为解决汽轮机组低压缸轴承振动大的问题，对低压转子振动响应特性进行了研究。基于转子动力学理论建立了转子-轴承支撑系统有限元分析模型，考虑支撑刚度对转子系统振动的影响，计算了不同支撑刚度下转子轴承振动、轴振和绝对轴振响应特性。研究表明：不同支撑刚度下转子不平衡振动响应差异较大，柔性支撑下，轴承振动较大，轴振较小；转子绝对轴振能够较为真实的反映实际振动情况，3 000 r/min工作转速时，柔性支撑下轴承振动对转子不平衡力变化较为敏感；现场可通过精细动平衡降低轴承振动。

In order to solve the abnormal bearing vibration fault of lowpressure cylinder of steam turbine unit,the vibration response characteristics of lowpressure rotor are studied.Based on rotor dynamics theory,the finite element analysis model of rotorbearing support system is established.Considering the influence of support stiffness on rotor system vibration,the relationship among bearing vibration,relative shaft vibration and absolute shaft vibration under different support stiffness is calculated.The analysis shows that the rotor unbalance vibration response is different under different support stiffnesses.Under flexible support,the bearing vibration is relatively larger than shaft vibration.The absolute shaft vibration of the rotor can reflect the actual vibration situation.When the working speed is 3 000 r/min,the bearing vibration under the flexible support is more sensitive to the variation of rotor unbalance force.The bearing vibration can be reduced by the fine dgnamic balance on site.

TK261