JP2014139428A - Method of making surface cooling channels on component using lithographic molding techniques - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming cooling channels in hot gas path components that eliminates the need for post-casting machining operation.SOLUTION: The invention provides a method of casting a component including one or more surface cooling channels. The method includes casting a ceramic core into a flexible mold of a core section, and casting a ceramic shell in at least two sections into respective flexible molds of a first shell section and a second shell section. A ceramic casting vessel is subsequently formed by assembling the ceramic core within the ceramic shell sections. A metal substrate material is cast into the ceramic casting vessel. Removal of the ceramic casting vessel reveals a substrate of the component having defined therein an interior passageway, one or more cooling passages in fluidic communication with the interior passageway, and one or more surface grooves in fluidic communication with the one or more cooling passages.

Description

  The subject matter disclosed herein generally relates to turbine systems, such as gas turbine systems, and more particularly to micro-channel cooling therein.

  In a gas turbine engine, air is compressed in a compressor and mixed with fuel in a combustor to produce hot combustion gases. Energy is extracted from this gas in a high pressure turbine (HPT), which provides power to the compressor, and in a low pressure turbine (LPT), it provides power to the fan in turbofan aircraft engine applications, and in marine and industrial Applications provide power to the external shaft.

  During operation of a gas turbine engine, the temperature of the combustion gas may exceed 3000 ° F., which is significantly higher than the melting temperature of the metal part of the engine that contacts such gas. The operation of such engines at gas temperatures above the melting temperature of the metal part is a well established field and depends in part on supplying cooling air to the outer surface of the metal part by various methods. ing. The metal parts of such engines that are particularly susceptible to high temperatures and require special attention regarding the cooling action are the metal parts forming the combustor and the components located in the tail of the combustor.

  The efficiency of the engine increases with the temperature of the combustion gas. However, since the combustion gases heat various components along their flow paths, it is necessary to cool them to achieve a long engine life. Typically, the hot gas path components are cooled by extracting air from the compressor. Such a cooling process reduces engine efficiency because the extracted air is not used in the combustion process.

  Techniques for cooling gas turbine engines have been developed and include various patents relating to various aspects of cooling circuits and mechanisms in various hot gas path components. For example, combustors include radially outer and inner liners that require cooling during operation. The turbine nozzle includes a hollow vane supported between an outer band and an inner band, which also needs to be cooled. Turbine rotor blades are hollow and typically contain a cooling circuit, which is surrounded by a turbine shroud, which also needs to be cooled. Hot combustion gases are exhausted from the exhaust pipe, which may also be lined and suitably cooled.

  In all such example gas turbine engine components, thin metal walls of high strength superalloy are typically used to increase durability while minimizing the need to cool it. To do. Various cooling circuits and mechanisms are adapted to such individual components in each corresponding environment within the engine. For example, a series of internal cooling paths or serpentine paths may be formed in the hot gas path components. Cooling fluid is supplied from the plenum to the serpentine path, and the cooling fluid can flow through this path to cool the substrate and coating of the hot gas path components. However, such cooling methods typically have relatively low thermal conductivities and non-uniform component temperature profiles.

  The use of micro-channel cooling technology can significantly reduce the cooling requirements. Micro-channel cooling reduces the temperature difference between the hot and cold sides of the load-carrying substrate material for a given thermal conductivity by installing a cooling device as close as possible to the heating zone. However, current techniques for forming micro-channels typically require the use of machining operations after casting to form the micro-channels and coolant feed holes. Machining operations after casting are potentially accompanied by a destructive process and typically require a long time.

  Accordingly, it would be desirable to provide a method for forming a cooling channel in a hot gas path component that eliminates the need for post-cast machining operations.

US Patent Application Publication No. 2011/0135262

  In one embodiment, a method for casting a component that includes one or more surface cooling channels is disclosed. The method includes casting a ceramic core from a flexible mold of one or more core portions, and, in at least two portions, a first outer shell portion and a second outer shell portion capable of each. Casting a ceramic shell in a flexible mold. Next, a ceramic casting container is formed by assembling the ceramic core in the ceramic shell. A metal substrate material is cast into a ceramic casting vessel. Thereafter, the ceramic casting container is removed. By removing the ceramic casting vessel, an internal passage, one or more cooling passages in fluid communication with the internal passage, and one or more surface grooves in fluid communication with the one or more cooling passages are provided. The component substrate defined therein is exposed.

