Patent Application
20110271683
The subject matter disclosed herein relates to the art of turbomachines and, more particularly to an injection nozzle assembly for a turbomachine.
In general, gas turbomachine engines combust a fuel/air mixture that releases heat energy to form a high temperature gas stream. That is, fuel and air are directed through an injection nozzle into a combustor and ignited to form a high temperature gas stream. The high temperature gas stream is channeled to a turbine via a hot gas path. The turbine converts thermal energy from the high temperature gas stream to mechanical energy that rotates a turbine shaft. The turbine may be used in a variety of applications such as providing power to a pump or an electrical generator.
Currently, there is a need to lower turbomachine emissions. One path to lower emissions lies in creating a more stable flame front within the combustor. In many injection nozzle assemblies, a fluid flow is passed through a swirler. The swirler, as the name implies, imparts a swirl to the fluid flow with one benefit being increased downstream stability. At present, the velocity distribution of the flow downstream of the swirler can be highly non-uniform. This non-uniformity includes a velocity peak around mid-span, and a steep gradient toward an inner radius of the injection nozzle assembly. This velocity profile may create stability issues within the combustor. These stability issues may prevent machine operation in modes that lower emission levels.
According to one aspect of the invention, a turbomachine includes a compressor, a turbine, a combustor operatively coupled to the compressor and the turbine, and an injection nozzle assembly mounted in the combustor. The injection nozzle assembly includes a swirler member for conditioning a fluid flow passing through the injection nozzle assembly. The swirler member includes a hub portion, a plurality of vanes that extend from the hub portion, and at least one flow conditioning band. The at least one flow conditioning band extends about the hub portion and between the plurality of vanes to provide a localized flow impediment within the injection nozzle assembly.
According to another aspect of the invention, a turbomachine injection nozzle assembly includes a swirler member for conditioning a fluid flow passing through the injection nozzle assembly. The swirler member includes a hub portion, a plurality of vanes that extend from the hub portion, and at least one flow conditioning band. The at least one flow conditioning band extends about the hub portion and between the plurality of vanes to provide a localized flow impediment within the injection nozzle assembly.
According to yet another aspect of the invention, a method of conditioning an airflow in a turbomachine injection nozzle assembly includes guiding a fluid into the turbomachine injection nozzle assembly, and directing the fluid through a swirler member arranged in the turbomachine injection nozzle assembly. The swirler member includes a hub portion, and a plurality of vanes radiating from the hub portion. The method further includes passing the fluid across the plurality of vanes, and impeding a portion of the fluid passing between the plurality of vanes.
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 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.
With reference to
As shown, combustor 6 is coupled in flow communication with compressor 4 and turbine section 10. Combustor 6 includes an end cover 30 positioned at a first end thereof and a combustion chamber 34 positioned at a second end thereof. End cover 30 provides support to a plurality of fuel or injection nozzle assemblies, two of which are indicated at 38 and 39. At this point, reference will be made to
Injection nozzle assembly 38 includes a fuel inlet portion 44 having a valve assembly 45. Injection nozzle assembly 38 also includes a centerbody 54 that defines, in part, a primary mixing zone 58. Fuel and air are mixed, enter into primary mixing zone 58 and pass into combustion chamber 34 to be ignited. During certain operational modes, a portion of the fuel is directed through a secondary fuel nozzle 63 before being reintroduced into primary mixing zone 58. Secondary fuel nozzle 63 includes an upstream end 66 that is fluidly linked to fuel inlet 44 and a downstream end 67 that leads toward combustion chamber 34. Downstream end 67 includes a plurality of outlets, one of which is indicated at 69 in
In accordance with an exemplary embodiment illustrated in
In accordance with one aspect of the exemplary embodiment, each flow conditioning band 94, 95 includes a rectangular profile such as indicated at 110 in
Each of the above profiles establishes a particular impediment to the fuel/air mixture flow passing through primary mixing zone 58 to achieve a more stable flame front. As shown in
At this point it should be understood that the exemplary embodiments can be employed in a wide array of gas turbomachine and are not limited to the examples shown. Also, while the injection nozzle assembly is shown and described as including two flow conditioning bands, it should be apparent that number and position of the flow condition bands could vary depending upon the desired velocity profile. Finally, it should be understood that the profiles shown for the flow condition band are exemplary and could include various other geometries.
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.
