Effect of axial short slot casing treatment and its center deviation on stability of a transonic axial flow compressor

In order to increase the stability margin of axial compressor with low efficiency losses, this paper studies the influence of axial short slot casing treatment and its axial position on compressor performance. A transonic axial compressor rotor, NASA rotor37, is taken as the research object, and the solid wall case and three axial slot casing treatments with different axial positions are studied by numerical simulation. The results show that the configuration with a center deviation of 0 (CT _C) has the best effect, with a margin improvement of 7.6% and an efficiency reduction of 0.09%; the configuration with an upstream positioned axial slot (CT_L) is the second, with a margin improvement of 5.4% and an efficiency reduction of 0.28%; the configuration with a downstream positioned axial slot (CT_T) is the worst, with a margin improvement of 3.6% and an efficiency reduction of 0.3%. A shift of the slot in downstream direction is not effective because it only affects the extent of boundary layer separation and has little effect on the development of the tip leakage flow. The upstream positioned axial slot with unsatisfactory effect affects the tip leakage flow trajectory and weakens the radial vortex at the blade tip, but it cannot affect the subsequent development of the leakage vortex. The short slot casing treatment in the central position effectively inhibits the development of the vortex. At the same time, it affects the development of the boundary layer to some extent and ensures the lower efficiency reduction while obtaining better stability margin.