提高小孔供气静压气体径向轴承稳定性方法的探讨

对通过向轴承系统引入附加阻尼以提高小孔供气静压气体径向轴承稳定性的方法进行了回顾和分析，介绍了“O”形橡胶圈加稳、Sixsmith式、双气膜、切向进气四种附加阻尼的小孔供气静压气体径向轴承和胶圈加稳切向小孔供气及双气膜切向小孔供气两种复合形式的小孔供气静压气体径向轴承。并对这几种轴承的结构型式、研究发展、应用范围和优缺点进行了详细的描述。     

透平机小孔气体轴承性能的研究

利用有限元法求解稳态和摄动雷诺方程，对双排径向小孔静压气体轴颈轴承的静，动特性进行了分析。     

狭缝节流径向气体静压轴承的结构设计研究

针对狭缝节流径向气体静压轴承,利用基于有限体积法的Fluent软件进行流场三维建模仿真,研究分析了狭缝的宽度、深度、位置、形状及轴承长径比等因素对轴承静态特性的影响,得到以下结论:当狭缝宽度z=3~4μm、狭缝深度H=15~17 mm、狭缝距端面L2=10~15 mm时,轴承具有最佳静态特性;轴承长径比在0.8~1.5区间,随轴承长径比的增大,轴承静态特性逐渐改善;与连续狭缝相比,非连续狭缝轴承具有较好的静态特性。     

静压气体轴承设计支持系统的研究

本文介绍了静压气体轴承设计支持系统的总体方案。在分析了静压气体轴承设计特点的基础上,提出了一种用事件并借鉴面向对象的技术来表达的基于知识推理的方法来实现本系统的设计。     

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。     

小孔节流静压止推气体轴承静特性的数值分析

介绍了计算流体力学软件 FLUENT 及其在气体轴承研究中的应用.针对环形小孔节流静压止推气体轴承,基于 FLUENT 软件进行了简化假设并建立了计算模型,利用 FLUENT 软件对止推气体轴承模型进行了数值分析,求解了环形小孔节流静压止推气体轴承的压力场分布、耗气量和承载能力等轴承静特性,并成功捕捉到了大气膜间隙下供气孔周围的压力突降区.对计算结果进行了分析,并与文献计算值以及试验值进行了对比,验证了数值分析的可靠性.     

小孔节流方式对气体静压轴承工作刚度影响的分析

本文对小孔节流方式中的简单孔节流和环形孔节流形式对气体静压轴承工作风度的影响进行了理论分析,通过比较从而得出,采用简单孔节流方式的轴承比环形孔节流方式的轴承具有更高的工作刚度。     

气体静压轴承的计算机辅助设计

将VB编程语言应用于气体静压轴承的工程计算及参数的优化设计，以获得合理的结构参数。用VB编写的设计软件使用方便快捷，大大提高圆柱气体静压轴承设计精度和效率，实现了设计自动化。     

气体静压轴承的计算机辅助设计

将VB编程语言应用于气体静压轴承的工程计算及参数的优化设计，以获得合理的结构参数。用VB编写的设计软件使用方便快捷，大大提高气体静压轴承设计精度和效率。实现了设计自动化。     

新型径向槽结构静压气体轴承静态特性研究

设计一种新型径向槽结构静压气体轴承,其周向和径向截面分别呈椭圆弧形和扇形。建立该径向槽结构静压气体轴承CFD模型,分析径向槽结构参数如深度、半径、数目、角度和试验参数供气压力,对静压气体轴承承载能力和刚度的影响。研究结果表明:静压气体轴承承载能力随槽结构深度、数目、角度和供气压力增加逐渐增大,随槽结构半径增加先增大后减小;槽结构数目和供气压力对其承载能力影响尤为显著;静压气体轴承径向槽结构参数和供气压力影响其刚度及最佳刚度对应的气膜厚度,其中槽结构半径、数目和供气压力对刚度值影响显著,槽结构角度和半径对最佳刚度对应的气膜厚度影响显著。由此可见,径向槽结构参数显著影响静压气体轴承的承载能力和刚度。     

轴向缝切向进气轴颈轴承稳定性的试验研究

本文设计了组合式及嵌入式轴向缝切向进气轴颈轴承,将其装配到与１５０Ｎｍ＾３／ｈ制氧机配套的中压透平膨胀机上进行试验,实测了不同设计参数下的轴承失稳转还,并分析了影响轴承失稳转速的各种因素。     

轴向缝切向进气径向气体轴承的稳定性研究

本文利用小扰动法分析了轴向缝切向进气径的气体轴承的稳定性问题,在理论分析中考虑了气流的惯性项对该类轴承稳定的影响,得出了轴承的设计参数怀轴承失稳转速及失稳涡动比的关系曲线,实验结果与计算结果吻合较好。     

