Multi-objective optimization design of labyrinth seal of shrouded stator cavity in a low-speed research compressor

Abstract

The shrouded stator is widely used in aero-engines and the leakage flow from the cavity has a strong effect on the performance of the stator. Due to the high degree of geometric freedom of the tooth shape, it is difficult to find the optimal geometry directly through a large number of sample calculations. In this research, a multi-objective optimization design method was used for the structure of labyrinth seal teeth and the optimal shape was found. The effect of the optimal seal teeth on the stator was analyzed in a low-speed research compressor. It is found that two different optimized shapes of seal teeth meet the optimization requirements. There is a significant difference in the cavity depth, but they have similar intervals and angles of inclination of seal teeth. The total pressure loss coefficient below 20% span decreases by 9.18% and the outlet static pressure coefficient below 20% span increases by 1.76%. For both optimal results, the leakage flow becomes closer to the pressure side of the stator. The leakage flow climbs in the radial direction in the rear of the passage. The vortex near the suction side disappears. Instead, two vortexes with opposite rotating directions exist in the passage. The range of the vortex in the radial direction expands.