关键词: 高负荷;带转速差;串列叶轮;射流-尾迹;数值模拟

Abstract: In order to make breakthroughs in the limitation of the rim speed of the centrifugal impeller due to the material stress level and advance the understanding of the fundamental mechanism of the highly-loaded centrifugal compressor stage,a highly-loaded centrifugal compressor stage with differential-rotating on tandem impellers with impeller of conventional design were investigated at design speed numerically. The differential-rotating on tandem impellers were designed using the new idea design method. Comparison and analysis for the performance and flow field between different impeller configurations showed that the whole-stage isentropic efficiency at the design point with the rational distribution of the differential-rotating on tandem impellers increased by 1.96%, the pressure ratio increased by 0.14. The losses caused by layer interactions between shock wave and boundary layer are reduced. In addition the “jet-wake” flow structure caused by secondary flow is suppressed, and the blade load distribution is redistributed, the non-uniform flow at the impeller exit is improved, and the absolute Mach number at the impeller exit is also reduced. The capacity of impeller diffusion is further improved, which contributed to the gain of the efficiency and performance of compressor stage.

Key words: Highly-loaded;Differential-rotating;Tandem impellers;Jet-wake;Numerical simulation