透平膨胀机组动静压径向推力联合浮环轴承推力部分静动态性能研究

给出了动静压径向推力联合浮环轴承推力部分内、外层油膜Reynolds方程和边界条件,通过有限元计算得到了不同间隙和转速下内、外层油膜的压力分布和静、动态特性参数。采用深腔作为节流腔,分析计算了该内置扁毛细管节流的相当节流比。该推力浮环轴承与透平膨胀机组原来使用的五瓦可倾瓦轴承相比,稳定工作时摩擦功耗降低约26%。     

高速水润滑动静压轴承环面节流器节流系数研究

采用Fluent建立了用于高速水润滑动静压轴承的环面节流器的有限元模型,计算了环面节流器的流场,研究了小孔直径、油膜厚度、压力差和主轴转速与节流系数的关系,探讨了节流系数的变化规律。结果表明:在油膜厚度较小时,节流器性能主要取决于轴颈线速度和压力差,说明在半径间隙较小的高速水润滑动静压轴承性能计算中,根据运行参数取节流系数是很有必要的。     

不同孔式节流器对圆盘止推气体轴承静特性的影响

采用保角变换有限元方法计算采用相同供气孔径的不同孔式节流器对静压圆盘止推气体轴承静特性(包括承载力特性、静刚度特性及流量特性)的影响。对承载力和流量特性的分析结果与Kazim ierski的研究结果一致,即:采用相同供气孔径的简单孔式和环形孔式节流器止推轴承,在其他几何参数和工作参数相同的条件下,前者的承载力系数高于后者,但后者的单位载荷气体消耗率要小于前者。对静刚度特性的分析结果表明,同尺寸供气孔径的简单孔式节流器与环形孔式节流器止推轴承,在其他几何参数和工作参数相同的条件下,可以实现的最大静刚度相当,但前者最大静刚度点对应的气膜高度大于后者,因此采用简单孔式节流器时,止推轴承的设计工作点对应的气膜高度可以大一些,这意味着可在一定程度上降低对轴承制造精度的要求。     

主动控制节流气体润滑轴承静动态特性研究

将表面节流与主动控制节流相结合,提出了一种新型的主动控制节流气体润滑轴承,采用工程简化计算与有限元分析相结合,对轴承进行了理论分析,建立了该轴承的理论分析模型,较好地解决了数值计算中多重迭代与快速收敛问题,理论分析和试验研究结果表明,该轴承通过主动控制节流器对轴承压力的反馈控制,轴承静动态性能显著提高。     

减振器双节流孔闭式油路稳态行为特征有限元分析

本文以汽车减振器工作状态为基础原型，用高级有限元分析软件ANSYS建立了双节流孔闭式油路稳态模型，分析了不同阀振速度下减振器模型的内部流场、压力场、剪应力场分布的变化规律，为复杂闭式油路边界形状设计提供理论依据；同时也分析了计算了此模型中节流孔壁剪应力与减振速度的函数关系以及壁压力与节流孔长度的关系，为以后的节流流孔阻尼力计算提供数值基础。     

基于ANSYS Workbench的气体静压轴承径向特性分析

提出一种基于ANSYS Workbench的径向特性分析方法。基于计算流体力学的相似原理,建立小孔气体静压主轴的有限元模型,并使用FLUENT模块计算得到主轴微小气膜间隙内的压力场;通过Static Structure静力分析模块进行强度校核,并获取主轴的承载力;基于DOE实验设计方法计算小孔气体静压主轴的径向刚度,并分析周向节流孔个数和节流孔孔径对径向刚度的影响。结果表明,节流孔孔径越大,刚度越小;节流孔周向数量增加,刚度增大。计算结果与实验结果吻合较好,证明该方法的可行性。     

基于流固耦合的薄膜节流器仿真分析

应用有限元分析软件ANSYS和流固耦合分析方法,对新型岛式薄膜节流器和常规薄膜节流器在同等边界条件下,进行模拟仿真分析,得到两种节流器上、下腔液体压力分布及两种薄膜变形.仿真对比分析证实了新型岛式薄膜中心圆台变形平缓,使薄膜不易塑性变形,减小了薄膜节流静压轴承由于局部液压冲击产生的系统失稳,利于薄膜节流器的设计计算.     

