1. College of Water Conservancy & Hydropower Engineering, Hohai University, Nanjing, Jiangsu 210098, China; 2. College of Energy & Electrical Engineering, Hohai University, Nanjing, Jiangsu 210000, China; 3. Canal Irrigation Management of Jiangsu Province, Huaian, Jiangsu 223200, China
In order to study influences of number of guide vanes and their relative position on the performance of an axial-flow pump unit, the diffusers with three different numbers of guide vanes and four different relative positions were designed. Base on computational fluid dynamics software, the flows under five working conditions of(0.8-1.2)Qd were calculated and analyzed for each diffuser model. According to the results of numerical simulation, the optimal diffuser model was selected, i.e. the number of guide vanes was 5 and the distance between the runner exit and the diffuser inlet was 0.086D, and then an experiment on the performance of a pump unit with this model was carried out. The experimental data were compared with the numerically simulated results. The results showed that at a constant number of impeller blades increased number of guide vanes raised the hydraulic loss across the diffuser and outlet conduit, resulting in a declined pump unit efficiency. When the numbers of impeller blades and guide vanes are kept constant, a too large or too small distance between the runner exit and the diffuser inlet decreases the hydraulic loss across the diffuser and outlet conduit as well as the outlet velocity circulation at the diffuser exit, showing an impaired pump unit efficiency. The error between experiment and numerical simulation was within 4%, confirming the reliable and accurate numerical simulations. The results can provide a reference for hydraulic design optimization of diffuser and efficiency improvement of pump unit.
GUO Chu-,ZHENG Yuan-*,ZHOU Da-Qing- et al. Effects of number of guide vanes and their relative position on performance of a low head axial-flow pump unit[J]. Journal of Drainage and Irrigation Machinery Engin, 2019, 37(3): 204-210.
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