基于多孔质节流器的水润滑动静压轴承的设计

针对水润滑轴承的特殊形式以及要求达到的技术指标,采用陶瓷多孔质材料作为节流器,并推导出水润滑形式下的相关节流参数。程序采用有限差分法求解各偏微分方程,得出不同形式水润滑轴承的承载能力、刚度和摩擦功率等性能参数;通过对相同轴承形式采用油润滑时的计算,给出了水、油两种润滑形式性能的对比;综合各性能指标,完成水润滑轴承形式的选择以及结构尺寸的设计。     

Steady state solution of finite hydrostatic porous oil journal bearings with tangential velocity slip

A theoretical investigation has been made into the static characteristics of hydrostatic porous oil bearings with tangential velocity slip at the porous interface. A numerical method has been employed to solve the governing differential equations with a wide range of bearing parameters. Slip has been conventionally treated by choosing permeability factors and slip coefficients as independent parameters, and also more realistically by choosing practical values of shaft radius/radial clearance and slip coefficients as independent parameters. The effect of slip, eccentricity ratio, slenderness ratio, speed parameter and anisotropy of permeability on the load carrying capacity, friction coefficient, attitude angle and the oil flow rate has also been investigated. The results are presented in the form of graphs which may be useful for design of such bearings.     

Analysis of tapered land aerostatic bearings for combined radial and thrust loads (yates' configuration)

In this paper the analysis of tapered land aerostatic Yates' bearings for supporting combined radial and thrust loads is presented. Air flow in the journal and thrust bearings is expressed in terms of the Reynolds equation and the Navier-Stokes equations respectively. The pressure distributions in the bearing clearance are obtained by solving these equations using a finite difference numerical technique. The effects of various design and operational parameters on the performance of the combined journal and thrust bearing are reported. In conclusion, guidelines for the optimal design of such bearings are suggested.     

基于数值模拟的小孔节流空气静压轴承静动态特性研究

为了提高小孔节流空气静压轴承的静动态性能,基于流体力学和固体力学的基本控制方程,建立小孔节流空气静压轴承双向流固耦合数值模拟模型;采用静态数值模拟方法获取了设计参数对承载力和刚度的影响规律,进一步对微气膜间隙内三维流场特性进行了分析,有效降低了微气膜间隙内气体冗余现象对空气静压轴承动态稳定性的影响,并在数值计算的基础上对空气静压轴承结构和工作参数进行优化设计;在气体静压试验平台上对自行研制的空气静压轴承进行静动态特性测试。试验结果表明:所提出的数值模拟方法具有很好的预测效果;所采用的优化设计方法能够显著提升空气静压主轴的静动态特性。     

Thermal characteristics of a non-newtonian fluid in a porous thrust bearing

A study of the behavior of an externally pressurized circular porous thrust bearing using a non-newtonian fluid lubricant was made. The governing Navier-Stokes equations were reduced to a set of ordinary differential equations and were solved numerically with the cross-flow Reynolds number and the Prandtl number as parameters. The pressure distribution and the lift force were evaluated. The effects of cross-viscosity coefficients on the flow and heat transfer characteristics of the bearing were determined.     

导轴承性能热流体动力分析

建立了导轴承性能热流体动力分析的数学模型,应用有限元法对表示油膜压力的Reynolds方程及表示油膜温度的Energy方程和表示温度和粘度关系的粘温方程进行了联立求解,获得了多瓦导轴承的瓦块压力分布,温度分布及其它轴承静态和动态参数.并根据这些参数对多瓦导轴承的性能作了分析,其结果对该轴承设计具有一定的指导作用,并对运行过程具有预测作用.     

Effects of geometric parameters on static load capacity of a double-row four-point contact ball bearing

The geometric parameters, which are difficult to design because of the lack of a corresponding theory and tool, of a double-row four-point contact ball bearing, determine its carrying capacity. In this study, a mechanical model (nonlinear algebraic equations) with the effect of the row spacing, which is different from the current theory for a single-row ball bearing, has been developed. Also, using the corresponding calculation procedure programmed by MATLAB, the effects of the geometric parameters on the load capacity of the bearing have been studied. Some design suggestions have been made for the bearing geometric parameters: to improve the contact strength between the ball and raceway, the row spacing should be designed as small as possible if the bending strength of the mid beam among the rows is enough. To avoid more interference force, the negative clearance should be near zero.     

