高水头混流式水轮机内部固液两相流数值分析

针对泥沙直径对混流式水轮机蜗壳和导水机构内部流场产生影响的问题进行了初步研究,采用固液两相流模型对某电站的高水头混流式水轮机进行了全流道数值模拟,通过单一变量法来研究不同来流泥沙的直径对蜗壳和导水机构内部压力及泥沙分布产生的影响。研究结果表明:与清水相比,含沙水流会不同程度地使蜗壳和导水机构内部的水压力载荷增加,在相同工况下,蜗壳底部、蜗壳鼻端、固定导叶和活动导叶头部的泥沙浓度较大;小直径下泥沙分布均匀,随着泥沙直径的增加,泥沙浓度的梯度变大,泥沙分布更加集中,从而会使磨损加剧。该研究成果可为在含沙水流中运行的水轮机设计提供参考。

Numerical analysis of internal solid-liquid two-phase flow in high-head Francis turbine

To study the influence of sediment diameter on the internal flow field in volute and water-guide apparatus of Francis turbines, the solid-liquid two phase flow model was used to simulate the whole flow passage of the high-head Francis turbine in a hydropower station.The single variable method was adopted to study the effect of inflow sediment with different diameter on the internal pressure and sediment distribution in volute and water-guide apparatus.The results show that sediment-laden flow, compared with clean water, increases the internal water pressure load in volute and water-guide apparatus to different degrees.Under the same operating condition,sediment concentration is high at the bottom and nose of the volute as well as at the head of the stationary guide vane and moving guide vane.The distribution of sediment with small diameter is even, but as the sediment diameter increases, the sediment concentration gradient becomes larger and the sediment is more concentrated, which will intensify the wear of components.The study can provide reference for the design of turbine operating under sediment-laden flow condition.