线支承扇形瓦推力轴承热动力润滑性能分析

建立了线支承扇形瓦推力轴承中油膜压力、油膜厚度、能量方程和粘温方程等的无量纲表达式,研究了各种刮瓦形式和支承线的倾斜度对推力轴承的油有膜厚度分布和温度分布的影响,研究表明,对于可倾瓦来说,各种刮瓦形式并不能有效降低润滑油的温升,不会明显改善推力轴承的润滑性能;推力轴承在经过长期运行后,推力瓦块支承线因受压缩将会向内倾斜,瓦块外半径处沿圆周方向上的油膜厚度显著减小,从而使润滑油温升大大提高,明显降低了推力轴承的润滑性能。     

Hydrodynamic Pressure Generation in a Pocketed Thrust Washer

The objective of this study was to experimentally investigate hydrodynamic pressure generation in surface-pocketed thrust washers. A novel method of pressure mapping was developed to allow for in situ measurement of the pressure generated by surface modifications. Thin-film pressure transducers, located just below the thrust washer surface, were used to measure pressure variations as a function of the operating conditions. Contour maps showing the cavitation region and the location of peak pressure were clearly displayed. The experimental work presented maps the pressure profiles with real-time, high-resolution sensors. The thin-film pressure transducers were used to investigate the pressure interactions between surface features. In addition to the experimental setup, a model of the contact was developed using ANSYS FLUENT. Cavitation, friction, film thickness, and load support were all compared with experimental results and the two were shown to be in good agreement. The model demonstrated an accurate prediction of the pressure profile but varied slightly with the predicted load support of the thrust washer. The simulation was then used to optimize the pocket density for the experimental operating conditions. The optimal bearing design had the highest load-carrying capacity with a low friction coefficient.     

Dynamic Characteristics and Stability Analysis of a Wavy Thrust Bearing

A numerical procedure to analyze wavy thrust bearings is described. The numerical model is developed by assuming that two circular plates rotate relative to each other. The upper plate is assumed to be flat and rotating, whereas the lower plate is assumed to be stationary and wavy in surface geometry. A Reynolds-equation-based procedure is used to simulate the dynamics engendered by various wavy geometries and loading conditions. The equilibrium position of the journal results from the equilibrium between the forces generated by the fluid-film pressures and the externally applied loads. A numerical small perturbation technique is applied to calculate the linear stiffness and damping characteristics of the bearing at the equilibrium position. Using a three-degrees-of-freedom system with one axial and two rotational displacements, nine linear stiffness coefficients (three principal and six cross-coupled coefficients) and nine linear damping coefficients are calculated. These linear coefficients are then used to calculate the eigenvalues of the system by solving the homogeneous equations of motion. The stability of the bearing system is then expressed using the lowest logarithmic decrement obtained from these eigenvalues. Using this procedure, a parametric study is carried out to examine the effects of external load, location of the applied load, bearing number, and bearing wave amplitude on journal equilibrium position, bearing linear stiffness, damping characteristics, and bearing stability.     

可倾瓦推力轴承中工况参数对动特性的影响

采用对油膜压力进行泰勒级数展开的方法,导出了油膜对镜板的作用力和油膜对可倾瓦的力矩的刚度阻尼系数。分析了工况参数如速度、载荷、油温等参数对这些动特性系数的影响。研究表明,如果工况参数使油膜厚度减小,则油膜对镜板的作用力和油膜对可倾瓦的力矩的刚度阻尼系数均会增大。     

弹性金属塑料瓦推力轴承的滑移问题研究

本文对流体力学的经典雷诺方程中固液界面无滑移假设对于弹性金属塑料瓦的适用性提出疑问，从理论上论证在一些表面能低的聚合物表面存在滑移的可能性，并进行对比实验，实验证明在聚四氟乙烯与润滑油的界面上存在滑移现象，发现滑移是在剪切速率和油膜厚度达到一定值才出现的，滑移速度随着转速的提高和膜厚的减小而增大。在分析以聚四氟乙烯为表面的弹性金属塑料轴瓦的润滑机理时，应当对雷诺方程进行修正，计入滑移因素的影响。     

