基于内流场的能量回收透平的结构优化

摘要

A type of horizontal double-channel francis hydraulic turbine was designed based on the working principle of vane hydraulic machinery. In order to optimize its structure, ensure the performances and maximize the efficiency of water-power recovery, a three-dimentional tubulence numerical simulation was performed for the inner flow field of the turbine with and without guide vanes under clear water medium, based on the Navier-Stokes equation and the standard two-equation turbulent model of κ-ε, using the body-fitted coordinates, unstructured-tetrahedron grid and SIMPLEC algorithm. The research indicates that compared to the turbines without guide vanes,the velocity circulation and pressure distribution in the runner＇s blade inlet, the velocity and pressure distribution in the blade surface and the internal flow state of the draft tube are more uniformity when the guide vanes exist,which increases the energy conversion index of the runner and provides a theoretical and practical reference for the further researches on the structure of energy recovery turbines.%基于叶片式水力机械工作原理，设计出一种卧式双流道混流式水力透平机。为了对其结构进行优化，保证性能，使水能回收效率最大化，基于Navier—Stokes方程和标准的κ-ε双方程紊流模型，采用贴体坐标、非结构化四面体网格和SIMPLEC算法，对无导叶和有导叶的透平机在清水介质下的内部流场进行三维湍流数值模拟计算。研究结果表明：有导叶的水力透平机转轮叶片进口处速度环量、压力分布、叶片上的速度与压力分布以及吸出管内的流动状态都要优于无导叶的水力透平机，从而增加了转轮的能量转换指数。模拟结果为进一步研究能量回收透平机的结构提供了理论依据和实际应用参考。