三峡电站厂房结构振动计算与试验研究

Computation of vibration in powerhouse of Three Gorges Project and prototype verification

本文利用三峡电站73m水头水轮机模型试验中脉动压力的实测数据,构造出整个流道内脉动压力场,求出了厂房结构在各种振源联合作用下的动力响应。为了验证计算结果并完善下一步研究工作中的计算模型,还对三峡发电厂房的结构振动进行了现场测试,并与计算结果进行对比。结果表明,厂房结构的竖向位移的幅值、频率和最大值位置与计算结果比较接近,这不仅验证了厂房结构的竖向位移是由尾水管内的脉动压力引起,而且说明计算模型中尾水管内的荷载假定是可行的。同时,对于竖向加速度,除去峰值区域的测点外,测试结果的幅值与计算结果相差不大。由于蜗壳内以及导叶后转轮前区域的脉动压力频率在模型与原型的转换关系上存在不确定性,以及计算中没有考虑直接作用于楼板上的母线电磁力,使得楼板竖向加速度测试结果的幅值存在峰值区域,且其频率与计算结果存在偏差。

The pulsating pressure data measured in draft tube of hydro-turbine model test for the Three Gorges Power Station working under 73 m water head are utilized to generate the pulsating pressure field in the whole flow passage. On this basis, the dynamic responses of the powerhouse under the combined actions of different vibration sources are calculated. The computational result is verified by prototype measurement data. The comparison shows that the prototype measured vertical displacement of the powerhouse floor is in good agreement with the computational amplitude, frequency and position of maximum value. It verifies that the vertical displacement of the powerhouse is caused by the pulsating pressure occurred in draft tube. Furthermore, the agreement of vertical acceleration between computation and prototype measurement are also fair except for the measurement points in the area of peak value.