Patent Application
20150040566
The subject matter disclosed herein relates to the art of turbomachines and, more particularly, to a helical seal for a turbomachine.
Gas turbomachines include a compressor portion linked to a turbine portion through a common compressor/turbine shaft and a combustor assembly. An inlet airflow is passed through an air intake toward the compressor portion. In the compressor portion, the inlet airflow is compressed through a number of sequential stages toward the combustor assembly. In the combustor assembly, the compressed airflow mixes with a fuel to form a combustible mixture. The combustible mixture is combusted in the combustor assembly to form hot gases. The hot gases are guided to the turbine portion through a transition piece. The hot gases expand through a number of turbine stages acting upon turbine buckets mounted on wheels to create work that is output, for example, to power a generator, a pump, or to provide power to a vehicle.
Additional gases, in the form of compressed air, flow from the compressor portion into the turbine portion for cooling. Seals are provided in the turbomachine to substantially isolate the hot gases and compressed airflow for cooling. Additional seals are positioned to prevent gases at a higher pressure leaking toward gases of a lower pressure without creating work resulting in a reduction in turbomachine efficiency. Other seals are provided about rotating components to prevent compressor airflow leakage.
According to one aspect of the exemplary embodiment, a helical seal system includes a first component, and a second component rotatable relative to the first component. The second component extends from a higher pressure portion to a lower pressure portion through an intermediate portion. A helical seal is provided on the intermediate portion of the second component. The helical seal includes at least one thread component having a pitch that is configured and disposed to draw fluids from the lower pressure portion toward the higher pressure portion when the second component is rotated.
According to another aspect of the exemplary embodiment, a turbomachine includes a housing, a compressor portion, and a turbine portion operatively connected to the compressor portion. The turbine portion includes at least one turbine stage having a turbine spacer wheel. A shaft is arranged in the housing and is operatively connected to at least one of the compressor portion and the turbine portion. The shaft extends from a higher pressure portion to a lower pressure portion. A combustor assembly including at least one combustor is fluidically connected to the compressor portion and the turbine portion. A helical seal is provided on one of the shaft and the turbine spacer wheel. The helical seal includes at least one thread component having a pitch that is configured and disposed to draw fluids from the lower pressure portion toward the higher pressure portion when the one of the shaft and the turbine spacer wheel is rotated.
According to yet another aspect of the exemplary embodiment, a turbomachine system includes a first component and a second component rotatable relative to the first component. The second component extends from a high pressure portion to a low pressure portion through an intermediate portion. A helical seal is provided on the intermediate portion of the second component. The helical seal includes at least one thread component having a pitch that is configured and disposed to draw fluids from the low pressure end toward the high pressure end when the second component is rotated.
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.
A turbomachine in accordance with an exemplary embodiment is illustrated generally at 2, in
Air enters compressor portion 4 through an inlet (not separately labeled). The air passes through a plurality of compressor stages (also not separately labeled) toward turbine portion 6 and combustor 22. Compressed air enters combustor 22 and mixes with fuel to form a combustible mixture. The combustible mixture combusts forming hot gases that flow along a hot gas path 24 of turbine portion 6. The hot gases expand through a number of turbine stages 28 toward an exhaust 29. In the exemplary embodiment shown, the hot gases expand through a first stage 30, a second stage 32, and a third stage 34. First stage 30 includes a first plurality of nozzle components 37 and blade components 38. Second stage 32 includes a second plurality of nozzle components 40 and blade components 41, and third stage 34 includes a third plurality of nozzle components 43 and blade components 44. Nozzle components 37, 40 and 43 guide the hot gases toward respective ones of blade components 38, 41 and 44. The hot gases impinge upon the blade components 38, 41 and 44 creating a rotational force that is passed to a driven system, such as a generator, a pump or the like (not shown).
Turbine portion 6 also includes a first turbine spacer wheel 47 having an outer diametric surface sealing component 48 and a second turbine spacer wheel 49 having an outer diametric surface sealing component 50. First and second turbine spacer wheels 47 and 49 are interposed between adjacent turbine wheels (not separately labeled). First turbine spacer wheel 47 is positioned between first and second stages 30 and 32 and second turbine spacer wheel 49 is positioned between second and third stages 32 and 34. Each outer diametric surface sealing components 48 and 50 includes a helical seal 55 (
As best shown in
In a manner similar to that described above, first thread component 82 and second thread component 83 each includes a pitch (not separately labeled) that pumps fluid from a low pressure portion of rotor 8 to a high pressure portion of rotor 8 to reduce ambient air ingestion along outer diametric surface 12. The particular angle of the pitch may vary depending upon the position of helical seal 80. In accordance with another aspect of the exemplary embodiment, first and second thread components 82 and 83 are materially integrally formed with outer diametric surface 12. More specifically, first thread component 82 and second thread component 53 are machined into rotor 8. However, it should be understood, that first thread component 83 and second thread component 83 may be formed on a separate sleeve-like component that is secured to outer diametric surface 12.
Reference will now follow to
In accordance with one aspect of the exemplary embodiment, thread component 113 includes a pitch (not separately labeled) that creates a reverse fluid flow across outer diametric surface 48. More specifically, the fluid flows from a low pressure portion to a high pressure portion of wheelspace portion 51 to reduce leakage flow from turbine portion 6. The particular angle of the pitch may vary. In accordance with another aspect of the exemplary embodiment, thread component 113 is materially integrally formed with outer diametric surface component 48. More specifically, thread component 113 is machined into outer diametric surface component 48. However, it should be understood, that thread component 113 may be formed on a separate sleeve-like component that is secured to first turbine spacer wheel 47.
Reference will now follow to
In a manner similar to that described above, first thread component 137 and second thread component 138 each includes a pitch (not separately labeled) that pumps fluid from a low pressure portion to a high pressure portion of wheelspace portion 51 to reduce leakage flow. The particular angle of the pitch may vary. In accordance with another aspect of the exemplary embodiment, first and second thread components 137 and 138 are materially integrally formed with outer diametric surface 48. More specifically, first and second thread components 137 and 137 are machined into first turbine spacer wheel 47. However, it should be understood, that first thread component 137 and second thread component 138 may be formed on a separate sleeve-like component that is secured to first turbine spacer wheel 47.
At this point it should be understood that the exemplary embodiments describe a helical seal that creates a reverse fluid flow to opposed leakage fluid in a turbomachine. The particular pitch of the helical seal may vary. The number and geometry of the thread components may also vary. Further, the location of the helical seal may vary and should not be considered to be limited to the particular arrangement shown. More specifically, the helical seal may be positioned as a turbine inter-stage seal, 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.
