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本文以压比为6.1的跨音速离心叶轮为研究对象,采用定常和非定常数值模拟分析了叶尖区域激波与泄漏涡的相互作用和泄漏涡的非定常特征.随着流量减小,激波与泄漏涡的相互作用增强,最终导致泄漏涡破裂.小流量下泄漏涡的破裂引起叶片载荷的变化,叶片载荷的变化反过来影响泄漏涡的强弱,如此形成一个非定常循环过程.单通道模拟得出非定常流动的频率为0.668 BPF,双通道和三通道模拟得到的频率则为0.88 BPF.但三种模型得出的非定常机理相同.“,”In this paper,the transonic centrifugal impeller with a pressure ration of 6.1 is choose as the study object.The unsteady characteristics of tip leakage vortex and the interaction between shock and tip leakage vortex in the tip region are investigated by steady and unsteady numerical simulation.The results shows that,the interaction between shock and tip leakage vortex becomes stronger as the mass flow rate decreases,and finally the tip leakage vortex breaks down.At snall mass flow rate,the broken-downed tip leakage vortex induces the variation of blade loadings.In turn,the changed blade loadings will alter the intensity of tip leakage vortex.Such alternative behavior finally results in the periodic process.The single-passage numerical simulation shows that the oscillation frequency of unsteady flow is 0.668 BPF,and the two-passage and three-passage simulations indicate the oscillation frequency is 0.88 BPF,but the three numerical models shows the same unsteady flow mechanism.