基于CFD的主轴密封泵板装置结构优化设计

Structural optimization design of impeller vane of shaft seal pump based on CFD

为研究混流式水轮机主轴密封泵板装置内泄漏水流动特性,应用计算流体动力学软件,针对新疆红山嘴一级电站4号水轮机,将不同泵板装置作为研究对象,研究提高其水力效率的可行性以及对主轴密封降压的效果.在模型准确基础上对泵叶角度和泵盖高度分别进行改进,对两者联合结构共计22种改进模型进行数值模拟.研究结果表明:泵叶斜置45°且泵盖高度比为0.0815的联合改进结构对主轴密封真空度提高率可达60.9%;泵盖高度比比泵叶角度改变对该装置水力效率提高更有利;泵盖存在“最不利高度比”,泵盖位置的确定需避免最不利高度比0.1359.该研究结果将模型结构参数化使得结论的普适性有一定提高,为工程实际主轴密封设计改造提供了一定的理论依据.

In order to study the leakage water flow characteristics in the shaft seal of the pump impeller in the Francis turbine,CFD software was used to explore the feasibility of improving hydraulic efficiency and pressure reduction effect in the shaft seal in term of No.4 turbine in the Xinjiang Hongshanzui 1st cascade hydropower station based on different pump impellers.The impeller vane angle and height were varied on the basis of model accuracy,respectively.Twenty-two improved geometric models were numerically simulated in total.The results show that the impeller with 45°vane angle and 0.0815 height ratio can increase the vacuum degree in the shaft seal by 60.9%.The change in vane height is more favorable to the hydraulic efficiency improvement of the impeller than that in vane angle.There is a most unfavorable height ratio for the impeller shroud.In the position determination of the shroud,the most unfavorable height ratio of 0.1359 must be avoided.Since the study is based on parameterization of model structure,the universality of conclusion is improved in some extent,and a certain theoretical basis is provided for the shaft seal design and transformation in engineering.