共查询到20条相似文献,搜索用时 15 毫秒
1.
建立刚性球头支撑和弹性橡胶垫支撑可倾瓦推力轴承热弹流耦合模型;在弹性橡胶垫支撑可倾瓦推力轴承橡胶垫的弹性变形分析中采用了变形协调矩阵方法,以协调匹配橡胶垫变形和水膜厚度分布,同时在搜索稳态解的过程中引入模拟退火算法;基于变分原理求解Reynolds方程,得到了轴承水膜压力分布,并比较2种推力轴承在转子存在角不对中时的静特性。结果表明:理想工况下,刚、弹支可倾瓦推力轴承稳态特性没有明显区别;当转子存在不对中时,刚性球头支撑可倾瓦轴承在不同瓦块之间受力偏载严重,进而导致瓦面最小水膜厚度过小,瓦块容易出现磨损,而弹性支撑瓦不同瓦块之间水膜力分布更均匀,利于轴承的长期可靠运行。 相似文献
2.
Experimental study on the characteristics of pad fluttering in a tilting pad journal bearing 总被引:2,自引:0,他引:2
The fluttering characteristics of the upper unloaded pads in a tilting pad journal bearing were studied experimentally. In order to investigate the fluttering phenomena of the pad, the absolute vibration of the pad, the relative vibration between the bearing and the shaft, and the circumferential film thickness/film pressure were measured with the variation of the supply oil flow rate, the shaft speed, and bearing load. By analyzing the circumferential distributions of the film thickness, it was identified that the film shape of the upper pad continuously alternates between the wedge shape and the diverged shape in the rotational direction while the shaft is rotating. And it was discovered that the pads tend to a representative sub-synchronous self-excited vibration exactly like classical rotor-bearing instability, defined as the oil whirl and oil whip phenomena, with the increase of rotating speed from the cascade plot of the pad. The major finding was that the incipient fluttering velocity of the pad increased with the increase of the supply oil flow rate but decreased with the increase of the bearing load. The experimental results also showed that the fluttering amplitudes of the pad can be effectively suppressed by controlling the supply oil flow rate. 相似文献
3.
For several reasons, almost all bearings operate in a misaligned condition, the present research work deals with analyzing the performance of a misaligned tilting-pad journal bearing under transient loading condition. The elastic and thermal distortions of the pad are considered and finite element analysis is used to calculate the pad’s elastic deformation. Using finite difference method, the Reynolds equation is simultaneously solved with the energy equation to calculate the pressure distribution and hence the other bearing performance characteristics. A modified fluid film thickness equation is used to take the effect of shaft misalignment and bearing elastic and thermal distortion into consideration.The results have shown that considering the thermo-elasto-hydrodynamic distortion improves the bearing performance in the case of misalignment shaft. And, at low values of shaft misalignment, the decrease in oil film thickness due to shaft misalignment is compensated by the increase in oil film thickness due to elastic and thermal distortions. 相似文献
4.
5.
This work reports the thermal analysis of hydrodynamically lubricated cycloidal profiled pad thrust bearing (CPPTB) using an efficient numerical method based on Lobatto quadrature technique. The performance parameters with smooth and rough surfaces of cycloidal and plane profiled pads are presented for various operating inputs. Significant increase in magnitude of pressure and substantial reduction in coefficient of friction are observed in the presence of relatively large amplitude of roughness over the surface of stationary pads. Comparisons are made for performance parameters achieved with plane profiled pad thrust bearing (PPPTB) and CPPTB. The load carrying capacity of CPPTB is found significantly high than the PPPTB for the provided set of operating parameters. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
6.
