无限短径向轴承动态雷诺方程考虑润滑油压粘效应时的解析解

在无限短径向轴承理论中,引入了线性化的压粘方程式,结合在动态情况下的雷诺方程,用富利叶正弦变换方法,得到油膜压强及油膜力的解析解。作为第一个特例,得到了转子失稳后油膜压强及油膜力的解析解。作为第二个特例,得到了静态时的解析解,算例的数值结果与文献中的叙述一致。为了检查所导出的公式的可信度,取压粘系数α等于０,使问题退化成为具有恒粘度的有关公式,其数值结果与有关文献的相应数值结果作了广泛比较,两者吻合度甚好。     

在短径向轴承中考虑压粘效应的润滑计算

在本文中应用线性化的压粘方程对短径向轴承的润滑进行了计算,得到了油膜中压强的解析解,并以此解析解为基础,推导了承载量系数,摩擦力,功耗等公式。计算结果与一些文献中关于润滑现象的家性叙述是一致的,在本文中考虑压粘效应的公式化描述可为设计计算提供依据。     

短径向轴承的脂润滑控制方程式

润滑油中常常包含有稠化剂等添加物,从而使润滑油表现为塑性润滑剂,因此发展脂润滑理论是需要的。为研究短径向轴承脂润滑特性,基于Ostwald模型推导了短径向轴承的脂润滑控制方程式。为了检查建立方程式的可靠性,置流变指数n=1,所得结果与牛顿流体的相应控制方程完全一致。可以用所建立的新方程分析脂膜的压强分布规律,并且能为短径向轴承脂润滑设计计算提供了理论基础。     

基于分离变量的滑动径向轴承雷诺方程通解

对滑动径向轴承的雷诺方程,采用分离变量方法,进行分析和求解。针对径向轴承油膜厚度沿径向保持不变的情形,分析了雷诺方程的特征值和特征函数,给出了雷诺方程的通解;针对径向轴承油膜厚度分布的一般情形,分析了雷诺方程的特征值和特征函数,给出了雷诺方程的通解;针对滑动径向轴承的油膜厚度一般表示式,分析并给出了雷诺方程的通解。这些研究,为分析和求解雷诺方程,描述和计算滑动径向轴承的油膜厚度和油膜力,提供了有效的方法,从而可以从理论上较精确地分析和研究滑动径向轴承特性,指导滑动径向轴承及转子系统的设计,改善滑动径向轴承的特性。     

静压径向气体轴承静态特性数值分析

对静压径向气体轴承的静态特性进行了详细的理论研究,采用二阶有限差分方法数值求解无量纲雷诺方程,编制Matlab迭代程序计算轴承的气膜压力分布。仿真分析了各种轴承结构参数和工作参数下静压气体轴承的承载、刚度和质量流量等静态性能的变化规律。仿真结果表明轴颈的转速对静压气体轴承的承载、刚度和质量流量等静态特性施加着重要影响,在分析轴承性能时必须考虑轴颈的旋转效应。当轴颈的转速不断增大时,轴承的气膜压力、承载能力和稳态刚度等静态性能能够得到显著提升。     

离心效应对轴承径向工作游隙的影响

高速运转的轴承,其径向工作游隙会因高速运转产生的离心效应而变化。若外圈固定、内圈旋转时,轴承径向游隙将减小;反之则增大。按照弹性力学理论,推导出轴承径向工作游隙变动量的计算公式。     

气体径向轴承弹性均压槽力学性能分析

设计了一种新型高刚度动静压气体径向轴承.建立了弹性薄板可变均压槽的数学模型,并通过有限差分法、ANSYS软件分析、解析法等不同的方法对可变均压槽的力学性能进行分析对比.结果表明,利用有限差分法对弹性薄板变形进行数值分析是可行的.     

考虑扰动频率的可倾瓦轴承扰动压力雷诺方程数值模拟

考虑扰动频率的影响,建立流体动压润滑可倾瓦轴承扰动压力雷诺方程。针对目前可倾瓦轴承有限差分数值算法不易联立求解等问题,提出基于PDE工具箱有限元数值求解方法。理论分析和计算结果均表明,扰动压力是轴承参数、静态工作点参数和扰动频率的函数,扰动压力与扰动频率密切相关;扰动频率为0时,复数域扰动压力虚部为0;随着扰动频率的增大,扰动压力实部变化不大,虚部随之增大。     

