Casing treatment using oblique slots for a single-stage transonic axial compressor

Abstract

Abstract This work presents a casing treatment design using oblique slots to improve the stability of a single-stage transonic axial compressor, NASA Stage 37. 36 individual slots are distributed uniformly on the rotors’ shroud. Numerical simulations were performed to find the effects of the casing treatment on the compressor’s stability as well as the adiabatic efficiency and pressure ratio. The oblique slots were found to effectively alleviate the negative influence of the tip leakage flow on the compressor’s performance, thus increasing the stall margin without significant sacrifices in efficiency and pressure rise. Three geometric parameters of the casing treatment were examined. The results showed that, with the oblique slots, the highest stall margin reached 13.59% - a 37% increase from the smooth casing case, with about 0.17% and 0.09% reductions in the peak efficiency and maximum pressure ratio, respectively.