The load support and other performance characteristics of any bearing depend on its film thickness profile which can be significantly affected by elastic deformations. The effect of bearing surface deformation on the static performance of slider bearings is reported. Deformation of bearing pads was calculated by three-dimensional elasticity equations using a finite element method.To generalize the study, a non-dimensional deformation coefficient relating the geometrical parameters of bearing pad, the clearance space, the elasticity coefficient of the pad material, the lubricant viscosity and the velocity of the slider is defined. The static characteristics are calculated and compared for different values of the deformation coefficient. The effect of Poisson's ratio v of the pad material on the performance of a slider bearing for steel (v = 0.3) and brass (v = 0.4) as pad materials is reported. 相似文献
7.
Average flow model with elastic deformation for CMP 总被引:3,自引:0,他引:3
We present a three-dimensional (3D) average flow model considering elastic deformation of pad asperities for chemical mechanical planarization. To consider the contact deformation of pad asperities in the calculation of the flow factor, 3D contact analysis of a semi-infinite solid based on the use of influence functions is conducted for computer-generated rough surfaces. The average Reynolds equation and boundary conditions of both force and momentum balance are used to investigate the effects of pad roughness and external pressure conditions on a film thickness and wafer position angles. It is found that the position angles decrease with the increasing of the applied pressure and the roughest pad has the highest position angles at any given load. Comparing elastic and rigid pads, the minimum film thickness formed between the elastic pad and the wafer is thinner than that between the rigid pad and the wafer. 相似文献
8.
Theoretical considerations of static and dynamic characteristics of air foil thrust bearing with tilt and slip flow 总被引:2,自引:0,他引:2
The thrust pad of the rotor is used to sustain the axial force generated due to the pressure difference between the compressor and turbine sides of turbomachinery such as gas turbines, compressors, and turbochargers. Furthermore, this thrust pad has a role to maintain and determines the attitude of the rotor. In a real system, it also helps reinforce the stiffness and damping of the journal bearing. This study was performed for the purpose of analyzing the characteristics of the air foil thrust bearing. The model for the air foil thrust bearing used in this study is composed of two parts: one is an inclined plane, which plays a role in increasing the load carrying capacity using the physical wedge effect, and the other is a flat plane. This study mainly consists of three parts. First, the static characteristics were obtained over the region of the thin air film using the finite-difference method (FDM) and the bump foil characteristics using the finite-element method (FEM). Second, the analysis of the dynamic characteristics was conducted by perturbation method. For more exact calculation, the rarefaction gas coefficients perturbed about the pressure and film thickness were taken into consideration. At last, the static and dynamic characteristics of the tilting condition of the thrust pad were obtained. Furthermore, the load carrying capacity and torque were calculated for both tilting and nontilting conditions. From this study, several results were presented: (1) the stiffness and damping of the bump foil under the condition of the various bump parameters, (2) the load carrying capacity and bearing torque at the tilting state, (3) the bearing performance for various bearing parameters, and (4) the effects considering the rarefaction gas coefficients. 相似文献
9.
Fuxi Liu Yanjun Lu Qimeng Zhang Yongfang Zhang Parag Gupta Norbert Müller 《Lubrication Science》2016,28(4):207-220
Three‐pad fixing pad aerodynamic journal bearings (TPFPAJBs) have been widely used in precision instruments due to their low friction, high stability and non‐pollution. In order to improve the load performance of TPFPAJBs, parabolic grooves are opened in the bearing pad surfaces. By opening parabolic grooves in various bearing pad surfaces, the effects of the orientation angle, distance, width and depth of the grooves on the load performance of micro‐grooved TPFPAJBs can be investigated. The numerical results show that the location of the micro‐grooved bearing pads can greatly affect the load performance of micro‐grooved TPFPAJBs. When the given bearing pad surface is grooved, the effects of the bearing number and width‐to‐diameter ratio on the load performance of micro‐grooved TPFPAJBs can be studied. The bearing number and width‐to‐diameter ratio are observed to have significant influences on the load performance of micro‐grooved TPFPAJBs. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
10.
