiment of FIG. 5, a triangular groove 308 shown in the embodiment of FIG. 7, a convex-rectangular groove (shown in FIG. 13).
[0054] FIG. 12 is a schematic diagram depicting a fluid flow pattern 590 for the labyrinth seal system 500 illustrated in FIG. 11. The labyrinth seal system 500 is configured to control a flow of the fluid 526 through a clearance 516 defined between the abradable component 506 and the rotatable component 504. The flow of the fluid 526 through the clearance 516 is regulated using the plurality of triangular-rectangular grooves 508, the teeth 510, the plurality of projections 560, and the plurality of labyrinth seal pockets 514. In one embodiment, regulating of the fluid 526 involves recirculating a portion 526a of the fluid 526 within each triangular-rectangular groove 508. The portion 526a of the fluid 526 is deflected by each triangular-rectangular groove 508 and each projection 560. The portion 526a of the fluid 526 is further recirculated at a region 550 formed downstream relative to each projection 560 and upstream relative to a tip 552 of a corresponding proximate tooth 510. The portion 526a of the fluid is impinged against the tip 552 of the corresponding proximate tooth 510. In one embodiment, regulating the fluid 526 further involves recirculating another portion 526b of the fluid 526 within each labyrinth seal pocket 514 to restrain the flow of the fluid 526 through the clearance 516.
[0055] The exemplary labyrinth seal system 500 defines a tortuous flow path for the flow of the fluid 526 resulting in deflection of the flow of the fluid 526 and subsequent reduction in leakage flow of the fluid 526 through the clearance 516. The labyrinth seal system 500 facilitates to reduce the leakage flow of the fluid 526 through the clearance 516 in a range from about 22 percent to about 30 percent compared to the conventional labyrinth seal system shown in FIG. 3A.
[0056] FIG. 13 is a schematic diagram of a portion of a labyrinth seal system 600 in accordance with another exemplary embodiment. The labyrinth seal system 600 includes a stationary component 602, a rotatable component 604, and an abradable component 606. The abradable component 606 includes a plurality of convex-rectangular grooves 608 disposed facing teeth 610 of the rotatable component 604. The abradable component 606 is coupled to a surface 612 of the stationary component 602 such that each convex-rectangular groove 608 faces a labyrinth seal pocket from a plurality of labyrinth seal pockets 614 formed between adjacent teeth 610 of the rotatable component 604. Each groove 608 includes a convex portion 622 and a rectangular portion 624 separated by an imaginary line 630. In certain embodiments, at least one groove of the labyrinth seal system 600 is a convex-rectangular groove 608. The labyrinth seal system 600 reduces a leakage of a fluid 626 through a clearance 616 defined between the abradable component 606 and the rotatable component 704 in a range from about 15 percent to about 20 percent compared to the conventional labyrinth seal system shown in FIG. 3A.
[0057] FIG. 14 is a schematic diagram of a portion of a labyrinth seal system 700 in accordance with another exemplary embodiment. The labyrinth seal system 700 includes a stationary component 702, a rotatable component 704, and an abradable component 706. The abradable component 706 includes a plurality of grooves 708a-708d disposed facing teeth 710 of the rotatable component 704. In the illustrated embodiment, a groove 708a of the plurality of grooves 708a-708d is a triangular-rectangular groove, a groove 708b is a rectangular groove, a groove 708c is a triangular groove, and the groove 708d is a convex-rectangular groove. The labyrinth seal system 700 further includes a projection 760 disposed downstream relative to the triangular groove 708c. The projection 760 protrudes towards a labyrinth seal pocket of a plurality of labyrinth pockets 714 formed between adjacent teeth 710 of the rotatable component 704. The labyrinth seal system 700 reduces a leakage of a fluid 726 through a clearance 716 defined between the abradable component 706 and the rotatable component 704, in a range from about 16 percent to about 30 percent compared to the conventional labyrinth seal system shown in FIG. 3A.
[0058] FIG. 15 is a schematic diagram of a portion of the labyrinth seal system 108 shown in accordance with the exemplary embodiment of FIG. 1. The labyrinth seal system 108 includes the rotatable component such as the aft-shaft 24 and the stationary component such as the bearing housing 112 having teeth 114, and the abradable component 116.
