CH708326A2 - Gas turbine shroud cooling. - Google Patents

Abstract

A shroud segment (130) for a housing of a gas turbine includes a body adapted for attachment to the housing proximate a localized critical process location (144) in the housing. The body has a leading edge (132), a trailing edge (134) and two side edges (136, 138). The critical process location (144) is between the leading edge (132) and the trailing edge (134) when the body is attached to the housing. A cooling channel (146, 148, 158, 160) is provided in the body along one of the side edges (136, 138) having an inlet (166, 154) or an outlet (152, 164) near the critical process location (144). Are defined. The cooling passage (146, 148, 158, 160) is sized large enough to cool the side edge (136, 138) adjacent the cooling passage (146, 148, 158, 160) to a desired level during operation of the gas turbine. The critical process locations (144) may be related to temperatures, pressures or other measurable characteristics related to the gas turbine during use.

Description

Field of the invention

The present invention is generally directed to the cooling of a turbine shroud element that may be disposed in a hot gas path of the turbine.

Background of the invention

Turbines are used extensively in a variety of aerospace, industrial and power generation applications to perform work. Each turbine generally includes alternating stages of circumferentially-mounted stator vanes and rotating blades. The stator vanes may be attached to a stationary component, e.g. a housing surrounding the turbine, and the rotating blades may be attached to a rotor disposed along an axial centerline of the turbine. A compressed working fluid, such as e.g. Steam, combustion gases or air flow along a gas path through the turbine to produce work. The stator vanes accelerate and direct the compressed working fluid to the subsequent stage of rotating blades to impart movement to the rotating blades to rotate and perform work. If some of the compressed working fluid is moving radially outward of the desired flow path, the efficiency of the turbine may decrease. As a result, the housing surrounding the turbine often includes radially inner shells of shrouds, which are often formed in segments. The shrouds surround and define the outer periphery of the hot gas path and may be disposed about both the stator vanes and the rotating blades.

The turbine shrouds are typically cooled in the same manner to remove heat transferred from the hot gas path. U.S. U.S. Patent 7,284,954 describes a turbine shroud segment that includes many small cooling fluid passages machined through the turbine shroud. A fluid, e.g. Compressed air from an upstream compressor may be supplied through the fluid channels for cooling the turbine shroud. Other shroud segments utilize only a larger cast «core» flow path, rather than the multiple smaller machine generated channels as above. The core extends along an entire side of the shroud segment from an axially upstream end to an axially downstream end.

Although both types of shroud segment cooling passages operate properly, further improvements in the system for cooling turbine shrouds would be welcome, particularly systems that improve the cooling fraction provided by a given stream and / or the axially selective targeted cooling along desired locations allows the shroud segments.

Brief description of the invention

Aspects and advantages of the invention will be set forth in the description which follows, or may be obvious from the description, or may be learned by practice of the invention.

[0006] According to certain aspects of the present disclosure, a shroud segment for a housing of a gas turbine may include a body adapted for attachment to the housing proximate a localized critical process location in the housing. The body has a leading edge, a trailing edge, and two side edges, and a first surface facing the housing and a second surface opposite a first surface facing a first gas surface. The critical process location is between the leading edge and the trailing edge when the body is attached to the housing. At least two cooling channels are defined in the body along one of the side edges. A first one of the cooling channels has an inlet and extends to an outlet, one of which adjoins the critical process location from the inlet or outlet. A second of the cooling channels has an inlet and extends to an outlet, one of which is adjacent to the critical process location from the inlet or outlet. The first and second cooling channels are sized large enough to cool the one side edge to a desired level during operation of the gas turbine. Various options and modifications are possible.

The first cooling channel of the shroud segment may have a first portion along the leading edge and a second portion along one side edge.

The second cooling channel of each shroud segment mentioned above may have a first portion along one side edge and a second portion along the trailing edge.

The shroud segment of each type mentioned above may further have at least two additional cooling channels along the other of the side edges, wherein the two additional cooling channels are substantially symmetrical to the at least two cooling channels with respect to a central plane extending between the leading edge and the trailing edge Body are.

The first cooling channel of each shroud segment mentioned above may have a second outlet adjacent to the critical process location along the other side edge.

The first cooling channel of each shroud segment mentioned above may have a first portion along the leading edge and a second portion along one side edge, a third portion along the leading edge, and a fourth portion along the other side edge.

The second cooling channel of each shroud segment mentioned above may have a second inlet adjacent to the critical process location along the other side edge.

