水流激励下转轮叶片的振动与裂纹耦合机理及安全评估方法研究

项目名称： 水流激励下转轮叶片的振动与裂纹耦合机理及安全评估方法研究

项目编号： No.51465001

项目类型： 地区科学基金项目

立项/批准年度： 2015

项目学科： 机械、仪表工业

项目作者： 李兆军

作者单位： 广西大学

项目金额： 48万元

中文摘要： 转轮叶片的振动与裂纹问题不仅严重影响到其自身的正常工作，更直接关系到水轮发电机组的安全稳定运行，因而积极开展有关水轮发电机组转轮叶片的振动特性及其疲劳裂纹形成与扩展机理等问题广泛而深入的研究，对确保水电站安全高效运作是十分迫切的任务。本项目在分析水流激励下转轮叶片流固耦合关系以及转轮叶片疲劳裂纹特征的基础上，应用有限单元法建立能全面反映转轮叶片水力、机械、裂纹故障和动力学状态的非线性流固耦合动力学方程，根据非线性振动理论和断裂力学理论研究转轮叶片在水流激励下的振动规律及其疲劳裂纹动态变化规律，探明转轮叶片的振动行为与水力参数、结构参数、裂纹故障参数之间的内在关系，揭示水流激励下转轮叶片的振动与裂纹之间的耦合机理，进而根据安全系统工程理论确定转轮叶片的安全评估方法，从而为转轮叶片的设计、制造、运行及控制等提供更多和更加接近客观实际的理论依据。

中文关键词： 转轮叶片；流固耦合；非线性振动；疲劳裂纹；安全评估

英文摘要： The vibration and cracks of runner blades not only seriously affect their normal work, but also directly affect the stable operation of hydraulic turbine-generator unit. Therefore, it is a great urgent task to deeply study the vibration characteristics of runner blades and the mechanism of fatigue crack formation and propagation of runner blades in order to ensure that the hydropower station can work well. So the purpose of this project is to study the vibration-crack interaction mechanism and safety assessment method of runner blades exerted by the hydraulic excitation. Firstly, based on the fluid-structure interaction relation and crack characteristics of runner blades under the hydraulic excitation, the nonlinear fluid-structure interaction dynamic equations of runner blades are established by the finite element methods, which can reflect the characteristics of fluid, structure, crack and dynamics of runner blades. Secondly, based on the nonlinear vibration theories and the fracture mechanics, the vibration characteristics of runner blades and the dynamic characteristics of cracks of runner blades are studied, when the runner blades are subjected to the hydraulic excitation. Thirdly, based on the dynamic equations of runner blades, the intrinsic relations among the dynamic characteristics of runner blades and the hydraulic parameters, structural parameters and cracked parameters are discovered. Fourthly, the vibration-crack interaction mechanism of runner blades is obtained by analyzing the nonlinear fluid-structure interaction vibration and the dynamic characteristics of cracks of runner blades. Finally, according to the theory of safety system engineering, the safety assessment method of runner blades is determined based on the vibration-crack interaction relation of runner blades. The above studies can provide actual theories for the designing, manufacturing, running and controlling of runner blades.

英文关键词： Runner blade;Fluid-structure interaction;Nonlinear vibration;Fatigue crack;Safety assessment