Patent Application
20110162377
The subject matter disclosed herein relates to the art of turbomachines and, more particularly, to a turbomachine nozzle.
In general, gas turbomachine engines combust a fuel/air mixture that releases heat energy 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 reducing supplied fuel and operate the turbomachine with a leaner fuel/air mixture. While a lean fuel/air mixture results in lower emissions, fuel nozzle temperatures are higher. That is, by lowering the amount of supplied fuel, the flame is located closer to the nozzle. As such, temperatures on end portions of the nozzle and adjoining swirler hub are increased. The increased temperature on the swirler hub results in cracks and fissures. The cracks/fissures typically develop at an interface between sleeve portions and swirler portions of the nozzle.
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 provided with a hub portion including an internal surface. The injection nozzle assembly also includes a nozzle section including a first end that extends to a second end, and a nozzle tip member fluidly coupled to the second end of the nozzle section and the swirler member. The nozzle tip member includes a body having a first end section that extends from the nozzle section to a second end section arranged in the hub portion of the swirler member. The nozzle tip member includes an external surface, and a discharge port. At least one of the external surface of the nozzle tip member and the internal surface of the swirler member hub portion is provided with a plurality of grooves. The plurality of grooves are configured and disposed to cool the nozzle tip member.
According to another aspect of the invention, an injection nozzle assembly for a turbomachine includes a swirler member provided with a hub portion having an internal surface, a nozzle section including a first end that extends to a second end, and a nozzle tip member fluidly coupled to the second end of the nozzle section and the swirler member. The nozzle tip member includes a body having first end section that extends from the nozzle section to a second end section arranged in the hub portion of the swirler member. The nozzle tip member includes an external surface, and a discharge port. At least one of the external surface of the nozzle tip member and the internal surface of the swirler member hub portion is provided with a plurality of grooves. The plurality of grooves are configured and disposed to cool the nozzle tip member.
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 best shown in
As shown, combustor liner 46 is positioned radially inward from combustor casing 44 so as to define a combustion chamber 48. An annular combustion chamber cooling passage 49 is defined between combustor casing 44 and combustor liner 46. A transition piece 55 couples combustor 6 to turbine 10. Transition piece 55 channels combustion gases generated in combustion chamber 48 downstream towards a first stage turbine nozzle 62. Towards that end, transition piece 55 includes an inner wall 64 and an outer wall 65. Outer wall 65 includes a plurality of openings 66 that lead to an annular passage 68 defined between inner wall 64 and outer wall 65. Inner wall 64 defines a guide cavity 72 that extends between combustion chamber 48 and turbine 10.
During operation, air flows through compressor 4 and compressed air is supplied to combustor 6 and, more specifically, to injector assemblies 38 and 39. At the same time, fuel is passed to injector assemblies 38 and 39 to mix with the air and form a combustible mixture. The combustible mixture is channeled to combustion chamber 48 and ignited to form combustion gases. The combustion gases are then channeled to turbine 10. Thermal energy from the combustion gases is converted to mechanical rotational energy that is employed to drive shaft 12.
More specifically, turbine 10 drives compressor 4 via shaft 12 (shown in
At this point it should be understood that the above-described construction is presented for a more complete understanding of exemplary embodiments, which are directed to the structure of injection nozzle assemblies 38 and 39. However, as each injection nozzle assembly 38, 39 is similarly formed, a detail description will follow referencing injection nozzle assembly 38 with an understanding the injection nozzle assembly 39 is similarly formed.
As best shown in
Nozzle section 85 includes a nozzle tip member 124. As best shown in
With this arrangement, nozzle tip member 124 is arranged within central hub portion 120 of swirler member 117. The plurality of grooves 114 and the plurality of grooves 147 define a plurality of passages that extend between nozzle section 85 and internal surface 121 of central hub portion 120. The plurality of passages provide a conduit or channel through which a fluid flow may pass. The fluid flow lowers temperatures of hub portion 120 to reduce any heat stress to swirler member 117. More specifically, when turbomachine 2 is run in a lean mode, heat stresses tend to develop at hub portion 120. By providing passages between hub portion 120 and nozzle section 85, fluid flows along external surface 111 of pilot tip member 106 and external surface 142 of nozzle tip member 124 to provide a cooling effect. At this point it should be understood that while shown on nozzle tip member 124, the plurality of grooves could also be formed on an internal surface (not separately labeled) of swirler member 117.
Reference will now follow to
At this point, it should be understood that the present exemplary embodiments provide a system for cooling internal portions of a turbomachine nozzle assembly. More specifically, the exemplary embodiments provide cooling passages between nozzle tip portions and an inner hub portion of a swirler member to reduce heat stress. Of course, while the plurality of grooves are shown to include generally rectangular and generally circular cross-sections, other geometries can also be employed without departing from the scope of the claimed embodiments.
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.