计入润滑油粘压效应和表面形貌的倾斜轴颈轴承润滑分析

提出了轴颈倾斜情况下的轴承油膜厚度方程。采用平均Reynolds方程，分析了倾斜轴颈轴承的润滑性能。通过不考虑和考虑润滑油粘压效应的轴承润滑性能对比，验证了分析倾斜轴颈轴承润滑性能时计入润滑油粘压效应的重要性；通过光滑轴承与粗糙轴承润滑性能的对比，验证了分析倾斜轴颈轴承润滑性能时考虑表面粗糙度影响的必要性。计算了不同偏心率、轴颈倾斜角、表面粗糙度、表面方向参数下的轴承润滑性能，结果表明，表面粗糙度在最小油膜厚度较小时对倾斜轴颈轴承润滑性能产生影响，而表面方向参数在最小油膜厚度与综合粗糙度的比值较小时会对倾斜轴颈轴承润滑性能产生显著影响。     

Boundary Conditions of Cavitation Regions in Journal Bearings

The behavior of the oil in a cavitation region is studied. Boundary conditions of the pressure distribution at the inlet and at the outlet border of such a region are given. Calculation of the power loss in a cavitated zone is demonstrated.     

基于块不完全分解的共轭梯度法求解雷诺方程的算法研究

本文提出一种新的求解径向滑动轴承雷诺方程的算法--基于块不完全分解的共轭梯度(BIFCG）法，通过大量的数值试验，分析了影响该算法求解精度的几种因素。并对迭代步数、计算时间等与SOR法进行了研究。     

Generalized Universal Reynolds Equation for Variable Properties Fluid-Film Lubrication and Variable Geometry Self-Acting Bearings

The present article represents a theoretical further development of Dowson's equation (1). The developments presented herein start from the fundamental Dowson concept and proceed to a final generalization, which, by using a spherical coordinate system, accounts for the previously neglected curvature effect. The generalization brought about by this system of coordinates allows the derivation of the Generalized Universal Reynolds Equation (GURE) to best suit liquid and gas film lubrication, with variable properties. This single equation can now be customized by a simple change in angle, allowing all common classes of self-acting bearings to be modeled. Dowson's development in Cartesian coordinates lends itself only to geometries of small curvatures when compared to the film thickness and thus can be unwrapped. GURE's flexibility of spherical coordinates eliminates the minimal curvature assumption for Cartesian geometries. GURE provides a single-equation approach to cylindrical journal bearings, flat-plate thrust bearings, and conical and spherical bearings.     

Effects of Excitation Frequency and Orbit Magnitude on the Dynamic Characteristics of a Highly Preloaded Three-Lobe Journal Bearing

The independent effects of excitation frequency and excitation magnitude on experimentally derived bearing coefficients for a highly preloaded three-lobe journal bearing were studied. The effect of excitation frequency was determined by applying external dynamic forces at half-synchronous, synchronous, and twice synchronous frequencies with respect to the operating speed. Effect of excitation magnitude was independently determined by applying either three or four different amplitudes of excitation force to the bearing resulting in orbit sizes ranging up to 30% of clearance. Applying static forces to the bearing housing controlled the Sommerfeld number, and thus, the static operating position. Data was reduced as linear dynamic coefficients, and presented relative to excitation frequency and excitation magnitude over a range of Sommerfeld numbers from 0.2 to 3.0 and operating eccentricities from 0.3 to 0.9. In general, neither excitation frequency nor excitation magnitude was shown to have a measurable effect over the ranges studied.     

三油楔轴承润滑模拟及平衡位置求解

运用差分法求解三油楔轴承的非线性油膜力,基于弦截法求解三油楔轴承的轴心平衡位置,讨论了轴心平衡位置随载荷而变化.通过对润滑状态的模拟,得出:三油楔轴承的安装角对轴承油膜的承载能力有很大影响;运用弦截法和位置求解问题的分解方法,能够高效地求解轴心的位置;轴心平衡位置受系统载荷的影响,这种影响是非线性的,但在轻载和重载情况下,可以对轴心的平衡位置进行线性化处理,有助于平衡位置的求解.     

300MW汽轮发电机组径向可倾瓦轴承性能研究

本文详细分析了热弹变形对轴承性能的影响，结果表明热变形对轴承性能的影响较小，而热弹变形对轴承性能的影响较大。     

Approximate Formula for the Contact between Truncated Surfaces and Frictional Characteristics of a Journal Bearing in Mixed Lubrication

This paper presents an approximate formula for the contact of a non‐Gaussian distribution of truncated surfaces, which is useful for mixed lubrication theory, and gives a method for the determination of the truncation parameters in this formula from a measured roughness profile. Using this approximate formula for a contact, the approximate formula for the friction coefficient of a journal bearing in mixed lubrication, which was previously proposed by the authors, is modified for truncated surfaces, and the frictional characteristics are demonstrated for various parameters of truncated roughness using the modified formula.