Claims:1. A system (28) comprising:
a stationary component (36) comprising an inlet recess portion (52) and an aft fin (56); and
a rotatable component (38) disposed within the stationary component (36) to define a tip shroud cavity (46) there between, wherein the rotatable component (38) comprises an airfoil (40) and a shroud (42) coupled to the airfoil (40), wherein the shroud (42) comprises:
an overhanging portion (58) disposed at a leading edge (66) and proximate to the inlet recess portion (52);
a deflecting portion (60) disposed at a trailing edge (68) and inclined towards the stationary component (36); and
an aft abradable portion (62) disposed proximate to the deflecting portion (60) and facing the aft fin (56) inclined towards the rotatable component (38).

2. The system (28) of claim 1, wherein the stationary component (36) further comprises a forward fin (54) disposed between the inlet recess portion (52) and the aft fin (56) and inclined towards the shroud (42).

3. The system (28) of claim 2, wherein the shroud (42) further comprises a forward abradable portion (64) disposed between the overhanging portion (58) and the aft abradable portion (62) and facing the forward fin (54).
4. The system (128) of claim 1, wherein the shroud (142) further comprises a forward fin (164) disposed between the overhanging portion (158) and the aft abradable portion (162) and inclined towards the stationary component (136).

5. The system (228) of claim 1, wherein the inlet recess portion (252) comprises a concave portion (254) defining at least a portion of the tip shroud cavity (246).

6. The system (28) of claim 1, wherein the overhanging portion (58) has a predefined length (L) and inclined at a predefined angle (p) relative to a central axis (A) extending along an axial direction of the system (28).

7. The system (28) of claim 1, wherein the inlet recess portion (52) has a first inlet portion (52a) inclined at a first predefined angle (ß1) relative to a central axis (A) extending along an axial direction of the system (28) and a second inlet portion (52b) inclined at a second predefined angle (ß2) relative to the first inlet portion (52a).

8. The system (28) of claim 1, wherein the deflecting portion (60) is inclined at a predefined angle (?) relative to a central axis (A) extending along an axial direction of the system (28).

9. A gas turbine engine (10) comprising:
a compressor (14);
a combustor (16) coupled to the compressor (14); and
a turbine (18, 20) coupled to the combustor (16), wherein the turbine (18, 20) comprises:
a stationary component (36) comprising an inlet recess portion (52) and an aft fin (56); and
a rotatable component (38) disposed within the stationary component (36) to define a tip shroud cavity (46) there between, wherein the rotatable component (38) comprises an airfoil (40) and a shroud (42) coupled to the airfoil (40), wherein the shroud (42) comprises:
an overhanging portion (58) disposed at a leading edge (66) and proximate to the inlet recess portion (52);
a deflecting portion (60) disposed at a trailing edge (68) and inclined towards the stationary component (36); and
an aft abradable portion (62) disposed proximate to the deflecting portion (60) and facing the aft fin (56) inclined towards the rotatable component (38).

10. The gas turbine engine (10) of claim 9, wherein the stationary component (36) further comprises a forward fin (54) disposed between the inlet recess portion (52) and the aft fin (56) and inclined towards the shroud (42).

11. The gas turbine engine (10) of claim 10, wherein the shroud (42) further comprises a forward abradable portion (64) disposed between the overhanging portion (58) and the aft abradable portion (62) and facing the forward fin (54).
12. The gas turbine engine (10) of claim 10, wherein the shroud (42) further comprises a forward fin (164) disposed between the overhanging portion (158) and the aft abradable portion (162) and inclined towards the stationary component (136).

13. The gas turbine engine (10) of claim 9, wherein the inlet recess (252) portion comprises a concave portion (254) defining at least a portion of the tip shroud cavity (246).

14. The gas turbine engine (10) of claim 9, wherein the overhanging portion (58) has a predefined length (L) and inclined at a predefined angle (p) relative to a central axis (A) extending along an axial direction of the gas turbine engine (10).

15. The gas turbine engine (10) of claim 9, wherein the inlet recess portion (52) has a first inlet portion (52a) inclined at a first predefined angle (ß1) relative to a central axis (A) extending along an axial direction of the gas turbine engine (10) and a second inlet portion (52b) inclined at a second predefined angle (ß2) relative to the first inlet portion (52a).

16. The gas turbine engine (10) of claim 9, wherein the deflecting portion (60) is inclined at a predefined angle (?) relative to a central axis (A) extending along an axial direction of the gas turbine engine (10).

