Influence of bleeding positions in self-recirculating casing treatments on the stability of a subsonic axial compressor

Abstract

The three-dimensional numerical simulation was used to study the effects of self-recirculating casing treatment (SRCT) on the stability and performance of a subsonic axial flow compressor. The control variable method was used to compare three SRCT structures with different axial bleeding positions. The mechanism of the influence of different SRCTs on the compressor stability was revealed. Unsteady calculation results show that as the bleeding position moves downstream, the stall margin obtained by SRCT increases first and then decreases. SRCTs with bleeding positions at 0.4, 0.8, and 1.3 axial chord length (Ca) obtain 19.74%, 22.72%, and 15.97% stall margin improvement, respectively. The internal flow field analysis shows that the 0.8Ca bleeding position is close to the low-speed fluid at the blade tip, and there is a large pressure difference between the bleeding port and the injection port. This structure can suppress the secondary flow in the blade passage, thereby reducing the mixing loss caused by the tip leakage flow and the mainstream. The airflow inside the SRCT with 0.8Ca bleeding position is smooth, and the flow loss caused by the bleeding effect is low. Therefore, the compressor efficiency of this structure is the highest.