The second cooling channel of each shroud segment mentioned above may have a first portion along one side edge and a second portion along the trailing edge, a third portion along the other side edge, and a fourth portion along the trailing edge.

The second cooling channel of each shroud segment mentioned above may include a plurality of outlets.

The body and the first and second cooling channels of each shroud segment mentioned above may be formed of cast metal.

In accordance with certain further aspects of the present disclosure, a gas turbine may include a compressor section, a combustion section downstream of the compressor section, and a turbine section downstream of the combustion section. The turbine section includes a housing defining a localized critical process location and a plurality of shroud segments attached circumferentially to the housing. Each shroud segment includes a body adapted for attachment to the housing. At least one of the bodies has a leading edge, a trailing edge and two side edges, and a first surface facing the housing and a second surface facing a hot gas path opposite the first surface. The critical process location is between the leading edge and the trailing edge when the body is attached to the housing. At least two cooling channels are defined in the body along one of the side edges. A first one of the cooling channels has an inlet and extends to an outlet with one of the inlet or the outlet adjacent to the critical process location. A second of the cooling channels has an inlet and extends to an outlet, with one of the inlet or the outlet adjacent to the critical process location. The first and second cooling channels are configured sufficiently large to cool the one side edge to a desired level during operation of the gas turbine. As above, various options and modifications are possible.

The first cooling channel of the gas turbine may have a first portion along the leading edge and a second portion along the one side edge.

The gas turbine of each type mentioned above may further have at least two additional cooling channels along the other of the side edges, the two additional cooling channels being substantially symmetrical with respect to the at least two cooling channels with respect to a central plane extending between the leading edge and the trailing edge Body are.

The gas turbine of each type mentioned above may further have at least two additional cooling channels along the other of the side edges, the two additional cooling channels being substantially symmetrical to the at least two cooling channels with respect to a central plane of the body extending between the leading edge and the trailing edge extends.

The first cooling passage of each gas turbine mentioned above may have a second outlet adjacent to the critical process location along the other side edge.

The first cooling passage of each gas turbine mentioned above may have a first portion along the leading edge and a second portion along one side edge, a third portion along the leading edge, and a fourth portion along the other side edge.

The second cooling passage of each gas turbine mentioned above may have a second inlet adjacent to the critical process location along the other side edge.

The second cooling passage of each gas turbine mentioned above may have a first portion along one side edge and a second portion along the trailing edge, a third portion along the other side edge, and a fourth portion along the trailing edge.

The second cooling channel of each shroud segment mentioned above may include a plurality of outlets.

The body and the first and second cooling channels of each gas turbine mentioned above may be formed of cast metal.

Those skilled in the art will recognize the features and aspects of such embodiments better after reviewing the specification.

Brief description of the drawings

A complete and basic disclosure of the present invention including its best mode for those skilled in the art will be described in more detail in the remainder of the specification with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of an exemplary gas turbine incorporating aspects of the present disclosure; FIG.

FIG. 2 is a simplified cross-sectional view of a portion of the gas turbine of FIG. 1 illustrating a shroud segment; FIG.

Fig. 3 is a plan view of a shroud segment as in Fig. 2;

FIG. 4 is a side view of the shroud segment of FIG. 3; FIG.

Fig. 5 is a sectional view of the shroud taken along line 5-5 in Fig. 3;

Fig. 6 is an isometric view of the shroud segment of Fig. 3;

Fig. 7 is a plan view of a first alternative shroud segment;

Fig. 8 is a plan view of a second alternative shroud segment; and

Fig. 9 is a plan view of a third alternative shroud segment.

Detailed description of the drawings

Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar terms in the drawings or the description have been used to designate the same or similar parts of the invention. As used herein, the terms "first", "second" and "third" may be used interchangeably to distinguish one component from another, and are not intended to indicate location or meaning of the individual components. In addition, the terms "upstream" and "downstream" refer to the relative location of components in a fluid flow path. For example, component A is upstream of component B as fluid flows from component A to component B. Conversely, component B is downstream of component A when component B receives a fluid flow from component A.

Each example is given in the context of an explanation of the invention and not a limitation of the invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield yet a further embodiment of the invention. Thus, the present invention is intended to include such modifications and variations as fall within the scope of the appended claims and their equivalents.

FIG. 1 is a schematic view of an exemplary gas turbine that may include a shroud element according to the present disclosure. FIG. As shown, the gas turbine 11Q includes an inlet section III, a compressor section 112, a combustion section 114, a turbine section 116, and an exhaust section 117. A shaft (rotor) 122 may be common to the compressor section 112 and the turbine section 116 and may further connect to a generator 105 to produce electricity.