  In another embodiment, a method of casting a component that includes one or more surface cooling channels is disclosed. The method provides a particular model of a desired ceramic casting vessel, wherein the casting vessel defines a component geometry and includes an internal passage and one or more cooling fluids in fluid communication with the internal passage. Including a channel and one or more surface grooves in fluid communication with the one or more cooling channels. This model is digitally divided into a plurality of parts, each of which is converted into a mold, where the plurality of parts include one or more precision metal inserts to create an internal passageway, 1 The component geometry, including one or more cooling channels and one or more surface grooves, and one or more alignment features are defined. A flexible mold is then cast from each mold. A ceramic core is cast from each flexible mold. In at least two parts, a ceramic outer shell is cast from each flexible mold. A ceramic casting vessel is formed by assembling a ceramic core in a ceramic shell. Next, the metal is cast into a ceramic casting vessel. The ceramic casting vessel is subsequently removed to provide an inner passage, one or more cooling passages in fluid communication with the inner passage, and one or more surfaces in fluid communication with the one or more cooling passages. The substrate of the component having a groove is exposed.

  In yet another embodiment, a method for casting a component that includes one or more surface cooling channels is disclosed. The method provides a particular model of a desired ceramic casting vessel, wherein the casting vessel defines a component geometry and includes an internal passage and one or more cooling fluids in fluid communication with the internal passage. Including a channel, one or more surface grooves in fluid communication with the one or more cooling channels, and digitally dividing the model into a plurality of portions. The plurality of portions define one or more core portions and at least two outer shell portions. Each of the plurality of portions is then converted into a mold. One or more precision metal inserts are disposed in one or more of the plurality of portions to provide an internal passage, one or more cooling channels, one or more surface grooves, and one Or defining a component geometry including a plurality of alignment features. Next, a flexible mold is cast from each mold. Each flexible mold is assembled to define a cavity therebetween. A ceramic core is cast from each flexible mold and a ceramic shell is cast from each flexible mold in at least two parts. A ceramic casting vessel is formed by assembling a ceramic core within a ceramic shell portion utilizing one or more alignment mechanisms. The metal is then cast into a ceramic casting vessel. The ceramic casting vessel is then removed to provide an internal passage, one or more cooling passages in fluid communication with the internal passage, and one or more surface grooves in fluid communication with the one or more cooling passages. The substrate of the component having Finally, a coating is disposed on at least a portion of the surface of the substrate, and the one or more surface grooves and coating cool the component by defining one or more surface cooling channels.

  These and additional features provided by the embodiments discussed herein will be more fully understood in view of the following detailed description in conjunction with the drawings.

  The embodiments described in the drawings are exemplary, exemplary in nature, and are not intended to be limited to the embodiments defined by the claims. The following detailed description of exemplary embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

1 is a schematic diagram of a gas turbine system including components with surface cooling channels according to one or more embodiments shown or described herein. FIG. 1 is a schematic cross-sectional view of an example airfoil configuration that includes a surface cooling channel in accordance with one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional view of one step in a method of making a component that includes a surface cooling channel, according to one or more embodiments shown or described herein. FIG. 6 is a flow chart depicting one implementation of a method of creating a component that includes a surface cooling channel according to one or more embodiments shown or described herein.

  One or more specific embodiments of the present disclosure are described below. In an attempt to achieve a concise description of such an embodiment, not all functions of the actual implementation may be described in the specification. In the development of any such actual implementation in any engineering or design project, a number of to achieve this developer's specific objectives, for example, to comply with system-related and commercial-related constraints It should be understood that implementation specific decisions need to be made and this may vary from implementation to implementation. Further, although such development efforts are complex and time consuming, it is nevertheless understood that it is routine to undertake design, fabrication and manufacture for those skilled in the art having the benefit of this disclosure. .

  In addressing elements of various embodiments of the present disclosure, the articles “a”, “an”, “the” and “above” are intended to mean that there are one or more elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the elements described.

