Impact of IGV/rotor interaction on rotor flow field in an axial compressor

The IGV/rotor interaction phenomenon in turbomachinery has been research focuses for years, but until now such researches have been restricted to qualitative description of flow phenomenon without theory instructions. So this very important unsteady phenomenon can not be included in turbomachinery design regime to further improve turbomachinery performance. By the theory of flow instability and receptivity, the rule of using this phenomenon to improve turbomachinery performance can be found. The IGV/rotor interaction phenomenon in a one stage low speed axial compressor was investigated experimentally. A 2D digital particle image velocimetry was used to acquire the quantitative flow field structure around the rotor with and without IGV. The rotor flow is evidently unsteady even under steady flow condition. With IGV/rotor interaction, the rotor flow field was changed significantly. The intensity of rotor wakes was reduced, flow separation on rotor suction side was suppressed and the tip leakage flow was suppressed periodically. Besides IGV wake interaction and periodic variation in flow angle, different response of the rotor unsteady flow to different unsteady IGV/rotor excitation frequency was decided to be the most important reason for the compressor performance changes.