采用数值模拟计算的方法研究了90°弯管对涡轮增压器装配的离心压气机进口流场产生的畸变，比较了两种不同轴向位置弯管所致的进口畸变对压气机性能的影响，并对压气机内部的三维非定常流动进行了频域分析．结果表明，弯管畸变对离心压气机性能的恶化程度与弯管所在位置有关，距离叶轮进口较远的弯管影响较大．畸变引起压气机性能在大流量时有明显降低，在小流量时性能恶化程度较小．弯管畸变导致叶轮进口前的压力脉动增强，大流量时改变了叶轮流道上游和叶顶间隙内的压力频谱结构，显著提高了转子基频的扰动强度．同时畸变也造成了叶片振动和蜗壳舌部噪声的恶化，在小流量工况下的作用更加明显．%Inlet distortion from 90° bend-pipe of turbocharger centrifugal compressor was investlgated by numerical simulation. Performance of compressors with two different axial position bend-pipe inlets was compared and the internal unsteady flow was analyzed by frequency-domain method. Results show deterioration in performance strongly depends on position of bent pipes, and large influence is presented in the case where impeller has long distance to bent pipe outlet. Distortion makes noticeable decline in com- pressor performance under large mass flow and slight drop under low mass flow. The pressure fluctuation at impeller inlet is increased because of bend-pipe distortion, altering the frequency spectrum structure of impeller upstream and tip clearance, and resulting in enhancement on rotor dominant frequency amplitude. The distortion also makes the blade vibration and aerodynamic noise at tongue especially at low mass flow rate.
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