An Investigation of the IGV/Rotor Interaction in a Low Speed Axial Compressor Using DPIV

IGV/rotor interaction phenomenon in axial compressors is important, because different matching states of IGV and rotor can result in significant differences in performance of the compressors. An experimental investigation of IGV/rotor interaction is performed on a one stage low speed axial compressor. The performance of the compressor is measured with the number of IGV varied within a wide range. Different IGV results in very different performance of the compressor, and the performance does not change with the number of IGV monotonously. Flow field around a rotor blade is measured using 2D Digital Particle Image Velocimetry (DPIV) and dynamic pressure probes, without IGV and with the IGV which brings the largest stall margin to the compressor. Comparison of flow fields reveals that the IGV wakes change the flow field around the rotor blade significantly. The wake of the rotor blade is weakened and its structure is changed. The rotor exit total pressure is elevated throughout the entire span. The tip leakage flow is suppressed, so relevant blockage is reduced and consequently the stable operating range of the compressor is extended. The relatively high turbulence intensity and periodic changes in flow velocity and direction brought by IGV wakes to the rotor may account for some of the observed changes in the flow field structure and the compressor performance. The flow instability and receptivity theory must be included to explain all the experimental results, and to utilize the rotor/stator interaction phenomena during the compressors design process.