Aeroacoustics benefit of stator lean effect for rotor-stator interactions

This paper focuses on the noise reduction benefit of stator lean effect for rotor-stator interaction. The compressor with different blade lean angles of downstream stator is investigated by numerical and aeroacoustic studies. The stator with three special lean angles has been employed for numerical studies to obtain the unsteady loading of the stators' blade surface. The compressor has also been tested to get the free field noise spectra at the inlet and the interface of rotor-stator of the compressor. The RMS pressure and the pressure disturbance coefficient distribution reveal the unsteady characteristics of rotor-stator interaction at different downstream stator blade lean angles. The time-spatial contours of the axial velocity demonstrates the effect of time delay on the rotor wake intersection with the leading edge of the stator blade, and the phase distribution of the wake presented the detailed distribution of the wake phase. The blade lean is effective to obtain a significant reduction for the unsteady force and to get large phase lag for the rotor's wake of rotor-stator interaction. Leaned positive blade has better benefit than the negative for the noise reduction and the phase lag of the wake. (C) 2013 Institute of Noise Control Engineering.