导叶开度对混流式水轮机转轮内部流态的影响

基于数值模拟方法，以梯级水光蓄互补联合发电系统示范工程中的猛固桥电站混流式水轮机为研究对象，对水轮机在不同特征水头、不同导叶开度工况下转轮叶片表面受力及流道内流场特性进行研究，分析导叶开度改变对水轮机转轮内流态的影响规律。结果表明：导叶开度对于混流式转轮进口流态的影响较大，导叶开度越小入流速度波动程度越大，来流对叶片头部冲击越大，在进口处产生严重的冲击损失；随导叶开度减小，转轮叶片表面等压线与进口边夹角增大，在上冠交接区域产生小三角区低压，使转轮流道出口更易产生空化损失。

Effect of Opening Degree of Guide Vane on the Internal Flow Pattern of Francis Turbine Runner

On the basis of numerical simulation method,taking Mengguqiao Hydropower Station in the demonstration project of combined generation system with cascade hydro photovoltaic pumped hybrid power as the research object,the surface forces and internal flow patterns of runner blades of hydroturbine under different water head and opening degree of guide vane were studied,and the influence rule of the change degree of opening of guide vane on the flow patterns of turbine runner was analyzed.The results show that the opening degree has strong bear on the inlet flow pattern of the Francis turbine runner. The lower the opening degree of guide vane is,the greater the fluctuation of the inlet flow velocity is,and the larger the impact of incoming flow on the head of blade is,which causes the serious impact loss at the inlet.With the reducing of opening degree of guide vane,the angle between the runner blade surface isobaric and inlet side increases,and the low pressure of small triangle is produced in the upper crown intersection area,which makes the runner outlet more easily produce the cavitation loss.