The present invention relates generally to an article containing internal cooling channels located near at least one surface; and, more particularly, to a gas turbine component such as a nozzle, bucket or shroud that contains at least one closed cooling channel disposed within a portion of a first layer and a portion of a second layer, wherein the second layer may contain at least one of the component surfaces.
In a gas turbine, pressurized air is mixed with fuel and ignited to generate hot pressurized gases. The hot pressurized gases pass through successive turbine stages that convert the thermal and kinetic energy from the hot pressurized gases to mechanical torque acting on a rotating shaft or other element, thereby producing power used for both compressing the incoming air and driving an external load, such as an electric generator. As used herein, the term “gas turbine” may encompass stationary or mobile turbomachines, and may have any suitable arrangement that causes rotation of one or more shafts.
The components exposed to the hot pressurized gases; particularly, the nozzles, buckets and shrouds; typically contain a plurality of internal channels through which a pressurized fluid, such as compressed air, is caused to flow for the purpose of cooling the component base material. The cooling fluid may be redirected to other portions of the turbine or may exit to the flow of hot pressurized gases through one or more of the component surfaces.
It is often advantageous to form the surfaces and near surface portions of the nozzles, buckets and shrouds from different materials than the base material, in order to insulate the base material from the hot pressurized gases and protect the base material from environmental degradation. These materials may be applied to the base material by a coating method, or may be mechanically attached or metallurgically bonded to the base material.
It is further advantageous to provide additional cooling to the near surface portions of the nozzles, buckets and shrouds to improve the heat transfer qualities of these components; notwithstanding the insulating and protective qualities of the materials used to form the surface and near surface portions. Furthermore, gas turbine nozzles, buckets and shrouds are typically formed by casting methods that use cores to define the internal cooling channels, which limits the extent to which a cooling channel can be located in proximity to a base material surface of the cast component because the cores may move during the casting process.
In view of the above, there is a desire for producing internal channels located within the near surface portions of gas turbine components such as nozzles, buckets and shrouds that may be formed from a plurality of materials.
Embodiments of the present invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather, these embodiments are intended only to provide a brief summary of possible forms of the invention. Furthermore, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below, commensurate with the scope of the claims.
According to a first embodiment of the present invention, a gas turbine system includes at least one compressor, at least one combustor, and at least one turbine; wherein the at least one turbine includes at least one component having a base material; a first layer bonded to the base material and including a first inner surface, a first outer surface, and at least one first channel disposed within a portion of the first layer and being open at the first outer surface; and a second layer bonded to the first layer and including a second inner surface, a second outer surface, and at least one second channel disposed within the second layer, and being open at the second inner surface and fluidically connected with the at least one first channel, thereby forming at least one closed cooling channel disposed within a portion of the first layer and a portion of the second layer.
According to a second embodiment of the present invention, a gas turbine component includes a base material; a first layer bonded to the base material and including a first inner surface, a first outer surface, and at least one first channel disposed within a portion of the first layer and being open at the first outer surface; and a second layer bonded to the first layer and including a second inner surface, a second outer surface, and at least one second channel disposed within the second layer, and being open at the second inner surface and fluidically connected with the at least one first channel, thereby forming at least one closed cooling channel disposed within a portion of the first layer and a portion of the second layer.
According to a third embodiment of the present invention, a gas turbine component includes a base material; a first layer bonded to the base material and including a first inner surface, a first outer surface, and at least one first channel disposed within a portion of the first layer and being open at the first outer surface; and a second layer bonded to the first layer and including a second inner surface, a second outer surface, and at least one second channel disposed within the second layer, and being open at the second inner surface and fluidically connected with the at least one first channel, thereby forming at least one closed cooling channel disposed within a portion of the first layer and a portion of the second layer; which is obtainable by preparing the first layer, applying the second layer to the first outer surface, forming the at least one first channel and the at least one second channel by directionally removing material beginning at the first inner surface and progressing toward the first outer surface and the second inner surface, and bonding the first layer to the base material.
According to a fourth embodiment of the present invention, a method for preparing a gas turbine component includes the steps of preparing a first layer comprising a first inner surface and a first outer surface; applying a second layer comprising a second inner surface and a second outer surface to the first outer surface; forming at least one first channel in the first layer and at least one second channel in the second layer by directionally removing material beginning at the first inner surface and progressing toward the first outer surface and the second inner surface, thereby forming at least one closed cooling channel disposed within a portion of the first layer and a portion of the second layer; and bonding the first layer to a base material.
These and other features, aspects and advantages of the present invention may become better understood when the following detailed description is read with reference to the accompanying figures (FIGS), wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
Specific embodiments of the present invention are described below. This written description, when read with reference to the accompanying figures, provides sufficient detail to enable a person having ordinary skill in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. However, in an effort to provide a concise description of these embodiments, every feature of an actual implementation may not be described in the specification, and embodiments of the present invention may be employed in combination or embodied in alternate forms and should not be construed as limited to only the embodiments set forth herein. The scope of the invention is, therefore, indicated and limited only by the claims, and may include other embodiments that may occur to those skilled in the art.
