抽汽式机组油膜振荡的产生机理及处理措施

某台抽汽式机组在带负荷的过程中突然出现了比较罕见的油膜振荡,并且尚未确定哪些因素激发了本次油膜振荡.为了避免机组在运行过程中再出现油膜振荡,对引起该枫组发生油膜振荡的机理进行了研究.结果表明,一方面,轴承检修过程存在容易引起轴承自激振动故障的缺陷；另一方面,由于转子热态中心与冷态中心之间的区别,在机组投运抽汽的过程中,蒸汽干扰力与轴承本身的缺陷相互耦合导致油膜振荡故障.通过对该轴承的顶隙进行处理,该轴承的振动大幅降低,投抽汽时再也没有出现过油膜自激振动.验证了抽汽产生的蒸汽干扰力和轴承本身稳定性不好是导致该机组出现油膜振荡的两个主要因素,为抽汽式机组的设计、安装和运行提供重要参考.

Generation Mechanism and Treatment for Oil Whip of Extraction Steam Unit

An unusual oil whip occurred suddenly in an extraction steam unit during the process with load, and the factors caused the oil whip were uncertain. In order to avoid oil whip occurring again during operation, the mechanism of oil whip of the unit was analyzed. The analysis showed that, on the one hand there were defects during bearing ma- intenance process which easily caused self-excited vibration. On the other hand, due to the rotor center difference be- tween thermal state and cold state, the steam interference and rotor defects coupling together led to oil whip during steam extraction. By reducing the top-clearance of the bearing,the vibration was decreased greatly, and oil self-excit- ed vibration does not occur by steam extraction. It verifies that the two main factors for oil self-excited vibration were steam interference caused by extraction and bad stability of bearing. It provides reference for design, installation and operation of extraction steam unit.