Single stage axial compressor stability management with self-recirculating casing treatment

A discrete self-recirculating casing treatment (RCT) with converging nozzle and Coanda jet is designed and introduced in a high speed transonic axial compressor stage. Numerical parametric studies for various injection skew/yaw angles are carried out to quantify the effect on the performance parameters such as stall margin improvement, total-to-total pressure ratio, and stage isentropic efficiency. All the investigated cases yield sufficient stall margin improvements with no loss in pressure ratio and compressor efficiency compared to the solid casing. Stall margin improvement is higher at lower speeds. Detailed flow investigation of the role played by the jet injection at the compressor endwall region is highlighted. Flow diagnostics is carried out numerically for various flow parameters such as Mach number, static pressure, and total pressure variations. The low momentum fluid that usually builds and occupies the adjacent blade passage at near stall condition is delayed further downstream due to the injection of the high-velocity jet