  Methods are disclosed for making surface cooling channels in high performance products made from metals, ceramics, polymers and / or composite systems, such as airfoils. This method makes it possible to produce an airfoil design with improved cooling characteristics, which eliminates the need to machine the surface cooling channel after casting. In one embodiment, the coolant outlet mechanism may be placed in the applied coating after placing the coating, or oriented so that the surface cooling channel exits away from the edge of this portion. Sometimes it is done.

  This fabrication method utilizes a novel forming or casting process based on the use of lithography and lithographic machining techniques to create a three-dimensional model of the finished airfoil. The method is described in more detail herein.

  FIG. 1 is a schematic diagram of a gas turbine system 10. The system 10 can include one or more compressors 12, a combustor 14, a turbine 16, and a fuel nozzle 20. The compressor 12 and the turbine 16 may be coupled to one or more shafts 18. The shaft 18 may be a single shaft or may be formed by combining a plurality of shaft portions together.

  The gas turbine system 10 may include several hot gas path components. The hot gas path component is an optional component of the system 10 that is at least partially exposed to the hot gas flow through the system 10. For example, blade assemblies (also known as blades or blade assemblies), nozzle assemblies (also known as vanes or vane assemblies), shroud assemblies, transition parts, retaining rings and compression All machine exhaust components are hot gas path components. However, it should be understood that the hot gas path components of the present disclosure are not limited to the above examples and may be any components that are at least partially exposed to the hot gas stream. Further, the hot gas path components of the present disclosure are not limited to components in the gas turbine system 10, but may be any machine or any component of that component that may be exposed to high temperature flows. Please understand that this is possible.

  As the hot gas path component is exposed to the hot gas stream, the hot gas path component may be heated by the hot gas stream and reach a temperature at which the hot gas path component fails. Accordingly, there is a need for a system that cools the hot gas path components to allow the system 10 to operate with a hot gas stream even at high temperatures and increase the efficiency and performance of the system 10.

  In general, the cooling system of the present disclosure includes a series of small cooling channels, or microchannels, that are formed on the surface of a hot gas path component. The hot gas path component can include one or more grooves and a coating that fills these grooves to form a microchannel. A cooling fluid may be supplied from the plenum to the microchannel, and the cooling fluid may flow through the microchannel to cool the coating and the substrate.

  Referring now to FIG. 2, an example of a hot gas component 30 having an airfoil configuration is shown. As noted, the component 30 comprises a substrate 32 with an outer surface 34 and an inner surface 36. The inner surface 36 of the substrate 32 defines at least one hollow interior space 38. In an alternative embodiment, instead of a hollow interior space, the hot gas component 30 may include a supply cavity. The outer surface 34 of the substrate 32 defines a number of surface cooling channels 40. Each surface cooling channel 40 extends at least partially along the outer surface 34 of the substrate 32 and is in fluid communication with at least one hollow interior space 38 via one or more cooling passages 41. A coating 42 is disposed over at least a portion of the outer surface 34 of the substrate 32, and more specifically, over one or more grooves 44 formed in the outer surface 34 of the substrate 32, and the grooves In combination with the coating 42, the surface cooling channel 40 is formed. In one embodiment, the hot gas component 30 may include a plurality of coatings 42, and the surface cooling channel 40 may be in the substrate 32 or in part in the substrate 32 and in one or more coatings 42. Sometimes formed.

  As described below, the methods disclosed herein include lithography and lithographic machining techniques to provide a three-dimensional model of an airfoil that includes completed components, and more particularly, a plurality of surface cooling channels. To produce. Initially, a digital model of a component such as an airfoil is formed using a computerized design system, the use of which is well known in the art. The digital model is then divided into parts for casting. A plurality of castings are finally assembled into a casting vessel in which the alloy is cast. The final removal of the casting vessel reveals a coolable structure having an internal passage, one or more cooling passages in fluid communication with the internal passage, and one or more open surface cooling channels. . This method eliminates the need for machining after casting to form a surface cooling channel with open components.

  As pointed out above, an example embodiment made by the method disclosed herein is the creation of a gas turbine airfoil, which is an internal hollow fluid in fluid communication with a plurality of surface cooling channels. Includes a passage.

  Referring to FIGS. 3-16 in more detail, several steps in the method of making the component 30 are disclosed. More particularly, several steps in a method for manufacturing a ceramic core 52 and a ceramic outer shell 54 of a ceramic casting container 56 are disclosed, the container having a component 30 therein. A plurality of internal passages, one or more cooling paths, and one or more surface cooling channels.

