Experimental and numerical study on stability enhancement casing treatment in a counter-rotating axial compressor

To fill the gap in experimental research on adaptive stability enhancement casing treatment in stabilization of the counter-rotating axial compressor (CRAC), this paper takes a two-stage CRAC as the research object, and conducts a discrete distributed self-recirculating casing treatment (SRCT) stability augmentation experiment. The stabilization improvement approach previously proposed, cross-stage front-jet SRCT (F_SRCT) scheme, is verified by dynamic measurement experimentation. The results show that F_SRCT can increase the stall margin by 7.21 % at the design speed condition. At the range of 50 % ∼ 100 % speed conditions, F_SRCT improves the stall margin by 5.80 % ∼ 8.12 % without reducing the peak efficiency. Besides, F_SRCT also increases the total pressure ratio by 0.30 % ∼ 1.16 %, which indicates that F_SRCT promotes the power capacity of the rotors. F_SRCT changes the propagation form and velocity of stall cells, diminishes the circumferential propagation of stall cells and mitigates the flow instability between stages, thereby suppressing the stall onset and altering the mode of stall development. Additionally, the beneficial effect of F_SRCT on the tip flow field accelerates the instability recovery rate, which enhances the safety of mechanical operation. The aforementioned surprised results highlight the potential for achieving adaptive stabilization of CRACs, thereby laying a solid foundation and confidence for future research work.