Patent Application
20090183511
The subject invention relates generally to gas turbines. More particularly, the subject invention relates to fuel nozzles for gas turbine engines.
Gas turbines typically include a quantity of fuel nozzles (or swozzles) in a combustor section of the gas turbine. Each nozzle is a component having one or more passages for delivering a mixture of fuel and air to a combustion chamber for ignition. A fuel nozzle often includes a swirler to improve mixing of the fuel and air into a consistent, homogeneous mixture prior to ignition. The swirler includes a plurality of vanes extending from the nozzle and having an aerodynamic profile. The swirler vanes often include passages which provide fuel to fuel holes on a surface of the swirler vanes. As fuel exits the fuel holes, it mixes with fluid, typically air, passing the swirler vanes. Size and space limitations usually result in swirler vanes having an abrupt turn near the trailing edge of the swirler vane that may produce flow separations in the swirler or downstream of the swirler which can lead to detrimental effects on fuel nozzle performance, for example, flame holding. Typically, to solve flow problems such as the above, the vane profile is modified requiring new casting processes and casting tooling for each iteration, modifying the pattern of fuel holes on the vanes which may have detrimental effects on, for example, mixing efficiency and thus nozzle performance.
A fuel nozzle for a combustor of a gas turbine engine includes a nozzle inlet, a combustion area and a swirler disposed between the nozzle inlet and combustion area. The swirler includes a plurality of swirler vanes, each swirler vane capable of creating a pressure difference in fluid flow through the swirler between a pressure side and suction side of the swirler vane. The swirler further includes at least one through airflow hole located in at least one swirler vane of the plurality of swirler vanes. The through airflow hole is capable of utilizing the pressure difference between the pressure side and suction side to promote flow through the at least one airflow hole.
A method for operating a combustor of a gas turbine engine includes urging a fluid flow into a nozzle inlet, urging fuel into the fluid flow and flowing the fuel and fluid flow into a swirler, the swirler having a plurality of swirler vanes, thus mixing the fuel into the fluid flow. The method further includes creating a pressure difference in the fluid flow through the swirler between a pressure side and a suction side of each swirler vane of the plurality of swirler vanes and flowing at least a portion of the fluid through at least one through airflow hole in at least one swirler vane of the plurality of swirler vanes, thus reducing the pressure difference between the pressure side and the suction side of the swirler vane. The mixture of fuel and fluid flow is ignited in a combustion area.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
Shown in
The center body 20 is substantially annular in cross-section and is capable of carrying a fluid, for example, fuel therethrough. The plurality of swirler vanes 18 include turning sections 24. The turning sections 24 are capable of turning or inducing swirl in a fluid flow, which in some embodiments is air, flowing past the swirler vanes 18. A curvature of the turning section 24 creates a pressure differential between a pressure side 26 and a suction side 28 of the swirler vane 18. The swirler vane 18 may have one or more internal plenums 30 as best shown in
The swirler vanes 18 include at least one airflow hole 40. The airflow holes 40 are disposed in the turning section 24 and are configured as through-holes extending through a solid cross section of swirler vane 18. The at least one airflow hole 40 allows transfer of some of the airflow from the pressure side 26 to the suction side 28 as shown by arrows 42. The airflow transfer prevents separation of an aerodynamic boundary layer from the turning section 24 thus preventing flame holding, and/or other detrimental effects on combustor performance. In the embodiment shown in
In some embodiments, as shown in
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
