【作者】 杨晓明；

【导师】 马震岳；

【作者基本信息】 大连理工大学 ， 水利水电工程， 2006， 博士

【摘要】 随着水电建设的快速发展，机组容量和尺寸急剧增大，转速相应提高，机组振动及其诱发的水电站厂房结构振动问题日益突出，成为目前研究的热点和难点。我国已建的一些高水头、大容量水电站，出现了明显的振动问题，影响了机组的正常运行。针对这些实际问题，对机组振源和振动的研究更加紧迫。本文分析了水轮机密封系统的非线性动力特性，研究了水轮发电机组支承结构即导轴承、推力轴承的动力特性，探讨了机组动荷载传递方式。通过研究厂房、机组及其传力系统振动力学模型的建立，分析机组与厂房的动力特性，从而为机组和厂房结构的动力优化设计和振动控制提供理论指导和技术依据，具有重要的科学意义和工程价值。 第一章绪论部分介绍了水电站机组与厂房结构的振动问题和研究现状，对机组支承结构即导轴承、推力轴承动力特性、水轮机迷宫密封系统振动特性及机组动荷载作用方式及传递途径进行了简要的描述。 第二章用有限元法建立了水轮发电机组轴系振动力学模型，计算机组轴系统横向振动的自振频率，研究分析立式机组轴系统的稳定性。通过改变系统各参量，对机组临界转速和动力反应进行了敏感性分析，提出对振源控制和机组轴系统结构优化的建议，为合理选择机组形式和优化支承结构提供依据。 第三章研究了推力轴承与导轴承对水轮发电机组的耦合作用。用有限元法建立了轴系横向振动力学模型，采用复模态分析方法计算了机组轴系统横向回转振动的自振频率及临界转速。分析了推力轴承与导轴承耦合作用对立式机组轴系统稳定性的影响。 第四章分析了在Muszynska非线性密封力作用下水轮机转轮密封系统自激振动的动力特性，研究迷宫密封对水轮机转轮系统动力稳定性的影响。分别采用Muszvnska非线性密封力模型与八参数线性模型，分析了密封结构对系统运动特性的影响。 第五章研究弹性支承对水轮机密封系统的影响。本章在上一章的基础上假设采用短轴承支承，用非线性油膜力模拟系统的弹性支承，建立弹性支承水轮机密封系统力学模型，并与刚性支承进行对比，分析临界失稳转速的变化情况。 第六章考虑了导轴承动力特性的不固定性，研究机组与厂房耦合系统的动力学问题，揭示耦联振动的机理，建立了水电站机组与厂房的耦联振动模型，分析机组与厂房的动力特性及其相互影响。通过不同计算模型的比较，探讨水电站机组与厂房的相互作用机理，为以后的水电站厂房、水轮发电机组的抗振设计提供有益的参考。更多还原

【Abstract】 The capacity and dimension of water turbinegenerating set has been sharply increasing with the rapid development of hydropower construction. At the same time, rotational speed has been increasing correspondingly. As a result, the vibration problem of water turbinegenerating set and the vibration of hydropower station’s house are standing out gradually, which becomes an important issue to be studied. Obvious vibration has been happening in some hydropower stations with large capacity and high water head, which affects the normal work of water turbinegenerating sets. So it is an urgent work to study the vibration sources and vibration problems.nonlinear dynamic characterastics of labyrinth seal-rotating wheel system in hydraulic turbines has been analyzed in this thesis. Dynamic characteristics of journal bearing and thrust bearing have also been studied. The action and transmit mode of vibration loads has been discussed. A vibration mechanical model of hydropower house, water turbinegenerating set and transmit force system has been made to research their dynamic characteristics, which would provide theoretical and technical instruction for optimizing the structure and controlling the vibration of hydropower house and water turbinegenerating set.Chapter one simply introduces the vibration of hydropower house and water turbinegenerating set and its studying situation. This part also simply summarizes the dynamic characteristics of supporting structure, the vibration characteristics of seal-rotating wheel system in hydraulic turbines and the action and transmit mode of vibration loads.In chapter two, the lateral vibration mechanical model of shaft system is created based on the finite element method (FEM), and the critical rotation speed of transverse revolving vibration of shaft system is calculated. Sensitivity analysis of critical rotate speed and dynamic response is performed by changing different parameters of the system. According to the results, the thesis gives suggestions about how to control the vibration sources and how to optimized the structure of shaft system in water turbinegenerating set.In chapter three, the couple behavior between the thrust bearing and journal bearing of water turbinegenerating set is investigated. The finite element method is used to analysis the lateral vibration mechanical model of shaft system, the natural frequency of transverse revolving vibration of shaft system is calculated according to complex model method. Through analysis the influence of couple behavior between thrust bearing and journal bearing to investigate stability of shaft system in water turbinegenerating set.更多还原