动静压推力轴承动特性分析

本文利用有限差分法,对一个高速外圆磨床主轴上的一浅腔动静压推力轴承的动特性进行了理论分析,其结果对提高主轴的性能是非常有益的。     

推力轴承二维流动油膜中的温度因子分析

在对可倾瓦推力轴承中的油膜厚度方程 ,油膜压力方程 ,能量方程以及油膜对可倾瓦的力矩方程等方程进行无量纲化的基础上 ,进行了数值分析 ,提出了温度因子的概念。研究表明 ,对于给定的推力轴承 ,油膜中温度的分布只与温度因子有关 ,对于不同的转速 ,温度因子为一常量     

大型可倾瓦推力轴承弹流润滑问题的域外法解

介绍域外在处理弹流润滑问题是的应用，和边界元不相比，域外不需要对边界单元作繁琐的奇异积分处理，因而编程简捷，计算精确。作为算例，用域外法联立求解雷诺方程和弹性变形方程，计算了大型可倾瓦推力轴承的油膜压力、弹性变表和相应的特性参数。     

Three-Dimensional Thermohydrodynamic Analyses of Rayleigh Step Air Foil Thrust Bearing with Radially Arranged Bump Foils

A three-dimensional (3D) thermohydrodynamic (THD) model for air foil thrust bearings (AFTBs) is presented. The nonisothermal Reynolds equation is solved using pressure boundary conditions at the cooling air plenum considering local temperature-dependent viscosity and density. Air film temperature is calculated using the 3D energy equation with thermal boundary conditions at the top foil, thrust runner, and top foil’s leading edge. The cooling air plenum distributes the cooling air to multiple radially arranged cooling channels. The plenum temperature and pressure are found from mass and energy balance equations applied to the plenum. Temperature fields of the top foil, bump foils, thrust disc runner, bearing plate, and cooling air channels are also solved through appropriate energy balance equations with their surroundings. A robust computational algorithm with multiple iteration loops was developed to find all the temperature fields. THD analyses were performed for AFTB with outer radius of 50 mm up to 100,000 rpm. As the cooling air source pressure is increased, the plenum pressure also increases and its temperature decreases due to more cooling capacity. However, cooling effectiveness is not necessarily proportional to the pressure because the flow residence time inside the cooling channels is inversely proportional to the pressure. The analyses show that the thrust disc temperature is a parabolic function with speed, and thermal expansions of the thrust disc and thrust plates contribute to the most significant driving force of thermal instability. Optimum cooling air pressure was found around 12,500 Pa for the proposed AFTB design at the reference simulation condition.     

Nonlinear Simulation of Rotor Dynamics Coupled with Journal and Thrust Bearing Dynamics under Nonlinear Suspension

This study performs a dynamic analysis of a rotor supported by an oil-film journal and thrust bearings. The analysis of the rotor-bearing system is investigated under the assumptions of an incompressible lubricant, a flexible rotor, and negligible side leakage in the thrust bearing. The numerical results show that the nonlinear dynamics of the system vary with the nondimensional speed ratio and the initial value of the displacements in the horizontal, vertical, and axial directions. Specifically, some routes of periodic responses, subharmonic motions into chaos, out of chaos to subharmonic responses, or suddenly into chaos, suddenly out of chaos to periodic ones were found.     

