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利用商用CFD软件对一小型车用离心压气机建立了数值模型,并将模拟结果与实验结果进行了对比:稳态的设计转速最高压比相差不超过0.5%,最高效率相差不超过1.5%;非稳态模拟和实验得到的失速频率均为3000Hz,模拟结果真实可信。主要利用设计转速下小流量工况时的非稳态数值模拟结果对喘振发生前离心压气机各部件的非稳态流动特点进行了详尽阐述。研究结果表明:小流量工况时离心压气机各部件均出现非稳态流动现象,这种非稳态效应在各部件中表现出不同的特点,且随着流量的减小这种非稳态效应会不断加剧。
A commercial CFD software was used to establish a numerical model for a small centrifugal compressor. The simulation results were compared with the experimental results. The steady state design speed did not differ by more than 0.5% and the maximum efficiency did not differ by more than 1.5%. Unsteady state simulation and experimentally obtained stall frequency are 3000Hz, the simulation results are credible. The characteristics of unsteady flow in each component of the centrifugal compressor before the surge are expounded in detail by using the unsteady numerical simulation results at the low flow rate conditions at design speed. The results show that the unsteady flow phenomenon occurs in all parts of the centrifugal compressor under the condition of low flow rate, and this unsteady state has different characteristics in all components. With the decrease of flow rate, this unsteady state The effect will continue to intensify.