离心泵全流场与非全流场数值计算

为研究不同计算域对离心泵数值计算结果的影响,采用虚拟分块网格划分技术和标准k-ε湍流模型,对5台不同比转数离心泵设计工况下的内部流动进行了三维定常全流场与非全流场数值模拟.基于全流场和非全流场数值计算结果分别进行了性能预测和内流场特征分析,并将性能预测结果与试验结果进行了对比分析.结果表明：不同计算域对数值计算结果影响显著;全流场数值模拟性能预测精度高于非全流场数值模拟,扬程预测精度平均高1.54%,效率预测精度平均高1.67%;流场分析发现两种计算方法得到叶轮内的静压分布基本一致,而蜗壳内静压分布存在着明显差异;全流场数值计算得到的叶轮与蜗壳的间隙速度分布呈现层状分布,而非全流场数值计算得到的结果呈三角形分布;由于全流场计算区域考虑叶轮进口口环、前后盖板间隙流的影响,其数值计算得到的蜗壳断面内二次流分布并不完全对称.

Numerical calculation of whole and non-whole flow field in centrifugal pumps

numerical Based on the whole and non-whole flow domain methods, the influence of flow domain on the results in centrifugal pumps was investigated by calculating three-dimensional steady incompressible turbulent flows. The standard k -ε turbulence model and virtual block technology were also adopted. The internal flow fields and hydraulic performance of five centrifugal pumps with different specific speeds were calculated at the design conditions. Also, the hydraulic performance obtained was compared with the test. It is observed that the influence of flow domain is remarkable. The whole flow domain method shows a higher accuracy rather than the non-whole flow domain one, for example, the prediction accuracies in head and efficiency are improved by 1.54% and 1.67%, respectively. The static pressure distributions in the impellers obtained by the two methods are basically the same, but those in the volutes are significantly different. The velocity profile in the gap between impeller and volute is layered for the whole domain method. However, it is triangular for the non-whole domain one. The secondary flow pattern within the cross-seetions of volute is not completely symmetry, h is believed that the flows in the wearing-ring gap and the chamber between the impeller and the pump casing, whieh have been considered in the whole flow domain method, affect the development of that secondary flow.