大型电站锅炉炉墙振动研究

大型电站锅炉炉墙结构振动的原因很复杂,主要有燃料燃烧不均匀或爆发性连续脉冲;烟气流过管束时形成的卡门涡街;炉膛空腔的声学共振;从结构外振源传来的振动等。炉墙振动过大会造成绝热层开裂、焊接松脱等恶劣后果,锅炉内爆则会引起灾难性的破坏,但目前锅炉结构设计从未考虑其动态特性。本文对国产大型电站锅炉(主要是30万千瓦电站直流锅炉)的炉墙和刚性梁振动进行了较全面的实测,对测试数据进行了谱分析和传递函数分析,研究了炉墙各区域的振幅分布及频率分布,又从相关分析中研究了振动的随机性,定性地分析了燃烧、卡门涡街、声学共振等所引起的振动的频率范围,从而肯定了目前国产30万千瓦电站锅炉炉墙振动的主要振源在于燃烧。

On the Vibration of Boiler Structures in Large Power Plants

This article describes fully the comprehensive measurement made of the vibrations of the furnace walls and the attached back stays on the boiler plants which are made in China (mainly the once-through boiler of the 300MW generating units type). The measured data are processed in order to get the power spectrum of the flue gas pressure and the welded tube wall's vibration. Moreover, the transfer function between them is analysed to detect the dynamical characteristics of the system and the randomness of the vibrations due to burning Karman vortices and sound resonance in the furnace chamber are also qualitatively examined. Finally, the paper concludes that combustion is the principal vibration source of the 300 MW doiler plants in operation in various power plantf of China; and with this, improvement measures are correspondingly suggested.