Compressor area 112 may include an axial flow compressor in which a working fluid 100, such as, for example, is used. Ambient air enters the compressor from the inlet region III and passes through alternate stages 113 of stationary vanes and rotating blades (shown in FIG. 1). The compressor housing 118 encloses the working fluid 100 while the stationary vanes and rotating blades accelerate and deflect the working fluid to produce a continuous stream of compressed working fluid. Most of the compressed working fluid flows downstream through the combustion region 114 and then through the turbine region 116.

The combustion region 114 may include any type of combustor known in the art. A combustion chamber housing 115 may circumferentially surround part or all of the combustion region 114 to supply the compressed working fluid 100 from the compressor region 112 to a combustion chamber 119. Fuel 101 is also supplied to the combustion chamber 119. Possible fuels include, for example, one or more of blast furnace gas, coke oven gas, natural gas, vaporized liquid natural gas (LNG), hydrogen and propane. The compressed working fluid 100 mixes with the fuel 101 in the combustion chamber 119, where it burns to produce combustion gases of high temperature and pressure. The combustion gases then enter the turbine section 116.

As shown in FIGS. 1 and 2, alternating stages of rotating blades 124 and stationary vanes 126 are secured to rotor 122 and turbine shell 120, respectively, in turbine section 116. The working fluid 100, such as e.g. Steam, combustion gases or air, flows along a hot gas path through a turbine 110 from left to right as shown in FIG. 2. The first stage of stationary nozzles 126 accelerates and directs the working fluid 100 to the first stage of rotating blades 124, causing the first stage of rotating blades 124 and the rotor 122 to rotate. The working fluid 100 then flows over the second stage of stationary nozzles 126, which accelerate the working fluid and divert it to the next stage of rotating blades (see FIG. 1), and the process repeats for each successive stage.

As shown schematically in FIG. 1, the radially inner portion of the turbine housing 120 may include a series of shrouds 128. The shrouds 128 in FIG. 1 are formed around blades 124. FIG. 2 illustrates shrouds 128 formed about buckets 124 as well as vanes 126. The shrouds 128 may be formed in segments, such as those shown in FIG. as segment 130 of FIGS. 2-6. It should be understood that although an example of a shroud segment is illustrated with respect to a blade 124, the present disclosure also includes shroud segments formed around vanes 124. Therefore, there should be no limitation on the location of shrouds in the housing 120.

As shown in Figure 3, each shroud segment 130 may substantially comprise a body having multiple sides. In particular, each segment 130 has a leading edge 132, a trailing edge 134 and two side edges 136 and 138. A first surface 140 faces (radially outward) the housing 120 and a second surface 142 opposite the first surface is (radially inward) the hot gas path facing where the working fluid 100 flows.

A critical process site 144 (defined below) is located between the leading edge 132 and the trailing edge 134, substantially aligned with the rotating blades 124. For example, the critical processing station 144 could include a location of maximum or other critical temperature along the segment during gas turbine use, a location of maximum or other critical pressure along the segment during gas turbine use, a location of maximum or other critical gas heat transfer coefficient, or a location of maximum or other critical Be burden. The critical process station 144 could be a location where cooling gases can enter or exit the segment after passing through a channel to allow for sufficient cooling of the segment while accommodating rewind margin limitations.

Moreover, the critical process location need not be an absolute maximum, it could be any desired value that can be used to determine optimal flow and heat transfer characteristics in the gas turbine or in the segment itself. Much depends on the desired properties of the gas turbine flow at the location of the segment 130 and so forth. The critical process location along the segment 130 could vary at different stages in a gas turbine. Further, two or more such critical process locations could be present along only one element 130.

At least two cooling channels 146, 148 are defined in the segment 130 along one of the side edges 136. The first cooling channel 146 has an inlet 150 that may be on the first surface 140 (as shown) proximate the leading edge 132. The first cooling channel 146 also has an outlet 152 adjacent to the critical processing station 144. The second cooling channel 148 has an inlet 154 that may be located (as shown) on the first surface 140 adjacent to the critical processing station 144. The second cooling channel 148 has at least one outlet 156 that may be proximate the trailing edge 134 (as shown).

It should be understood that the flow through one or both of the channels 146, 148 may be the reverse of that shown. For example, the flow in the first channel 146 could be opposite (upstream) to that through the second channel 148. In other words, the flow could be from port 152 to port 150 (inversion of the inlet / outlet functions) if desired. The flow through the second channel 148 could also be similarly reversed.

