Effect of Self-Recirculation-Casing Treatment on High Pressure Ratio Centrifugal Compressor

Abstract

The self-recirculation-casing treatment is a widely used method to enhance the aerodynamic stability of a centrifugal compressor for turbocharging in internal combustion engine. This paper presents an investigation on the effects as well as the mechanism of the self-recirculation-casing treatment on the stability enhancement of a transonic centrifugal compressor with a vaneless diffuser by a numerical method. First, the experimental measurement is carried out on the compressor with/without the self-recirculation-casing treatment for performance comparison and three-dimensional computational fluid dynamics validation. Next, the steady numerical method is applied to obtain the insights of the flowfield in the compressor with/without the self-recirculation-casing treatment. The results manifest that the stable flow range is evidently improved by the self-recirculation-casing treatment. The self-recirculation-casing treatment improves the stability of the compressor mainly due to three reasons: reduction of the blade loading, suction of the low-momentum flow near the shroud, and depression of the circumferential flow distortion in the impeller.