Mechanism Affecting the Performance and Stability of a Centrifugal Impeller by Changing Bleeding Positions of Self-Recirculating Casing Treatment

This study aimed to investigate the influence of bleeding position a self-circulating casing on aerodynamic performance transonic centrifugal compressor. Three types structures with positions 11% Ca (the axial chord length blade tip), 14% and 20% from leading edge were studied by using numerical simulation method, Krain impeller taken as research object. It was found that all three self-recirculating treatments can expand stable operating range impeller, at medium small flow rates, total pressure ratio efficiency increase gradually backward movement position. The treatment restrain development tip leakage vortex, reduce blockage area, improve stability sucking low-energy fluid. farther back is, greater mass rate for fluid in blade-tip passage becomes. Additionally, inhibition effect better improving be obtained. best air is Ca, but it not directly above center solid wall passage. Instead, downstream area.