弹性变形对径向轴承弹流润滑性能的影响 总被引:5,自引:2,他引:3
本文以上具有不同弹性模量、泊松系数的两种轴承材料为例分析了弹性变形对有限长径向滑动轴承的弹流润滑性能的影响。流体动力润滑方程采用雷诺方程,应用力学问题的通用有限元软件MARC产生柔度矩阵计算弹性变形。对比分析了二种轴承的油膜压力分布、油膜厚度分布、最小油膜厚度以及承载能力。 相似文献
11.
12.
13.
M. Wasilczuk 《Lubrication Science》2003,15(3):265-273
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. 相似文献
14.
15.
Effects of operating conditions and supply hole diameter on the performance of a rectangular aerostatic bearing 总被引:2,自引:0,他引:2
The present study is an experimental investigation of the performance characteristics of an externally pressurized rectangular recessed gas bearing operating under different working conditions. It includes the measurements of pressure, load carrying capacity, and mass flow rate. The experiments covered a wide range of film thicknesses and supply pressures. In addition, pads of different supply hole diameters were used. The results obtained from the present investigation show that the effect of varying the supply hole diameter on bearing performance is significant. Increasing the supply hole diameter to bearing length ratio has the effect of increasing the recess pressure and load carrying capacity. Further, as the supply pressure and/or film thickness increases the dimensionless load carrying capacity decreases and the lubricant mass flow rate increases. 相似文献
16.
可倾瓦推力轴承在变载荷下的瞬态润滑性能研究 总被引:1,自引:0,他引:1
建立了可倾瓦推力轴承中的油膜厚度方程、瞬态油膜压力方程、瞬态油膜温度方程以及求解油膜力和瓦块力矩的数学模型,提出了基本方程的数值求解过程,研究了可倾瓦推力轴承变载荷下的瞬态润滑性能。结果表明,随着载荷的增大,油膜厚度减小,油膜温升增大。在达到同样载荷时,对于较大的载荷变化率,其油膜温升反而较小。另外,随着载荷的增大,瓦块的倾角也.随之逐渐增大。 相似文献
17.
多叶动压气体滑动轴承因其结构简单、摩擦阻力低、旋转精度高和无环境污染等优点,在高速离心分离机、空气压缩机和透平膨胀机等旋转机械中应用广泛。为探究多叶动压气体滑动轴承的静态性能,通过数学变换将三叶动压轴承的气体润滑Reynolds方程转化为标准偏微分方程形式,利用有限差分法和超松弛迭代法进行数值求解,研究气膜厚度和气膜压力分布、承载力、摩擦因数和质量流量等静态性能,随偏心率、预负荷系数、轴承数、长径比及瓦块分布位置的变化规律。结果表明:三叶轴承的承载力和轴颈表面摩擦因数随偏心率和长径比的增加而增加,而偏位角和质量流量随偏心率和预负荷系数的增加则呈现出相反的变化趋势;随着轴承数和预负荷系数的增大,承载力和摩擦因数显著提高,偏位角和质量流量则逐渐减小;瓦块分布位置对三叶动压气体滑动轴承的静态性能影响显著,其中瓦上承载方式的承载力、偏位角和质量流量明显高于瓦间承载方式。 相似文献
18.
19.
20.
考虑变黏度、密度的情况,建立多瓦可倾瓦径向滑动轴承的数学模型,用有限差分法求解其热流体动力润滑(THD)模型,分别计算12块瓦可倾瓦径向滑动轴承的最小油膜、压力分布和三维温度场分布,分析不同载荷、不同转速、不同润滑油黏度等对轴承各瓦的热润滑性能影响。结果显示,建立的模型及其计算程序能计算分析多瓦可倾瓦径向滑动轴承的热润滑问题。润滑油黏度和转子转速对多瓦可倾瓦径向滑动轴承的热润滑性能有较大的影响;瓦块绕支点的倾斜以及瓦块所处的角度位置会影响部分瓦块的热润滑性能,出现与普通圆形径向滑动轴承不一致的润滑性能变化。 相似文献