小孔节流静压气体轴颈轴承的静态特性研究

通过对小孔节流静压气体轴颈轴承润滑方程的分析,利用泛函求极值法将二阶偏微分方程降为一阶,采用有限元方法,利用三角单元线性插值函数,简化压力分布方程式的计算,对轴承的参数进行了优化,得到了轴承上各点的压力分布和轴承的承载能力和支承刚度,并分析了轴承间隙和偏心率等因素对承载能力和刚度的影响。     

狭缝节流气体静压润滑方程式的离散化和相容性条件

提出了一种将常用不同结构形式的狭缝节流气体静压轴承基本方程式的相容变换条件,把结构种类繁多的狭缝节流气体静压轴承的分析,变换成统一的等价标准形式轴承的计算,使自动化编程成为可能。还利用加权余量法把偏微分方程式离散化,把二阶偏微分方程降阶为一阶,放松了对插值函数连续度的要求,便于借助有限元技术分析狭缝节流气体静压轴承的流场参数,给出了计算轴承承载特性的方法。同时,将该方法成功地应用于动压轴承的计算中。     

新型阶梯圆柱销节流向心静压轴承特性研究

采用内部节流的静压轴承具有刚度高、不易堵塞等优点,但节流腔占据很大面积,造成轴承尺寸增大.文中将传统的节流腔改进为阶梯圆柱销式,最大限度地减少节流腔的面积,在不增加轴承尺寸的情况下提高了静压轴承的承载能力和刚度.该新型阶梯圆柱销节流器结构简单,工艺性良好,容易做成装配式结构.文中推导了该节流器的液阻及节流比,并通过计算比较了毛细管、小孔和阶梯圆柱销节流下向心静压轴承的无量纲承载能力和油膜刚度.     

小孔节流深浅腔动静压轴承承载特性解析研究

小孔节流深浅腔动静压轴承是一种采用小孔节流器实现节流作用及浅腔实现二次节流作用的动静压混合轴承。针对现有理论不能解析研究油腔结构参数及工作参数对承载特性影响规律的不足,以及计算流体力学数值仿真软件计算时周期长,而不便于工程设计人员应用的缺点,基于油腔压强分段线性化的思想,建立分析小孔节流深浅腔动静压轴承的油腔压强、承载能力、静刚度、进油流量及温升等承载特性的解析方法。进而以该方法研究动静压轴承的供油压强、主轴转速、进油孔径、浅腔深度、初始油膜厚度等参数对轴承承载特性的影响规律。研究发现,在其他结构参数及工作参数一定的条件下,浅腔深度为初始油膜厚度的2～3倍时,轴承刚度接近最大、温升接近最低。通过油腔压强的解析值与试验值的比较,证实了该方法的有效性和研究结果的正确性。     

伴随孔对小孔节流气体静压轴承内部气旋现象的抑制

气浮轴承的微振动现象严重制约轴承工作精度的提高,而轴承压力腔内部的气旋现象是轴承存在微振动的主要原因。为抑制气旋现象,提出一种带伴随孔的复合节流静压止推轴承,采用数值模拟的方法研究伴随孔的直径和位置对气旋的抑制作用以及对轴承静态性能的影响。结果表明：采用主进气孔与增加伴随孔的复合节流方式会使承载力和出口流量小幅下降,但带伴随孔的复合节流静压止推轴承对压力腔内的气旋现象有明显的抑制作用;其他条件不变,随伴随孔直径及伴随孔与主进气孔轴线间距的增大,承载力与出口流量总体呈现先下降再上升的趋势;随伴随孔直径的增大,轴承压力腔内气旋受到的抑制效果先增强后减弱,随着小孔与主孔距离的增大,对气体旋的抑制作用不断减弱。     

Performance of membrane compensated multirecess hydrostatic/hybrid flexible journal bearing system considering various recess shapes

The paper describes a theoretical study concerning the performance of an externally pressurized multirecess hydrostatic/hybrid flexible journal bearing system by varying the geometric shape of recess and using the membrane flow valve restrictor as a compensating element. The four different recess geometries of the bearing studied in the present study are a square recessed bearing, a circular recessed bearing, an elliptical recessed bearing and a triangular recessed bearing. The equation governing the flow of lubricant in a journal bearing together with 3D elasticity equation and restrictor flow equation are solved by using the Finite Element Method. The study describes the effect of recess shape, bearing flexibility and a method of compensation on the performance characteristics of a hydrostatic/hybrid journal bearing system. A comparative performance of the membrane compensated hydrostatic/hybrid journal bearing system has also been studied vis-à-vis capillary, orifice and constant flow valve restrictors. The results presented in this study amply demonstrate that the shape of recess/pocket of a hydrostatic/hybrid flexible journal bearing system affects the performance of the bearing quite appreciably and a proper selection of recess shape along with a suitable compensating device is needed to get an improved performance from the bearing.     