  As noted, the method includes forming one or more surface channels, or grooves 44, in the outer surface 34 of the hot gas component 30 so as to be in fluid communication with the internal passage 38 (most in FIG. 2). Well-provided). In the illustrated example, a plurality of grooves 44 are formed in the outer surface 34. Each of the grooves 44 extends at least partially along the surface 34 of the component 30. In one embodiment, for example, as shown in FIG. 3, a model 50 of a desired ceramic casting vessel 56 is first provided, which defines a component 30 and includes a plurality of inserts (described below). To define an internal passage 38 (FIG. 2), one or more cooling passages 41 (FIG. 2), and one or more grooves 44 (FIG. 2). The model is digitally divided into a plurality of parts, as shown in FIG. More specifically, the model is digitally partitioned to define one or more core portions (with one core portion 60 shown) and at least two outer shell portions 62 and 64. In the illustrated embodiment, the core portion 60 is shown as being defined by a single portion, but may be too complex to be formed as a single portion, and alternatively is formed as a plurality of core portions. Note that this may be the case. In one embodiment, each of the core and outer shell can be divided into two or more parts to facilitate fabrication and to include more precise details.

  Next, referring to FIG. 5, each of the plurality of portions, more specifically, the core portion 60 and the plurality of outer shell portions 62 and 64 are converted into a mold 66. Each mold 66 is formed from the digital model 50 using well-known machining processes and converts each portion 60, 62, 64 to a respective mold 66. Each of the molds 66 is formed from the digital model 50 using known machining processes and converts each portion 60, 62, 64 to a respective mold 66. At least one of the plurality of portions 60, 62 and 64 includes a plurality of precision metal inserts 70 so that the geometry of the component 30 includes one or more cooling channels 41 and one or more surface grooves 44. Define the geometric shape. With the three-dimensionality in mind, rather than the two-dimensional cross section shown in the drawings of such parts, in one embodiment, the metal insert 70 may be formed with its own multiple layers, eg, etched, It may then be formed of copper sheets stacked or fixed in place. In addition, one or more precision metal inserts 70 may be included to define one or more alignment features 72. More specifically, as shown in FIG. 5, the core portion 60 is converted into two cooperating molds 67 and 69 which ultimately will be the ceramic core of the ceramic casting vessel 56. 52 is formed. Each of the molds 66 is formed of some flexible and stable metal or metal alloy that can be machined. In a preferred embodiment, the mold 66 is formed of an aluminum material for cost advantages and ease of machining. Each of the molds 66, and more specifically the molds 67 and 69, incorporate a machined surface 68, a precision metal insert 70, and an alignment mechanism 72 to provide the desired shape of the component to be cast. reflect. In one preferred embodiment, the precision metal insert 70 is formed of etched copper and includes one or more cooling channels 41 (FIG. 2) and one or more surface grooves 44. Is reflected. Copper is the preferred material for the precision metal insert 70 in that it is easily crafted by etching or lithographic techniques, but any metal or alloy is also a subject for such techniques to work. For example, as shown in FIG. 3, the final geometry of each groove 44 has a bottom 46 and a top 48, and the bottom 46 is wider than the top 48 so that each groove 44 is on the inside. It is a groove 44 having a hollow shape. For example, as pointed out in FIG. 3, the method further includes forming one or more cooling passages 56 coupled to the bottom 46 of each groove 44 to provide a space between the groove 44 and one hollow interior space 38. Realizing the fluid communication. The one or more cooling channels 56 are typically circular or elliptical in cross section. The one or more cooling channels 56 are perpendicular to the bottom 46 of each groove 44 (shown in FIG. 3), or more generally, 20-90 degrees relative to the bottom 46 of the groove 44. It may be formed at an angle in the range. Although the groove 44 is described herein as an inwardly recessed type groove, it is also contemplated herein that the groove 44 is made as an open type groove. The overall surface geometry 74 resulting from the mold 66 is a combination of a machined surface 68 and a precision machine insert 70 that represents the final shape of the ceramic core 52. is there.

  Referring now to FIG. 6, a plurality of flexible molds 80 are then cast from mold 66, and more specifically from molds 67 and 69. With this flexible mold 80, the resulting surface geometry 74 of each mold 66, more specifically the machined surface 68 of each mold 67 and 69, and the precision metal insert 70 are provided. It becomes possible to duplicate.

