带90°弯管的离心压气机进口畸变数值研究

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.

Numerical Simulation on Inlet Distortion of Centrifugal Compressor with 90 degree Bent Pipe

To understand the effects of centrifugal compressor inlet distortion caused by 90°bent pipe, two different axial position inlet bent pipe were numerically simulated with compressor and the influence on compressor performance was analyzed. The results show different performance deterioration between different bent pipes, the larger distance between bent pipe outlet and impeller inlet creates more decrease. The bent pipe makes the flow field of impeller inlet strongly disordered. The distortion causes a noticeable decline in compressor performance under large mass flow and a slightly drop under low mass flow. The affect of inlet distortion amplifies and develops to the volute inlet while the mass flow rate increases, which function with circumferential distortion caused by volute tongue, makes the performance decreased. When the mass flow rate is low, the inlet distortion reduces the flow loss in impeller passage, which could maintain the performance of compressor at low mass flow.