Analysis of Stall Inception Characteristics in a Contra-Rotating Compressor Under Circumferential Pressure Distortion Conditions

The complex aerodynamic configuration of a contra-rotating compressor leads to intricate stall disturbance characteristics. This study investigates a large-scale, low-speed axial contra-rotating compressor using high-frequency dynamic pressure sensors mounted at the tip of the front and rear rotors to capture initial stall disturbances under varying inlet conditions. The results indicate that under uniform inflow, stall disturbances at the design speed manifest as rotating stall, consistently propagating in the direction of the rear rotor’s rotation. When the inlet condition is altered to circumferential pressure distortion, the stall characteristics remain similar to those observed in uniform inflow. However, the swirl induced by pressure distortion causes significant fluctuations in the pre-stall pressure sequence upstream of the distorted region, with the disturbance energy gradually intensifying over time. Furthermore, a cross-correlation algorithm effectively identifies these pre-stall disturbances, demonstrating improved stall warning capabilities compared to uniform inflow conditions.