Patent Application
20120137695
The present application relates generally to gas turbine engines and more particularly relates to an improved tip design for a gas only insert for use with a fuel nozzle so as to minimize hot gas ingestion and the like and the damage that may be caused thereby.
Gas turbines for power generation are generally available with fuel nozzles configured for either “dual fuel” or “gas only” operation. The “gas only” configuration refers to burning, for example, only natural gas. The “dual fuel” operation refers to having the capability of burning either natural gas or a liquid fuel. The “dual fuel” configuration generally is applied in situations where oil is used as a backup fuel in the event that natural gas is unavailable. The “gas only” configuration is offered to reduce costs because the nozzle parts and the associated equipment used for liquid fuel operations are not required. In general, fuel nozzles are designed to have “dual fuel” capabilities. The “gas only” version is a modification of the dual fuel design in which the liquid fuel parts (e.g., oil, atomizing air, and water passages and the like) are removed from the nozzle and replaced with a component of a similar size and shape, but without the internal features of the liquid fuel cartridge. This replacement component generally is known as a “gas only insert.” Other configurations and other components also may be used.
Known gas only inserts, however, have experienced overheating while the tubes leading to the gas only insert tips have experienced bulging and other types of deformation. This overheating and deformation may be due to hot gas ingestion into the gas only insert tip. Specifically, conditions may exist that allow for the transfer of heat back into the gas only insert tip and the accompanying tube. High tip and tube temperatures may be more prevalent during high combustion dynamics in certain fueling modes and/or during fuel transfers. Such overheating and deformation may require premature replacement of the overall nozzle and the added expense and downtime associated therewith.
There is thus a desire for an improved design of a gas only insert tip and an overall “gas only” fuel nozzle design. Such a gas only insert tip and fuel nozzle design should be substantially resistant to overheating and deformation caused by hot gas ingestion and the like. Moreover, such a gas only insert tip and fuel nozzle design should provide consistent performance with a long lifetime.
The present application thus provides a fuel nozzle. The fuel nozzle may include a tube and a gas only insert tip positioned on the tube. The gas only insert tip may include a tip aperture. A plug may be positioned within the tip aperture.
The present application further provides a gas only insert for use with a fuel nozzle. The filet nozzle may include a tube and a tip positioned on the tube. The tip may include a tip end and a breather hole positioned with the tip end. The breather hole may include a diameter sufficiently large to allow an internal the tube to breath without allowing hot gas ingestion therethrough.
The present application further provides a combustor. The combustor may include a number of fuel nozzles. One or more of the fuel nozzles may include a tube and a gas only insert tip. The gas only insert tip may include a tip end with a breather hole therein.
These and other features and improvements of the present application 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, and/or other types of fuels. The gas turbine engine 10 may be one of any number of different gas turbine engines offered by General Electric Company of Schenectady, N.Y. such as a heavy duty 9FA gas turbine engine and the like, The gas turbine engine 10 may have other configurations and may use other types of components. Other types of gas turbine engines also may be used herein. Multiple gas turbine engines 10, other types of turbines, and other types of power generation equipment also may be used herein together.
The plug 130 may include a small diameter breather hole 140 in the middle thereof. The breather hole 140 may have any shape, length, or configuration. The breather hole 140 of the plug 130 may have a diameter 150 that may be sized to allow the internal volume of the gas only insert tip 100 and the associated tube 125 to breathe while preventing hot gas ingestion back therethrough. Specifically, the breather hole 14 may have the diameter 150 of about 0.06 (about 1.524 millimeters) inches or so in this example. Given the tip aperture 120 diameter of about 0.25 inches (about 6.35 millimeters), the breather hole 140 may reduce the size of the tip aperture 120 by about four (4) to one(1). Other sizes and ratios may be used herein. The breather hole 125 may be effective in any fuel mode and/or fuel transfers and the like.
The gas only insert tip 100 may have about the same tip mass as the tip 55 described above so as to avoid changes in the natural mechanical frequencies therein. A number of vanes 160 also may be used herein. The gas only insert tip 100 thus may have no negative impact on overall function or combustion dynamics. The plug 130 may be made out of the wrought nickel-based alloy materials and the like so as to reduce catalyst concerns.
The plug 130 may be used as a retro-fit into the existing tip 55. In original equipment, the breather hole 140 may be positioned within the tip end 115 itself or other type of structure.
The gas only insert tip 100 with the plug 130 therein and/or the unitary gas only tip 170 thus reduces the internal temperatures within the tip 100 and the tube 125 and also reduces and/or eliminates bulging or other types of deformation within the tube 60 in any fuel mode. The gas only insert tips 100, 170 described herein provide these benefits without negatively impacting on overall system performance.
It should be apparent that the foregoing relates only to certain embodiments of the present application and that 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.
