厂顶溢流式水电站厂房振动分析

本文以国内某厂顶溢流式厂房为研究对象,建立了动力分析有限元模型,结合厂房结构自振特性及可能的振源特性进行了共振校核。根据试验资料,利用相关分析原理推求了水流的点-面脉动压力转换系数,采用时程分析法比较了机组动荷载和水流脉动压力对结构振动响应幅值和频率特性的影响。研究表明,水流脉动压力频率与厂房结构的自振频率相差较大,不会引发厂房结构的共振;机组荷载是引起厂房结构振动的主要因素,水流脉动压力的影响较小;厂房上部结构的振动响应水平高于下部结构,因此设计中应注意上部结构的刚度突变问题。

Vibration analysis of roof overflow powerhouse

For a roof overflow powerhouse under construction in China,a dynamic finite element model of the powerhouse was established to study its vibration characteristics.First the natural frequencies and vibration model were calculated,then the resonance check was made by analyzing some possible excitation sources.According to the available experimental data the conversion coefficient of fluctuating pressure from-point-to-area was deduced through the correlation analysis theory.Detailed studies on the amplitude and frequency characteristics of the structural vibration induced by the fluctuating pressure of flow and the dynamic loads generated by the hydrogenerators were conducted.The study leads to the conclusions that there is little possibility of powerhouse resonance due to the large frequency difference between the fluctuating pressure of flow and the natural frequency of the powerhouse;the main cause leading to the powerhouse vibration is the oscillation of the water-turbine generator set;the upper part of the powerhouse is more sensitive to the vibration response than the lower part,so more attention should be paid in design.