液体静压和动静压滑动轴承动态特性分析计算

本文根据小扰动原理,对液体静压和动静压滑动轴承进行了动态特性分析,研制了用不等步长有限差分法计算八个动态特性系数的通用计算程序.本文既考虑了油腔的静压作用,又考虑了封油面上的动压效应,列出了求解静压和动静压滑动轴承动特性计算的全部过程和具体公式,用不等步长差分法导出了动态雷诺方程的迭代格式,并对静压轴承油腔边界条件的处理进行了较深入地讨论.     

新型螺旋油楔动静压滑动轴承的油腔结构研究

针对一种新型的螺旋油楔动静压滑动轴承,研究了油腔螺旋角、油腔深度以及油腔包角等油腔结构对该新型轴承静态性能的影响。结果表明,合适的油腔结构参数可以有效地实现轴承内润滑流体的分流,避免润滑油的重复加热,使轴承在保证一定的承载能力的前提下,降低轴承的摩擦功耗及轴承温升。     

出油孔对螺旋油楔动静压滑动轴承性能的影响

针对当前制约动静压滑动轴承应用的温升问题,在对一种螺旋油腔动静压滑动轴承的动静态特性分析的基础上,设计了相应的实验装置,采用理论和实验的方法研究了轴承的出油孔对轴承静动态性能的影响。理论和实验结果均表明,出油孔的存在对油膜的压力分布仅有较小的影响,对承载力及动态性能的影响甚微,但却会大幅度增加轴承的出油量,通过出油孔流出轴承的润滑油量大约为端泄流量的十几倍,即通过出油孔能更多地带走摩擦产生的热量,更有利于轴承的温升降低。在需要降低轴承温升的应用中,在油腔中适当添加出油孔,并合理布置进出油孔的位置,可以实现对性能影响较小的情况下,大幅度降低轴承的温升。     

动静压滑动轴承的稳定性分析

根据有限元法对几种类型动静压滑动轴承的计算结果讨论了它们静态承载能力及动态稳定性，并将３６０度圆柱孔动压滑动轴承和油腔式静压滑动轴承的静、动特性与几种动静压滑动轴承的静、动特性进行了对比，从理论上确定了动静压滑动轴承的承载能力优于油腔式静压滑动轴承，动静压滑动轴承的动特性优于３６０度圆柱孔动压滑动轴承。     

浅油腔滑动轴承的试验研究

本文讨论了油腔式滑动轴承静、动特性的试验原理，在自行研究的动静压滑动轴承试验台上对浅油腔轴承进行了试验研究，获得了一批有价值的试验数据，与理论结果有较好的吻合，对浅油腔轴承在工业中应用提供了依据。     

螺旋油楔动静压滑动轴承三维CFD仿真分析

以轴承流体域为研究对象,建立了螺旋油楔动静压滑动轴承的三维实体模型,利用Fluent软件对其流场及温度场进行数值仿真,比较了螺旋油楔轴承与普通三油楔轴承静态性能的差异,同时分析了螺旋角及轴承间隙对螺旋油楔轴承静态性能的影响规律。结果表明:两种轴承的油膜压力及温度分布存在较大差异;轴承油腔的螺旋形分布及进出油孔的分开设置能够减少润滑油的二次加热并能提高轴承端泄量,有利于温升降低;高速轻载工况下螺旋油楔轴承静态性能要明显优于普通三油楔轴承;合理选择轴承螺旋角及轴承半径间隙可以保证螺旋油楔轴承具有较好的润滑特性。     

小孔式动静压滑动轴承稳定性分析

用伽辽金法及摄动理论建立了小孔式动静压滑动轴承的有限元模型，并对其进行了静，动特性分析。分析结果表明，小孔式动静压轴承载能力明显优于油腔式静压轴承，其动特性也优于几何尺寸相同的圆柱孔动压滑动轴承。     

动静压滑动轴承基本方程和特性系数无量纲化研究

在对滑动轴承基本方程-Reynolds方程进行无量纲化时,动压轴承和动静压轴承所用方法有所不同,相应的无量纲静、动态特性系数也有很大的不同.本文建立了两种轴承无量纲静、动态特性系数之间的关系,在此基础上导出了计算动静压滑动轴承失稳转速的修正公式.作为算例计算了某型号超高速动静压轴承的失稳转速.     

基于小孔节流的静压油膜轴承动态特性分析

静压轴承的动静态特性在很大程度上受到节流装置的影响,以小孔节流的静压轴承为研究对象,开展其动态特性理论的研究。利用两平行平板缝隙液体流量公式推导了轴承油腔流出的流量数学模型,并充分考虑了主轴转子速度对流量的影响因素,使之更符合实际工况;在对小孔节流后流入轴承油腔的流量方程进行线性化处理的基础上,建立了静压轴承系统的流量连续性方程;结合轴承-主轴系统动力学方程,推导出小孔节流的静压轴承系统动态特性的传递函数,分析了小孔节流静压轴承系统的动态特性。结果表明:小孔节流的四油腔静压轴承动态响应速度在0.06~0.12 s范围内变化,增大供油压力、油腔承载面积、主轴转速及减小油膜粘度、油膜间隙等均有助于提高轴承系统的响应速度。研究结果对于指导工程设计具有一定的参考价值。     

不对称三油腔动静压轴承设计及仿真验证

介绍了不对称三油腔动静压轴承的设计计算分为静压腔设计和动压面设计两步骤的设计思路。将静压腔的设计按四油腔静压轴承的设计公式计算;考虑到下油腔是动压面润滑油的来源,动压面的设计按包角为120°的径向滑动轴承设计公式计算,并建立了与设计手册中油膜压力变化规律相符的包角为120°径向滑动轴承的CFX有效模型。CFX模型边界条件修改后的仿真结果接近理论公式计算,验证了设计思路。     

FLUID FLOW SEPARATION CHARACTER ON NOVEL HYBRID JOURNAL BEARING

The influence of the structure and running parameters of a novel spiral oil wedge hybrid journal bearing on the fluid flow trace is investigated. The governing equation of the flow trace of lubricant is set up, and the simulation is carried out by using finite difference method. The results show that the lubricant flow status and end leakage quantity are greatly influenced by spiral angle, and that the rotating speed has little influence on the flow status. With advisable geometry design, the separation of lubricant between different oil wedges can be obtained, which can decrease the temperature rise effectively.     

