大型双向流道泵装置优化匹配与试验研究

研究了一种双向流道立式泵装置,综合考虑了进水流道出口流速分布均匀度和进水流道水力损失2个目标函数,应用CFD技术对双向进水流道喇叭口悬空高度进行了多方案的优化比选,当悬空高等于0.57D(D为水泵叶轮直径)时进水流道水力损失增加较小,且流道出口流速分布均匀度最好.通过对出水流道喇叭管出口高度的多方案计算比较,得到双向出水流道扩散喇叭管出口高度对流道水力性能的影响规律:当出水流道扩散喇叭管的高度较高时,流速较大,流道水力损失较大;随着扩散喇叭管高度的逐渐降低,出水流道水力损失逐渐减小;当喇叭管的高度降低到一定程度,水力扩散损失占据主导作用,随着喇叭管高度的进一步降低,其水力扩散损失越来越大;当喇叭管出口至流道顶板高度等于0.48D时,对应的出水喇叭管高度为最优.将优化匹配的双向进出水流道配置优选的水泵模型,进行泵装置模型试验,在低扬程3.26 m时,装置效率可达71.2%,可为同类型泵装置的优化设计提供参考.

Hydrodynamic optimization of large pump installation with two-way channel and experiment

Large vertical pump installations with two-way channel have been widely used in reversible pumping stations. However, the optimal design theory and method for the two-way channel remain imperfect, causing a low hydraulic efficiency in such an installation. Consequently, a vertical pump installation with two-way channel is studied. By considering the velocity uniformity at the outlet of entry channel and the hydraulic loss across the channel as two objective functions, the open height of the channel is optimized using CFD technique through comparing multiple design cases. It is shown that when the open height is equal to 0.57D the hydraulic loss not only increases less but the outlet velocity uniformity is also the best. The effects of discharge channel height on hydraulic performance of the discharge channel are identified. A bigger discharge channel height can result in a higher discharge velocity and a more significant hydraulic loss. The hydraulic loss across the discharge channel decreases gradually with reducing discharge channel height. However, once the height is below a certain value, the diffusion hydraulic loss in the channel becomes dominant, causing an increasing hydraulic loss. This suggests that there is an optimal discharge channel height at which the minimum hydraulic loss is achievable. In this paper, this height is 0.48D. An optimally selected pump is installed in a pumping installation with the optimized two-way channel, then a hydraulic performance test on the installation is carried out, showing 71.9% hydraulic efficiency at 3.26 m low net head. This two-way channel can provide a reference for installation optimization of the same sort of pumps in the future.