斜螺旋面—平面组合扇形固定瓦推力轴承的性能

本文对斜螺旋面一平面扇形组合瓦推力轴承性能和润滑油离心效应进行了分析,取得反映离心力影响程度的无量纲数的判断值和瓦面斜面部位的周向与径向间隙比的最佳搭配关系,系统地给出了这类轴承的设计计算用线图和资料。图9表6参4     

基于CFD的水润滑斜－平面瓦推力轴承承载能力分析

水润滑斜-平面推力轴承用水作为润滑介质,传统油润滑斜-平面推力轴承的计算公式及图表不再适用。基于计算流体动力学(CFD)理论,建立不同的水膜润滑模型并进行仿真计算,在水槽尺寸一定时,分析最小水膜厚度、瓦块中径上瓦斜面升高比、瓦块中径上斜面和平面之比以及转速对某斜-平面瓦推力轴承承载力的影响。结果表明:水膜的厚度是影响水膜承载力的主要因素,水润滑斜-平面瓦轴承轴向承载力随着水膜厚度的减小而增加;当水槽尺寸、最小水膜厚度以及转速一定,瓦斜面占长比为0.7、瓦斜面升高比为2时,轴承承载能力最大;在靠近水槽的轴承壁面上产生了空化现象;对于某个特定结构的轴瓦,推力环转速的变化不影响水膜压强中心的位置。     

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。     

螺旋面扇形瓦推力轴承热动力润滑性能分析

提出了一种适用于推力轴承的新型瓦——螺旋面扇形瓦,并对其热动力润滑性能进行了分析。螺旋面瓦与平面瓦比较,因其本身具有一定的斜度而具有许多特点,如油膜厚度大,承载能力大,剪切速率低,粘性耗散小,温升较小,功耗少而且制造加工容易等,因此可以很好地取代平面扇形瓦。     

水润滑推力轴承推力瓦应力场分析

水润滑推力轴承工作时,推力瓦和推力环端面间的高速相对运动会产生大量摩擦热,导致端面温升和热变形,使推力瓦产生局部高温和高应力,影响水对推力轴承的润滑效果、传递轴向推力效果、轴承寿命和安全性。基于ANSYS软件平台,建立水润滑推力轴承斜面平台固定推力瓦危险截面有限元分析模型,分析推力瓦危险界面的变形和应力场。结果表明:推力瓦的最大变形和最大Von Misses应力均出现在离推力瓦进水方向2/3瓦长处。     

螺杆泵斜-平面固定瓦推力轴承润滑特性分析

为了提升润滑油系统可靠性,避免轴承磨损,采用CFD分析螺杆泵斜-平面固定瓦推力轴承的润滑特性。计算该螺杆泵螺杆轴向力,得到油膜承载力数值范围;采用有限差分法得到油膜压力分布与厚度分布,采用有限体积法仿真分析不同油膜厚度、不同进油温度时轴承的压力场。仿真结果表明：温度通过影响润滑油黏度对轴承压载产生影响,当油膜厚度固定时,进油温度越低,润滑油黏度越大,轴承所受压载越大;当进油温度一定时,油膜厚度降低,则承载能力增加。因此,在低温启动滑油泵时,油膜由薄变厚平衡螺杆轴向力的过程中,轴承压载可能会超过许用压载,从而导致轴承磨损。     

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。     

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。     

推力轴承斜面平台瓦结构参数对弹性变形的影响

应用MATLAB软件对不同结构推力轴承斜面平台瓦块的弹流润滑性能进行数值计算分析。结果表明:弹性变形使轴承内压力分布缓和,水膜厚度变大,局部最大压力降低;推力轴承长宽比接近1∶1时,轴承变形较小;载荷不同,使轴承的变形量最小的最佳外内径比也不相同。     

新型推力瓦（EMP）轴承的数学模型和型面分析

本文描述了可倾式弹性金属氟塑料（ＥＭＰ）瓦推力轴承的热弹流数学模型并对推力瓦型面进行分析。根据ＥＭＰ瓦实际运行工况，作者提出了ＥＭＰ瓦表面存在滑移的假设，对Ｒｅｙｎｏｌｄｓ方程引进了滑移边界条件。     

Improving the performance of spring-supported thrust bearing by controlling its deformations

The performance of the spring-supported thrust bearing is studied with three-dimensional thermo-elastic hydrodynamic lubrication theory. The generalized Reynolds equation, the energy equation, the heat conduction equation, and the thermo-elastic deformation equation are solved simultaneously using the combination of the finite difference method and finite element method. Thermo-elastic deformation plays an important role in the performance of the spring-supported thrust bearing. Several factors such as spring pattern, pad thickness and initial pad geometry are analyzed. The results show that the above factors influence the performance of the bearing significantly. Suggestions based on the results are put forward to assist design considerations.     

