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采用数值模拟计算的方法研究了90°弯管对离心压气机进口流场产生的畸变,并对比了两种弯管在不同轴向位置时其内部流场的区别,分析了弯管所致的进口畸变造成压气机性能下降的原因.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.与无弯管相比,弯管造成叶轮进口的流场紊乱.畸变引起压气机性能在大流量时有明显降低,在小流量时恶化程度较小.这是因为流量增大时,进口畸变的作用增强,可以一直发展到蜗壳入口,并与舌部引起的周向畸变联合作用导致压气机性能下降.流量减小时,进口畸变的影响会减弱叶轮流道中的损失,有利于保持近失速状态下的压气机性能.
The numerical simulation is used to study the distortion of 90 ° elbow flow field of centrifugal compressor. The difference of the internal flow field between two kinds of elbows in different axial positions is analyzed. The reason of the decrease of the performance of the compressor caused by the inlet distortion is analyzed.The results show that the deterioration of the performance of the centrifugal compressor is related to the location of the elbow and the distance to the elbow far away from the impeller.Compared with no elbow, The elbow causes turbulence in the flow field at the inlet of the impeller Distortion results in significantly reduced compressor performance at high flow rates and less at low flow rates due to increased import distortions as flow rates increase, When the flow rate decreases, the influence of the inlet distortion will weaken the loss in the flow passage of the impeller and is favorable for maintaining the performance of the compressor in the near-stall state.