  As best shown in FIG. 7, following the curing operation, molds 67 and 69 are removed, exposing flexible mold 80. The flexible molds 80 are positioned and aligned with respect to each other so as to define a cavity 82 therebetween. The cavity 82 indicates the shape of the core 52 made of ceramic. In one embodiment, utilizing an alignment insert 84 in the form of an alignment mechanism 72 helps to properly align each side of each flexible mold 80 with respect to each other.

  Referring now to FIG. 8, after aligning the two sides of the flexible mold 80, the cavity 82 is filled with a ceramic casting 86. After curing, the flexible mold 80 is removed, exposing the ceramic core 52, which forms one or more cooling channels 41 and one or more surface grooves 44. The precise features are included, which ultimately form one or more surface cooling channels 40.

  In addition to making the ceramic core 52, the ceramic casting container 56 further includes a ceramic outer shell 54. Accordingly, the ceramic shell 54 is then cast in at least two portions 62 and 64, which are then joined together and combined with the ceramic core 52 to include one or more surface grooves 44. The component 30 can be made. As described in detail above, in a preferred embodiment of making an airfoil, such as, for example, airfoil 30 of FIG. 2, the outer shell portions 62 and 64 are made of a digital model 50 of a ceramic outer core 54 (FIG. 3). And FIG. 5). In a preferred embodiment, the digital model 50, more specifically a ceramic casting vessel 56, is divided into a suction side and a pressure side. Alternative locations for the division of the ceramic casting vessel 56 are also envisaged herein, depending on design parameters including shape and ease of fabrication, where some parts are more than two It is understood that the outer shell portion may be required.

  Referring now to FIGS. 9 and 11, a mold for each outer shell portion 62 and 64 comprising the ceramic outer shell 54 of the ceramic casting vessel 56 is made. More particularly, as shown, first mold 90 and second mold for each outer shell portion 62 and 64 in a general manner similar to that described above with respect to core portion 60. A mold 92 is produced. FIG. 9 shows a first mold 90 on the outer side 94 of the outer shell portion 62, which is made in preparation for the subsequent casting of the outer 94 flexible mold. FIG. 11 shows a second mold 92 on the inner side 96 of the outer shell portion 62 that is made in preparation for the subsequent casting of the inner 96 flexible mold. Although not shown, additional molds are made in a similar manner for the shell portion 64, which depicts both the inside and the outside of the shell portion 64. In one embodiment, molds 90 and 92 are formed of a flexible metal material such as aluminum or a metal alloy. As detailed above, a precision metal insert (not shown) similar to the precision metal insert 70 of FIGS. 3-8 is inserted into the molds 90 and 92 when precise tooling is required. There is also a case. In addition, in one embodiment, a cooperating alignment mechanism 98 is included in each mold 90 and 92 to facilitate aligning the molds 90 and 92 in subsequent steps of making a flexible mold. There is also a case.

  A flexible mold is then created for each mold 90 and 92. More specifically, as shown in FIGS. 10 and 12, the flexible mold 100 is formed from a mold 90, and the flexible mold 102 is formed from a mold 92. The flexible molds 100 and 102 are formed in the manner generally described above with respect to the flexible mold 80 of the core portion 60. In addition, an additional flexible mold is made in a similar manner for the shell portion 64, which depicts both the inside and the outside of the shell portion 64.

  Next, as best shown in FIG. 13, the flexible molds 100 and 102 created for the shell portion 62 are positioned and aligned to define a cavity 82 therebetween. In the embodiment shown, the cavity 104 represents the shape of a portion of the final ceramic shell 54. Utilizing the alignment insert 106 in the formed alignment mechanism 98 can help to properly position one side of each of the flexible molds 100 and 102 relative to each other. After aligning the two sides of the flexible molds 100 and 102, the cavity 104 is filled with a ceramic casting 108. After curing, the flexible molds 100 and 102 are removed, exposing a portion of the ceramic casting vessel 56, more specifically one side of the ceramic outer shell 54. This process is repeated to produce the remaining side of the ceramic shell 54 of the ceramic casting vessel 56.

