On the Stall and Choke Limits of Supersonic Centrifugal Impellers

Abstract

Although a supersonic centrifugal compressor develops a very high pressure ratio, it can hardly change the flow rate at a given shaft speed, therefore, it is seldom used for industrial applications. In this paper two types of impellers were tested, clarifying the problems ralative to stall and choke which decide the flow range. Regarding choke, it is shown that the throat blockage is increased with the inlet relative Mach number due to the deceleration to the throat in the case of supersonic inflow. Regarding inducer stall, it is clarified that the camber of the inducer is an important parameter in addition to the inlet relative Mach number and the incidence angle.