共查询到19条相似文献,搜索用时 93 毫秒
1.
为了研究瓦面凹槽对可倾瓦推力轴承润滑性能改善的优势,在瓦块进油边设计一种圆弧槽结构,建立考虑槽结构的可倾瓦推力轴承热动力润滑模型,分析不同槽深和槽半径对轴承性能的影响规律。结果表明:在瓦块进油边开槽可以改善轴承润滑性能,与不开槽相比,油膜厚度和瓦块的进油流量增加,油膜温度降低;当槽深达到一定值后,油膜温升增大;推力轴承润滑性能随着槽半径增加而变差,轴承各性能参数随槽深的增加表现出极值特性;最优开槽参数为(1.2~1.5,1),该参数下轴承最小油膜厚度比无槽轴承的增加约10%,最大油膜温度降低约3℃。 相似文献
2.
3.
4.
5.
6.
7.
8.
9.
10.
为了揭示表面粗糙度对圆柱滚子轴承线接触稳态弹流润滑性能的影响,本文建立了具有表面粗糙度的圆柱滚子轴承弹流润滑模型,并推导出了摩擦系数方程;采用有限差分法求解了圆柱滚子轴承的弹流润滑性能,并分析了余弦粗糙度幅值、波长和纹理角度对圆柱滚子轴承弹流润滑性能的影响.数值结果表明:随着粗糙度幅值的增大,油膜厚度和油膜压力在粗糙度波峰波谷处的波动增大;随着粗糙度波长的增大,油膜厚度逐渐减小,油膜压力的波动逐渐减小;横向粗糙度更有利于提高承载能力,降低摩擦系数.因此,在合理的范围内增加粗糙度的幅度和波长,采用交叉纹理,有利于提高圆柱滚子轴承的弹流润滑性能. 相似文献
11.
《机械与工业》2000,1(2):141-150
Theoretical and experimental analysis of thermal effects in fixed geometry thrust bearings. This paper deals with both theoretical and experimental analyses of thermal phenomena in thrust bearings. The test allowed us to measure the pressure and the temperature fields and the minimal film thickness separating the two surfaces in relative motion. The experimental data are obtained on a hydrodynamic thrust bearing with eight fixed pads. The influence of operating conditions (applied load and rotational speed) on the thrust bearing performance is also analysed. The numerical simulation is done using a thermohydrodynamic computer code taking into account the local thermal effects. 相似文献
12.
Experiments on thermal effects in a hydrodynamic thrust bearing 总被引:1,自引:0,他引:1
The objective of this work is to analyse the characteristics of a fixed-geometry thrust bearing in typical operating conditions and to give experimental results in order to validate future thermohydrodynamic models. The influence of the applied load, the rotational speed and the feeding temperature on the thrust bearing performance is presented and discussed. 相似文献
13.
建立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 ,提出基本方程的数值求解过程 ,研究可倾瓦推力轴承变转速下的瞬态润滑性能。 相似文献
14.
为研究某水轮发电机组推力轴承的油膜润滑及冷却情况,建立推力轴承数值模拟计算模型,分析轴承温度和压力分布,基于流固耦合方法计算轴瓦变形情况。结果表明:该推力轴承轴瓦变形量极小,可以忽略其对轴承安全运行的影响;但该推力轴承在轴瓦外径处最大温度已超出安全运行范围,而且高温区域面积较大,影响轴承安全运行。基于正交试验方法,分析主要运行参数对推力轴承温度的影响程度。结果表明:进油压力对轴承温度影响最大,其次是进油温度,镜板转速对轴承温度的影响很小;随着润滑油进油压力和进油温度增加,推力轴瓦温度会随之上升,而随着镜板转速的增加,推力轴瓦温升减小。通过极差分析得到推力轴承最优工况组合,对于水轮发电机组的安全稳定运行有着一定的指导意义。 相似文献
15.
A three-dimensional (3D) thermohydrodynamic (THD) model for air foil thrust bearings (AFTBs) is presented. The nonisothermal Reynolds equation is solved using pressure boundary conditions at the cooling air plenum considering local temperature-dependent viscosity and density. Air film temperature is calculated using the 3D energy equation with thermal boundary conditions at the top foil, thrust runner, and top foil’s leading edge. The cooling air plenum distributes the cooling air to multiple radially arranged cooling channels. The plenum temperature and pressure are found from mass and energy balance equations applied to the plenum. Temperature fields of the top foil, bump foils, thrust disc runner, bearing plate, and cooling air channels are also solved through appropriate energy balance equations with their surroundings. A robust computational algorithm with multiple iteration loops was developed to find all the temperature fields. THD analyses were performed for AFTB with outer radius of 50 mm up to 100,000 rpm. As the cooling air source pressure is increased, the plenum pressure also increases and its temperature decreases due to more cooling capacity. However, cooling effectiveness is not necessarily proportional to the pressure because the flow residence time inside the cooling channels is inversely proportional to the pressure. The analyses show that the thrust disc temperature is a parabolic function with speed, and thermal expansions of the thrust disc and thrust plates contribute to the most significant driving force of thermal instability. Optimum cooling air pressure was found around 12,500 Pa for the proposed AFTB design at the reference simulation condition. 相似文献
16.
Turbocharger bearings have to work under high temperature, and are moreover rotated at high speed. They have to be designed by overcoming the high temperature. The type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing's inner temperature. In this study, the influence of aerated oil on a high-speed journal bearing is also examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of an air–oil mixture in a fluid-film bearing. Convection to the walls and mixing with supply oil and re-circulating oil are considered. The considered parameters for the study of bubbly lubrication are the oil inlet port's type, oil aeration level and shaft speed. It is found that the type of oil inlet ports and shaft speed play important roles in determining the temperature and pressure distribution, and the friction in a journal bearing at high-speed operation. Also, the results show that, under extremely high shaft speed, the high shear effects on aerated oil and the high-temperature effects cancel out each other. So, the bearing load and friction show almost no difference between aerated oil and pure oil. 相似文献
17.
18.
The thermohydrodynamic performance of a thrust bearing with circular pads is analysed taking into consideration the three-dimensional variation in lubricant viscosity. The effect of centrifugal forces is included. A Reynolds' equation incorporating centrifugal forces is derived for the thermohydrodynamic case. The system of equations is solved by a finite difference method. The results show that at the upper limits of laminar operation centrifugal forces alter considerably the load, the frictional force and the lubricant inflow. They might either overestimate or underestimate the bearing performance characteristic, depending on the pad's geometry and the operating conditions of the bearing. 相似文献
19.
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