Patent Application
20170175576
The subject matter disclosed herein relates to gas turbine engines, and more specifically, to turbine shrouds for gas turbine engines.
A turbomachine, such as a gas turbine engine, may include a compressor, a combustor, and a turbine. Gases are compressed in the compressor, combined with fuel, and then fed into to the combustor, where the gas/fuel mixture is combusted. The high temperature and high energy exhaust fluids are then fed to the turbine along a hot gas path, where the energy of the fluids is converted to mechanical energy. High temperatures along the hot gas path can heat turbine compoments (e.g., turbine shroud), causing degradation of components.
Certain embodiments commensurate in scope with the originally claimed subject matter are summarized below. These embodiments are not intended to limit the scope of the claimed subject matter, but rather these embodiments are intended only to provide a brief summary of possible forms of the subject matter. Indeed, the subject matter may encompass a variety of forms that may be similar to or different from the embodiments set forth below.
In a first embodiment, a system includes a shroud segment for use in a turbine section of a gas turbine engine, including a body including a leading edge, a trailing edge, a first side edge, and a second side edge, a pair of opposed lateral sides between the leading and trailing edges and the first and second side edges. The system includes a first lateral side of the pair of opposed lateral sides which interfaces with a cavity having a cooling fluid. The system also includes a second lateral side of the pair of opposed lateral sides which interfaces with a hot gas flow path, a first channel disposed within the body, where the first channel includes a first end portion and a second end portion. The first end portion is disposed adjacent the first side edge and the second end portion is disposed adjacent the second side edge. The system also includes a second channel disposed within the body, where the second channel includes a third end portion and a fourth end portion. The third end portion is disposed adjacent the first side edge and the fourth end portion is disposed adjacent the second side edge. The first and second channels receive the cooling fluid from the cavity to cool the body, and the first end portion and the fourth end portion each include a portion having a free end. Each free end has width in a direction from the leading edge to the trailing edge greater than an adjacent portion of the portion coupled to the free end.
In a second embodiment, an apparatus includes a gas turbine engine, including a compressor, a combustion system, and a turbine section. The apparatus includes a casing, an outer shroud segment coupled to the outer casing, an inner shroud segment coupled to the outer shroud segment to form a cavity configured to receive a discharged cooling fluid from the compressor. The inner shroud segment includes a body having a leading edge, a trailing edge, a first side edge, and a second side edge, a pair of opposed lateral sides between the leading and trailing edges and the first and second side edges, where a first lateral side of the pair of opposed lateral sides is configured to interface with the cavity, and a second lateral side of the pair of opposed lateral sides is configured to interface with a hot gas flow path. The apparatus also includes a plurality of channels disposed within the body and extending from adjacent the first side edge to adjacent the second side edge, wherein each channel of the plurality of channels comprises a first end portion having a portion and a second end portion. The plurality of channels are configured to receive a cooling fluid from the cavity to cool the body. The first end portions each comprises a portion having a free end, and each free end has a width in a direction from the leading edge to the trailing edge greater than an adjacent portion of the portion coupled to the free end.
In a third embodiment, a system includes a shroud segment for use in a turbine section of a gas turbine engine. The system includes a body including a leading edge, a trailing edge, a first side edge, a second side edge, and a pair of opposed lateral sides between the leading and trailing edges and the first and second side edges. A first lateral side of the pair of opposed lateral sides is configured to interface with a cavity having a cooling fluid, and a second lateral side of the pair of opposed lateral sides is configured to interface with a hot gas flow path. A first channel is disposed within the body, and the first channel includes a first end portion and a second end portion. The first end portion is disposed adjacent the first side edge and the second end portion is disposed adjacent the second side edge. A second channel is disposed within the body, and the second channel comprises a third end portion and a fourth end portion. The third end portion is disposed adjacent the first side edge and the fourth end portion is disposed adjacent the second side edge. The first and second channels are configured to receive the cooling fluid from the cavity to cool the body, and the first end portion and the fourth end portion each include a portion having a free end. The free end has an elliptic shape and a straight portion adjacent the free end.
