基于CFD混流式水轮机上冠转轮泵结构优化研究

为研究中高水头混流式水轮机上冠转轮泵工作特性及优化可行性，以红山嘴一级电站3号水轮机为例，建立现转轮泵及11种结构优化模型，利用CFD商业软件，基于SST湍流模型对不同结构转轮泵在9种流量工况下展开数值模拟。将上冠流道泄漏水流动特性、主轴密封真空度及转轮泵效率作为研究指标，结果表明：上冠流道泄漏水流动特性依赖于转轮泵的结构类型；减小转轮泵“泵盖高度比”或斜置动泵叶对提高主轴密封真空度均有显著效果(最佳结构可提高66.9%)，同时须兼顾其工作效率；额定工况下，转轮泵工作效率较低，建议转轮上冠开设合适的泄水孔补给流量提高其效率；该电站可将泵叶斜置45°、泵盖高度比H_p=0.0543的转轮泵作为最佳改进方案。

RESEARCH ON PUMP STRUCTURE OPTIMIZATION OF FRANCIS TURBINE UPPER CROWN RUNNER BASED ON CFD

In order to study the working characteristics and optimization feasibility of the upper crown runner pump of medium and high head Francis turbine, taking the No. 3 turbine of Hongshanzui First Stage Power Station as an example, the existing runner pump and 11 structural optimization models are established, using CFD commercial software, based on The SST turbulence model carries out numerical simulations of runner pumps with different structures under 9 flow conditions. Taking the leakage flow characteristics of the upper crown channel, the vacuum degree of the main shaft seal and the working efficiency of the runner pump as the research indexes, the results show that the leakage flow characteristics of the upper crown channel depend on the structure type of the runner pump; reducing the "pump cover height ratio" of runner pump or inclining the pump blades has a significant effect on improving the vacuum degree of main shaft seal （the best structure can increase 66.9%）, and its working efficiency must be considered at the same time; under the rated working condition, the working efficiency of the runner pump is low, therefore it is recommended to set up appropriate drain holes on the upper crown of the runner to make up the flow and improve its efficiency; the power station can set the pump blades at an angle of 45° and the runner pump with pump cover height ratio H_P=0.0543 as the best improvement scheme. The study quantifies the structural parameters of the upper crown runner pump, which makes the conclusion universal, and provides a certain reference basis for adding runner pump at the top of the upper crown of medium and high head Francis turbine and its optimization.