Effect of axial slot casing treatment on a counter-rotating axial compressor performance and stability

Abstract

For the purpose of exploring the stall margin improvement capacity potential of axial slot casing treatment (ASCT) technology in the axial counter-rotating compressor (CRAC), the effects of ASCT position and radial deflection angle on the overall performance and stall margin of the counter-rotating axial compressor were studied by numerical method. To reveal the stability expansion mechanism of ASCT in a counter-rotating axial compressor and the effect of casing treatment on the rotor/rotor interference effect between the front and rear rotors. The results show that the axial slot position has little effect on stall margin improvement, but has a great influence on peak efficiency. The peak efficiency loss can be reduced by increasing the radial deflection angle of the ASCT. The stall margin can be improved by about 10% by arranging the ASCT on the rear rotor. The suppression of tip leakage flow by axial slot and the transport of low-energy fluid in tip region can delay the occurrence of the stall, but the mixing of flow in slot increases the efficiency loss.