带有圆周方向均压槽的静压气体止推轴承的气锤自激

通过开设均压槽,可以增加静压气体轴承的承载能力和刚度,但是如果气体轴承的均压槽等参数设计不合理,会出现一种振动现象——气锤自激振动,尤其是设计高压重载气体止推轴承时。针对常用的圆盘止推气体轴承,建立轴承活动件的动力学方程,再运用小扰动方法和流量连续性方程得到了气锤自激振动的稳定性判别方程。通过求解稳定性判别方程,发现供气压力越大,自激振动的倾向性越强;气膜间隙在一定范围内容易引起自激振动;节流孔直径越大,自激振动的倾向性越强;当止推轴承的外径和内径的比值比较小时,容易发生气锤自激。通过计算得到了不发生气锤自激振动的轴承设计参数,可用于高压重载气体止推轴承的设计。     

Theoretical Analysis of Piston-Ring Lubrication Part I—Fully Flooded Lubrication

A one-dimensional analysis for lubrication between the piston ring and cylinder wall has been developed. A fully flooded inlet condition and axisymmetric geometry are considered. The piston ring is treated as a reciprocating, dynamically-loaded bearing with combined sliding and squeeze motion. A system of two nonlinear differential equations is used to model the lubrication including the Reynolds cavitation boundary condition. A numerical procedure is then developed to obtain the cyclic variations of film thickness, frictional force, power loss, and oil flow across the ring.

Results are presented for a typical automotive engine. The effects of ring profile, ring tension, and engine speed are examined. It is shown that this analysis can be used to study the influence of ring design parameters in order to improve the design of the ring pack in reciprocating engines.     

基于正交试验的静压径向气体轴承数值分析*

以气动涡轮支承结构静压径向气体轴承为研究对象,建立静压径向气体轴承的微分模型,利用工程数值方法计算轴承承载力、刚度和气体质量流量,运用正交试验法研究节流器参数对轴承性能的影响,以及不同优化方向下轴承的综合性能。结果表明：不同的优化方向节流器参数的敏感性不同,以气体质量流量为优化方向明显不符合设计需要,以承载力为优化方向得到的轴承综合性能最好;平均气膜厚度、节流孔直径和数量是影响轴承承载特性的主要因素,节流孔直径越小承载性能越好。     

Influence of elastic effects on the performance of slot-entry journal bearings

Modern high-performance machines require bearings to operate under stringent conditions. For bearings operating under heavy loads, the bearing deformations can no longer be neglected as they are comparable to the order of magnitude of the fluid film thickness. This paper describes the performance of slot-entry hydrostatic/hybrid journal bearings by considering bearing shell flexibility in the analysis. The relevant governing equations have been solved by the finite element method. Slot-entry journal bearings of two separate configurations have been studied over a wide range of bearing operating and geometric parameters. Elastic effects are found to significantly affect the static and dynamic performance characteristics of the bearing studied. The study indicates that, for given operating conditions, to get optimum performance of a bearing proper selection of the bearing flexibility parameter ( ), the concentric design pressure ratio ( ) and the type of bearing configuration (symmetric/asymmetric) are essential.     

A survey of finite element techniques for mechanism design

During the creation of a modern machine system, the designer must generally develop a mathematical model to investigate the levels of vibrational activity, dynamic stresses, bearing loads and often the acoustic radiation associated with the system. Since all of these phenomena may be represented by field theories whose governing equations of motion may be stated as either differential, integral or integro-differential equations, they are all amenable to solution by the single most powerful computational tool available to the analyst: the finite element method. Mechanism design methodologies based on this versatile technique are reviewed herein, their different characteristics are highlighted and future trends indicated.     

Dynamic behaviour of aerostatic rectangular thrust bearings

A theoretical study to determine the dynamic stiffness and damping characteristics of an aerostatic rectangular thrust bearing is presented. The governing non-linear partial differential equation of film pressure is linearized using a first-order perturbation method. The perturbed equations are solved numerically to determine the dynamic load, which in turn gives the stiffness and damping characteristics. The effect of various parameters on stiffness and damping is also investigated.     

