Centrifugal compressor having an asymmetric self-recirculating casing treatment

摘要

A centrifugal compressor has a casing 7. In the casing 7 is formed a back-flow channel 9 to return fluid from a downstream position of an impeller full blade leading edge 6a to an upstream position of the impeller full blade leading edge 6a. The back-flow channel 9 includes a suction ring groove 9a and a back-flow ring groove 9b. The suction ring groove opens at the downstream position on the inner face 7a of the casing 7, and extends in the circumferential direction. The back-flow ring groove opens at the upstream position on the inner face 7a, and extends in the circumferential direction. Distribution in the circumferential direction of the axial-direction position of the suction ring groove 9a or a width of the suction ring groove 9a is asymmetric with reference to the rotation axis.