润滑油剪切流动对发电机不稳定振动影响分析  

Analysis of Influence of Shear Flow of Lubricating Oil on Unstable Vibration of Generator Unit

作　　者：李振 杨建刚[2] 陈慧慧 何明圆 王洪凯 LI Zhen;YANG Jiangang;CHEN Huihui;HE Mingyuan;WANG Hongkai(Fujian Fuqing Nuclear Power Co.,Ltd.,Fuqing 350318,China;School of Energy and Environment,Southeast University,Nanjing 211102,China)

机构地区：[1]福建福清核电有限公司,福建福清350318 [2]东南大学能源与环境学院,江苏南京211102

出　　处：《原子能科学技术》2024年第S01期149-156,共8页Atomic Energy Science and Technology

基　　金：中核集团“青年英才”项目。

摘　　要：为研究核电站发电机组上发生的不稳定振动现象,建立了考虑润滑油剪切流动热效应的转子动力学分析模型。采用一维能量平衡方程求解润滑油在轴承微小间隙内流动引发的轴颈温差,将温差产生的等效热弯矩作用于转轴上,得到了发电机组转子弯曲变形。采用有限元法建立了弯曲转子在不平衡力激励下的动力学模型。研究结果表明,轴承间隙内润滑油剪切流动会导致轴颈截面出现温差。在核电机组轴承参数合理范围内,温差会达到10℃,其对振动的影响相当于发电机转轴上G2.5级不平衡量的影响。剪切流动产生旋转性不平衡量,导致振动波动。其对振动的影响和润滑油黏度、轴承间隙、偏心率和不平衡力等因素有关。减小润滑油黏度、增大轴承间隙、减小偏心率和不平衡量可以减小不稳定振动。开展了调节润滑油温工程验证试验,试验结果表明提高润滑油温以减小润滑油黏度,有助于减小不稳定振动,计算分析结果与工程实践结果一致。本研究建立的模型能够用于核电站发电机组不稳定振动分析。In order to study the unstable vibration of generator unit in nuclear power plant,a rotor dynamics analysis model was established,in which the thermal effect induced by oil shear flow in bearing was considered.One-dimensional energy balance equation was used to solve the journal temperature difference caused by the flow of lubricating oil in the bearing small gap.The average journal temperature difference and its angle during a whirling cycle were obtained.The effect of crosssectional temperature gradient on shaft bending deformation was calculated,and the equivalent bending moment was obtained.The equivalent bending moment was input to the shaft in finite element model,and the bending deformation of the generator shaft was calculated.The results show that the temperature difference of the journal is induced by the shear flow of lubricating oil in the bearing clearance.The temperature difference of the journal increases with the increase of journal eccentricity and bearing clearance.After the eccentricity of the journal increases to a certain extent and the bearing clearance decreases to a certain extent,the temperature difference of the journal section increases rapidly,exhibiting typical nonlinear characteristics.If the amplitude of synchronous whirling orbit increases,the dynamic eccentricity increases and the cross-sectional temperature difference increases.Journal temperature difference of a certain nuclear power generation unit was calculated using the model.Within a reasonable range of bearing parameters in nuclear power units,the temperature difference can reach 10℃.Its impact on vibration is equivalent to the impact of G2.5 level imbalance force on the generator.The periodic vibration fluctuation phenomenon that occurred on a certain type of nuclear power unit was introduced.Test shows that the fluctuation amplitude is related to the lubricating oil temperature.It is pointed that the journal temperature difference produces rotational unbalance,resulting in vibration fluctuation.Unstable vibration is re

关 键 词：轴承 热弯曲 发电机 温度梯度 剪切流动 

分 类 号：TL48[核科学技术—核技术及应用] TM623.7[电气工程—电力系统及自动化]