Numerical investigation of stator suction-type self-circulating casing treatment effects on the aerodynamic performance of a single-stage axial flow compressor

This study addresses the technical challenge that conventional self-recirculating casing treatments predominantly enhance the compressor stability with minimal efficiency gains. Focusing on a transonic axial flow compressor, National Aeronautics and Space Administration Stage35, the research designed an innovative stator suction-type self-circulating casing treatment (SS-SCT), which features the suction slots on the stator instead of the traditional self-circulating casing treatment's suction port. Using multipassage unsteady numerical simulations, this paper investigated the underlying mechanisms by which the SS-SCT affects the compressor performance. The numerical results reveal that the SS-SCT not only increases the compressor stall margin by 3.36% but also enhances the efficiency by 0.13% at the design point and by 0.6% at the near-stall point. The jetting action of the SS-SCT mitigates the detrimental effects of the rotor tip leakage flow and alleviates the blockages in the rotor tip passage at the near-stall point, thereby improving the compressor stability. Concurrently, the suction slots extract the low-speed fluid generated by the boundary layer separation in the stator passage, reducing flow losses, and consequently enhancing the compressor efficiency.