水轮机泥沙磨损两相湍流场数值模拟

为研究水轮机内部泥沙磨损的固液两相流动特性,应用基于计算多相流动力学理论中欧拉-欧拉方法的代数滑移混合多相流模型,采用多面体网格技术、标准k-ε湍流模型和压力速度耦合的SIMPLEC算法,转动区域应用多重参考系模型,对混流式水轮机全流道进行了三维定常泥沙磨损两相湍流场的数值模拟.利用商业CFD求解器ANSYS Fluent,获得了小开度工况下水轮机泥沙磨损发生的部位与程度,分析水轮机流道内泥沙磨损的特征规律,其中叶片上泥沙颗粒分布模拟结果与真机转轮实际磨损情况相符,表明该方法可以准确预测水轮机各过流部件的泥沙磨损情况,对揭示泥沙颗粒与水相互作用的固液两相湍流场诱发水轮机振动的影响机理及解决工程实际问题具有重要的意义,而且具有较高的工程应用价值.

Numerical simulation of two-phase turbulent flow in Francis turbine passage on sediment erosion

This study aims to investigate the flow behavior of solid-liquid two-phase flow based on sediment erosion in Francis turbine, the numerical simulation of three-dimensional two-phase turbulent flow in the Francis turbine passage was conducted by the mixture model for an algebraic slip formulation in the Euler—Euler approach based on the CMFD theory, the polyhedron mesh technique, standard k-ε model, SIMPLEC algorithm and multiple reference frame model. The silt volume fraction distributions in guide vanes and blade passage were obtained in the small opening case by the ANSYS Fluent software. The position and degree of sediment erosion in the Francis turbine passage were analyzed. The simulation results coincided with the distribution of sediment particles on the blade runner practical wear. The results show that this method can be used to simulate the 3D turbulent flow and true multiphase flow with sediment erosion in Francis turbine,which provides a significant reference for revealing the influence mechanism of the sediment particles interacting with water in the solid-liquid two-phase turbulent flow field that can induce turbine vibration and solving practical engineering problems.