Thermal characteristics of misaligned finite journal bearings

Adiabatic analysis of a journal bearing is presented for maximum allowable misalignment with a length: diameter ratio of one. The direction of journal misalignment is allowed to vary up to the axial plane containing the load vector. Reynolds and energy equations are solved simultaneously using finite differences, considering both axial and spiral oil inlet conditions. The results show that bearing behaviour is significantly affected by journal misalignment. It is also noted that thermal effects are more pronounced for bearings with axial rather than spiral oil inlet grooves.     

螺旋槽流体动压滑动轴承数值分析

对螺旋槽流体动压滑动轴承进行了研究。由于圆弧形油腔斜置,为计算准确在斜坐标系下推导出了雷诺方程、油膜厚度方程和速度方程的有限差分公式。运用有限差分法,对轴承的承载力、压力和流体质点的流动轨迹等进行了数值分析,对计算结果进行了讨论。结果表明：螺旋形油楔很好地实现了冷热油的分流,避免了润滑油的反复加热,导致轴承承载力降低;偏心率和螺旋角对油膜压力有不同程度的影响。     

卧式水电机组局部多油楔径向滑动轴承研究

针对卧式水电机组用径向滑动轴承载荷日益提高的现状,设计一种局部多油楔瓦面结构的径向滑动轴承。通过联立求解膜厚方程、雷诺方程、密度方程、黏度方程、能量方程和固体热传导方程等,获得轴承的热流润滑特性,并与椭圆径向滑动轴承的热流特性进行对比。结果表明,局部多油楔径向滑动轴承具有较大的动压承载区域和较小的油膜压力梯度以及较低的油膜温升,可以大幅度提高轴承的承载能力。     

Texture shape effects on hydrodynamic journal bearing performances using mass-conserving numerical approach

ABSTRACT

It is a known fact that incorporating textures in the contact surfaces can significantly enhance bearing performances. The purpose of this paper is to outline the effects of texture bottom profiles and contour geometries on the performances of hydrodynamic textured journal bearings. The analysis was conducted using computational approach to test eight texture shapes: rectangular, cylindrical, spherical, triangular (TR, T1, T2, T3) and chevron. The steady-state Reynolds equation for modelling the hydrodynamic behaviour of thin viscous film was solved using finite difference technique and mass conservation algorithm (JFO boundary conditions), taking into account the presence of textures on both full film and cavitation regions. The comparison with the benchmark data shows good consistency and an enhancement in bearing performances (load carrying capacity and friction). The results clearly show that the mechanisms of wedge effect and micro-step bearing for the full/partial texturing feature are the main crucial parameters, where the convergent wedge effect present in T2 triangular texture shape can significantly enhance the load-carrying capacity, while the divergent wedge action causes a net load loss. Considering the right arrangement of textures on the contact surface, their surface contours can have a significant impact on the performance of hydrodynamic journal bearings at high eccentricity ratios.     

油气两相流对滑动轴承油膜破裂位置的影响

滑动轴承油膜破裂位置是滑动轴承静特性之一。本文在引入新型气油两相流流变模型后，组织了一套适用于油气两相流润滑工况下滑动轴承的数值计算理论，用数值计算的方法研究了油气两相流对滑动轴承油膜破裂位置的影响，得出了一组规律性的结论。     

Testing of a Large Adjustable Hydrodynamic Journal Bearing

The design and testing of two novel adjustable hydrodynamic journal bearings are outlined. Each was designed to replace a conventional bearing in a large marine gearbox. They were tested in a land based rig and their performances compared with that of the conventional bearing.

The novel bearings demonstrated the ability to suppress journal centre orbits, to reposition the journal centre in any direction, and to operate with significantly reduced temperature rise. One of the bearings also demonstrated the ability to translate the journal centre in a controlled manner by an amount exceeding double the clearance of the conventional bearing. Implications of such characteristics are considered as potential benefits in various bearing applications.     

表面织构排布方式对径向滑动轴承摩擦性能的影响

基于Navier-Stokes方程,建立表面织构化滑动轴承数值分析模型,采用压力耦合方程的改进半隐式(SIMPLEC)算法进行求解,分析表面织构排布和形状对滑动轴承摩擦性能的影响。结果表明：在收敛楔入口排布十字形织构时可以显著提高承载能力;在收敛楔中部周向排布沟槽和短沟槽织构比轴向排布更能显著改善轴承摩擦性能,且排布倒椭圆、菱形和十字纹理可以更明显地改善滑动轴承的摩擦性能;在收敛楔出口排布织构不能改善滑动轴承的摩擦性能,而在发散楔只有三角形织构可以改善轴承的摩擦性能。设计5种新型复合织构排布方式,分析其对轴承摩擦性能的提升效果。结果发现：复合型织构比单一类型织构更有利于提高轴承摩擦性能,其中在收敛楔入口布置十字形织构,收敛楔中部分别布置周向沟槽、短沟槽和十字形织构,发散楔布置三角形织构的3种复合型织构设计轴承性能提升效果显著,使承载力分别提高了15.69%、15.66%和17.16%,摩擦因数降低了3.75%、4.17%和2.92%。