Numerical analysis of stall margin enhancing casing treatments of a small size centrifugal compressor stage

In the present paper, two different casing treatment configurations were designed firstly to enhance the stall margin of a small size centrifugal compressor stage. The results indicate that traditional inlet recirculation at impeller inlet does not extend the stall margin of the stage, and the circumferential grooves only extend the stall margin by about 2.41%. Thus a new type casing treatment configuration which adopts inlet recirculation and circumferential grooves simultaneously was proposed in this paper. The results indicate that the new configuration expends the stall margin by about 13.25%.