大尺寸静压轴承温度场数值模拟

为了能够数值模拟出较详细和较准确的大尺寸静压轴承内部流体的温升分布,以重型装备中所广泛应用的大尺寸静压轴承为研究对象,建立了模拟静压轴承本体及轴承内部三维流动的数学模型及边界条件;利用计算流体动力学（CFD）原理,采用有限体积法并选取FLUENT中的分离式求解器进行求解,得出了轴承周期端面较准确的不对称温度分布,并分析了部分重要参数对温度分布的影响。研究结果对大尺寸静压轴承结构设计及工作台运行的可靠性有指导意义。     

带过渡深腔的动压轴承的优化设计与试验

为了提高动压轴承的承载能力和稳定性,提出一种带过渡深腔的动压轴承的新结构。由雷诺方程出发,纳入带腔动压轴承的边界条件,采用细分网格的差分算法,对轴承进行性能分析与优化设计得到带过渡腔的动压轴承的系列的特性数据和结构参数。新轴承具有承载能力大和稳定性高的特点。与普通动压轴承比较,在常用工况下,新轴承的承载能力可增大18%～98%,偏位角可由43°降低到14°,轴承稳定运转速度可提高10%～75%。在HZS-1轴承试验台上测量了轴承的油膜压力分布及偏心比。试验结果与理论分析结果具有良好的一致性。     

电磁径向轴承结构参数设计研究

以某导弹转动惯量测试平台中电磁径向轴承的结构参数设计为例，详细研究了电磁轴承结构参数设计的几个关键问题，提出了有静载时差动控制电磁铁静态工作点的设置及启浮问题的新思想，新方法，给出了具体的设计步骤，对电磁轴承结构参数设计有实际的指导意义。     

Analysis of tapered land aerostatic thrust bearing operating under nonsteady loads

Analysis of the dynamic operation of tapered land aerostatic thrust bearing to find the stability criterion is presented. The rate of change of bearing air mass content is calculated by change in mass inflow and outflow rate and equated to the actual rate of change of air mass content derived from the governing equations. Effects of various design and operational parameters on the load carrying capacity, mass flow rate and stability of the bearing were studied.     

非线性径向主动电磁轴承-转子系统的耦合动力学特性及稳定性

研究径向主动电磁轴承支承的不对称转子系统的动力行为及稳定性。转子模型中考虑了陀螺效应，结合分散PID(pmponional integral differential)控制器方程和转子运动方程，形成系统方程。将预估—校正机理和Newton-Raphson方法相结合，给出一种径向主动电磁轴承—转子系统线性失稳转速即Hopf分岔点所对应转速的计算方法。基于打靶法及将预估—校正机理和打靶法相结合形成的一种轨迹预测追踪的延续算法，研究系统非线性不平衡周期响应及稳定性边界。结合Floquet分岔理论研究随系统控制参数改变径向主动电磁轴承—转子系统周期运动的局部稳定性和分岔行为。     

轴承腔油气两相泡状流动的数值研究

航空发动机轴承腔过热或着火等现象与腔内油气两相泡状流动有关,需要通过数值计算研究两相泡状流动特性,从而为轴承腔润滑设计提供参考依据。针对上述问题,以某型航空发动机轴承腔为对象,建立轴承腔润滑油气液两相泡状流动模型,借助该模型研究润滑油介质运动状态。在建立模型方程时,考虑气泡直径尺寸大小和破裂聚合的影响,引入气泡种群方程和破裂聚合模型,并基于两流体模型和 两方程湍流模型,建立轴承腔内润滑油两相泡状流动计算模型。通过数值计算,模拟出轴承腔内润滑介质流场,最后利用国外文献的试验数据对理论分析进行了验证。研究表明,轴承腔润滑介质中气泡直径尺寸分布状态以及与转速的关系,揭示空泡率、转子转速和润滑介质进口速度等工况条件对轴承腔润滑油性能的影响。与国外试验数据的对比证明了该理论分析方法在航空发动机轴承腔润滑系统设计的可靠性和可行性。     

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。