These and other features, aspects, and advantages of the present subject matter 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:
One or more specific embodiments of the present subject matter will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present subject matter, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
As discussed in detail below, certain embodiments of turbine shrouds associated with gas engines reduce the hot gas leaks between the pressure side and the suction side of a turbine blade. The turbine shrouds also provide cooling flows (e.g., air) to the turbine blade to reduce premature failure of the blade and associated blade components or may cool areas between adjacent shrouds. The turbine shrouds as described herein utilize multiple cooling channels. The cooling channels may be formed on either side of a shroud body (e.g., inner shroud segment or outer shroud segment). The cooling channels may be machined into the shroud body via a suitable process, such as electrical discharge machining, which helps control the pressure drop across the cooling channel (e.g., by producing consistently sized exit hole diameters). The cooling channels also include free ends disposed on the hook portion. The free ends (e.g., targets) couple to the inlet passages to receive the cooling fluid. The target features enable the inlet passages (e.g., forming feedholes) to intersect the channels, thereby improving cooling of the shroud segments. The inlet passages and the free ends (e.g, targets) are aligned and exit metering holes are electrical discharge machined such that the inlet passages may receive a cooling flow (e.g., air). As described in detail below, multiple cooling channels (e.g., a first channel, a second channel) may be disposed on the shroud segment. The inner shroud segment may include a shroud body having a leading edge and a trailing edge. The body has a first side edge and a second side edge. A pair of opposed lateral sides may be disposed between the leading edge and the trailing edge. The opposed lateral sides may be described as a first lateral side and a second lateral side. The first lateral side (e.g., a bottom side of shroud body) interfaces with a cavity defined by the inner shroud segment and the outer shroud segment. The outer shroud segment is coupled to the inner shroud segment. The second lateral side (e.g., outermost side of shroud body) may be configured to interface with a hot gas flow path (e.g., exhaust gases).
The first channel includes a first end portion and a second end portion, disposed adjacent the first side edge and adjacent the second side edge, respectively. The second channel is disposed within the shroud body and includes a third end portion and a fourth end portion. The third end portion and the fourth end portions are disposed adjacent the first side edge and adjacent the second side edge, respectively. The first and second channels receive a cooling fluid (e.g., air) from the cavity formed between the first lateral side and the second lateral side. The cooling fluid cools the shroud body and the space between adjacent shrouds as it flows through the cooling channels. Both the first end portion and the fourth end portion include a portion having a free end (e.g., target). The free end (e.g., target) may have a width in a direction from the leading edge to the training edge greater than an adjacent portion of the portion that is coupled to the free end. The end portions may include target features that enable the inlet passage to intersect the cooling channels to receive the cooling fluid, thereby improving cooling of the shroud segments.
Turning to the drawings,
As depicted, the inner turbine shroud segment 40 includes a body 42 having an upstream or leading edge 44 and a downstream or trailing edge 46 that both interface with a hot gas flow path 47. The body 42 also includes a first side edge 48 (e.g., first slash face) and a second side edge 50 (e.g., second slash face) disposed opposite the first side edge 48 both extending between the leading edge 44 and the trailing edge 46. The body 42 further includes a pair of opposed lateral sides 52, 54 extending between the leading and trailing edges 44, 46 and the first and second side edges 48, 50. In certain embodiments, the body 42 (particularly, lateral sides 52, 54) may be arcuate shaped in the circumferential direction 34 between the first and second side edges 48, 50 and/or in the axial direction 30 between the leading and trailing edges 44, 46. The lateral side 52 is configured to interface with a cavity 56 defined between the inner turbine shroud segment 36 and the outer turbine shroud segment 38. The lateral side 54 is configured to be oriented toward the hot gas flow path 47 within the turbine 18.
As described in greater detail below, the body 42 may include multiple channels (e.g., cooling channels or micro-channels) disposed within the lateral side 54 to help cool the hot gas flow path components (e.g., turbine shroud 40, inner turbine shroud segment 36, etc.). A pre-sintered preform (PSP) layer 58 may be disposed on (e.g., brazed onto) the lateral side 54 so that a first surface 60 of the PSP layer 58 together with the body 42 defines (e.g., enclose) the channels and a second surface 62 of the PSP layer 58 interfaces with the hot gas flow path 47. The PSP layer 58 may be formed of superalloys and brazing material. In certain embodiments, as an alternative to the PSP layer 58 a non-PSP metal sheet may be disposed on the lateral side 54 that together with the body 42 defines the channels. In certain embodiments, the channels may be cast entirely within the body 42 near the lateral side 54. In certain embodiments, as an alternative to the PSP layer 58, a barrier coating or thermal barrier coating bridging may be utilized to enclose the channels within the body 42.