17. A method for controlling a flow of a leakage fluid (72) through a system (28), the method comprising:
receiving the leakage fluid (72) through a tip shroud cavity (46) defined there between a stationary component (36) and a rotatable component (38) disposed within the stationary component (36),
wherein the stationary component (36) comprising an inlet recess portion (52) and an aft fin (56), wherein the rotatable component (38) comprises an airfoil (40) and a shroud (42) coupled to the airfoil (40), wherein the shroud comprises (42): an overhanging portion (58) disposed at a leading edge (66) and proximate to the inlet recess portion (52), a deflecting portion (60) disposed at a trailing edge (68) and inclined towards the stationary component (36), and an aft abradable portion (62) disposed proximate to the deflecting portion (60) and facing the aft fin (56) inclined towards the rotatable component (38);
regulating the flow of the leakage fluid (72), using the inlet recess portion (52), the overhanging portion (58), the aft fin (56), and the aft abradable portion (62); and
regulating a mixing of the leakage fluid (72) with a main fluid (70) flowing along the airfoil (40), using the deflecting portion (60).

18. The method of claim 17, wherein regulating the flow of the leakage fluid (72) comprises recirculating a portion of the leakage fluid (72) within the tip shroud cavity (46) by deflecting the flow of the portion of the leakage fluid (72), using at least one of the inlet recess portion (52), the overhanging portion (58), the aft fin (56), and the aft abradable portion (62).

19. The method of claim 17, further comprising regulating the flow of the leakage fluid (72), using a forward fin (54) of the stationary component (36) and a forward abradable portion (64) of the shroud (42), wherein the forward fin (54) is disposed between the inlet recess portion (52) and the aft fin (56) and inclined towards the shroud (42), and wherein the forward abradable portion (64) is disposed between the overhanging portion (58) and the aft abradable portion (62) and facing the forward fin (54).

20. The method of claim 17, further comprising regulating the flow of the leakage fluid (72) using a forward fin (164) of the shroud (142), wherein the forward fin (164) is disposed between the overhanging portion (158) and the aft abradable portion (162) and inclined towards the stationary component (136).

