进口导叶/叶轮/扩压器非定常相干的数值研究

在非零进口导叶预旋角度下,采用非定常的方法对进口导叶/叶轮/扩压器三部件之间非定常相干进行了数值模拟,研究了进口导叶/叶轮/扩压器三部件之间动静相干的机理。结果表明,叶轮由于受进口导叶尾流和扩压器势反冲效应的双重非定常影响,叶轮受非定常影响最小的区域出现在叶片50%弧长附近,最大的非定常影响出现在叶轮和扩压器之间的动静交界面上。当离心压缩机前带有进口导叶预旋时,扩压器受前面两部件的同时影响,扩压器叶片上的非定常变化沿流向比较均匀。

Numerical Investigation of Unsteady IGV-Impeller-Diffuser Interaction in a Centrifugal Compressor

The present understanding of the unsteady interaction mechanism between inlet guide vane(IGV) wake with centrifugal compressor impeller and its vaned diffuser is quite rough.We carry out investigation on the motion and distortion mechanism of the IGV wake and large size vortice in the centrifugal compressor impeller and its vaned diffuser for the improvement of the reliability and aerodynamic performance of the centrifugal compressor.Numerical simulation of the unsteady IGV-impeller-diffuser interaction in a centrifugal compressor is performed.The mechanism of the unsteady IGV-impeller-diffuser interaction is explored. Results show that the minimum unsteadiness in impeller occurs to the middle part of the blade,it is due to the dual unsteady influence of the IGV wake,large size vortice behind IGV and the potential repercussion of the diffuser on the impeller;and the maximum unsteadiness appears at the hub of the interface between the impeller and vaned diffuser.When the IGV prewhirl occurs,the unsteady distribution of variation is uniform along the diffuser vane due to the simultaneous influence of IGV and impeller blade wake.