随着我国水电事业的快速发展以及水电设备制造水平的提高，水轮机的单机容量、水力效率、空化性能等参数不断提高，与此同时，由于振动引起的稳定性问题却日益突出，水轮机组关键部件产生裂纹破坏的现象普遍存在，已经成为制约水电站经济效益以及我国水电事业发展的重要因素。研究并提高水轮机的稳定性，以及开发认识其稳定性的有效方法，有着至关重要的意义。研究水轮机的应力特性是研究其稳定性最为直观、最为有效的方法。水轮机的应力特性主要由其自身结构和所承受的载荷决定。工作状态下的水轮机内部是一个非常复杂的流固耦合问题：水流流过固定导叶、活动导叶、转轮等过流部件表面，在结构表面形成的压力差、冲击等使结构产生变形、振动；而变形振动的结构又反过来影响流场。当水轮机在偏离最优工况以及变工况下运行时，这种流固耦合效应尤为明显。随着计算机技术以及数值仿真技术的不断发展，流固耦合方法逐渐成为一个热门的研究课题，越来越多的学者运用流固耦合方法来解决工程实际问题，流固耦合技术在水轮机设计过程中也得到了广泛的应用，并取得了良好的成果。本文主要工作内容：（1）对混流式水轮机进行三维湍流定常计算，分析其流动特性；以流动计算的结果为基础，采用单向耦合方法，计算转轮的静应力，分析静应力变化的规律。（2）研究水轮机转轮强度优化的规律及方法，并对转轮几何模型进行优化。（3）采用顺序流固耦合方法，计算水轮机转轮的动应力，并分析动应力的特性。

With the development of hydropower and hydropower equipment manufacturing level, the unit capacity water efficiency cavitation performance and so on of Francis Turbine are increasing. But the stability problem caused by vibration is increasingly prominent. In recent years, crack damage of key components of Turbine is widespread, which has been an important restricted factor of the economic benefits of hydropower station and the development of hydropower of China. It has crucial importance to research and improve the stability of the turbine, and to develop an effective way to understand the stability of Francis Turbine.Stress characteristic of Turbine Runner is the most intuitive show of the stability of it. The stress characteristic of turbine runner is determined by its own structure and the load of it. It’s a very complex problem when the turbine in operation state because of its complex FSI effect. The pressure differences on structure surfaces are produced when the water flow by the surface of vanes, guide vanes runner and so on. Then the vanes guide vanes and runner deform because of the pressure difference. At the same time the deformations vibrations of the structure which in turn affects the flow field. And this FSI effect is particularly evident when the turbine is running far from the optimal operating conditions .With the development of computer technology and numerical simulation technology, FSI method has become a very hot research topic, and a growing number of scholars used FSI methods to solve their engineering problems, and achieved good results. Main content of this article: (1) Analyze the flow characteristics of Francis Turbine with steady three-dimensional turbulent flow method. Then calculate the static stress of turbine runner with one-way coupling method.(2) The study of runner strength optimization, and optimize the geometry of turbine runner.(3) Transient stress calculation with the two way coupled method. Analysis the stress characteristics of Francis turbine runner