21. The method of claim 17, wherein regulating the mixing of the leakage fluid (72) with the main fluid (70) comprises deflecting the flow of the leakage fluid (72) substantially parallel to a flow of the main fluid (70).
, Description:BACKGROUND
[0001] Embodiments of the present invention relate to a system having a tip shroud cavity defined there between a stationary component and a rotatable component having a tip shroud, for example, a gas turbine engine.
[0002] In a gas turbine engine, air is pressurized in a compressor and subsequently mixed with a fuel and combusted in a combustor to generate combustion gases. One or more turbines disposed downstream relative to the combustor, extract energy from the combustion gases and drive at least one of the compressor, a fan, a propeller, and any other mechanical load via a shaft. Each turbine includes one or more rotors, wherein each rotor includes a disk holding an array of turbine blades or buckets. Further, each turbine blade has a pressure side, a suction side, a leading edge, and a trailing edge and is surrounded by a stationary casing. The relative motion between the stationary casing and an unshrouded rotating turbine blade results in leaking of at least a portion of the combustion gases from the pressure side to the suction side over a tip of the turbine. As a result, undesirable pressure losses and reduction in aerodynamic performance of the turbine are caused.
[0003] The turbine blade having a tip shroud is used to minimize the leakage of the combustion gases, thereby improving aerodynamic performance of the turbine. The tip shroud is disposed within the stationary casing to define a tip shroud cavity. The shape of the tip shroud cavity is configured in such a way to prevent contact and/or rub between the rotating turbine blade and the stationary casing during transient operating conditions or during displacement caused due to thermal expansion between the rotating turbine blade and the stationary casing. As a result, the tip shroud cavity has a large volume and combustion gases are entrained into the tip shroud cavity thereby producing leakage vortices at a plurality of locations within the tip shroud cavity, resulting in undesirable pressure losses. Further, downstream of the tip shroud cavity, the entrained combustion gases mix abruptly with mainstream combustion gases, thereby producing a leakage vortex and resulting in further undesirable pressure losses.
[0004] Accordingly, there is a need for an enhanced system having a tip shroud cavity and associated method to minimize leakage of combustion gases into the tip shroud cavity and reduce downstream mixing losses.
BRIEF DESCRIPTION
[0005] In accordance with one exemplary embodiment, a system is disclosed. The system includes a stationary component and a rotatable component disposed within the stationary component to define a tip shroud cavity there between. The stationary component includes an inlet recess portion and an aft fin. The rotatable component includes an airfoil and a shroud coupled to the airfoil. The shroud includes an overhanging portion, a deflecting portion, and an aft abradable portion. The overhanging portion is disposed at a leading edge and proximate to the inlet recess portion. The deflecting portion is disposed at a trailing edge and inclined towards the stationary component. The aft abradable portion is disposed proximate to the deflecting portion and facing the aft fin which is inclined towards the rotatable component.
[0006] In accordance with another exemplary embodiment, a gas turbine engine is disclosed. The gas turbine engine includes a compressor, a combustor, and a turbine. The compressor and the turbine are coupled to the combustor. The turbine includes a stationary component and a rotatable component disposed within the stationary component to define a tip shroud cavity there between. The stationary component includes an inlet recess portion and an aft fin. The rotatable component includes an airfoil and a shroud coupled to the airfoil. The shroud includes an overhanging portion, a deflecting portion, and an aft abradable portion. The overhanging portion is disposed at a leading edge and proximate to the inlet recess portion. The deflecting portion is disposed at a trailing edge and inclined towards the stationary component. The aft abradable portion is disposed proximate to the deflecting portion and facing the aft fin which is inclined towards the rotatable component.
[0007] In accordance with yet another exemplary embodiment, a method for controlling a flow of leakage fluid through a system is disclosed. The method involves receiving the fluid through a tip shroud cavity defined there between a stationary component and a rotatable component disposed within the stationary component. The stationary component includes an inlet recess portion and an aft fin. The rotatable component includes an airfoil and a shroud coupled to the airfoil. The shroud includes an overhanging portion, a deflecting portion, and an aft abradable portion. The overhanging portion is disposed at a leading edge and proximate to the inlet recess portion. The deflecting portion is disposed at a trailing edge and inclined towards the stationary component. The aft abradable portion is disposed proximate to the deflecting portion and facing the aft fin which is inclined towards the rotatable component. The method further involves regulating the flow of the leakage fluid, using the inlet recess portion, the overhanging portion, the aft fin, and the aft abradable portion. Further, the method involves regulating a mixing of the leakage fluid with a main fluid flowing along the airfoil, using the deflecting portion.
