运西水电站竖井贯流式水轮机性能优化

采用雷诺时均方程(RANS),选择S-A湍流模型,运用SIMPLEC算法,利用CFD数值模拟技术,数值模拟了不同方案的运西水电站水轮机流道内流场,分析了转轮直径、叶片翼型、叶片个数、叶片安放角、转轮轮毂、转轮转速、导叶翼型、导叶轴线与机组中心线夹角、导叶个数、叶片及导叶安装位置、导叶开度对水轮机性能的影响,叶片数为3时水轮机装置性能较优,机组最高效率点分别在转速为187.5r/min、导叶个数为15时出现。对原有流道可改变部件做适当优化后,将优化后的转轮应用于电站进行数值计算,根据全流道的数值模拟结果,预测电站改造后机组的水力性能。根据数值计算的结果制作模型水轮机和真机进行模型试验和真机测试。结果表明,数值模拟结果与模型实验以及现场运行结果曲线的变化趋势一致,数值模拟结果基本能够准确反映电站的外特性和内部流场特征。

Performance optimization of shaft tubular water turbine at Yunxi hydropower station

Using Reynolds averaged Navier-Stokes (RANS) equation, the standard S-A turbulent flow model, SIMPLEC algorithm, and Computational Fluid Dynamics, we conducted numerical simulation of the flow field in the flow channel of the water turbine at Yunxi hydropower station under different schemes, and analyzed the effects of the impeller diameter, blade airfoil, number of blades, blade angle, wheel hub, impeller speed, guide vane airfoil, angle between the guide vane axis and centerline of the unit, number of guide vanes, installation positions of blades and guide vanes, and guide vane opening on the performance of the water turbine. When there were 3 blades, the performance of the turbine unit was optimal. The maximum efficiency of the unit occurred when the speed was 187.5 r/min and the number of guide vanes was 15. We optimized the parts of the original flow channel, and applied the optimized runner to the power station for numerical calculation. According to the results of numerical simulation of the whole flow channel, we predicted the hydraulic performance of the unit after renovation. According to the numerical calculation results, we made a model water turbine and conducted model tests and prototype tests. The results showed that the numerical simulation, model test, and on-site operation results had a consistent variation trend, and that the numerical simulation results can basically accurately reflect the external characteristics and internal flow field characteristics of the power station.