Patent Application
20100183428
This invention is directed generally to turbine engines, and, more particularly, to cooling systems for turbine engine components.
Typically, gas turbine engines include a compressor for compressing air, a combustor for mixing the compressed air with fuel and igniting the mixture, and a turbine assembly for producing power. Combustors often operate at high temperatures, which can exceed 2,500 degrees Fahrenheit. Various components in the combustor and the turbine assembly are exposed to these high temperatures. As a result, such components must be made of materials capable of withstanding such high temperatures. Alternatively or in addition, such components can have cooling systems and features to enable the component to survive in an environment which exceeds the capability of the material. While there are numerous cooling configurations in the art, there is a continuing need for improved cooling systems for turbine engine components.
Aspects of the invention are directed to a cooling system for a turbine engine component having an outer wall and an inner wall. The system also includes a cooling module located between the outer wall and the inner wall.
The cooling module has a serpentine coolant flow passage defined by the outer wall, the inner wall and at least one wall extending from the inner wall to the outer wall. In one cooling module, the flow passage is configured such that coolant flow in one portion of the flow passage is in the same direction as coolant flow in a neighboring portion of the flow passage. The neighboring portions of the flow passage can be substantially parallel to each other. In one embodiment, the flow passage can have a generally rectangular spiral conformation. Coolant can be introduced to the flow passage through a coolant supply inlet. The coolant supply inlet can be centrally located within the module.
In another cooling module, the flow passage is configured such that coolant flow in one portion of the flow passage is in the opposite direction as coolant flow in a neighboring portion of the flow passage. The neighboring portions of the flow passage can be substantially parallel to each other. In one embodiment, a coolant supply inlet that is located at an outer end of the module.
A plurality of microfins are distributed along the flow passage. The microfins extend from the outer wall to the inner wall. The plurality of microfins can be aligned in a row along at least a portion of the flow passage. In addition, a plurality of trip strips can be distributed along the flow passage. The trip strips can extend from the inner wall and/or the outer wall. The trip strips can be arranged so as to define a generally v-shaped configuration along at least a portion of the flow passage. For instance, one or more pairs of trip strips can be arranged in a generally v-shaped configuration. The trip strips can disrupt laminar flow along the flow passage. In one embodiment, the plurality of microfins can be distributed along a central region of the flow passage. In such case, a first plurality of trip strips can be positioned on a first side of the microfins, and a second plurality of trip strips can be positioned on an opposite side of the microfins.
The cooling system can further include an exhaust diffusion region. The exhaust diffusion region and the flow passage can be separated by a wall. One or more metering holes can be provided in the wall such that the exhaust diffusion region and the flow passage are in fluid communication. The exhaust diffusion region can include a transverse rib positioned such that coolant exiting the at least one metering hole impinges on the transverse rib. The exhaust diffusion region can include an exhaust diffuser passage permitting fluid communication with the exterior environment of the component. Thus, coolant can be discharged from the cooling system through the exhaust diffuser passage so as to film cool an outermost surface of the component.
Another cooling system according to aspects of the invention includes a turbine engine component having an outer wall and an inner wall. A plurality of cooling modules are located between the outer wall and the inner wall. In one embodiment, at least some of the plurality of cooling modules are provided in an aligned arrangement. In another embodiment, at least some of the plurality of cooling modules are provided in a staggered arrangement.
Each of the plurality of cooling modules has a serpentine coolant flow passage defined by the outer wall, the inner wall and at least one wall extending from the inner wall to the outer wall. A plurality of microfins are distributed along the flow passage. The microfins extend from the outer wall to the inner wall. A plurality of trip strips are distributed along the flow passage. The trip strips can disrupt laminar flow along the flow passage. The trip strips can extend from the inner wall and/or the outer wall.
Each cooling module further includes an exhaust diffusion region. The exhaust diffusion region and the flow passage are separated by a wall. One or more metering holes are provided in the wall such that the exhaust diffusion region and the flow passage are in fluid communication. The exhaust diffusion region includes an exhaust diffuser passage, which permitting fluid communication with an exterior of the component, including the exterior environment of the component. Thus, coolant can be discharged from the cooling system through the exhaust diffuser passage so as to film cool an outermost surface of the component.
A system according to aspects of the present invention can provide cooling and other benefits to various turbine engine components. This detailed description is intended only as exemplary. Embodiments of the invention are shown in
A cooling system 10 according to aspects of the invention can be used in connection with a turbine engine component 12 that must be cooled during engine operation. For instance, the component 12 can be a liner, a turbine blade or a turbine vane, just to name a few possibilities. The component 12 can have an outer wall 14 having an outer surface 16 and an inner surface 18. At least a portion of the outer surface 16 can be coated with a thermal barrier coating 20. The component 12 can further include an inner wall 22 or backing plate. The terms “inner” and “outer” are intended to indicate the relative proximity of such items to the hot gas flow 24 to which the component 12 is exposed.
