Patent Application
20150064019
The present application and the resultant patent relate generally to gas turbine engines and more specifically relate to gas turbine components with porous cooling sections created by direct metal laser melting manufacturing techniques and the like.
Gas turbine systems are widely utilized in fields such as power generation. Overall gas turbine performance and efficiency generally may be increased by increasing internal combustion temperatures. The components that are subject to the high temperatures in the hot gas path, however, must be cooled. For example, an airfoil and other components of a nozzle and the like may be disposed in the hot gas path and exposed to the relatively high combustion temperatures. A cooling flow therefore may be routed from the compressor or elsewhere and provided to the various components in the hot gas path.
A variety of methods may be used for cooling the airfoils and the other components. These methods may include running a cooling flow on the interior side of the component, running the cooling flow through an impingement sleeve that impinges the flow on the backside of the component so as to increase the heat transfer coefficient therein, running the coolant through cooling holes to the exterior of the component to convectively cool, and exhausting the coolant from the cooling holes as film to provide a layer of cool air over the exterior so as to reduce exterior temperatures. Although the use these methods may provide adequate cooling for the airfoils, a further increase in cooling efficiency is desired. Such an increase in efficiency would allow a reduction in the cooling flows required to cool the airfoils and other components and also may provide a reduction in emissions and/or an increase in firing temperatures.
The present application and the resultant patent thus provide a hot gas path component for use with a gas turbine engine. The hot gas path component may include an airfoil, an internal cooling cavity, and a porous section created by a direct metal laser melting technique. The porous section may be built into the airfoil or the airfoil may be built separately and attached to the airfoil.
The present application and the resultant patent further provide a method of cooling a hot gas path component for use with a gas turbine engine. The method may include the steps of providing the hot gas path component with an internal cooling cavity, creating a porous section via a direct metal laser melting technique, flowing a cooling medium to the internal cooling cavity, and flowing the cooling medium through the porous section to provide transpiration cooling. The creating step may include building up the porous section on the hot gas path component or building the porous section separately and attaching the porous section to the hot gas path component.
The present application and the resultant patent further provide an airfoil for use with a gas turbine engine. The airfoil may include a pressure side, a suction side, an internal cooling cavity, and a porous section with a porous media created by a direct metal laser melting technique.
These and other features and improvements of the present application and the resultant patent will become apparent to one of ordinary skill in the art upon review of the following detailed description when taken in conjunction with the several drawings and the appended claims.
Referring now to the drawings, in which like numerals refer to like elements throughout the several views,
The gas turbine engine 10 may use natural gas, liquid fuels, various types of syngas, and/or other types of fuels and combinations thereof. The gas turbine engine 10 may be any one of a number of different gas turbine engines offered by General Electric Company of Schenectady, N.Y., including, but not limited to, those such as a 7 or a 9 series heavy duty gas turbine engine and the like. The gas turbine engine 10 may have different configurations and may use other types of components. Other types of gas turbine engines also may be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment also may be used herein together.
The airfoil 110 also may have a porous trailing edge section 220. The porous trailing edge section 220 may be filled with a porous media 230. The porous media 230 may be formed from any suitable porous material or materials having a matrix with a number of voids therein. The porous media 230 may be formed from a metal foam, a metal alloy foam, a ceramic foam, such as a ceramic matrix composite foam, a carbon fiber foam, and similar types of porous materials. Non-limiting examples of specific materials may include Rene 142, Rene 195, MarM247, GTD111, GTD444, IN738, H282, H230, IN625 and the like. The foam typically may be formed by mixing a material, such as a metal, a ceramic, a carbon fiber, and the like with another substance and then melting the substance so as to leave the porous foam. The porous media 230 may be “printed” or built up via a direct metal laser melting (“DMLM”) process and the like. Different types of sintering techniques and other types of manufacturing techniques also may be used herein to create the components herein. The porous media may vary in porosity/permeability throughout based on optimizing the cooling flow therethrough. For example, permeability may be lowest in regions of highest heat load so that more coolant flows through these regions as compared to regions where the heat load and the coolant demand may be lower. A cooling medium 240 may flow through the voids in the porous media 230 so as to facilitate cooling in a highly efficient manner.
The porous trailing edge section 220 may be built directly onto the airfoil 110 or the porous trailing edge section 220 may be built separately and attached by any number of different techniques. These techniques may include including brazing, arc welding, high energy density welding such as laser welding and electron beam welding, TLP bonding, diffusion bonding, or different types of mechanical attachment. The buildup of the porous media 230 may be made over an existing component or as part of building a component as a whole. The use of the DMLM process enables high heat transfer through the porous media 230 while providing a high quality joint between the airfoil 110 and the porous trailing edge section 220. The porous trailing edge section 220 may have an external sleeve 250 extending in whole or in part to direct the flow to exit over only a certain section or sections of the trailing edge. The external sleeve 250 may be a metallic component, a thermal barrier coating, and the like. The coating may be an aluminide and the like sprayed thereon. The cooling medium 240 thus flows through the airfoil 110 and exits via the porous trailing edge section 220 so as to cool the trailing edge 180. Other components and other configurations may be used herein.
A number of alternative hot gas path components 100 also may be used herein. Specifically, DMLM techniques may be used to build both porous and solid features of the hot gas path component 100. These DMLM techniques may be used to vary the porosities and/or the permeability at different locations within the porous media 230. The DMLM techniques thus can be used to build multiple different discrete porous structures inside or outside thereof. Other methods of making and attaching the porous material may be used as well.
The hot gas path component 100 provides these integral porous features so as to enable better heat transfer as well as providing transpiration cooling. The use of the porous media 230 thus should reduce overall cooling load requirements. Specifically, the porous media has been shown to have a significantly higher heat transfer coefficient as compared to known airfoil materials as well as provides superior control over the distribution of coolant over the part. Using such a process on the hot gas path components in multiple locations may increase heat transfer capability while reducing cooling flow requirements. Moreover, the use of the DMLM process provides the porous foam with an integral joint to the base metal when built directly onto the part or as a whole with the part. The DMLM process also provides control over the porosity and the permeability throughout the part.
It should be apparent that the foregoing relates only to certain embodiments of the present application and the resultant patent. Numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.
This invention was made with U.S. government support under contract number DE-FC26-05NT42643 awarded by the Department of Energy. The government has certain rights in this invention.
