【作者】 吕桂萍；

【导师】 唐任远；

【作者基本信息】 沈阳工业大学 ， 电机与电器， 2004， 博士

【摘要】 水轮发电机组的振动及转轮裂纹问题多年来一直为人们所关注。近几年来，国内先后建设一批大中型水轮发电机组，如岩滩、潘家口、二滩、五强溪、小浪底等，但这些无论是国内自行设计开发还是从国外引进的机组，投入运行后，先后不同程度出现机组振动、转轮裂纹等问题，严重影响了机组的安全运行，引起水电部门及制造厂商的高度重视。 本文从我国水电事业发展需要出发，为避免水电机组产生振动及防止转轮叶片产生裂纹，对水轮发电机组大部件刚强度及动态特性的影响因素进行了研究。 从有限元的分割原理及数值插值理论出发，建立了有限元离散节点的数学模型并编制了相应的软件，主要包括： ·对三次样条插值函数进行改进，提出了有限元离散节点的计算格式及软件。在该计算格式中，实现了几何形状复杂的多维问题向一维问题的转换，从而提高了有限元离散节点的计算精度。 ·提出了缩短有限元刚强度及动态特性分析周期的技术。首先确立了从数学模型到力学模型的快速转换格式，从而缩短了分析研究周期，使得由原来需半年工作日才能完成的工作，缩短到了1个工作日内完成。 ·针对以往大部件有限元分析建模周期长等问题，建立了水轮发电机组大部件刚强度及动态特性分析建模程序库。 采用上述软件及程序对影响水轮发电机组大部件刚强度及动态特性的因素进行了研究，包括： ·从上、下机架刚度出发，提出了上、下机架筋板厚度对其刚度影响最为敏感的观点。定量地分析了筋板厚度的临界值，为筋板的优化设计提供了可靠依据。同时指出，上、下机架的固有频率与筋板的厚度成正比。 ·重新建立了定子机座动态特性分析模型，弥补了传统定子机座动态特性分析模型的不足。同时确定了对定子机座动态特性影响的主要因素。沈阳工业大学博士学位论文 .更正了传统降低叶片应力水平的观点，并给予了完善。同时增加了在叶片与下 环连接处施加补强三角块应力水平的研究。补充了施加补强三角块对X型叶片转轮 动态特性影响因素的研究，填补了施加补强三角块在X型叶片转轮动态特性缺少研 究的空白。 .根据混流式转轮动态特性，定性地分析了下环厚度对转轮固有频率的影响，提 出了转轮在水中的固有频率避开机组基频的措施，同时指出了由于转轮动态特性不 良引起机组共振的解决方向。 .定性地分析了轴流式叶片枢轴位置及尺寸与叶片动态特性的关系，提出了由于 叶片动态特性不良而使叶片产生裂纹的解决方案。 本文的研究成果己被哈尔滨电机厂有限责任公司成功地应用到三峡右岸、岩滩、龙滩、三板溪、拓林、恶滩、尼尔基、谏壁等水电站的结构设计之中，其中，岩滩、拓林机组已经投入运行，没有出现振动等现象。更多还原

【Abstract】 The vibration of hydroelectric generating set and the crack of runner have been interested in for many years. In recent years, some large-sized and medium-sized hydroelectric generating set have been built, For example YANTAN hydropower PANJIAKOU hydropower, ERTAN hydropower, WUQIANGXI hydropower and XIAOLANGDI hydropower etc. But when these sets are in motion, the variation of hydro-election generating set and crack of the runner are appearing frequently in varying degrees regardless the sets are manufactured by home or abroad, which influence safety of operationIn order to avoid the vibration of hydroelectric generating set and the create of blade in runner, the effect factors of stiffness and dynamic behavior for the large part of hydroelectric generating set have been investigated.The mathematic model of the finite element node and the software of numerical interpolation are presented by using the partitioned principle of the finite element method and the theory of numerical interpolation. The main work of this dissertation is as follow: The computational format and the software at finite element node based on the cubic spline interpolation function which has been improved by author have been presented. Using this computational format the transformation frame multiple-dimensional problem with complex geometry shape into one-dimensional problem is realized, so that computation precision is increased. The technology for shortening cycles of stiffness and dynamic performance analysis has been presented based on the fast transformation from mathematic model to mechanical model, which makes the computation time shortened from half years working day to one.In view of the problem of high time consume for model set up in the finite element analysis, the program library for analyzing the stiffness and the dynamic performances of large of hydroelectric generator has been set up. Using this software and program library the factors for influencing the stiffness and the dynamic performances have been investigated including: Through the stiffness analysis for upper and lower spider, the concept that the rib thickness is the most sensitive factor for affecting the stiffness and that the natural frequency of upper and lower spider are proportional to the rib thickness have been presented, and the critical value of rib thickness has been given through the quantitative analysis, which provides a reliable foundation for the rib optimization design. The new model for analyzing the dynamic characteristic of the stator frame has been set up, and the defect of the conventional model dynamic characteristic analysis of stator frame is remanded. The main factors to affect the dynamic characteristic of stator frame have been determined. The conventional point of view for reducing the blade stress lever has been connected and improved. The investigations on the stress lever of the blade and on the affecter factor to the dynamic characteristic of the runner with X type blade after adding the triangle blade at the joint between the outside blade and the crown have been carried out. According to the dynamic characteristics of mixed-flow runner, the affecting of the thickness of the band to the natural frequency has been analyzed and the measure for avoiding the natural frequency of the runner frame the basic frequency has been provided, and the direction for solving the resonance of hydroelectric generating set caused by had dynamic behavior of the runner is pointed out. The relationship between the position size of Kaplan turbine’s blade pivot and the blade dynamic characteristic has been investigated and the scheme for solving crack on the blade caused by had blade dynamic behavior has been presented.The result has been applied in THREE GORGES, YANTAN, LONGTAN, SANBENXI, ETAN, NIERJI, JIANBI etc. water power station by HABIN Electric machinery Co. Ltd. The YANTAN, ZHELIN water power have been moving, no vibration and crack in the set.更多还原