【摘要】 基于N-S方程和标准k-ε紊流模型,用数值模拟的方法分析了混流式水轮机活动导叶和转轮的匹配关系。计算了3种不同比转速水轮机对应导叶高度下的导叶和转轮的耦合流动,分析了活动导叶出流角与转轮进水角的匹配关系,活动导叶出流角和转轮进水角与活动导叶几何出水角的关系。结果表明,转轮从上冠到下环进水角不同,导叶沿高度方向出口轴面速度和转轮沿高度方向进口轴面速度是不均匀的,导叶沿高度方向出口速度矩和转轮沿高度方向进口速度矩也是不均匀的。用数值模拟的方法计算了水力损失,并通过与试验结果的比较,提出了水力设计或改型优化设计时的注意事项。更多还原

【Abstract】 Based on N-S equation and the standard k-ε turbulence model, the numerical simulations of flow field through three different specific speed Francis turbines including the guide vanes and the runner were performed. The effect of three different wicket gate heights on the matching between the runner and the guide vanes were investigated. The matching between the guide vanes outlet angle and the runner inlet angle, the relationship between the outflow angle of the guide vane and the inflow angle of the runner and the guide vane geometric outlet angle were also analyzed respectively. The investigated results showed that the distribution of the runner inflow angle was uneven from the crown to the band, that the distribution of the meridional velocity at guide vane outlet and the one at runner inlet were inhomogeneous along altitude direction. Similarly, the distribution of the speed moment at guide vane outlet and the one at runner inlet was uneven. Based on the calculated results of flow field, the hydraulic efficiencies corresponding to these different wicket gate heights were obtained and were compared to experimental results. Attention should be paid to hydraulic design for type modification.更多还原