In certain embodiments, the body 42 includes hook portions to enable coupling of the inner turbine shroud turbine segment 36 to the outer turbine shroud segment 38. As mentioned above, the lateral side 52 of the inner turbine shroud segment 36 and the outer turbine shroud segment 38 define the cavity 56. The outer turbine shroud segment 38 is generally proximate to a relatively cool fluid or air (i.e., cooler than the temperature in the hot gas flow path 47) in the turbine 18 from the compressor 24. The outer turbine shroud segment 38 includes a passage (not shown) to receive the cooling fluid or air from the compressor 24 that provides the cooling fluid to the cavity 56. As described in greater detail below, the cooling fluid flows to the channels within the body 42 of the inner turbine shroud segment 36 via inlet passages disposed within the body 42 extending from the lateral side 52 to the channels. Each channel includes a first end portion that includes a hook-shaped portion having a free end and a second end portion. The second end portion may include a metering feature (e.g., a portion of the body 42 extending into the channel) to regulate flow of the cooling fluid within the channel or to reduce blockage of the channel. In certain embodiments, each channel itself (excluding the second end portion) acts as a metering feature (e.g., includes a portion of the body 42 extending into the channel). In other embodiments, inlet passages coupled to the hook-shaped portion may include a metering feature (e.g., portion of the body 42 extending into the inlet passage). In certain embodiments, the channel itself, the second end portion, or the inlet passage, or a combination thereof includes a metering feature. In addition, the cooling fluid exits the channels (and the body 42) via the second end portions at the first side edge 48 and/or the second side edge 50. In certain embodiments, the channels may be arranged in an alternating pattern with a channel having the first end portion disposed adjacent the first side edge 48 and the second end portion disposed adjacent the second side edge 50, while an adjacent channel has the opposite orientation (i.e., the first end portion disposed adjacent the second side edge 50 and the second end portion disposed adjacent the first side edge 48). The hook-shaped portions of the channels provide a larger cooling region (e.g., larger than typical cooling systems for turbine shrouds) by increasing a length of cooling channel adjacent the slash faces while keeping flow at a minimum. In addition, the hook-shaped portion enables better spacing of the straight portions of the channels. The shape of the channels is also optimized to provide adequate cooling in the event of plugged channels. The disclosed embodiments of the inner turbine shroud segment may enable cooling of the inner turbine shroud segment with less air (e.g., than typical cooling systems for turbine shrouds) resulting in reduced costs associated with regards to chargeable air utilized in cooling.
As depicted, some of the channels 74 (e.g., channel 86) include the hook-shaped portion 78 of the first end portion 76 disposed adjacent the side edge 50 and the second end portion 82 disposed adjacent the side edge 48, while some of the channels 74 (e.g., channel 88) include the hook-shaped portion 78 of the first end portion 76 disposed adjacent the side edge 48 and the second end portion 82 disposed adjacent the side edge 50. In certain embodiments, the channels 74 are disposed in an alternating pattern (e.g., channels 86, 88) with one channel 74 having the hook-shaped portion 78 disposed adjacent one side edge 48 or 50 and the second end portion 82 (e.g., in certain embodiments having the metering feature) disposed adjacent the opposite side edge 48 or 50 with the adjacent channel 74 having the opposite orientation. As depicted, the channels 74 extend between the side edges 48, 50 from adjacent the leading edge 44 to adjacent the trailing edge 46. In certain embodiments, the channels 74 may extend between the side edges 48, 50 covering approximately 50 to 90 percent, 50 to 70 percent, 70 to 90 percent, and all subranges therein, of a length 90 of the body 42 between the leading edge 44 and trailing edge 46. For example, the channels 74 may extend between the side edges 48, 50 covering approximately 50, 55, 60, 65, 70, 75, 80, 85, or 90 percent of the length 90. This enables cooling along both of the side edges 48, 50 as well as cooling across a substantial portion of the body 42 (in particular, the lateral side 54 that is oriented toward the hot gas flow path 47) between both the leading edge 44 and the trailing edge 46 and the side edges 48, 50.
The shroud 42 may include multiple cooling channels 74. For example, the illustrated embodiment depicts a first channel 86 and a second channel 88. The first channel 86 includes a first end portion 76 and a second end portion 82. The first end portion 76 may be disposed adjacent the first side edge 48, and the second end portion 82 is disposed adjacent the second side edge 50. The second channel 88 is disposed within the shroud body 42 and includes a third end portion and a fourth end portion. The third end portion is disposed adjacent the first side edge 48, and the fourth end portion is disposed adjacent the second side edge 50. Though the discussion herein describes two cooling channels 74, the shroud body 42 may include 2 to 100, 5 to 50, or 10 to 30 cooling channels and all subranges therebetween.