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 schematic diagram of a gas turbine engine in accordance with one exemplary embodiment;
[0010] FIG. 2 is a schematic diagram of a low pressure turbine of the gas turbine engine in accordance with the exemplary embodiment of FIG.1;
[0011] FIG. 3 is a schematic diagram of a portion of the low pressure turbine in accordance with the exemplary embodiments of FIGS.1 and 2;
[0012] FIG. 4 is a schematic diagram of a system of the low pressure turbine in accordance with the exemplary embodiments of FIGS. 1, 2, and 3;
[0013] FIG. 5 is a schematic diagram depicting a fluid flow pattern for the system in accordance with the exemplary embodiments of FIGS. 1, 2, 3, and 4;
[0014] FIG. 6 is a schematic diagram of a system having a tip shroud cavity in accordance with another exemplary embodiment;
[0015] FIG. 7 is a schematic diagram of a system having a tip shroud cavity in accordance with yet another exemplary embodiment;
[0016] FIG. 8 is a schematic diagram of a system having a tip shroud cavity in accordance with yet another exemplary embodiment; and
[0017] FIG. 9 is a schematic diagram of a system having a tip shroud cavity in accordance with yet another exemplary embodiment.
DETAILED DESCRIPTION
[0018] Embodiments of the present invention discussed herein relate to a system having a tip shroud cavity for turbomachines such as a gas turbine engine. In embodiments, the system includes a stationary component and a rotatable component. Such a system is configured to control leakage of a fluid (i.e. a leakage fluid) through the tip shroud cavity defined between the stationary component and the rotatable component to improve aerodynamic performance of the turbomachines. The system is further configured to improve the aerodynamic performance of the turbomachines by reducing mixing losses associated with mixing of the leakage fluid with a main fluid flowing along the airfoil.
[0019] In one embodiment, the stationary component includes an inlet recess portion and an aft fin. The rotatable component includes an airfoil and a shroud coupled to the airfoil. The shroud includes an overhanging portion, a deflecting portion, and an abradable portion disposed proximate to the deflecting portion. The overhanging portion is disposed at a leading edge and proximate to the inlet recess portion. The deflecting portion is disposed at a trailing edge and inclined towards the stationary component. The abradable portion is disposed proximate to the deflecting portion and facing the aft fin which is inclined towards the rotatable component.
[0020] In another exemplary embodiment, the system is configured to create a tortuous flow path for the leakage fluid in the tip shroud cavity to reduce the leakage of the fluid and thereby improve efficiency of the turbine. The tortuous flow path is created by recirculating a portion of the leakage fluid within the tip shroud cavity by deflecting the flow of the portion of the leakage fluid. In such an embodiment, at least one of the inlet recess portion, the overhanging portion, the aft fin, and the aft abradable portion is configured to deflect the leakage fluid within the tip shroud cavity to improve aerodynamic performance of the turbomachines. The tip shroud cavity is further configured to reduce mixing losses associated with mixing of the leakage fluid with the main fluid to further improve the aerodynamic performance of the turbomachines. In such an embodiment, the deflecting portion is configured to deflect the leakage fluid above the shroud and substantially parallel to the main fluid.
[0021] FIG. 1 illustrates a schematic diagram of a turbomachine such as a gas turbine engine 10 in accordance with one exemplary embodiment. The gas turbine engine 10 includes a fan 12, a compressor 14, a combustor 16, a high pressure turbine 18, and a low pressure turbine 20, arranged in a serial and an axial flow relationship along a central axis “A” extending along an axial direction of the gas turbine engine 10. The compressor 14 may be a multistage compressor and the high and low pressure turbines 18, 20 may be a multistage turbine. The compressor 14 and the high pressure turbine 18 are coupled to the combustor 16. The low pressure turbine 20 is disposed downstream relative to the high pressure turbine 18. The compressor 14, the combustor 16, and the high pressure turbine 18 may be collectively referred to as a core of the gas turbine engine 10.
[0022] During operation, the fan 12 is configured to receive a fluid such as air and generate a pressurized fluid. A portion of the pressurized fluid may be fed to an inlet of the compressor 14 and a remaining portion of the pressurized fluid may bypass the core to provide thrust to the engine 10. The compressor 14 is configured to receive the portion of the pressurized fluid from the fan 12 and compress the pressurized fluid to generate a compressed fluid. The combustor 16 is configured to receive the compressed fluid from the compressor 14 and a fuel such as natural gas from a plurality of fuel injectors (not shown) and burn the fuel and the compressed fluid within a combustion zone (not shown) to generate an exhaust fluid. The high pressure turbine 18 is configured to receive the exhaust fluid from the combustor 16 and expand the exhaust fluid to convert energy of the exhaust fluid to work. The high pressure turbine 18 is configured to drive the compressor 14 through an outer shaft 22. The low pressure turbine 20 is configured to receive an expanded exhaust fluid from the high pressure turbine 18 to convert remaining energy of the expanded exhaust fluid to work. The low pressure turbine 20 is configured to drive the fan 12 through an inner shaft 24.