[0059] In the illustrated embodiment, the abradable component 116 may include a honeycomb component having a plurality of honeycomb cells or a porous component. In one embodiment, the abradable component 116 includes a plurality of grooves 808 spaced apart from each other along the axial direction 90 of the labyrinth seal system 108. Each groove 808 extends along the circumferential direction 92 of the abradable component 116, facing the bearing housing 112. In the illustrated embodiment, each groove 808 is a triangular-rectangular groove. In other words, each groove 808 includes a rectangular portion 822 and a triangular portion 824 separated by an imaginary line 830. The abradable component 116 further includes a plurality of projections 860, where each projection 860 is disposed downstream relative to each groove 808. Each projection 860 protrudes towards a labyrinth seal pocket of a plurality of labyrinth seal pockets 814 formed between adjacent teeth 114 of the bearing housing 112. In certain embodiments, the plurality of grooves 808 may include at least one of a triangular groove, a rectangular groove, and a convex-rectangular groove.
[0060] The abradable component 116 is coupled to a surface 812 of the aft-shaft 24, facing the teeth 114 of the bearing housing 112. The abradable component 116 is coupled to the aft-shaft 24 such that each groove 808 faces the labyrinth seal pocket of the plurality of labyrinth seal pockets 814.
[0061] The aft-shaft 24 is disposed proximate to the bearing housing 112 to define a clearance 816 between the abradable component 116 and the teeth 114. During operation of the gas turbine engine, the aft-shaft 24 is configured to rotate along the circumferential direction 92 and a fluid 856 (also referred as “a leakage flow”) flows along the axial direction 90. The labyrinth seal system 108 is configured to regulate a flow of the fluid 826 through the clearance 816, using the plurality of grooves 808, the teeth 114, the plurality of projections 860, and the plurality of labyrinth seal pockets 814 and thereby reduce an amount of the fluid 826 flowing through the clearance 816. The fluid 826 is an exhaust gas received from the combustor or the turbine.
[0062] As discussed previously, each groove 808 is disposed facing the corresponding labyrinth seal pocket 814 formed between adjacent teeth 114. However, during certain transient operating conditions, the teeth 114 may contact certain portions of the abradable component 116, thereby damaging such portions of the abradable component 116. During such conditions, the damaged abradable component 116 may be easily removed from the aft-shaft 24 and replaced with another abradable component.
[0063] FIG. 16 is a flow diagram of a method 900 for controlling flow of a fluid through a labyrinth seal system in accordance with one exemplary embodiment. In one embodiment, the fluid is compressed air received from a compressor. In another embodiment, the fluid may include an exhaust gas stream received from a combustor or a turbine.
[0064] The method 900 includes receiving the fluid through a clearance defined between an abradable component and one of a stationary component and a rotatable component of the labyrinth seal system, including teeth facing the other of the rotatable and stationary components in step 902. The abradable component is coupled to a surface of the other of the stationary and rotatable components. The abradable component is disposed facing the teeth. The abradable component includes a plurality of grooves spaced apart from each other along an axial direction of the labyrinth seal system and extending along a circumferential direction of the abradable component.
[0065] The method 900 further includes regulating a flow of the fluid, using the plurality of grooves and the teeth in step 904. In one embodiment, regulating the flow of the fluid includes recirculating a portion of the fluid within each groove of the plurality of grooves and then deflecting the portion of the fluid using each groove of the plurality of grooves. Regulating the flow of the fluid further includes recirculating the portion of the fluid at a region formed downstream relative to each groove and upstream relative to a tip of a corresponding proximate tooth. Regulating the flow of the fluid further includes impinging the deflected portion of the fluid against the tip of the corresponding proximate tooth.
[0066] In certain embodiments, regulating the flow of fluid may further include using a projection disposed downstream relative to at least one groove of the plurality of grooves. In such embodiments, the portion of the fluid is deflected using the projection and recirculated at the region formed downstream relative to each groove and upstream relative to the tip of a corresponding proximate tooth. Further, the portion of the fluid is impinged against the tip of the corresponding proximate tooth.
[0067] Regulating the flow of the fluid further includes recirculating another portion of the fluid using a labyrinth seal pocket from a plurality of labyrinth seal pockets. In one embodiment, the plurality of labyrinth seal pockets is formed in one of the stationary and rotatable components. Each labyrinth seal pocket is formed between two adjacent teeth. Each groove is disposed facing the labyrinth seal pocket from the plurality of labyrinth seal pockets. The method 900 further includes reducing an amount of the fluid flowing through the clearance by regulating the flow of the fluid through the clearance in step 906.
[0068] In accordance with one or more embodiments discussed herein, an exemplary labyrinth seal system is configured to control a fluid flow through a clearance defined between an abradable component and one of a rotatable component and a stationary component including teeth. The abradable component is coupled to a surface of the other of the stationary and rotatable components, thereby reducing the risk of damaging the stationary component and/or the rotatable component during transient operating conditions. Further, the labyrinth seal system may be disposed in at least one pre-defined location in the gas turbine engine to control a leakage flow through the clearance.
[0069] While only certain features of embodiments have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended embodiments are intended to cover all such modifications and changes as falling within the spirit of the invention.