The first 86 and second 88 channels are configured to receive a cooling fluid (e.g., air) from the cavity to cool the body 42. The first end portion 76 and the fourth end portion 85 each comprises a hook-shaped portion 78 having a free end 80, and each free end has width in a direction from the leading edge 42 to the trailing edge 44 greater than an adjacent portion of the hook-shaped portion 78 coupled to the free end 80. In some embodiments, the hook-shaped portion 78 may have a radius of approximately 0.05 to 4 mm, 0.1 to 3 millimeters (mm), 1.14 to 2.5 mm, and all subranges therebetween. In some embodiments, the hook-shaped portion comprises a depth of approximately 0.05 to 4 mm, 0.1 to 3 mm, 1.27 to 2.5 mm, and all subranges therebetween. The depth of the hook-shaped portion may be less than, greater than, or approximately equal to the radius of the hook-shaped portion 78.
Though the cooling channels 74 described herein are described as having a hook-shaped end portion, the discussion herein is not intended to limit the geometry of the end portions of cooling channels. For example, the cooling channels may utilize any other suitable geometries at the end portions, including a spherical end portion, a rectangular square end portion, an ovular end portion, an elliptical end portion, a square end portion, or any other suitable polygonal shape. The first and fourth end portions 76, 85 include a target portion (e.g., free ends) for the inlet passage to be aligned with. The cooling channel 74 may then be coupled to the target portion (e.g., free ends) to provide a cooling flow across the shroud body 42. The target portions (e.g., free ends) are manufactured to be approximately the same size. For example, the target portions may be approximately constant in diameter. Manufacturing the target portions to be the same size enables the cooling channels to remain substantially free from debris by preventing any one cooling channel from becoming blocked or clogged. The target portions also enable controlled pressure drop and flow of the cooling fluid (e.g., air) through the cooling channels.
The end portion 80 may be elliptical (e.g., circular, oval, etc.) in shape. A substantially straight portion may be disposed adjacent (e.g., immediately downstream) to the free end 80. As described above, the hook-shaped portion 78 may have a radius 91 of approximately 0.05 to 4 mm, 0.1 to 3 mm, 1.14 to 2.5 mm, and all subranges therebetween. The hook-shaped portion 78 comprises a depth (represented by arrow 96) of approximately 0.05 to 4 mm, 0.1 to 3 mm, 1.27 to 2.5 mm, and all subranges therebetween. In some embodiments, the depth 96 of the hook-shaped portion 78 may be less than, greater than, or approximately equal to the radius 91 of the hook-shaped portion 78. It should be appreciated that though the above ranges relating to depth and radius 91 of the hook-shaped portion 78 are described, the ranges are not intended to be limited to the ranges described herein. As described above, the end portions 80 (e.g., hook-shaped portion 78) include target features that enable the inlet passage 94 to intersect the cooling channels 74 to receive the cooling fluid, thereby improving cooling of the shroud segment 36.
The free end 80 couples to a respective inlet passage 94 via the target (e.g., hook portion 78). The inlet passages 94 provide a cooling flow (e.g., cooling fluid, air) from the cavity to the cooling passages 74. In the illustrated embodiment, the width 95 of the straight portion adjacent the hook-shaped portion 78 is smaller than the width 81 of the hook-shaped portion 78. The width 95 of the adjacent portion is shown on a first straight portion 97. The first straight portion 97 is disposed adjacent to a first curved portion 99. The first curved portion 99 is disposed adjacent to a second straight portion 101. The second straight portion 101 is disposed adjacent to a second curved portion 103 that is disposed adjacent to a third straight portion 107. The second straight portion 107 is substantially perpendicular to the second straight portion 101. The first straight portion 97 and third straight portion 103 are substantially parallel to each other. The hook-shaped portion 78 has a portion (represented by arrow 96) that extends in a direction opposite direction 32 from a plane 87.
Technical effects of the disclosed embodiments include manufacturing multiple cooling channels to provide cooling flows (e.g., air) to the turbine blades to reduce the premature failure of blades and associated components. The cooling channels may be formed on an inner shroud segment and/or an outer shroud segment. The cooling channels and associated targets (e.g., free ends) may be formed by suitable techniques, such as electrical discharge machining. The cooling channels include free ends (e.g., targets) disposed on a hook-shaped portion. The free ends couple to the inlet passages to receive a cooling fluid from the cavity to cool the turbine shroud.
This written description uses examples to disclose the subject matter, including the best mode, and also to enable any person skilled in the art to practice the subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