透平膨胀机新型切向小孔气体轴承静特性的实验研究

为减小普通切向小孔供气轴承的耗气量,本文提出了一种新型切向小孔供气轴承。静态性能的测试表明,这种新型轴承具有耗气量小、刚度大等优点。     

Tri-Conical Gap-Shaped Externally Pressurized Gas Bearing Pads

Externally pressurized gas (EPC) bearing pads with convergent conical shapes can provide high load capacity and high stiffness. Research has revealed that if the suitable combination of gap difference and working gap height is chosen, the optimized diameter ratios for stiffness and load capacity are close to the same value, about 0.8 to 0.9, or the ratio of the diameter of the conical gap-shaped part over the pad diameter. The optimized diameter ratio is independent of the supply pressure, the pad diameter and the number of conical parts. Conversely, the stability of the bearings is controlled by the combination of the diameter ratio and the gap difference. From the analysis of the stability criteria and the optimized diameter ratio, the concept of the tri-conical gap-shaped EPG bearing pads was proposed. Numerical and experimental investigation shows that under the same stable conditions, tri-conical gap-shaped pads provide higher stiffness and higher load capacity than simple conical or parallel gap-shaped pads.     

Characteristics of Externally Pressurized Porous Gas Bearings Considering Structure Permeability

The performance of a finite length porous journal bearing fed by externally pressurized air is numerically analyzed in the present study. A quasi-linear numerical scheme associated with an underrelaxation factor is used to solve the pressure solutions of the nonlinear coupled partial differential equation (PDE). Two characteristic parameters, i.e., the feeding parameter Λp and a conventional bearing number Λ, are involved in the analysis. The results show that the aerodynamic lubricating effect is dominant for the porous bearing having a small Λp number, whereas the aerostatic effect prevails inside the bearing space as the Λp number is large. When the permeability parameter Λp is small, the aerodynamic effect is further promoted for the bearing operating at heavy load; herein the minimum film thickness becomes relatively small. It is found that a bearing with a small Λp will have a higher risk for the journal shaft to touch the bearing wall than a bearing with large Λp. Therefore, as far as the bearing safety and loading capacity are concerned, a porous journal bearing with Λp ranging between 0.5 and 1 is recommended in practical use.     

An Experimental Investigation into the Temperature Profile of a Compliant Foil Air Bearing

A series of tests was performed to determine the internal temperature profile in a compliant bump-type foil journal air bearing operating at room temperature under various speed and load conditions. The temperature profile was collected by instrumenting a foil bearing with nine type-K thermocouples arranged in the center and along the bearing's edges in order to measure local temperatures and estimate thermal gradients in the axial and circumferential directions. To facilitate the measurement of maximum temperatures from viscous shearing in the air film, the thermocouples were tack-welded to the backside of the bumps that were in direct contact with the top foil. The mating journal was coated with a high-temperature solid lubricant that, together with the bearing, underwent high-temperature start-stop cycles to produce a smooth, steady-state run-in surface. Tests were conducted at speeds from 20 to 50 krpm and loads ranged from 9 to 222 N.

The results indicate that, over the conditions tested, both journal rotational speed and radial load are responsible for heat generation with speed playing a more significant role in the magnitude of the temperatures. The temperature distribution was nearly symmetric about the bearing center at 20 and 30 krpm but became slightly skewed toward one side at 40 and 50 krpm. Surprisingly, the maximum temperatures did not occur at the bearing edge, where the minimum film thickness is expected, but rather in the middle of the bearing, where analytical investigations have predicted the air film to be much thicker. Thermal gradients were common during testing and were strongest in the axial direction from the middle of the bearing to its edges, reaching 3.78° C/mm. The temperature profile indicated the circumferential thermal gradients were negligible.     

基于有限差分法对不同润滑介质下静压气体轴颈轴承性能研究

利用有限差分方法编写一套可以用于分析动静压气体轴承性能的计算程序,并通过已有算例和试验验证本程序计算结果的可靠性。对不同润滑介质下静压轴颈轴承气体消耗量进行研究发现,不同分子量润滑介质下气体消耗量随偏心率变化表现出不同的变化规律,小分子润滑介质下气体消耗量与偏心率成正比,而大分子润滑介质下气体消耗量与偏心率成反比,并且此规律与节流小孔类型无关,小孔节流轴颈轴承气体消耗量大于环面节流类型轴颈轴承。相同供气压力和偏心率情况下,小分子润滑介质小孔节流轴颈轴承承载能力比环面节流类型轴承承载能力小,大分子润滑介质下正好相反。本程序方法为后来对俄罗斯油—气混合低温氦透平膨胀机气体轴承端改造奠定了理论基础。