In order to investigate the effect of bulk swirl on performance and stability of axial compressor

blade swirl generator was designed and numerically simulated with a transonic single rotor. The results showed that counter-rotating bulk swirl caused significant drop in coefficient and stall margin and increase in choke mass flow

angle of attack and total pressure ratio. Co-rotating bulk swirl led to decrease of choke mass flow

attack angle

total pressure ratio and stable operating range

and increase of coefficient. Co-rotating bulk swirl caused suction surface boundary layer separation beyond 50% blade span

and more serious tip leakage blocking

contributing a lot to unstable compressor.