Influence of recess shape on the performance of a capillary compensated circular thrust pad hydrostatic bearing

This work describes a theoretical study concerning the static and dynamic performance of a circular thrust pad hydrostatic bearing having recesses of different geometric shapes. The Finite Element Method has been used to compute the performance characteristics of a circular thrust pad hydrostatic bearing with circular, rectangular, elliptical and annular recesses. The performance has been compared on the basis of the same bearing operating and the same geometric parameters, i.e. the same ratio of bearing to pocket area ( ) and the same value of restrictor design parameter . Further, a comparative study of the various bearing configurations has been carried out vis-à-vis different compensating devices such as capillary, orifice, and constant flow valve restrictors so as to study the combined influence of the geometric shape of recesses and the compensating device on bearing performance. The computed results indicate that to get an improved performance from a hydrostatic circular thrust pad bearing, a proper selection of the geometric shape of the recess in conjunction with the type of restrictor and the value of the restrictor design parameter is essential.     

The restrictive effects of capillary compensation on the stability of the Jeffcott rotor-hybrid bearing system

The influence of restriction parameters, recess depth and land-width ratios on the load capacity and stability of a Jeffcott rotor supported by single-row, six-recessed hybrid bearings with capillary compensation is studied. The finite difference method is used to solve Reynolds equation, whilst the determination of stability threshold uses the Routh-Hurwitz method. The load capacity, stability threshold, and the critical whirl ratio, versus the changing restriction parameters, are each simulated for both shallow-recessed and the deep-recessed bearings with various land-width ratios. Simulated results indicate that small land sizes are necessary for shallow-recessed bearings in order to yield good performance, and these bearings are superior to deep-recessed bearings. Furthermore, both load capacity and stability threshold become correspondingly greater with a decrease in the restriction parameters. Nevertheless, the appropriate design of both restrictor and land size in deep-recessed bearings might well induce both load capacity and stability threshold greater than in shallow-recessed bearings.     

Orifice compensated multirecess hydrostatic/hybrid journal bearing system of various geometric shapes of recess operating with micropolar lubricant

The objective of the present paper is to study analytically the performance of four-pocket orifice compensated hydrostatic/hybrid journal bearing system of various geometric shapes of recess operating with micropolar lubricant. The modified Reynolds equation for micropolar lubricant is solved using FEM and the Newton-Raphson method along with appropriate boundary conditions. The results suggest that the influence of micropolar effect of lubricant on bearing performance is predominantly affected by the geometric shape of recess and restrictor design parameter. Therefore, the bearing designer must judiciously choose an appropriate geometric shape of recess in order to get an overall enhanced bearing performance.     

阶梯浅油腔动静压轴承动特性分析

本文提出了基于有限差分法的浅油腔动静压轴承动特性分析的偏号数法，并利用该法 两种在国产磨床中常用的浅油腔动静脉轴承的动特性。     

有限体积法与正交试验法相结合的动静压轴承结构优化设计

针对小孔节流深浅腔动静压轴承的性能优化问题,基于平行平板扩散流动计算模型及流量守恒原理,推导了微元控制体边界压力的插值函数,提出了分析小孔节流深浅腔动静压轴承的油腔压力、承载力、静刚度、进油流量及温升等承载特性的有限体积计算方法。使用该方法研究了供油压力、主轴转速、进油孔径、浅腔深度、初始油膜厚度等参数对小孔节流深浅腔动静压轴承承载特性的影响规律,从而得到了以上相关参数的优化区间。在此基础上,采用四因素三水平的正交试验法,在满足多目标性能最优的前提下,得到了小孔节流深浅腔动静压轴承结构参数与工作参数的最优组合。以该组参数试制了小孔节流深浅腔动静压轴承并建立了试验平台,测量了不同转速及供油压力下油腔的压力值。试验结果表明,轴承油腔压力试验数据及理论计算值随主轴转速的变化趋势一致;误差在11%以内。验证了有限体积法与正交试验法相结合的动静压轴承结构优化设计方法的正确性。