| 摘要 |
An axial flow or centrifugal flow compressor having arrays of blades (16) extending across a working medium flowpath (18) includes a casing treatment for enhancing the compressor's fluid dynamic stability. In one variant of the invention the casing treatment comprises one or more circumferentially extending grooves (40) that each receive indigenous fluid from the compressor flowpath at a fluid extraction site (56) and discharge indigenous fluid into the flowpath at a fluid injection site (58), circumferentially offset from the extraction site, where the migrated fluid is better able to advance against an adverse pressure gradient in the flowpath. Each groove is oriented so that the discharged fluid enters the flowpath with a streamwise directional component that promotes efficient and reliable integration of the introduced fluid into the flowpath fluid stream (20). In a second variant of the invention, the casing treatment comprises a circumferentially extending compartment (62), typically comprising a voluminous pressure compensation chamber (64) and a single passage (66) circumferentially coextensive with the chamber, for establishing fluid communication between the chamber and the flowpath. The voluminous character of the compartment attenuates the inordinate circumferential pressure difference across the tips of excessively loaded compressor blades (16), making the compressor less susceptible to tip vortex induced instabilities. One embodiment of the pressure compensating variant includes a passage (66) oriented similarly to the groove (40) of the grooved variant of the casing treatment so that fluid flowing from the passage enters the flowpath with a streamwise directional component.
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