Within the component 12, there can be a cooling system 10 configured in accordance with aspects of the invention. The cooling system 10 can be formed in any suitable manner. For instance, the cooling system 10 can be formed by either casting the cooling geometry within the component 12 to form a near wall cooling. Alternatively, the cooling system 10 can be machined into the outer wall 14. In such case, the inner wall 22 can be attached to the outer wall 14, such as by transient liquid phase (TLP) bonding.
A first cooling module 10a according to aspects of the invention is shown in
The coolant 10a can flow along a serpentine flow passage 34, which can be defined by the inner wall 22, the outer wall 14, and one or more walls 36 extending therebetween. The serpentine flow passage 34 can have a plurality of segments 38a, 38b, 38c, 38d, 38e, 38f, 38g, 38h, 38i, 38k. As shown in
The flow passage 34 can wind so that the coolant flow in one portion of the flow passage 34 is in the same direction as a neighboring or adjacent portion of the flow passage 34, as is shown in
The flow passage 34 can have any suitable width W. In one embodiment, the width W of the flow passage 34 can be substantially identical along the entire length of the flow passage 34. The width W of the flow passage 34 can be greater than the width W1 of the walls 36 that define in part the flow passage 34.
Along the flow passage 34, there can be numerous structures for disturbing the flow. For example, a plurality of microfins 42 can be distributed along the flow passage 34 in any suitable manner. For example, the microfins 42 can be generally equally spaced along the flow passage 34. The microfins 42 can be arranged in a single row (as shown in
The microfins 42 can have any suitable configuration. In one embodiment, the microfins 42 can have a substantially rectangular cross-sectional shape. Alternatively or in addition, the microfins 42 can have a substantially airfoil-shaped cross-section. The plurality of microfins 42 can be identical to each other, or at least one of the microfins 42 can be different from the other microfins 42 in one or more respects. The microfins 42 can extend from the outer wall 14 to the inner wall 22.
The first cooling module 10a can include additional structures for disturbing the flow along the flow passage 34. For instance, there can be a plurality of trip strips 44. The trip strips 44 can disrupt laminar coolant flow along the flow passage 34 and to improve the heat transfer cooling capability of the module 10a.
The trip strips 44 can be distributed along the flow passage 34 in any suitable manner. For example, the trip strips 44 can be generally equally spaced along the flow passage 34. In one embodiment, the trip strips 44 can be arranged on each side of the plurality of microfins 42. In one embodiment, the trip strips 44 on opposite sides of the microfins 42 can be in a generally v-shaped configuration, as shown in
The arrangement of the trip strips 44 can be substantially constant along the flow passage 34. Alternatively, the arrangement of the trip strips 44 can change on each segment 38a, 38b, 38c, 38d, 38e, 38f, 38g, 38h, 38i, 38j, 38k of the flow passage 34. In one embodiment, the trip strips 44 can alternate between two different arrangements of the trip strips 44. For instance, a first portion of the flow passage 34 could have a first arrangement of the trip strips 44, a second portion of the flow passage 34 could have a second arrangement of the trip strips 44, a third portion of the flow passage 34 could have the first arrangement of trip strips 44, a fourth portion of the flow passage 34 could have the second arrangement of trip strips 44, and so forth. In the case of the v-shaped configuration, flow passage segment 38h can have trip strips 44 oriented with the “open” or wide end of the v-shaped configuration facing the oncoming flow, and flow passage segment 38i can have trip strips 55 oriented with the “open” or wide end of the v-shaped configuration facing away from the oncoming flow, as is shown in
The trip strips 44 can protrude from the inner surface 18 of the outer wall 14 and/or a surface 26 of the inner wall 22. The trip strips 44 do not extend the entire distance between the outer wall 14 and the inner wall 22. Rather, the trip strips 44 can protrude a minimal distance from the surface on which they are provided. In one embodiment, the trip strips 44 can extend less than about one quarter of the distance between the outer wall 14 and the inner wall 22. Alternatively, the trip strips 44 can extend less than about one eighth of the distance between the outer wall 14 and the inner wall 22.
