Flow Pattern of Rotating Stall Cell in Axial Compressor

The results of measurements of the three-dimensional flowfield in a low-speed single-stage compressor operating in deep rotating stall are presented in this paper. The measurement technique includes a specially designed omnidirectional five-hole pressure probe, a specially designed near-wall hot-wire probe, high-frequency pressure transducers, and oil flow visualization. The test results provide a detailed description of the flow in and around the stall cell. The flow pattern of the cell is described by velocity vectors, streamlines, and pressure contours. A definition of the stall cell is proposed by using the streamlines in the frame of reference of the stall cell. Upstream of the rotor, the stall cell is characterized by a reversed jet flow at the rotor’s tip and downstream flow at the midspan and hub. Downstream of the stator, the stall cell is composed of low-speed wake flow with circumferential flow near the shroud from the trailing edge to the leading edge of the stall cell.