Effect Of Circumferential Total Pressure Distortion On Stability In An Axial Flow Compressor

The effect of circumferential total pressure distortion on aerodynamic stability was experimentally investigated in an axial flow compressor. Different circumferential distorted inflow fields were generated with a flat-baffle installed upstream the compressor. Using a collection of time-resolved pressure transducers mounted circumferentially and along the axial chord direction, the stall route, stall inception, and end-wall flow field were captured and systematically analyzed. Results show that the stall margin nearly linearly deteriorates as the distortion intensity increases. Although the propagating speed of stall inception is not influenced by the circumferential distorted inflow, its scale increases with the increment of the distortion intensity. In addition, the stall inception appears and develops into mature stall cell with small distortion intensity, which is similar to the uniform inflow. With strong circumferential distortion, the initiation of stall inception is affected by the inlet circumferential non-uniform. The disturbance appears downstream the circumferential distorted region because the unsteady fluctuation of tip leakage vortex is intense at the distorted region. Thereafter, it disappears at the undistorted region when the end-wall flow field recovers at undistorted region. The disturbance goes through several times of initiation-propagation-disappearance process before the stall inception formation. The rotating stall occurs when the disturbance does not disappear at the undistorted region. Through this investigation, the understanding of stall mechanism is deepened in the axial flow compressor with the circumferential distortion.