In operation, cooling air can be supplied through the supply inlet 30, which can be provided in the inner wall 22 of the first cooling module 10a. The cooling air can impinge onto the inner surface 18 of the hot outer wall 14. The cooling air can then flow along the serpentine flow passage 34, such as in the parallel flow configuration shown in
A second cooling module 10b according to aspects of the invention is shown in
The second cooling module 10b can include coolant supply inlet that is located at one end or corner of the module 10b. The coolant can flow along a serpentine flow passage 62. The serpentine flow passage 62 can have a plurality of segments 62a, 62b, 62c, 62d, 62e, 62f, 62g, 62h, 62i, 62j, 62k, 62l. As shown in
From the inlet 60, coolant 32 can flow toward the center of the module 10b. Arrows are shows to represent the general direction of coolant flow 64 along the passage 62. The flow passage 62 can be arranged so that the coolant flow in one portion of the flow passage 62 will be in the opposite direction of coolant flow in a neighboring or adjacent portion of the flow passage 62, as shown in
In operation, cooling air can be supplied through the supply inlet 60, which can be provided in the inner wall 22 of the second cooling module 10b. The cooling air can impinge onto the inner surface 18 of the hot outer wall 14. The cooling air can then flow along the serpentine flow passage 62, such as in a counter flow configuration of
It should also be noted that the second cooling module 10b can be relatively small. For example, the second cooling module 10b can be on the scale of about one inch square or less. Thus, the second cooling module 10b can be used to provide cooling to a localized portion of the wall. Thus, the second cooling module 10b can be used with other cooling modules, such as the first cooling module 10a, to provided tailored cooling flow for a particular location in the component 12.
Each of the above cooling modules 10a, 10b can exhaust coolant through an exhaust region 70 (
In the first chamber 76, the flow can impinge on a transverse rib 78. The flow can be diffused substantially uniformly in the first chamber 76. The flow is then forced to go around the rib 78. The flow can enter a second chamber 80 from which it is discharged from the component 12 at reduced exit momentum. The flow can exit through an exhaust diffuser passage 82 formed in the outer wall 14 and in any coating, such as a thermal barrier coating 20, on the outer wall 14. The exhaust diffuser passage 82 can be in the form of a slot. The cross-sectional area of the exhaust passage 82 can increase from the second chamber 80 to the outermost surface 84 of the component 12. The outermost surface 84 can be defined by the outer surface 16 of the outer wall 14 and/or the outer surface of any coating applied on the surface. The exiting flow can enter the hot gas flow 24 and can provide film cooling to the component 12.
The configuration of the exhaust region 70 minimize coolant penetration into the hot gas path 24. The configuration of the exhaust region 70 according to aspects of the invention can result in build up of the coolant in the sub-boundary layer next to the outermost surface 84. As a result, better film coverage in the direction of flow and in the circumferential direction can be achieved.
According to aspects of the invention, a plurality of cooling modules 11 can be provided to cool the component 12 (see
It should be noted that when a plurality of modules are provided, the modules 11 can all be identical to each other or at least one of the modules 11 can be different. The modules 11 can be any suitable module, including the first cooling module 10a and the second cooling module 10b.
It will be appreciated that a cooling module having the combination of a finned serpentine cooling passage and a diffusion exhaust region according to aspects of the invention can create a high level of cooling effectiveness for a component exposed to a hot operational environment. As a result, more uniform wall temperature for the component can be achieved.
Further, the double metering formation of the cooling modules—metering by a single coolant supply inlet 30, 60 and metering by holes 74 in the wall 72—can result in better cooling flow control. In addition, the modular nature of the cooling modules also allow cooling designs to be tailored to a local external heat load and pressure profile. Further, the small compartmentalized formation of the modules increases cooling design flexibility. Further, the risk of component failure is minimized if one of the cooling modules fails, as such failure will not affect the performance of the other cooling modules. With such a cooling construction approach, optimal usage of cooling air can be achieved.
As noted above, a thermal barrier coating can be applied onto external surfaces of a component exposed to hot gases during engine operation. In many prior systems, cooling exhaust holes are relatively small so care must be taken not to overcoat any cooling exhaust holes with the thermal barrier coating. However, the exhaust region 70 of the cooling modules 10a, 10b according to aspects of the invention have a relatively large exhaust diffuser passage 82. As a result, the passage 82 is sufficiently large such that inadvertent overspread of a thermal barrier coating onto the passage 82 may not substantially impact the performance of the passage 82. Thus, during refurbishment of the component, the thermal barrier coating can be removed and reapplied without the need for film cooling hole masking, which can result in appreciable time and labor savings.
The foregoing description is provided in the context of two possible cooling modules according to aspects of the invention. It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible within the scope of the invention as defined in the following claims.