[0023] In the illustrated exemplary embodiment, the low pressure turbine 20 includes a system 28 having a tip shroud cavity. In one embodiment, the system 28 may include a stationary component and a rotatable component. Such a system 28 is discussed in greater details below with reference to subsequent figures.
[0024] While the illustrated gas turbine engine 10 is a high-bypass turbofan engine, the principles described herein may be equally applicable to turboprop, turbojet, and turbo shaft engines, as well as other types of engines used for other vehicles or stationary applications. Furthermore, while the low pressure turbine 20 is used as an example, it will be understood that the embodiments of the present invention may be applied to any turbine having inner and outer shrouds, including without limitation to high pressure turbine 18, other intermediate-pressure turbines (not shown), and the compressor 14.
[0025] FIG. 2 illustrates a schematic diagram of the low pressure turbine 20 of the gas turbine engine 10 in accordance with the exemplary embodiment of FIG.1. In the illustrated embodiment, the low pressure turbine 20 includes stages “S” represented specifically by a first-stage “S1”, a second-stage “S2”, and a third-stage “S3”. Each of the stages “S” includes a nozzle 30 and a rotatable component 38 (i.e. a rotor). The nozzle 30 includes an annular array of stator blades 34, where each of the stator blades 34 is disposed along a circumferential direction “B” of the low pressure turbine 20. It should be noted herein that only one stator blade 34 in each of the stages “S” is shown in FIG. 2 for the ease of illustration. Each of the stator blades 34 is coupled to a stationary component 36 (i.e. a casing) of the low pressure turbine 20. The rotatable component 38 includes an annular array of airfoils 40 (i.e. rotor blades), where each of the airfoils 40 is disposed along the circumferential direction “B” of the low pressure turbine 20. It should be noted herein that only one airfoil 40 in each of the stages “S” is shown in FIG. 2 for the ease of illustration. The rotatable component 38 further includes an annual array of shrouds 42, where each of the shrouds 42 is coupled to a tip 44 of the corresponding airfoil 40. In the illustrated embodiment, the airfoils 40 are all co-rotating and coupled to the inner shaft 24.
[0026] The low pressure turbine 20 further includes the system 28 having a tip shroud cavity 46 disposed in at least one of the three stages “S”. In one non-limiting exemplary embodiment, the system 28 may be disposed in each of the stages “S” of the low pressure turbine 20. The system 28 includes the stationary component 36 and the rotatable component 38 disposed within the stationary component 36 to define the tip shroud cavity 46 there between. Specifically, the tip shroud cavity 46 is defined between the shroud 42 and the casing 36. Such a system 28 is discussed in greater detail below with reference to subsequent figures.
[0027] FIG. 3 illustrates a schematic diagram of a portion 48 of the low pressure turbine 20 in accordance with the exemplary embodiments of FIGS.1 and 2. In the illustrated embodiment, the portion 48 corresponds to one of the stages “S” of the low pressure turbine 20.
[0028] In the illustrated embodiment, the system 28 includes the stationary component 36 and the rotatable component 38. The stationary component 36 includes an inlet recess portion 52, a forward fin 54, and an aft fin 56. The forward fin 54 is disposed between the inlet recess portion 52 and the aft fin 56. The rotatable component 38 includes the airfoil 40 and the shroud 42. The shroud 42 is coupled to the airfoil 40, using a casing fillet 50. The shroud 42 includes an overhanging portion 58, a deflecting portion 60, an aft abradable portion 62, and a forward abradable portion 64. In the illustrated embodiment, the overhanging portion 58 is disposed at a leading edge 66 of the airfoil 40 and proximate to the inlet recess portion 52. The deflecting portion 60 is disposed at a trailing edge 68 of the airfoil 40 and inclined towards the stationary component 36. The aft abradable portion 62 is disposed proximate to the deflecting portion 60 and faces the aft fin 56 which is inclined towards the rotatable component 38. The forward abradable portion 64 is disposed between the overhanging portion 58 and the aft abradable portion 62.
[0029] During operation of the gas turbine engine 10, a main fluid 70 (i.e. the expanded exhaust fluid) is configured to flow from the high pressure turbine 18 to the low pressure turbine 20. The main fluid 70 flows along the nozzle 30 and the rotatable component 38. Specifically, the stator blade 34 of the nozzle 30 is configured to guide the main fluid 70 towards the airfoil 40 of the rotatable component 38 causing the rotatable component 38 to rotate along the circumferential direction “B” of the gas turbine engine 10. A portion 72 (i.e. a leakage fluid) of the main fluid 70 leaks into and flows through the tip shroud cavity 46. The system 28 is configured to regulate a flow of the leakage fluid 72 through the tip shroud cavity 46 and mixing of the leakage fluid 72 with the main fluid 70 at the trailing edge 68 of the airfoil 40.
[0030] FIG. 4 illustrates a schematic diagram of the system 28 of the low pressure turbine 20 in accordance with the exemplary embodiments of FIGS. 1, 2, and 3.
