中文摘要：

水轮机疲劳寿命问题直接关系到电站安全和工程效益的发挥。本文以国内某大型水电站安装的混流式水轮机为研究对象,通过引入新的耦合界面模型,实现了不稳定压力场与结构场的耦合特性分析。耦合计算采用有限元方法,得到了转轮在不同工况下的压力脉动载荷的时间历程。通过雨流计数法处理,获得了应力幅值及均值的概率密度函数。依据材料疲劳特性预测了转轮叶片的寿命。文中还分析了X形叶片转轮在运行稳定性方面所具有的特征。所取得的研究结果为大型水轮机的稳定运行和优化设计提供了依据。

英文摘要：

The fatigue reliability has significant effects on power plant safety and engineering benefit. By introducing a new coupled interface model, a Francis turbine installed at a large power plant in China is investigated through the unsteady fluid-structure interaction （FSI） analysis. The finite element method is adopted to solve the FSI problem. The dynamic stress of runner blade is presented in time domain and frequency domain in detail. A joint stress distribution density function describing the mean stress and amplitude is established with statistics method, including the rain flow counting algorithm. According to the fatigue properties of the blade material and the fatigue reliability model, the blade fatigue life is predicted. The operation stability of the runner with X type blade is also analyzed. The results are meaningful to stable operation and optimized design of large hydraulic turbines.