Nishida Yoshifumi, Kobayashi Hiromi, Nishida Hideo, Sugimura Kazuyuki
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J Turbomach. 2013 May;135(3):0310261-310268. doi: 10.1115/1.4007518. Epub 2013 Mar 25.
The effect of the design parameters of a return channel on the performance of a multistage centrifugal compressor was numerically investigated, and the shape of the return channel was optimized using a multiobjective optimization method based on a genetic algorithm to improve the performance of the centrifugal compressor. The results of sensitivity analysis using Latin hypercube sampling suggested that the inlet-to-outlet area ratio of the return vane affected the total pressure loss in the return channel, and that the inlet-to-outlet radius ratio of the return vane affected the outlet flow angle from the return vane. Moreover, this analysis suggested that the number of return vanes affected both the loss and the flow angle at the outlet. As a result of optimization, the number of return vane was increased from 14 to 22 and the area ratio was decreased from 0.71 to 0.66. The radius ratio was also decreased from 2.1 to 2.0. Performance tests on a centrifugal compressor with two return channels (the original design and optimized design) were carried out using two-stage test apparatus. The measured flow distribution exhibited a swirl flow in the center region and a reversed swirl flow near the hub and shroud sides. The exit flow of the optimized design was more uniform than that of the original design. For the optimized design, the overall two-stage efficiency and pressure coefficient were increased by 0.7% and 1.5%, respectively. Moreover, the second-stage efficiency and pressure coefficient were respectively increased by 1.0% and 3.2%. It is considered that the increase in the second-stage efficiency was caused by the increased uniformity of the flow, and the rise in the pressure coefficient was caused by a decrease in the residual swirl flow. It was thus concluded from the numerical and experimental results that the optimized return channel improved the performance of the multistage centrifugal compressor.
数值研究了回流通道设计参数对多级离心压缩机性能的影响，并采用基于遗传算法的多目标优化方法对回流通道形状进行了优化，以提高离心压缩机的性能。基于拉丁超立方抽样的敏感性分析结果表明，回流叶片的进出口面积比对回流通道中的总压损失有影响，回流叶片的进出口半径比对回流叶片的出口流动角有影响。此外，该分析表明，回流叶片数量对出口处的损失和流动角均有影响。优化结果是，回流叶片数量从14个增加到22个，面积比从0.71降低到0.66，半径比也从2.1降低到2.0。使用两级试验装置对具有两种回流通道（原始设计和优化设计）的离心压缩机进行了性能测试。实测的流动分布在中心区域呈现出旋流，在轮毂和机匣侧附近呈现出反向旋流。优化设计的出口流动比原始设计更均匀。对于优化设计，两级整体效率和压力系数分别提高了0.7%和1.5%。此外，第二级效率和压力系数分别提高了1.0%和3.2%。认为第二级效率的提高是由流动均匀性增加所致，压力系数的升高是由残余旋流的减小所致。因此，从数值和实验结果得出结论，优化后的回流通道提高了多级离心压缩机的性能。