  Referring now to FIG. 14, by assembling a ceramic core 52 in two ceramic shells 54, thereby defining a complete mold for the component 30, a ceramic casting vessel 56 is then formed. Is formed. The ceramic casting vessel 56 has a plurality of cavities 112 defined therein. In one embodiment, there may be a locating mechanism in the at least two outer shell portions 62 and 64, and thus in the resulting two ceramic outer shells 54, which is one or more core portions 60. , Thus aligned with and inserted into the top open position in the resulting ceramic core 52. Such a positioning mechanism makes it possible to “fix” in both the core and the outer shell, thereby leaving the surface channels open, and the molten metal can be separated from the ceramic core 52 and the ceramic outer. It becomes possible to keep the web between the shells 54 from filling.

The ceramic casting vessel 56 then utilizes a well-known process known in the art to melt the molten metal 110 into the ceramic casting vessel 56, and more particularly, the cavity defined therein. By receiving in 112, a cast gas turbine blade 30 including a plurality of surface grooves 44 is formed. In one preferred embodiment, the molten metal 110 is prepared from US Pat. No. 5,626,462, Melvin R., which is incorporated herein in its entirety. Any suitable metallic material can be included, as discussed in Jackson et al. “Double-wall airfoil”. Depending on the intended use of the component 30, this may include nickel-based, copper-based and iron-based superalloys. The nickel-based superalloy may include both γ and γ ′ layers, and in particular may be a nickel-based superalloy including both γ and γ ′ layers, in which case the γ ′ layer Occupies at least 40% of the volume of the superalloy. Such alloys are known to be advantageous because they combine desirable properties including high temperature strength and high temperature creep resistance. Metal material 110 may also be NiAl intermetallic alloys, and these alloys are known to have a combination of superior properties including high temperature strength and high temperature creep resistance, these properties being This is advantageous for use in turbine engine applications used in aircraft. In the case of niobium-based alloys, coated niobium-based alloys with excellent oxidation resistance are preferred, especially such alloys are Nb- (27-40) Ti- (4.5-10.5) Al. -(4.5-7.9) Cr- (1.5-5.5) Hf- (0-6) V, where the composition range is the proportion of atoms. The metallic material may also be a niobium-based alloy containing at least one secondary phase, such as an intermetallic compound containing niobium such as silicide, carbide or boride. Such an alloy is a composite material of a ductile phase (ie, a niobium-based alloy) and a reinforcing phase (ie, an intermetallic compound containing niobium). In other configurations, the metal material is a molybdenum-based alloy, such as a molybdenum (solid solution) -based alloy with a secondary phase of Mo ₅ SiB 2 and / or Mo ₃ Si. In other configurations, the metal material is a ceramic matrix composite (CMC), such as a silicon carbide (SiC) matrix reinforced with SiC fibers. In other configurations, the metal material is a TiAl-based intermetallic compound.

  The ceramic casting vessel 56 is then removed to provide an internal passage 38, one or more cooling passages 41 in fluid communication with the internal passage 38, and one in fluid communication with the one or more cooling passages 41. Alternatively, a component 30 having a plurality of surface grooves 44 is exposed, some of which are shown in FIG. For example, as pointed out in FIG. 15, the method further includes disposing a coating 42 over at least a portion of the surface 34 of the substrate 32 of the component 30. More particularly, in one embodiment, the coating 42 is disposed over at least a portion of the surface 34 of the substrate 32 so as to directly cover the open grooves of the one or more grooves 44. “Open” as used herein means that the grooves 44 are empty, that is, they are not filled with sacrificial filler. As shown in FIG. 15, for example, grooves 44 and coating 42 cool component 30 by defining several inwardly-shaped channels 40. The substrate 32 and the coating 42 can further define a plurality of exit film holes (not shown). An example coating 42 is provided in US Pat. No. 5,640,767 and US Pat. No. 5,626,462, which are hereby incorporated by reference in their entirety. As discussed in US Pat. No. 5,626,426, the coating 42 is applied to a portion of the surface 34 of the substrate 32.