[0031] As discussed in the embodiment of FIG. 3, the stationary component 36 includes the inlet recess portion 52, the forward fin 54, and the aft fin 56. The inlet recess portion 52 has a first inlet portion 52a inclined at a first predefined angle “ß1” relative to the central axis “A” and a second inlet portion 52b inclined at a second predefined angle “ß2” relative to the first inlet portion 52a. In the illustrated embodiment, the first predefined angle “ß1” is 30 degrees and the second predefined angle “ß2”is 15 degrees. In certain embodiments, the first predefined angle “ß1” is in a range of 0 degree to 40 degrees and the second predefined angle “ß2” is in a range of 0 degrees to 25 degrees. The forward fin 54 is inclined at a predefined angle “?” towards the shroud 42. In the illustrated embodiment, the predefined angle “?” is at -90 degrees relative to the central axis “A”. In certain embodiments, the predefined angle “?” is in a range of -30 degrees to -150 degrees. The aft fin 56 is inclined at a predefined angle “?” towards the shroud 42. In the illustrated embodiment, the predefined angle “?” is at -90 degrees relative to the central axis “A”. In certain embodiments, the predefined angle “?” is in a range of -30 degrees to -150 degrees.
[0032] As discussed in the embodiment of FIG. 3, the rotatable component 38 includes the airfoil 40 and the shroud 42 coupled to the airfoil 40. The shroud 42 includes the overhanging portion 58, the deflecting portion 60, the aft abradable portion 62, and the forward abradable portion 64. The overhanging portion 58 is inclined at a predefined angle “p” relative to the central axis “A”. Further, the overhanging portion 58 extends along the axial direction of the system 28. In the illustrated embodiment, the predefined angle “p” is at 20 degrees relative to the central axis “A”. In certain embodiments, the predefined angle “p” is in a range of 0 degree to 45 degrees. The overhanging portion 58 has a predefined length “L” extending towards the stationary component 36. In the illustrated embodiment, the predefined length “L” is 20% of axial chord of the airfoil 40. In certain embodiments, the predefined length “L” is in a range of 5% to 35% axial chord of the airfoil 40. The deflecting portion 60 is inclined at a predefined angle “?” relative to the central axis “A”. Further, the deflecting portion 60 extends along the axial direction of the system 28. In the illustrated embodiment, the predefined angle “?” is at 30 degrees relative to the central axis “A”. In certain embodiments, the predefined angle “?” is in a range of 0 degree to 40 degrees.
[0033] In one embodiment, the aft and forward abradable portions 62, 64 may be made of a honeycomb component having a plurality of honeycomb cells. In certain other embodiments, the aft and forward abradable portions 62, 64 may be made of a porous component. In one or more embodiments, the aft and forward abradable portions 62, 64 may be brazed to a surface 76 of the shroud 42. In one embodiment, the surface 76 is a flat surface. In certain other embodiments, the surface 76 may be a stepped surface. The rotatable component 38 is disposed within the stationary component 36 to define the tip shroud cavity 46 there between.
[0034] FIG. 5 is a schematic diagram depicting a flow pattern of the main fluid 70 and the leakage fluid 72 within the system 28 in accordance with the exemplary embodiments of FIGS. 1, 2, 3, and 4. The system 28 is configured to regulate a flow of the leakage fluid 72 through the tip shroud cavity 46. Specifically, the tip shroud cavity 46 includes a first sub cavity 46a, a second sub cavity 46b, and a third sub cavity 46c.
[0035] In one embodiment, regulating the leakage fluid 72 involves recirculating a first portion 72a of the leakage fluid 72 within the inlet recess portion 52 by deflecting the first portion 72a, using features 52a and 52b of the inlet recess portion 52 and the overhanging portion 58. The regulating step further involves recirculating a second portion 72b of the leakage fluid 72 within the first sub cavity 46a by deflecting the second portion 72b, using the forward fin 54, the forward abradable portion 64, and the overhanging portion 58. Further, the regulating step involves recirculating a third portion 72c of the leakage fluid 72 within the second sub cavity 46b by deflecting the third portion 72c, using the aft fin 56, the forward fin 54 and the aft abradable portion 62. Further, the regulating step involves deflecting a fourth portion 72d of the leakage fluid 72 in the third sub cavity 46c by using the deflecting portion 60. As a result, the system 28 defines a tortuous flow path for the leakage fluid 72 to flow through the tip shroud cavity 46, thereby reducing leakage of the fluid 72 through the tip shroud cavity 46 and increasing quantity of the main fluid 70 available for work extraction by the airfoil 40 leading to improvement in aerodynamic performance of the gas turbine engine 10.
[0036] In such embodiments, the aft and forward abradable portions 62, 64 may additionally provide a diffusion effect to the leakage fluid 72 to reduce the amount of the leakage fluid 72 flowing through the tip shroud cavity 46. Further, during certain transient operating conditions of the gas turbine engine 10, the aft fin 56 and the forward fin 54 may contact certain portions of the aft abradable portion 62 and the forward abradable portion 64 respectively, thereby damaging the aft and forward abradable portions 62, 64. The damaged aft and forward abradable portions 62, 64 may be easily removed from the surface 76 of the shroud 42 and replaced with suitable abradable portions.
[0037] The method further involves regulating a mixing of the leakage fluid 72 with the main fluid 70 flowing along the airfoil 40, using the deflecting portion 60. In one embodiment, the mixing of the leakage fluid 72 involves deflecting the leakage fluid 72 above the shroud 42 and substantially parallel to the main fluid 70 so as to further improve the aerodynamic performance of the gas turbine engine 10.
