考虑密封作用的混流式水轮机转轮动力特性分析

Dynamic Analysis of Francis Turbine Runner Considering the Effect of Sealing

大型混流式水轮机转轮振动现象严重影响了混流式水轮发电机组的安全、稳定运行,因此针对以上情况对机组转轮在实际运行中的模态特性研究就显得十分重要而有意义。本文以转子动力学为基础结合有限元分析方法,对混流式水轮机转轮进行了三维实体建模和模态分析,研究了混流式水轮机转轮在考虑密封作用影响下的动力特性,结果表明:在考虑转轮密封影响和不考虑转轮密封影响下,各阶频率和振型区别很大;密封能提高转轮的弯曲振动频率,对转轮的扭振和竖振影响较小;且随着转轮模态频率的升高,转轮的振动由整体的振动逐渐变为以叶片振动为主的振动。该方法为以后准确地分析预测机组在实际运行中转轮的振动情况提供了参考。

Large Francis turbine runner vibration phenomenon of Francis turbine has great impact on the safe and stable operation of the generating unit, so in view of the above situation, research of hydraulic turbine modal characteristics in actual operation is very important and meaningful. In this paper, finite element analysis method which is based on rotor dynamics, Francis turbine runner for the 3d entity modeling and modal analysis, Francis turbine runner are studied considering the dynamic characteristics under the influence of the sealing function. The results show that there is great difference between the frequency and mode of each order in considering and not considering the runner sealing effect; Seal can improve the bending vibration frequency of the runner and has little effection, the torsional vibration and vertical vibration of the runner; And with the increase of runner modal frequencies, the vibration of the runner as a the whole becomes gradually to the vibration predominated by the blade vibration. The method provides reference for accurate prediction of unit in actual operation in the future.