基于固液两相流动的低比转速混流式水轮机转轮内部流场模拟

Inner Flow Field Simulation of Francis Turbine Runner at Low Specific Speed Based on Solid Liquid Two-phase Flow

以云南省境内某调峰调频电站的低比转速混流式HLA351水轮机为原型,利用软件Pro/E对其转轮进行三维实体建模,采用混合四面体非结构网格对转轮模型进行网格划分,以固液两相流动数学模型为理论基础,将完成网格划分工作的转轮模型导入Fluent软件,采用SIMPLE算法,在笛卡尔坐标系中利用κ-ε-Ap两相紊流模型分别对仅有主叶片的水轮机转轮(长模型)以及主、副叶片结合的转轮(混合模型)在含沙水两相流动时的内部流场进行三维定常数值模拟。结果表明,混合模型转轮内流速和压力的分布相对于长模型更合理,从转轮进口到出口,速度差和压力差均较大,转换成旋转机械能的水能所占比重更大,水轮机效率更高,且相同部位上混合模型遭受磨损的情况更轻、性能更优。

＂Faking the low specific speed francis turbine which is in a regulative frequency and peak hydropower station in Yunnan province as prototype, the software Pro/E was used to model three-dimensional solid of runner. Mesh model of the runner was produced with unstructured tetrahedral grids. Based on the theory of solid liquid two-phase flow, the mesh model of the runner was put into the software Fluent. In the Cartesian coordinate system, the ~^-Av turbulent model and the SIMPI.E algorithm were used to numerically simulate three dimensional stationary flow of the runner with only main blade and combination of blades at the conditions of sand water two-phase flow. The results show that the mixed model of the velocity and pressure distribution of the runner flow passage is more reasonable than that of long mod- el. From the inlet of runner to the outlet, both the differences of velocity and pressure are larger. The ratio of rotational mechanical energy to water energy is larger and the efficiency of water turbine is higher. The degree of wear of the same position obtained by the mixed mode[ is smaller and the performance is excellent.