[0038] FIG. 6 is a schematic diagram of a system 128 in accordance with yet another exemplary embodiment. In one embodiment, the system 128 includes a stationary component 136 and a rotatable component 138 disposed within the stationary component 136 to define a tip shroud cavity 146 there between.
[0039] The stationary component 136 includes an inlet recess portion 152 and an aft fin 156. The rotatable component 138 includes an airfoil 140 and a shroud 142 coupled to the airfoil 140. The shroud 142 includes an overhanging portion 158, a forward fin 164, an aft abradable portion 162, and a deflecting portion 160. The forward fin 164 is disposed between the overhanging portion 158 and the aft abradable portion 162 and inclined at a predefined angle “s” towards the stationary component 136. In the illustrated embodiment, the predefined angle “s” is at 60 degrees relative to a central axis “A” extending along an axial direction of the system 128. In certain embodiments, the predefined angle “s” is in a range of 30 degrees to 90 degrees.
[0040] The system 128 is configured to receive the leakage fluid 172 through the tip shroud cavity 146 and regulate a flow of the leakage fluid 172 through the tip shroud cavity 146. In one embodiment, regulating the leakage fluid 172 involves recirculating a portion of the leakage fluid 172 within the tip shroud cavity 146 by deflecting the portion of the leakage fluid 172, using at least one of the inlet recess portion 152, the overhanging portion 158, the forward fin 164, the aft abradable portion 162, and the aft fin 156. The system 128 thereby defines a tortuous flow path for the leakage fluid 172 to flow through the tip shroud cavity 146, thereby reducing leakage of the leakage fluid 172 through the tip shroud cavity 146 and increasing quantity of the main fluid 170 available for work extraction by the airfoil 140 leading to improvement in aerodynamic performance of a gas turbine engine.
[0041] The method further involves regulating a mixing of the leakage fluid 172 with the main fluid 170 flowing along the airfoil 140, using the deflecting portion 160. In one embodiment, the mixing of the leakage fluid 172 involves deflecting the leakage fluid 172 above the shroud 142, substantially parallel with the main fluid 170 so as to further improve the aerodynamic performance of the gas turbine engine.
[0042] FIG. 7 is a schematic diagram of a system 228 in accordance with yet another exemplary embodiment. In one embodiment, the system 228 includes a stationary component 236 and a rotatable component 238 disposed within the stationary component 236 to define a tip shroud cavity 246 there between.
[0043] In the illustrated embodiment, the stationary component 236 includes an inlet recess portion 252 and an aft fin 256. The inlet recess portion 252 includes a concave portion 254 defining a portion of the tip shroud cavity 246. The rotatable component 238 includes an airfoil 240 and a shroud 242 coupled to the airfoil 240. The shroud 242 includes an overhanging portion 258, an aft abradable portion 262, a forward fin 264, and a deflecting portion 260. The overhanging portion 258 has a predefined length “L1” which is substantially less than the length “L” of the overhanging portion 58 discussed in the embodiment of FIG. 4. In the one embodiment, the predefined length “L1” is 5% of axial chord of the airfoil 240. In certain embodiments, the predefined length “L1” is in a range of 5% to 35% of axial chord of the airfoil 240. The forward fin 264 is disposed between the overhanging portion 258 and the aft abradable portion 262 and is inclined at a predefined angle “s” towards the stationary component 236. In the illustrated embodiment, the predefined angle “s” is 90 degrees relative to a central axis “A” extending along an axial direction of the system 228. In certain embodiments, the predefined angle “s” is in a range of 30 degrees to 90 degrees.
[0044] The system 228 is configured to receive the leakage fluid 272 through the tip shroud cavity 246 and regulate a flow of the leakage fluid 272 through the tip shroud cavity 246. In one embodiment, regulating the leakage fluid 272 involves recirculating a portion of the leakage fluid 272 within the tip shroud cavity 246 by deflecting the portion of the leakage fluid 272, using at least one of the inlet recess portion 252, the overhanging portion 258, the concave portion 254, the forward fin 264, the aft abradable portion 262, and the aft fin 256. The system 228 defines a tortuous flow path for the leakage fluid 272 to flow through the tip shroud cavity 246, thereby reducing leakage of the leakage fluid 272 through the tip shroud cavity 246 and increasing quantity of the main fluid 270 available for work extraction by the airfoil 240 leading to improvement in aerodynamic performance of a gas turbine engine.
[0045] The method further involves regulating a mixing of the leakage fluid 272 with the main fluid 270 flowing along the airfoil 240, using the deflecting portion 260. In one embodiment, the mixing of the leakage fluid 272 involves deflecting the leakage fluid 272 above the shroud 242 substantially parallel with the main fluid 270 so as to further improve the aerodynamic performance of the gas turbine engine.
[0046] FIG. 8 is a schematic diagram of a system 328 in accordance with yet another exemplary embodiment. In one embodiment, the system 328 includes a stationary component 336 and a rotatable component 338 disposed within the stationary component 336 to define a tip shroud cavity 346 there between.
