Patent Application
20170284222
The present invention is directed to turbine apparatuses, turbine nozzles, and turbine shrouds. More particularly, the present invention is directed to turbine apparatuses, turbine nozzles, and turbine shrouds including a redundant cooling configuration.
Gas turbines operate under extreme conditions. In order to drive efficiency higher, there have been continual developments to allow operation of gas turbines at ever higher temperatures. As the temperature of the hot gas path increases, the temperature of adjacent regions of the gas turbine necessarily increase in temperature due to thermal conduction from the hot gas path.
In order to allow higher temperature operation, some gas turbine components, such as nozzles and shrouds, have been divided such that the higher temperature regions (the fairings of the nozzles and the inner shrouds of the shrouds) may be formed from materials, such as ceramic matrix composites, which are especially suited to operation at extreme temperatures, whereas the lower temperature regions (the outside and inside walls of the nozzles and the outer shrouds of the shrouds) are made from other materials which are less suited for operation at the higher temperatures, but which may be more economical to produce and service.
Gas turbines typically operate for very long periods of time. Service intervals generally increase with time as turbines advance, but current turbines may have combustor service intervals (wherein combustion is halted so that the combustor components may be serviced, but the rotating sections are generally left in place) of 12,000 hours or more, and full service intervals (wherein all components are serviced) of 32,000 hours or more. Unscheduled service stops impose significant costs and reduce the gas turbine reliability and availability.
Incorporation of gas turbine components, such as nozzles and shrouds, which have high temperature regions and low temperature regions, may result in unscheduled service stops in the event where a high temperature portion fails (the high temperature portions being subjected to operating conditions which are more harsh than the operating conditions to which the low temperature portions are subjected), as the low temperature portions may be unable to survive in the turbine without the protection afforded by the failed high temperature portion until the next scheduled service interval.
In an exemplary embodiment, a turbine apparatus includes a first article and a second article. The first article includes at least one first article cooling channel. The second article is disposed between the first article and a hot gas path of a turbine, and includes at least one second article cooling channel. The at least one first article cooling channel is in fluid communication with and downstream from a cooling fluid source, and the at least one second article cooling channel is in fluid communication with and downstream from the at least one first article cooling channel.
In another exemplary embodiment, a method for redundant cooling of a turbine apparatus includes flowing a cooling fluid from a cooling fluid source through at least one first article cooling channel disposed in a first article, exhausting the cooling fluid from the at least one first article cooling channel into at least one second article cooling channel disposed in a second article, and flowing the cooling fluid through the at least one second article cooling channel. The second article is disposed between the first article and a hot gas path of a turbine.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.
Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts.
Provided are gas turbine apparatuses, such as turbine nozzles and turbine shrouds. Embodiments of the present disclosure, in comparison to apparatuses and methods not utilizing one or more features disclosed herein, decrease costs, increase efficiency, improve apparatus lifetime at elevated temperatures, decrease non-scheduled service outages, increase turbine service intervals, or a combination thereof.
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The first article 102 may include any suitable composition, including, but not limited to, a metallic composition. Suitable metallic compositions include, but are not limited to, a nickel-based alloy, a superalloy, a nickel-based superalloy, an iron-based alloy, a steel alloy, a stainless steel alloy, a cobalt-based alloy, a titanium alloy, or a combination thereof.
The second article 104 may include any suitable composition, including, but not limited to, a refractory metallic composition, a superalloy composition, a nickel-based superalloy composition, a cobalt-based superalloy composition, a ceramic matrix composite composition, or a combination thereof. The ceramic matrix composite composition may include, but is not limited to, a ceramic material, an aluminum oxide-fiber-reinforced aluminum oxide (Ox/Ox), carbon-fiber-reinforced carbon (C/C), carbon-fiber-reinforced silicon carbide (C/SiC), and silicon-carbide-fiber-reinforced silicon carbide (SiC/SiC).
In one embodiment, the second article 104 includes a thermal tolerance greater than a thermal tolerance of the first article 102. As used herein, “thermal tolerance” refers to the temperature at which material properties relevant to the operating of the turbine apparatus 100 are degraded to a degree beyond the useful material capability (or required capability).
