Abstract:In general, the flow in centrifugal pumps is exceedingly complex, especially under part-load condition in which rotation stall, flow separation and secondary flow are involved. The accuracy of CFD simulation of internal flow in a centrifugal pump under part-load condition is very important. However, this issue is rarely mentioned in literature. In this paper, a structured mesh in a low specific speed centrifugal pump is generated and the turbulent flow in the pump including suction pipe, impeller and volute is simulated by means of software ANSYS CFX 14.5. A grid-independence check is conducted when total number of cells and the number of cells in the impeller fluid domain are changed at 0.6 and 1.0 times the design flow rate. The head and absolute velocities in the impeller and volute obtained by PIV are adopted as more reasonable indexes to evaluate the CFD accuracy. It is shown that the grid-independence analysis can be performed satisfactorily by increasing total number of grid cells, but increasing the number of mesh cells of the impeller fluid domain is unnecessary. The number of grid cells has a great effect on the absolute velocity of fluid in the impeller, but a little impact on the absolute velocity in the volute. The accuracy of predicted absolute velocity in the volute and impeller under the design condition is higher than that at 0.6Qd. Comparisons in flow field and performance curve suggest the mesh model should be IGD eventually. These results will be helpful to the study on unstable. characteristics of internal flow in a low specific speed centrifugal pump under part-load condition by making use of numerical simulation technique.
张金凤, 黄茜, 袁寿其, 冒杰云, 王业芳. 基于PIV的低比转数离心泵网格无关性[J]. 排灌机械工程学报, 2016, 34(7): 567-572.
ZHANG Jinfeng, HUANG Xi, YUAN Shouqi, MAO Jieyun, WANG Yefang. Grid-independence in low specific speed centrifugal pump based on PIV. Journal of Drainage and Irrigation Machinery Engin, 2016, 34(7): 567-572.
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