微水头灯泡贯流式水轮机支撑及导叶联合设计

Joint design of supports and guide vanes in micro head bulb turbine

为了研究在1m左右的微水头的工况下,不同导流结构对灯泡贯流式水轮机内部流态及能量特性产生的影响,通过数值模拟方法,对无活动导叶的原方案进行优化,结合两种不同的支撑及两种不同宽度导叶下共六种不同方案的水轮机进行内部流场分析及性能研究.结果表明:水轮机增加导叶后,使水流在进入转轮前产生环量,但也增大了转轮前流道的水头损失;宽导叶导流后水流的切向速度及动量矩最大,但在圆周方向水流分布不均匀;窄导叶对水流的影响小于宽导叶;弯曲型支撑则将支撑和窄导叶结合起来,也结合了两者的优点,结构简单,转轮前水头损失较小,转轮进出口动量矩不是最大的,但水流对转轮的作用力矩最大,效率提高了5.8%,达82.7%,叶片表面压力变化梯度较小,空化性能良好.

The influence of different diversion structures of bulb hydro turbine on the internal flow and energy characteristics with the feature of about 1m micro water head was studied.The original scheme without guide vanes was optimized,and six different schemes of hydro turbines combined with two kinds of supports and two widths guide vanes were numerical simulated to analyze internal flow distribution and hydraulic performance.The results show that the water gets circuation by added guide vanes,but it also increases head loss of the conduit before runner.The tangential velocity and moment of momentum of water are largest after wide guide vanes diversion,while flow distribution in the circumferential direction is uneven.The impact on water flow of narrow guide vanes is less than wide guide vanes.Curved supports which are combined guide vanes with symmetric supports take advantages of them,and it has a simpler structure and lower cost before runner.Although its moment of momentum at runner inlet and outlet is smaller than some schemes,but the torque to runner caused by water flow is the largest,and the efficiency is improved by 5.8%,to 82.7%.The pressure gradient of blade surfaces is smaller with a good cavitation performance.