The terminology used herein is for describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.
Similarly, the terms “comprises”, “comprising”, “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any, and all, combinations of one or more of the associated listed items.
Certain terminology may be used herein for the convenience of the reader only and is not to be taken as a limitation on the scope of the invention. For example, words such as “upper”, “lower”, “left”, “right”, “front”, “rear”, “top”, “bottom”, “horizontal”, “vertical”, “upstream”, “downstream”, “fore”, “aft”, and the like, when used without further limitation, merely describe the specific configuration illustrated in the various views. Similarly, the terms “first”, “second”, “primary”, “secondary”, and the like, when used without further limitation, are only used to distinguish one element from another and do not limit the elements described.
Referring now to the figures (FIGS), wherein like reference numerals refer to like parts throughout the various views unless otherwise specified,
The rotating turbine stage 70 includes a plurality of circumferentially adjacent buckets 120 that are connected to and radially disposed about the rotating disk 75 (
The shroud 140 includes a base material 200, a first layer 205 including a first inner surface 210 and a first outer surface 215, and a second layer 220 including a second inner surface 225 and a second outer surface 230, wherein the second outer surface may form a portion of at least one surface of the shroud that may be in contact with the hot pressurized gases 35 during operation. At least one channel 235 is disposed within a portion of the first layer and a portion of the second layer, which is closed to the second outer surface 230 and has a sufficient cross-sectional area to allow a cooling fluid, such as pressurized air from the compressor 15 (
The closed cooling channel 235 may have the form of a rectangular cross-section, as shown in
The base material 200 may be formed from any suitable material or combination of materials having the strength, ductility and other properties required for the component. Nonlimiting examples include nickel-based superalloys such as Rene N5, GTD-111, and Inconel 738; cobalt- and iron-based superalloys, steel alloys, ceramics, and metallic or ceramic composites; which may be formed by any suitable method such as casting, forging, pressing, or machining.
The first layer 205 may be formed from any suitable material or combination of materials having the mechanical, thermal and environmental characteristics required for the component; and is preferably a pre-sintered preform (PSP) material formed from a mixture of a high melting alloy powder and a low melting alloy powder. Nonlimiting examples of high melting powders include structural alloys and environmental coatings such as Inconel 738, Rene 142, Mar-M247, and GT-33. Nonlimiting examples of low melting powders include braze alloys such as D15, DF4B, BNi-9, BNi-5, and B93. The proportion of low melting powder may range from about 5% to about 95% by weight, and may transition from a higher proportion of low melting powder near the first inner surface 210 to a lower proportion of low melting powder near the first outer surface 215. The thickness of the first layer may range from about 0.005 inch (0.125 mm) to about 0.5 inch (12.7 mm), but is preferably between about 0.01 inch (0.25 mm) to about 0.02 inch (0.5 mm). The first layer 205 may be formed as a flat sheet or contoured into any suitable geometry, including but not limited to the shape of the base material 200, using any suitable method.
The second layer 220 may be formed from any suitable material or combination of materials having the mechanical, thermal and environmental characteristics required for the component. Nonlimiting examples include PtAl, NiCrAlY (e.g. GT-33), and Yttria-Stabilized Zirconia (YSZ); which may be deposited onto the first layer using a thermal spray method such as Air Plasma Spray (APS), Vacuum Plasma Spray (VPS), or High Velocity Oxy-Fuel (HVOF); Physical Vapor Deposition (PVD), or a slurry method. The thickness of the second layer may be up to about 0.1 inch (2.5 mm), and is preferably about 0.01 inch (0.25 mm) to about 0.05 inch (1.3 mm).
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As described above, the present invention contemplates a gas turbine component such as a nozzle, bucket or shroud containing at least one closed cooling channel disposed within a portion of a first layer and a portion of a second layer, wherein the second layer may contain at least one of the component surfaces. The present invention also contemplates a method of forming a portion of at least one surface of a gas turbine component, wherein at least one closed cooling channel is located near the component surface.
Although specific embodiments are illustrated and described herein, including the best mode, those of ordinary skill in the art will appreciate that all additions, deletions and modifications to the embodiments as disclosed herein and which fall within the meaning and scope of the claims may be substituted for the specific embodiments shown. Similarly, other embodiments of the invention may be devised which do not depart from the spirit or scope of the present invention. Such other embodiments 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 languages of the claims. Likewise, the system components illustrated are not limited to the specific embodiments described herein, but rather, system components can be utilized independently and separately from other components described herein. For example, the components and assemblies described herein may be employed in any suitable type of gas turbine, aircraft engine, or other turbomachine having any suitable number and arrangement of stages, disks and shafts while still falling within the meaning and scope of the claims.
Number | Date | Country | |
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Parent | 13777019 | Feb 2013 | US |
Child | 15066119 | US |