水轮机径向滑动轴承润滑特性研究

发布时间：2018-03-20 10:54

本文选题：水轮机　切入点：径向滑动轴承　出处：《浙江大学》2014年硕士论文　论文类型：学位论文

【摘要】：由于旋转机械系统中各种异常振动的存在,常常引发灾难性的事故,其原因很难用线性理论来解释,人们逐渐认识到必须用非线性动力学理论来分析。多瓦可倾瓦滑动轴承常用于大型的汽轮机、水轮机和压缩机等旋转机械上,其工作性能直接影响整个机器的工作状态,因此,有必要对水轮机径向滑动轴承的润滑特性进行系统研究。本文第一部分阐述了研究水轮机径向滑动轴承润滑特性的工程意义,介绍了国内外研究径向滑动轴承润滑特性的相关方法和结论等,从转子动力学、瓦面热变形和瞬态热弹流润滑理论等几方面综述了径向滑动轴承润滑特性的研究进展,并以此提出了本文的研究内容。第二部分建立了考虑制造误差的多瓦可倾瓦径向滑动轴承热弹流润滑(TEHD)分析的计算模型,计算得到了考虑制造误差时的瓦块油膜厚度、油膜压力、瓦面温度分布等,并对比分析了多瓦可倾瓦径向滑动轴承在有无制造误差时的热弹流润滑特性差异。第三部分建立了多瓦可倾瓦径向滑动轴承热变形分析的数学模型,编制了考虑热变形影响的Fortran求解程序,对比分析两种情况下多瓦可倾瓦径向滑动轴承的弹流润滑特性差异,即仅考虑弹性变形和同时计入弹性变形和热变形；详细分析了轴瓦热变形对轴承弹流润滑特性的影响。第四部分建立了窄轴承在动载荷作用下的数学模型,利用Matlab编制相应的计算程序,分别分析冲击载荷、旋转载荷和任意动载荷(冲击载荷和旋转载荷的叠加)等不同类型载荷作用下窄轴承的润滑特性,通过计算得到不同载荷作用下的轴心运动轨迹。第五部分建立了多瓦可倾瓦轴承瞬态热弹流润滑的数学模型,包括瞬态雷诺方程、瞬态能量方程、瞬态热传导方程和运动方程,编制了相应的瞬态计算程序,分析多瓦可倾瓦轴承在启动阶段的瞬态润滑特性,通过计算得到轴承由初始位置运动到平衡位置的轴心运动轨迹,并得到平衡位置时轴承的各项润滑特性参数,包括油膜厚度、流体动压力、瓦面温度、瓦面热弹变形与动特性系数等。第六部分总结了本文的工作内容,指出了存在的不足以及需要进一步研究的内容。
[Abstract]:Due to the existence of various abnormal vibration in rotating machinery system, it often leads to catastrophic accidents, which is difficult to be explained by linear theory. People have come to realize that it is necessary to use nonlinear dynamic theory to analyze. Multi-tile tilting pad sliding bearings are often used in large rotating machinery such as steam turbines, water turbines and compressors, whose working performance directly affects the working state of the whole machine. It is necessary to study the lubrication characteristics of turbine radial sliding bearings. The first part of this paper describes the engineering significance of studying the lubrication characteristics of hydraulic turbine radial sliding bearings, and introduces the relevant methods and conclusions of studying the lubrication characteristics of radial sliding bearings at home and abroad, etc., from the rotor dynamics, The research progress on lubrication characteristics of radial sliding bearings is reviewed in the aspects of hot deformation and transient thermo-elastohydrodynamic lubrication theory of the bearing surface, and the research contents of this paper are put forward. In the second part, the calculation model of thermo-elastohydrodynamic lubrication (TEHDD) analysis of multi-tile tilting pad radial sliding bearing considering manufacturing error is established, and the thickness of tile oil film, oil film pressure and temperature distribution of tile surface are obtained when the manufacturing error is considered. The difference of thermo-elastohydrodynamic lubrication characteristics of multi-tile tilting pad radial sliding bearing with or without manufacturing error is compared and analyzed. In the third part, the mathematical model of thermal deformation analysis of multi-tile tilting pad radial sliding bearing is established, and the Fortran program considering the influence of thermal deformation is worked out. The difference of elastohydrodynamic lubrication characteristics of multi-tile tilting pad radial sliding bearing is compared and analyzed. The influence of bearing thermal deformation on the elastohydrodynamic lubrication characteristics of bearing is analyzed in detail. In the 4th part, the mathematical model of narrow bearing under the action of dynamic load is established, and the corresponding calculation program is compiled by Matlab to analyze the impact load respectively. The lubrication characteristics of narrow bearing under different loads, such as rotating load and random dynamic load (the superposition of impact load and rotating load), are calculated and the track of axial center motion under different loads is obtained. In the 5th part, the mathematical model of transient thermal elastohydrodynamic lubrication of multi-tile tilting pad bearing is established, including transient Reynolds equation, transient energy equation, transient heat conduction equation and motion equation, and the corresponding transient calculation program is worked out. In this paper, the transient lubrication characteristics of multi-tile tilting pad bearings at start-up stage are analyzed. The axial motion trajectory from the initial position to the equilibrium position is obtained, and the lubrication characteristic parameters of the bearing, including the thickness of the oil film, are obtained when the bearing is in the equilibrium position. Fluid dynamic pressure, tile surface temperature, tile thermoelastic deformation and dynamic characteristic coefficient, etc. Part 6th summarizes the work of this paper, points out the shortcomings and needs further study.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TK730.1

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