混流式水轮机上冠泵叶角度优化研究

Study on Angle Optimization of Upper Crown Pump Blade of Francis Turbine

为研究混流式水轮机转轮上冠泵板装置内部泄漏水流动特性,以红山嘴一级电站4号水轮机为例,基于计算流体力学理论,结合CFD商用软件平台,针对额定工况下辐射径向泵板装置内部流场迚行了稳态数值模拟,在模拟结果准确可靠的基础上,对泵叶布置形式迚行了优化对比分析。从泵腔内流体流态、主轴密封下侧真空度和泵板能耗三个角度分析了不同泵叶结构产生的影响。结果表明:泵板装置的存在可降低主轴密封下侧处压力,增大真空度;在同一工况下,泵叶斜置30°能耗最低且流态稳定,泵叶斜置45°主轴密封下侧能产生更大的真空度,为了满足该水电站主轴密封性能要求,泵叶斜置45°为最佳方案。

In order to study the flow characteristic of the internal leakage water in the upper crown pump plate device of the Francis turbine runner,taking the No.4 turbine of Hongshanzui first grade power station as an example,based on the computational fluid dynamics theory,combined with the CFD commercial software platform,the steady-state numerical simulation of the internal flow field of the radial pump plate device under rated condition was carried out.Based on the accurate and reliable simulation results,the layout forms of the pump blade were optimized and compared.The effects of different pump blade structures were analyzed from three aspects:the flow regime of fluid in the pump cavity,side vacuum degree under the spindle seal and energy consumption of the pump plate.The results show that the existence of the pump plate device can reduce the side pressure under the spindle seal and increase the vacuum degree;under the same working condition,when the pump blade is inclined at 30°,the energy consumption is the lowest and the flow regime is stable,and when the pump blade is inclined at 45°,the lower side under the spindle seal can generate a greater vacuum degree.In order to meet the requirements of the main shaft sealing performance of the hydropower station,the pump blade is inclined at 45°for the best solution.