Tip Flow Fields in a Low Aspect Ratio Transonic Compressor

Abstract

Experimental data and computational predictions are used to characterize the tip flow field of a high performance, low aspect ratio, transonic compressor. Flow structures near the first stage blade tip are monitored experimentally using two different data acquisition schemes. High frequency pressure and laser fringe anemometry data are used to experimentally define the tip flow structure. The high frequency pressure data were acquired with an array of pressure transducers mounted in the rotor casing. Laser data were acquired through a window in the same position. The transducer and laser data adequately define the shock structure at the tip. Both the movement of the shock wave in the blade passage during changes in compressor loading and the interaction between the shock wave and the tip leakage vortex are detected. Similar flow structures and compressor loading effects are numerically predicted using a three-dimensional Navier-Stokes algorithm. A fundamental understanding of the flow field at the blade tip is obtained using these three complementary methods.