【摘要】 混流式水轮机转轮内流是复杂的非定常三维湍流流动,由于结构上的原因,转轮在非设计工况下工作时会形成不稳定流场,产生三维非定常的附面层分离,同时进一步形成贯穿整个流道的叶道涡,影响转轮的运行稳定性。目前,转轮内流场的研究还只是基于通过数值模拟对速度场和压力场进行观察和分析,但对于各种分离流动机理性研究还做得不够深入。非线性动力学主要研究非线性动力系统中各种运动状态的定性和定量的变化规律,以及系统的长时间演化行为,其可以用于流体旋涡和分离流动机理分析。本文将通过对一个模型转轮数值模拟结果的动力学特性分析,对混流式水轮机非设计工况运行时内流分离和失稳的破坏形式加以分析。更多还原

【Abstract】 Inner flow in Francis turbine runner is a kind of complex unsteady 3-D turbulent flow.Because of the special structure,the inner flow field is unstable in off-designed operation point with unsteady 3-D boundary layer separation.At the same time,the channel vortex is induced along the whole massage,which can affect the operation stability of the runner.Nowadays,the research for inner flow field in runner still depends on the observation and analysis for velocity and pressure distribution obtained from numerical simulation.But the theoretical research for separation flow is not profound.The nonlinear dynamics mainly studies the qualitative and quantitative variation law for the movement status,and the evolvement behavior for a long time in nonlinear dynamic system,which can be used to study the vortex and separation flow.更多还原