Stability Enhancement With Controllable Speed Casing for Transonic Compressor Rotor in Different Speed Conditions

Abstract Controllable speed casing (CSC) represents an innovative approach to casing treatment designed to enhance the adaptability of casing treatment to the variable operating conditions of compressors. This study investigates the stability enhancement mechanism and effects of CSC at different rotor speed conditions in a transonic compressor. The results indicate that CSC can improve flow stability by reducing the intensity of the shock/tip leakage vortex interaction to varying degrees when the rotor operates at 80–110% design speed. Furthermore, the stability enhancement effect increases with the rotating speed of the CSC. However, when the rotor speed decreases to 60% design speed, causing the tip flow field to transition to subsonic flow, the rotation of the CSC aggravates the backflow within the tip leakage flow, resulting in the loss of efficacy of stability enhancement.