Study on the stability enhancement mechanism of a high-speed axial compressor under paired swirl distortion

Serpentine and buried air intake configurations are widely employed in modern fighter aircraft, which induces significant swirl distortion at the inlet and adversely affects compressor operational stability. This study investigates the instability mechanism and stability enhancement technology for high-speed axial compressors under paired swirl, employing combined numerical simulation and experimental verification. Research indicates that compressor stall is primarily caused by expansion of the tip leakage vortex and flow blockage from the forward migration. Casing treatment efficiently alleviates flow blockage by suppressing the formation and development of the tip leakage vortex, which not only improves the stall margin but also restructuring the radial flow pattern to improve the total pressure ratio, thereby facilitating more stable performance in high-speed compressors. In simulations and experiments, casing treatment increased the stall margin by 52.66% and 50.40%, respectively, while the peak efficiency saw only minor reductions of 0.05 and 0.13 percentage points, respectively.