摘要：通过某水电站2台混流式水轮机现场振动、噪声试验，对1#机组运行时出现异常噪声的振源进行查找，同时采用锤击法对水轮机蝶阀层压力钢管进行固有频率测试。分析发现，某种水力激振频率与压力钢管的固有频率在92%以上负荷区域运行时发生耦合并引起压力钢管共振，是导致异常噪声的主要原因。在此基础上提出了活门出水边修型以及加装蜗壳进人门孔导流板的处理方案，最终通过改善流道环境，使水力激振频率得到大幅提高，并降低了涡列能量，起到了很好的错频消振效果。研究表明，通畅的流道环境对于有效避免由于水力激振或涡列振动引起的结构共振问题具有重要意义。

[Abstract]: The vibration source of abnormal noise produced when unit 1# is running is researched, through vibration and noise test of two francis turbines of certain hydraulic power station. The natural frequency of the penstock is tested at the butterfly valve floor by hammering method. It is found that when load is above approximately 92 percent, certain hydraulic exciting frequency is coupling with the natural frequency of the penstock and cause resonance phenomenon, which is main cause of abnormal noise. furthermore, processing scheme of modifying the outlet edge of butterfly valve and adding guide plate to the man door of the spiral case is presented. Finally, by improving the through-flow environment, hydraulic exciting frequency is increased greatly and energy of vortex is reduced. This method has very good effect on eliminating vibration. Research indicates that expedite through-flow environment has important significance on avoiding resonance of structure caused by hydraulic exciting or vortex vibration.