The first and second cooling channels 146, 148 may be produced by casting rather than machining. For example, as is known, a mold could be used in which a filling substance is provided that matches the path of the first and second cooling channels 146, 148, the filling substance being burned out and / or chemically removed to subsequently supply the channels leave. Such manufacture using casting of at least a portion of the channels may be more cost effective than machining the channels or multiple smaller channels. Even if the channels are formed substantially by casting, inlets and outlets to the channels or other devices can be machined as part of the manufacture.

The first and second cooling channels 146, 148 may be made sufficiently large to cool the side edge 136 and / or an affected area to a desired level during operation of the gas turbine. The channel sizes are designed to allow sufficient current, to honor backflow reserves, and to allow heat transfer to cool the segment 130 to a desired temperature. If desired, in one example of a gas turbine, a segment 130 having a length of about 16.5 cm (about 6.5 inches), a width of about 7.6 cm (about 3.0 inches), and 0.25 inches in thickness, the channels 146, 148 have a cross-section of about 10.16 cm 2 (about 0.025 square inches). As a result, numerous small channels distributed along the locations of the cooling channels 146, 148 are not required for cooling the segment 130.

As shown, an additional set of cooling channels 158, 160 may be provided on another side edge 138. The channels 158, 160 may be, if desired, but not necessarily, substantially symmetrical with the channels 146, 148 along a central axis extending between the leading edge 132 and the trailing edge 134. As before, the first cooling channel 158 has an inlet 162 which may be located (as shown) on the first surface 140 near the leading edge 132. The first cooling passage 158 also has an outlet 164 adjacent to the critical processing station 144. The second cooling passage 160 has an inlet 166 which may be located (as shown) on the first surface 140 adjacent to the critical processing station 144. The second cooling channel 160 has at least one outlet 168 which may be located near the trailing edge 134 (as shown). As shown, the inlet 150 and the inlet 162 are a common single inlet. However, as discussed below, the inlets 150, 162 may be separate.

Various options and modifications are possible. For example, as shown in FIG. 3, the two second channels 148, 160 may have a plurality of outlets 156, 168, which may be along the trailing edge 134. Such multiple exits may be machined or cast and may be used to cool the trailing edge 134 when sufficiently spaced from the second channels 148, 160 to require additional cooling. Some or all of such multiple outlets could instead or even leave the exit segment 130 at locations other than the trailing edge 134, if desired.

Alternatively, as shown in Figure 7, the modified segment 130 has first channels 146, 158, each with its own individual inlet 150, 162 having first sections 170, 172 and second sections 174, 176 leading to outlets 152, 164 lead. As shown in FIG. 3, the first sections 170, 172 communicate with each other. If desired, some or all of the inlets in segment 130 or 130 could be located elsewhere than on the first surface 140.

As a further alternative, as shown in Fig. 8, the modified segment 130 has second channels 148, 160, each with individual inlets 154, 166 leading to first sections 178, 180 and second sections 182, 184 and then leading to the outlet (s) 156, 168. However, the second portions 182, 184 in Fig. 8 communicate with each other. Thus, instead of the structure shown in FIG. 3 having a first channel upstream from point 144 and two second channels downstream from point 144, a shroud segment as shown in FIG. 8 could have an upstream channel and a downstream channel along side edges 136, 138 at location 144.

Alternatively, as shown in FIG. 9, divisions may be provided at two or more critical process locations along the shroud segment. Along one side of the segment 130 '', a first channel 146 extends from the inlet 150 to the outlet 152, a second channel 148 extends from the inlet 154 to the outlet 153, and a third channel 179 extends from the inlet 155 to outlets 156 Similarly, along the other side, a first channel 155 extends from the inlet 162 to the outlet 164, a second channel 160 from the inlet 166 to the outlet 165, and a third channel 181 extends from the inlet 167 to outlets 168. Thus, FIG. that more than just a split between the leading edge 132 and the trailing edge 134 may be made at critical process locations, if desired. It should be understood that divisions need not be symmetric or even symmetrical along a given side of the segments or between sides of the segments.

The projecting segments may be secured to the turbine housing in various known ways by means of hooks, baffles, clamps, etc. The present invention is not limited to any such mounting arrangement, cooling mode, or any particular fluid used to cool the shroud segment. For example, such attachment may or may not provide for the cooling fluid to strike the segments first to create impingement cooling on the volume of the segment before fluid flows through the exposed channels. In addition, the segments may include attachment structures, cooling channel openings, etc., for receiving, contacting, or cooling the nozzles 126 when the segments are disposed along a series of nozzles as opposed to a series of blades 124.

