Investigation into effects of interaction among suction flow, shock wave and separation flow for a transonic compressor cascade

To explore a better control method of separating flow by reconstructing shock waves through boundary layer suction (BLS) technique, a high load transonic compressor cascade with BLS has been studied by numerical simulation. The BLS slot is located downstream of leading edge shock wave impingement point. The results show that with increase of BLS mass flow rate (C_m), the peak of Mach number on suction surface is enhanced and the shock wave moves downstream, which could increase the loss of shock wave while decreases the loss of boundary layer. The amount of improvement for the total pressure recovery coefficient is more than the decreased. For the cascade of this paper, cascade performance is improved with the increasing of C_m, but there is an optimum C_m of 1.2%. Compared 1.2% C_m with 0.0% C_m conditions, 1.2% C_m leads to the cascade total pressure recovery coefficient increase of 10%, boundary layer shape factor decrease of 18%, deviation angle decrease of 5° while the pressure rise keeps constant. Small C_m can not effectively improve the internal boundary layer flow parameters when the BLS slot rear of shock wave has been implemented. The boundary layer flow is greatly imporved when it is realized by BLS that the impingement point of oblique shock wave original from the cascade leading edge float downstream to the rear of passage shock wave.