关键词: 离心压气机;叶轮;叶片;流场特性;性能优化;数值仿真

Abstract: The method of offset splitter blade in traditional integrated centrifugal impeller is used for reference to enhance the performance of a high pressure ratio tandem centrifugal compressor. Numerical simulation is applied to analyze the effects of the exducer blade clocking arrangement on the flow field and performance of a high pressure ratio tandem centrifugal compressor. Based on the analysis of flow fields in compressor with different exducer offset values, the relationship between compressor flow losses and offset value is established. The results show that employing larger offset parameter γ can reduce the shock intensity at exducer blade 1 leading edge, which can also improve leakage vortex breakdown and flow separation caused by shock wave. But in cases of larger or smaller offset parameter, the low energy fluid mixing loss increases due to secondary leakage flow in the exducer tip region. The compressor exhibits the best overall performance with offset value of γ=65%. The pressure ratio and efficiency for case of γ=65% are improved by 1.5% and 1.4% than those for case of γ=50%, respectively. On the premise of no appearance of significant secondary leakage in exducer tip, a high value of the circumferential offset γ is to be adopted for exducer blade clocking arrangement optimization of tandem centrifugal compressor. Meanwhile the wake fluid of inducer balde should be prevented from participating in the exducer tip leakage.

Key words: Centrifugal compressor;Impeller;Blade;Flow field characteristics;Performance optimization;Numerical simulation