It is believed that the various embodiments of the foregoing shroud segments can be made at a lower cost than previous designs. In particular, the segments may be cast or forged, requiring reduced machining for inlets and outlets, and molding the larger channels by casting. In this way, the shroud can easily be made to contain the desired fluid channels that provide cooling to the sides of the segment. By dividing the channels at critical process locations 144 where maximum temperature, pressure, or other measurable parameters (maximum or not) are present, cooling may be advantageously located at a desired point while providing a more efficient flow with less leakage. The segments can thus be tuned in various ways to improve the thermal and fluidic behavior.

This description uses examples to disclose the invention, including its best mode, and also to enable any person skilled in the art to practice the invention, including the making and use of all elements and systems and practice of all methods involved. The patentable scope of the invention is defined by the claims, and may include other examples that will be apparent to those skilled in the art. Such other examples are intended to be within the scope of the invention 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 languages of the claims.

A shroud segment for a housing of a gas turbine includes a body adapted for attachment to the housing proximate a localized critical process location in the housing. The body has a leading edge, a trailing edge and two side edges. The critical process location is between the leading edge and the trailing edge when the body is attached to the housing. A cooling channel is defined in the body along one of the side edges with an inlet or outlet near the critical process location. The cooling channel is sized large enough to cool the side edge adjacent the cooling channel to a desired level during operation of the gas turbine. The critical process locations may be related to temperatures, pressures or other measurable characteristics related to the gas turbine during use.

Claims (10)

1. shroud segment for a housing of a gas turbine, comprising: a body adapted for attachment to the housing proximate a localized critical process location in the housing, the body having a leading edge, a trailing edge and two side edges, the body having a first surface facing the housing and an opposite surface facing the first surface Hot gas path facing second surface has, while the critical process location between the leading edge and the trailing edge is when the body is attached to the housing; and at least two in the body relative to a cooling channel defined by the side edges of which a first one of the cooling channels has an inlet and extends to an outlet, one adjacent to the critical process location from the inlet or outlet, a second one of the cooling channels has an inlet and extends to an outlet adjacent one of the inlet or outlet to the critical process location, wherein the first and second cooling channels are sized sufficiently large to cool the one side edge to a desired level during operation of the gas turbine. The shroud segment of claim 1, wherein the first cooling channel has a first portion along the leading edge and a second portion along the one side edge; and / or wherein the second cooling channel has a first portion along the one side edge and a second portion along the trailing edge. The shroud segment of claim 1, further including at least two additional cooling channels along the other of the side edges, wherein the two additional cooling channels are substantially symmetrical to the at least two cooling channels with respect to a central plane of the body extending between the leading edge and the trailing edge , The shroud segment of claim 1, wherein the first cooling channel has a second outlet adjacent to the critical process location along the other side edge; and / or wherein the first cooling channel includes a first portion along the leading edge and a second portion along one side edge, a third portion along the leading edge, and a fourth portion along the other side edge. The shroud segment of claim 1, wherein the second cooling channel has a second inlet adjacent to the critical process location along the other side edge. The shroud segment of claim 1, wherein the second cooling channel includes first portion along one side edge and a second portion along the trailing edge, a third portion along the other side edge, and a fourth portion along the trailing edge. 7. shroud segment according to claim 1, wherein the second cooling channel includes a plurality of outlets. 8. shroud segment according to claim 1, wherein the first and second cooling channel are formed of cast metal. 9. A gas turbine, comprising: a compressor section; a combustion region downstream of the compressor region; and a turbine region downstream of the combustion region, the turbine region including a housing defining a localized critical process location and a plurality of shroud segments circumferentially secured to the housing, each shroud segment including: a body adapted for attachment to the housing, at least one of the bodies having a leading edge, a trailing edge and two side edges, the body having a first surface facing the housing and a second surface facing a hot gas path opposite the first surface, the critical one Process location between the leading edge and the trailing edge is located when the body is attached to the housing; and at least two in the body relative to a cooling channel defined by the side edges of which a first one of the cooling channels has an inlet and extends to an outlet, one adjacent to the critical process location from the inlet or the outlet, a second one of the cooling channels Inlet and extending to an outlet, one of the inlet or the outlet adjacent to the critical process location, wherein the first and the second cooling channel are designed sufficiently large to cool the one side edge to a desired level during operation of the gas turbine. 10. The gas turbine of claim 9, wherein the first cooling channel has a first portion along the leading edge and a second portion along the one side edge; and / or wherein the second cooling channel has a first portion along the one side edge and a second portion along the trailing edge.