发动机曲轴油封结构参数对唇口接触性能的影响

为研究结构参数对发动机曲轴无簧油封唇口接触性能的影响,利用ANSYS软件建立了油封的轴对称有限元分析模型,计算分析了油封唇口腰厚、腰长、空气侧角度、圆角半径和过盈量等结构参数对唇口径向力和接触宽度的影响,结果表明:径向力随腰厚、唇口圆角半径和过盈量的增加分别呈非线性和近似线性增加,随腰长的增加而非线性减小,随空气侧角度的增加而呈先快速减小后缓慢增加的变化趋势;接触宽度随腰厚、唇口圆角半径和过盈量的增加呈非线性增加,随腰长和空气侧角度的增加而非线性减小。     

圆柱浮环液体动静压轴承止推环性能的有限元分析

本文对圆柱浮环液体动静压轴承的止推环静动态特性进行了有限元分析。提出了保证浮环正常工作的平衡条件,并据此给出了浮环轴承的设计准则;在有限元分析中求解了该轴承内、外膜压力场;用小扰动法分析了动态雷诺方程,得到内外膜的刚度系数和阻尼系数;在求得浮环静压、动压平衡的基础上,得到了该轴承的静、动态特性及稳定性参数。     

Comparison of an optimum‐profile hydrodynamic thrust bearing with a typical tilting‐pad thrust bearing

The oil gap profile in a hydrodynamic thrust bearing exerts a great influence on the bearing properties, and hence the optimisation of the oil gap profile is one method for improving the bearing properties. In the present work, the properties of two hydrodynamic thrust bearings have been experimentally compared under realistic load/ speed conditions. One was a typical tilting‐pad bearing and the other was an unconventional bearing with an elastic thrust plate. The latter was designed using oil gap profile optimisation and design parameter selection. Owing to the design method used, the oil gap profile was close to optimum for the assumed load/speed conditions. The results show a substantial increase in the minimum oil film thickness and lower temperature in the bearing with the elastic thrust plate. This improvement of properties is thought to be because of the optimised oil gap profile in the bearing.     

Influences of the geometrical parameters of aerostatic thrust bearing with pocketed orifice -type restrictor on its performance

This paper describes the study on the performance of aerostatic thrust bearing with pocketed orifice -type restrictor. Firstly, the performance of the bearings with different geometrical parameters was simulated and some experiments were made to verify the simulations. Then, the rational dimension of this kind of bearing is obtained by analyzing the influences of the bearing's geometrical parameters on its load carrying capacity (LCC), stiffness, mass flow rate (MFR) and the maximum gas velocity (MGV). Therefore, the design and optimization of the bearing is simplified, and further analysis shows that ignoring the influences of orifice length on the bearing's performance will result in large errors, when orifice diameter is small enough.     

可倾瓦推力轴承系统的稳定性研究

在可倾瓦推力轴承系统中,利用薄膜压力和薄膜厚度的Taylor级数展开式,对瞬态雷诺方程进行了求解,求出了薄膜力和瓦块所受力矩的Taylor级数展开式,建立了镜板和可倾瓦自由振动时的微分方程及其特征方程,以出口处与入口处薄膜厚度的比值,外载荷、瓦块倾角、镜板速度和薄膜动力粘度等为变量,经判断霍尔维茨行列式的值大于零时,表明可倾瓦推力轴承系统具有稳定性。一旦瓦块的支点确定后,出口处入口处薄膜厚度的比值即可确定,而与其它参数无关。镜板和瓦块的运动微分方程可进行解耦合求解。     

基于MATLAB轴承无心磨削工艺参数的优化

轴承零件对磨削技术和加工工艺要求很高,且生产效率低、成本高。为了得到满足条件的轴承零件,建立轴承零件无心磨削的数学模型,并应用MATLAB软件中的fmincon函数和遗传算法分别对工艺参数(工件线速度、磨轮线速度、径向进给量)进行求解优化,通过两种算法的结果对比选择一组更优的工艺参数进行生产验证,结果证明该组参数能使生产率大幅增加、生产成本显著下降。     

Dynamic stability experiments of compliant foil thrust bearing with viscoelastic support

In order to reduce the complexity of machine construction and improve the mechanical efficiency, high speed rotation machineries usually implement self-acting gas bearings to substitute the traditional oil-lubricated bearings. This paper presents test results of a gas thrust bearing with viscoelastic support which is designed for high speed turbo-machinery. The gas bearing, which belongs to compliant foil bearings, consists of a top thin metal foil and a bottom thin rubber foil. Static and stability experiments are conducted on a high speed gas turbine test rig. The static results indicate that the structural stiffness of test bearing generally increases with the increase in axial load and the decrease in thickness of bottom foil. In the rotation tests, rotor runs stably with small vibration amplitude, which is dominant in waterfall plot during whole speed up procedure. It shows that test bearing has preferable stability characteristics for high speed gas turbines.     

Investigation of tribological behaviors of annular rings with spiral groove

A series of experiments is conducted to study the tribological behavior of spiral groove thrust bearings. The experimental system consists of a nominally flat upper ring mating with a stationary spiral groove lower ring in fully flooded lubrication environment. Spiral groove thrust bearings with different spiral angles subjected to different loads and speeds are tested. Stribeck-like curves are obtained and their characteristics are discussed. Transition points from mixed to hydrodynamic lubrication are experimentally established. In addition, a theoretical model is developed to gain further insight into the frictional characteristics of spiral grooves in both the hydrodynamic regime and the mixed lubrication regime.