The Research Of Stiffness And Dynamic Behavior About Large Part For Hydroelectric Generating Set

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.