变转速下跨声速压气机的耦合扩稳方法

To explore an effective method to improve the stall margin of a transonic compressor at different operating speeds, this study couples the slot casing treatment and tip injection to enhance the compressor stability. The effects of the number, length, width of the slots and the nozzle circumferential width on the compressor performance are studied parametrically, and the mechanism of stability enhancement is revealed using unsteady numerical simulations. The results show that the stall margin increases by 9.31%, 8.26% and 8.68% at 100%, 80% and 60% speed, respectively, while the compressor efficiency at the design point is decreased correspondingly by 0.77%, 0.23% and 0.41%. The number, length and width of the slots have significant effects on the stall margin and the efficiency of the compressor, while the circumferential width of the nozzle has little effect on the compressor performance. A flow cycle composed of suction and injection is formed in the coupled casing treatment. The increase of the coupling strength is beneficial to the improvement of the stall margin, and detrimental to the compressor efficiency. The coupling casing treatment leads to the increase of the blade tip loading, meanwhile reducing the tip leakage intensity and eliminating the tip blockage caused by the tip leakage vortex, which is the main reason for the improvement of the compressor stall margin. The coupling casing treatment has the potential to enhance effectively the compressor stability at different speeds.