大容量燃气热水锅炉对流管束的振动分析和预防措施

针对一台58 MW燃气热水锅炉部分对流管束产生的开裂现象进行了深入的原因分析.对断口部分进行了宏观检查、金相组织分析和扫描电镜分析,对烟气冲刷对流管束时气柱的固有(驻波)频率、卡门涡流频率和水管固有振动频率分别进行了计算,并对该锅炉的对流管束进行了振动测试,得出了对流管束产生管子的共振会引发部分对流管脆性断裂的结论.并据此提出了一系列具体的预防和控制措施及建议,通过改变管子的固有频率解决此类问题的发生,为锅炉的安全稳定运行提供保障.

Vibration analysis and precaution of convection tube banks on a large-capacity gas-fuel fired hot water boiler

The cause of cracking of partial convection tube banks on a 58 MW gas-fuel fired hot water boiler was analyzed in this paper.A macroscopic examination on the fracture surface was carried out,and a microstructure analysis and scanning electron microscopy (SEM) analysis were made.Calculations were performed to obtain the natural (VSWR) frequency and Karman vortex frequency of the gas column resulting from flue gas flowing over the convection tube banks and the natural vibration frequency of water tubes,respectively.A vibration test on the convection tube banks of the boiler was conducted.It was concluded from the calculations and test that the tubes resonance of convection tube banks could lead to the brittle fracture of partial convection tubes.In addition,concrete precaution and control measures,and suggestions were offered.By changing the natural frequency of the tubes,e.g.,the tubes resonance and the brittle fracture of partial convection tubes can be avoided and the safe and steady operation of the boiler can be guaranteed.