  Advantageously, the formation of inwardly recessed grooves 44 eliminates the need to use a sacrificial filler (not shown) to apply the coating 42 to the substrate 32. This eliminates the need for filling and more difficult removal steps. By forming an inwardly recessed groove with a narrow opening 48 (top) (eg, with an opening 48 in the range of approximately 10-12 mils wide) without using sacrificial filler The opening 48 can be filled with a coating 42, thereby eliminating the additional processing steps (filling and leaching) in addition to eliminating the post-machining steps previously described for conventional channel formation techniques. Can do. For example, in the example configuration shown in FIG. 15, the coating 42 completely fills each groove 44 so that the coating 42 seals each surface cooling channel 40. In addition, in one embodiment, at least one coolant outlet 45 may be defined to penetrate the coating 42.

  Referring now to FIG. 16, a flowchart depicting one implementation of a method 150 for creating a component 30 that includes a surface cooling channel 40 according to one or more embodiments shown or described herein. It is shown. The method 150, in step 152, initially includes one or more surface cooling channels 40 by forming a model of the desired ceramic casting vessel that defines the component 30. A step of casting. The model includes an internal passage, one or more cooling passages in fluid communication with the internal passage, and one or more surface grooves in fluid communication with the one or more cooling passages. Next, in step 154, the model is digitally divided into a plurality of portions including a core portion and a plurality of outer shell portions. Each of the plurality of portions is converted to a metal mold at step 156. The plurality of portions includes a plurality of precision metal inserts to provide a component including an internal passage, one or more cooling passages, one or more surface grooves, and one or more alignment features. Geometric shapes can be defined. The molds are then aligned in step 158 to cast a flexible mold from each metal mold. Subsequent to the curing of the flexible mold, the mold is removed to expose the flexible mold, which is then aligned and the ceramic core from each flexible mold in step 160. And is used in step 162 to cast a ceramic outer shell. A ceramic casting vessel is then assembled at step 164 by assembling the ceramic core within the ceramic shell portion, wherein the assembling step comprises utilizing one or more alignment mechanisms. May be included. The metal material is cast in step 166 and then into a ceramic casting vessel. After cooling, the ceramic casting vessel is removed at step 168 and the internal passage, one or more cooling passages in fluid communication with the internal passage, and one or more in fluid communication with the one or more cooling passages. The components including the surface grooves are exposed.

  Although the disclosed method has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the disclosed method is not limited to such disclosed embodiments. I want you to understand. Rather, the method can be modified to incorporate any number of variations, alternatives, substitutes or equivalent arrangements not heretofore described, which are commensurate with the spirit and scope of the present disclosure. In addition, while various embodiments of the method have been described, it should be understood that aspects of the method may include only some of the described embodiments. Accordingly, the disclosed method should not be considered limited by the above description, but only by the scope of the appended claims.

DESCRIPTION OF SYMBOLS 10 Gas turbine system 12 Compressor 14 Combustor 16 Turbine 18 Shaft 20 Fuel nozzle 30 Hot gas component 32 Base body 34 Outer surface 36 Inner surface 38 Interior space 40 Surface cooling channel 41 Cooling path 42 Coating 44 Groove 45 Coolant outlet 46 bottom 48 top 50 model 52 ceramic core 54 ceramic outer shell 56 ceramic casting vessel 60 core portion 62 outer shell portion 64 outer shell portion 66 mold 68 machined surface 70 precision metal insert 72 alignment mechanism 74 Resulting surface 80 Flexible mold 82 Cavity 84 Alignment insert 86 Ceramic material 90 Mold 92 Mold 94 Outside part 62 96 Inside part 62 98 Alignment mechanism 100 Flexible mold 102 Flexible mold 104 cavity 106 Alignment Insert 108 Ceramic Cast Material 110 Molten Metal 120 Coating 122 Inner Recessed Surface Cooling Channel 150 Method 152 Define Components, Internal Passage, One or More Cooling Paths, and One or More And a desired ceramic casting vessel model including a surface groove.
154 This model is digitally divided into a plurality of parts.
156 Each of the plurality of portions is converted into a mold, where the plurality of portions can include a plurality of precision metal inserts to define a component geometry.
158 Cast a flexible mold from each mold.
160 Cast the ceramic core from each flexible mold.
162 Cast the ceramic shell from each flexible mold in at least two parts.
164 Forming a ceramic casting container by assembling a ceramic core within a ceramic shell portion, the assembly step may include utilizing one or more alignment mechanisms.
166 Metal is cast in a ceramic casting vessel.
168 By removing the ceramic casting vessel, an internal passage, one or more cooling passages in fluid communication with the internal passage, and one or more surface grooves in fluid communication with the one or more cooling passages The component having is exposed.