LEC型推力轴承回油结构与节能效果

本文分析了ＪＨＪ型推力轴承及ＬＥＧ型推力轴承的进回油方式对轴承性能的影响。用ＬＥＧ型推力轴承替代ＪＨＪ型推力轴承时,应该注意改变原轴承的回油结构。ＬＥＧ型推力轴承在氧气透平压缩压上应用时,实测的节能效果。     

影响弹簧支承式推力轴承性能的几个因素

本文对弹簧支承式推力轴承进行了三维热弹流研究,发现变形量对轴承性能有很大影响,为此,着重分析了决定轴承变形和油膜形状分布的几个因素对轴承性能影响情况,研究表明,弹簧布置方式,轴瓦厚度和型面形状能严重改变轴承性能,在进行轴承设计时必须对上述因素进行了优化,并提出了一些优化建议。     

水润滑扇形瓦推力轴承润滑性能的边界元分析

用边界元法分析水润滑扇形瓦推力轴承的润滑性能,将雷诺方程转化为类似泊松方程的形式,采用边界元法求解该方程,研制了一套C++计算程序,得到多组轴瓦参数下的水膜厚度、压力分布和相关润滑性能,可以显著降低代数方程组的阶数,从而减少计算所需时间,并可提高计算精度。研究表明瓦块张角和瓦块倾角对最小水膜厚度、最大水膜压力、摩擦功耗、压力中心位置和进水口流量有不同程度的影响,该研究将有助于合理的设计水润滑扇形瓦推力轴承的轴瓦参数。     

可倾瓦推力轴承中进口压力对热动力润滑性能的影响

从理论上研究了进口压力对推力轴承热动力润滑性能的影响。进口压力的存在,使油膜厚度增大,油膜内粘性能耗散减少,进油流量增大,温升减低,有利于提高润滑性能,轴承转速愈高,进口压力也就愈大。因此,进口压力是分析研究高速轻载可倾瓦推力轴承热动力轴承热动力润滑性能中的一个不可忽略的重要因素。     

新安装机组推力轴承温度过高的原因分析及排除

本文基于小水电站卧式机组的特点,结合具体事例对机组推力轴承温度过高的原因进行分析,并提出相应的改进措施,取得了较好的成效。     

轧钢机动压轴承油膜补偿与临界轧速分析

采用有限元方法求解雷诺方程,对形成动压润滑的临界轧制速度以及影响板厚轧制精度的油膜厚度进行计算机数值模拟以评价不同轧制工况下油膜轴承的承载能力性特性参数。计算得出的不同轧速下厚预报值以及临界轧速一实际数据吻合。     

圆形可倾瓦与扇形瓦推力轴承性能的比较

应用有限元程序分别对圆形瓦和扇形瓦推力轴承在中心支承条件下的性能进行了计算。并根据计算结果对两种瓦形的轴承性能作了比较。其结果和实验结论比较一致。最后得出圆形瓦轴承比扇形瓦轴承在某些方面有一定的优越性。     

陀螺电机轴连轴承生热分析

基于摩擦学理论,对轴连轴承组件生热进行了研究.针对轴连轴承组件的具体工况及结构特点,分析了轴连轴承组件的发热机理,建立了轴承组件内各部分功率损失计算模型,在此基础上得出了轴承总的生热和轴承各单元间的局部生热.以某型陀螺电机轴连轴承为例分析了不同工作转速和工作载荷对轴承总生热和各单元局部生热的影响.结果表明,轴承转速、轴...     

Hydrodynamic Calculation of a Thrust Bearing with an Adapted Profile

Russian Engineering Research - Hydrodynamic models are considered for thrust bearings with a profile adapted to the frictional conditions, when operating in incompressible electrically conducting...     

Analysis of the Hydrodynamic Effects in a Surface Textured Circumferential Gas Seal

A theoretical finite-element model was developed to study the hydrodynamic effect of micro-pores generated by laser surface texturing (LST) in a circumferential gas seal. The seal is represented by two non-contacting annular surfaces of a rotating shaft and a stationary ring. The micro-pores of spherical segment shape are distributed uniformly over one of the annular surfaces. The hydrodynamic dimensionless pressure distribution in the uniform clearance between the annular surfaces is obtained from a solution of the Reynolds equation for compressible viscous gas in a laminar flow.

Results of a parametric study along with a numerical example for a specific circumferential seal demonstrate a substantial hydrodynamic effect that can raise the opening average pressure in the seal clearance above the ambient one by up to 50 percent.