The cooling fluid source 112 may be any suitable source, including, but not limited to, a turbine compressor (not shown) or an upstream turbine component (not shown). The cooling fluid source 112 may supply any suitable cooling fluid 114, including, but not limited to, air.
The first article cooling channel 106 and the second article cooling channel 108 may, independently, include any suitable cross-sectional conformation, including, but not limited to circular, elliptical, oval, triangular, quadrilateral, rectangular, square, pentagonal, irregular, or a combination thereof. The edges of the first article cooling channel 106 and the second article cooling channel 108 may, independently, be straight, curved, fluted, or a combination thereof. The first article cooling channel 106 and the second article cooling channel 108 may, independently, include turbulators 116, such as, but not limited to, pins (shown), pin banks, fins, bumps, and surface textures.
In one embodiment, the at least one first article cooling channel 106 includes a minimum first cooling fluid pressure and the at least one second article cooling channel 108 includes a second minimum cooling fluid pressure. Each of the first minimum cooling gas pressure and the second minimum cooling fluid pressure are greater than a hot gas path pressure of the hot gas path 110.
In another embodiment, the at least one second article cooling channel 108 includes a flow restrictor 118. The flow restrictor 118 restricts a flow of cooling fluid 114 through the at least one first article cooling channel 106.
In one embodiment, the at least one first article cooling channel 106 includes at least one exhaust port 120, the at least one second article cooling channel 108 includes at least one inlet 122, and the at least one exhaust port 120 is coupled to the at least one inlet 122. The flow restrictor 118 may include an inlet 122 having a narrower orifice that the exhaust port 120. The coupling of the at least one exhaust port 120 to the at least one inlet 122 may be a hermetic coupling or a non-hermetic coupling. In a further embodiment, a sealing member 124 is disposed between the at least one exhaust port 120 and the at least one inlet 122. The sealing member 124 may be any suitable seal, including, but not limited to, an elastic seal. As used herein, “elastic” refers to the property of being biased to return toward an original conformation (although not necessarily all of the way to the original conformation) following deformation, for example, by compression. Suitable elastic seals include, but are not limited to, w-seals (shown), v-seals, e-seals, c-seals, corrugated seals, spring-loaded seals, spring-loaded spline seals, spline seals, and combinations thereof.
In another embodiment, the at least one second article cooling channel 108 includes at least one outlet 126, the at least one first article 102 includes at least one recycling channel 128, and the at least one outlet 126 is coupled to the at least one recycling channel 128. The at least one recycling channel 128 may be in fluid communication with a downstream component 130.
In one embodiment, a method for redundant cooling of a turbine apparatus 100 includes flowing a cooling fluid 114 from the cooling fluid source 112 through the at least one first article cooling channel 106, exhausting the cooling fluid 114 from the at least one first article cooling channel 106 into the at least one second article cooling channel 108, and flowing the cooling fluid 114 through the at least one second article cooling channel 108. Exhausting the cooling fluid 114 may include exhausting the cooling fluid 114 from at least one exhaust port 120 of the at least one first article cooling channel 106 into the at least one inlet 122 of the at least one second article cooling channel 108.
In the event of a failure of the second article 104, flowing the cooling fluid through the at least one first article cooling channel 106 may provide sufficient cooling to maintain a surface 132 of the first article 102 proximal to the hot gas path 110 at a temperature within a thermal tolerance of the first article 102 under operating conditions of the turbine for a predetermined length of time. The predetermined length of time may be any suitable length of time, including, but not limited to, a combustor service interval or a full service interval of the turbine. Suitable combustor service intervals may be an interval of at least 10,000 hours, alternatively at least 12,000 hours, alternatively at least 16,000 hours. Suitable full service intervals may be an interval of at least 20,000 hours, alternatively at least 24,000 hours, alternatively at least 32,000 hours.
In another embodiment, the cooling fluid 114 is flowed from the at least one second article cooling channel 108 into at least one recycling channel 128. In a further embodiment, the cooling fluid 114 is flowed from the at least one recycling channel 128 to at least one downstream component 130. The flow of cooling fluid 114 may be used for any suitable purpose, including, but not limited to, cooling the at least one downstream component 130.
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While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
