Recirculation casing treatment by using a vaned passage for a transonic axial-flow compressor

Abstract The tip leakage flow has an important influence on compressor performance particularly for the case of transonic compressors. Recirculation casing treatment is an effective approach to control the tip clearance flow which results in stability enhancement. Numerical simulations for a high-speed axial-flow compressor rotor with endwall recirculation, applying a state of the art design for the recirculation passageway are presented in the current study. Anti-swirl vanes are placed in the recirculation passageway. The effects of recirculation casing treatment on the compressor overall characteristics, stability, blade loading, and flow field are presented and discussed. Results show a significant range extension with a very small penalty in efficiency. Besides, the recirculated mass flow is only a few per cent of the main flowrate.