Claims (10)

A method of casting a component (30) comprising one or more surface cooling channels (40) comprising:
Casting (160) a ceramic core (52) from a flexible mold (80) of one or more core portions (60);
Casting (162) a ceramic outer shell (54) in each flexible mold (100, 102) of at least two outer shell portions (62, 64) in at least two portions;
Forming a ceramic casting vessel (56) by assembling the ceramic core (52) in the ceramic shell portion (54);
Casting (166) a metal substrate material (110) into the ceramic casting vessel (56);
By removing the ceramic casting vessel (56), an internal passage (38), one or more cooling passages (41) in fluid communication with the internal passage (38), and the one or more cooling passages. Exposing (168) the substrate (32) of said component (30) defining therein one or more surface grooves (44) in fluid communication with the channel (41). Defining the geometry of the component (30), the internal passage (38), one or more cooling passages (41) in fluid communication with the internal passage (38), and the one or more Forming a model (152) of a desired ceramic casting vessel (56) including one or more surface grooves (44) in fluid communication with the cooling passage (41);
Digitally dividing (154) the model into a plurality of portions defining the core portion (52), the first outer shell portion (62) and the second outer shell portion (64);
Converting each of the plurality of portions (52, 62, 64) into a mold (66, 69, 90, 92) (156), wherein the plurality of portions (52, 62, 64) is 1 By including one or more precision metal inserts (70), the internal passage (38), the one or more cooling passages (41), and the one or more surface grooves (44) Defining (156) a geometry of said component (30) comprising:
The method of claim 1, further comprising casting (158) the flexible mold (80, 100, 102) from each mold (66, 69, 90, 92). Placing a coating (42) over at least a portion of the surface (34) of the substrate (32), the one or more cooling channels (41), of the one or more surfaces The method of any preceding claim, wherein the groove (44) and the coating (42) further comprise cooling the component (30) by defining the one or more surface cooling channels (40). . The method of any preceding claim, further comprising defining at least one coolant outlet (45) through the coating (42). The method of any preceding claim, wherein the one or more surface grooves (41) are inwardly recessed grooves. A method of casting a component (30) comprising one or more surface cooling channels (40) comprising:
Defining the geometry of the component (30), the internal passage (38), one or more cooling passages (41) in fluid communication with the internal passage (38), and the one or more Forming (152) a model (50) of the desired ceramic casting vessel (56) including one or more surface grooves (44) in fluid communication with the cooling passage (41);
Digitally dividing the model (50) into a plurality of parts (52, 62, 64) (154);
Converting each of the plurality of portions (52, 62, 64) into a mold (67, 69, 90, 92), wherein the plurality of portions (60, 62, 64) are 1 Including one or more precision metal inserts (70), said internal passage (38), said one or more cooling passages (41), said one or more surface grooves (44), Defining (156) a geometry of the component (30) including one or more alignment features (72, 98);
Casting (158) a flexible mold (80, 100, 102) from each mold (67, 69, 90, 92);
Casting (160) a ceramic core (52) from each flexible mold (67, 69);
Casting (162) a ceramic outer shell (54) from a respective flexible mold (90, 92) in at least two parts;
Forming the ceramic casting vessel (56) by assembling the ceramic core (52) in the ceramic shell portion (54);
Casting (166) metal (110) into said ceramic casting vessel (56);
By removing the ceramic casting vessel (56), the internal passage (38), one or more cooling passages (41) in fluid communication with the internal passage (38), and the one or more Exposing (168) the substrate (32) of the component (30) having one or more surface grooves (44) in fluid communication with the cooling passage (41). The method further includes disposing a coating (42) over at least a portion of the surface (34) of the substrate (32), wherein the one or more surface grooves (44) and the coating (42) The method of claim 6, wherein the component (30) is cooled by defining the one or more surface cooling channels (40). The method of claim 6, wherein the one or more surface grooves (44) are inwardly recessed grooves. The method of claim 6, wherein each of the molds (67, 69, 90, 92) is formed of a metallic material. The method of claim 6, wherein the plurality of portions (60, 62, 64) define one or more core portions (62) and at least two outer shell portions (62, 64).