Patent Application
20190217429
The present application and the resultant patent relate generally to gas turbine engines and more particularly relate to systems and methods for resizing existing holes such as premix fuel inlet holes within a vane turbine fuel nozzle assembly in a fast, efficient, and safe manner.
In gas turbine engines, a combustor includes a number of fuel nozzles. The fuel nozzles typically include a subassembly of generally concentric tubes defining a central passage for supplying diffusion fuel gas and a pair of concentric passages for supplying premix fuel gas. Spaced from and surrounding the subassembly may be an inlet flow conditioner for directing and confining a flow of inlet air past a number of circumferentially spaced vanes carried by the subassembly. The vanes may be in communication with the concentric fuel gas supply passages. Particularly, the vanes may include outer and inner premix fuel supply holes for supplying gas from the respective passages for mixing with the flow of inlet air. The air-fuel gas mixture may be swirled by the vanes downstream of the premix fuel supply holes for subsequent combustion in a combustion chamber.
The fuel supply holes may be sized to achieve a predetermined pressure drop for a specific fuel energy content and may have a specific radial/axial pattern that achieves a radial fuel-to-air ratio that is favorable for overall combustor performance. If the energy content of the fuel increases, the hole sizes may need to be decreased. If it is desired to change the hole pattern on a nozzle, the hole positions also may change. To decrease the fuel hole size or change the overall hole pattern, the holes may be machined open and a cylinder of metal may be brazed into place before the new holes are installed. For repeatability, the cylinder outside diameter should be large enough to leave a sufficient segment of the cylinder perimeter after the new hole is installed when taking into account the original and final hole positions in addition to the cylinder outside diameter tolerances. The replacement piece, however, may be expensive and the overall process may produce excessive amounts of scrap as well as unneeded or outdated inventory.
The present application and the resultant patent thus provide a method of filling an existing hole in a surface of a turbine component. The method may include the steps of enlarging the existing hole, placing a rivet into the enlarged hole, welding the rivet into place, and grinding the rivet to be flush with the surface of the turbine component.
The present application and the resultant patent further provide a method of replacing an existing fuel supply hole in a vane of a fuel nozzle assembly. The method may include the steps of enlarging the existing hole, placing a rivet into the enlarged hole, fusion welding the rivet into place, grinding the rivet to be flush with the vane, and machining a new fuel supply hole in the vane. The new fuel supply hole is smaller than the existing fuel supply hole.
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, various types of syngas, liquid fuels, and/or other types of fuels and blends 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 outer premix fuel supply holes 76 may include a pair of the radially spaced premix fuel supply holes 76 through one wall 84 of the vane 74 and a single premix fuel supply hole 76 through the opposite side wall 86 of the vane 74. Downstream portions 88 of the vanes 74 may impart a swirl to the flow of premixed air and gaseous fuel flowing between the subassembly 60 and the inlet flow conditioner 62, the gaseous fuel being supplied to the air stream via the outer and inner premix fuel supply holes 76 and 78, respectively.
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The resizing steps described herein thus allows an upgraded configuration to the vanes 115 of the fuel nozzle assembly 120 or other type of turbine component 110. Moreover, unwanted fuel nozzle inventory may be retrofitted with vanes 115 having useful hole sizes and configurations and returned to service. The resultant fuel nozzle assembly 120 thus may have comparable or even improved dynamics, flame holding, emissions, and the like. As opposed to the known expensive brazed cylindrical plugs and aluminide closure methods, the use of the custom rivets 150 provides consistent hole to hole flow repeatability.
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.