[0047] In the illustrated embodiment, the stationary component 336 includes an inlet recess portion 352 and an aft fin 356. An inlet of 352a the inlet recess portion 352 is inclined at a predefined angle “ß” relative to the central axis “A” extending along the axial direction of the system 328. In one embodiment, the predefined angle “ß” is 30 degrees. In certain embodiments, the predefined angle “ß” is in a range of 0 degree to 40 degrees. The rotatable component 338 includes an airfoil 340 and a shroud 342 coupled to the airfoil 340. The shroud 342 includes an overhanging portion 358, an aft abradable portion 362, a forward fin 364, and a deflecting portion 360. The overhanging portion 358 is inclined at a predefined angle “p” relative to the central axis “A” extending along the axial direction of the system 328. In the illustrated embodiment, the predefined angle “p” is 0 degree. In certain embodiments, the predefined angle “p” is in a range of 0 degree to 45 degrees.
[0048] The system 328 is configured to receive the leakage fluid 372 through the tip shroud cavity 346 and configured to regulate a flow of the leakage fluid 372 through the tip shroud cavity 346. In one embodiment, regulating the leakage fluid 372 involves recirculating a portion of the leakage fluid 372 within the tip shroud cavity 346 by deflecting the portion of the leakage fluid 372, using at least one of the inlet recess portion 352, the overhanging portion 358, the forward fin 364, the aft abradable portion 362, and the aft fin 356. The system 328 defines a tortuous flow path for the leakage fluid 372 to flow through the tip shroud cavity 346, thereby reducing leakage of the leakage fluid 372 through the tip shroud cavity 346 and increasing quantity of the main fluid 370 available for work extraction by the airfoil 340 leading to improvement in aerodynamic performance of a gas turbine engine.
[0049] The method further involves regulating a mixing of the leakage fluid 372 with the main fluid 370 flowing along the airfoil 340, using the deflecting portion 360. In one embodiment, the mixing of the leakage fluid 372 involves deflecting the leakage fluid 372 above the shroud 342 substantially parallel with the main fluid 370 so as to further improve the aerodynamic performance of the gas turbine engine.
[0050] FIG. 9 is a schematic diagram of a system 428 in accordance with yet another exemplary embodiment. The system 428 includes a stationary component 436 and a rotatable component 438 disposed within the stationary component 436 to define a tip shroud cavity 446 there between.
[0051] In the illustrated embodiment, the stationary component 436 includes an inlet recess portion 452, a forward fin 454, and an aft fin 456. The rotatable component 438 includes an airfoil 440 and a shroud 442 coupled to the airfoil 440. The shroud 442 includes an overhanging portion 458, a deflecting portion 460, an aft abradable portion 462, and a forward abradable portion 464.
[0052] The system 428 is configured to receive the leakage fluid 472 through the tip shroud cavity 446 and configured to regulate a flow of the leakage fluid 472 through the tip shroud cavity 446. In one embodiment, regulating the leakage fluid 472 involves recirculating a portion of the leakage fluid 472 within the tip shroud cavity 446 by deflecting the portion of the leakage fluid 472, using at least one of the inlet recess portion 452, the overhanging portion 458, the forward fin 454, the forward abradable portion 464, the aft fin 456, and the aft abradable portion 462. The system 428 defines a tortuous flow path for the leakage fluid 472 to flow through the tip shroud cavity 446, thereby reducing leakage of the leakage fluid 472 through the tip shroud cavity 446 and increasing quantity of the main fluid 470 available for work extraction by the airfoil 440 leading to improvement in aerodynamic performance of a gas turbine engine.
[0053] The method further involves regulating a mixing of the leakage fluid 472 with the main fluid 470 flowing along the airfoil 440, using the deflecting portion 460. In one embodiment, the mixing of the leakage fluid 472 involves deflecting the leakage fluid 472 above the shroud 442, substantially parallel with the main fluid 470 so as to further improve the aerodynamic performance of the gas turbine engine.
[0054] In one non-limiting embodiment of the present invention, the system discussed in the embodiments of FIGS. 4-9 facilitates to further improve the aerodynamic performance of the gas turbine engine to up to 0.20 percent compared to the conventional system.
[0055] In one non-limiting embodiment of the present invention, the system having a tip shroud cavity discussed with reference to the embodiments of FIGS. 4-9 may be disposed between a tip of each stator blade and the rotatable component to control leaking of a fluid and also to improve an aerodynamic efficiency of the turbomachine.
[0056] In accordance with one or more embodiments discussed herein, an exemplary system is configured to control a leakage fluid flow through a tip shroud cavity defined between a stationary component and rotatable component. The exemplary system is further configured to further improve aerodynamic performance of a turbomachine by reducing the mixing losses of the leakage fluid with a main fluid. The abradable portions disposed on a surface of the shroud reduce the risk of damaging the rotatable component during transient operating conditions or during displacement caused due to thermal expansion between the rotatable component and the stationary component. Further, the system as discussed in one or more embodiments herein reduces the strength of leakage vortices at a plurality of locations within the tip shroud cavity and a leakage vortex at a location downstream of the tip shroud cavity.
[0057] 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.