中文摘要：

本文将叶轮、无叶扩压器和弯道组合一起对弯道进行研究，充分考虑了叶轮出口的射流／尾迹结构对弯道进口气流的影响。通过对不同弯道半径r与流道宽度b的比值r／b条件下，数值研究其对离心压缩机基本级气动性能的影响。对弯道内部流动及r／b值变化与离心压缩机级的总体性能的变化关系进行详细的对比分析。研究结果表明：r／b值的变化对弯道出口气流角影响显著，并存在一个使级效率为最大值的最佳r／b值。壁面摩擦是引起弯道内部总压损失的主要因素。

英文摘要：

A numerical investigation on flow in bend coupling impeller and vaneless diffuser in the centrifugal compressor with different ratios r/b of bend radius r to bend channel width b is presented. The jet-wake effect of impeller outlet is considered and the flow analysis in the bend and the performance of the centrifugal compressor stage are investigated. The results indicate that there has been an optimal value of r/b to make efficiency of the stage to the highest for specific compressor stage. with change of r/b, It significantly affects the flow angle of bend outlet. The prime reason of causing the total pressure loss in bend is the wall friction in the bend channel.