冲击载荷作用下的薄膜润滑数值分析

发布时间：2018-11-01 13:40

【摘要】：本文首先采用多重网格法和多重网格积分法对等温粗糙表面冲击弹流问题进行了数值模拟分析。研究了表面粗糙波纹波长对等温重力落球问题的影响。研究中还分析了钢球初始下落高度、初始油膜厚度和钢球质量对冲击油膜压力和膜厚的影响。研究发现，冲击高度的增加、初始油膜厚度的增加和钢球质量的增加均会使中心压力第一压力峰增大；中心膜厚随冲击质量的增加和初始油膜厚度的增加而增大，而最小膜厚随冲击高度的增加而增大，随初始油膜厚度的增加基本保持不变。随着波长的增大，，每一瞬时的振幅下降也会增大。初始润滑油膜厚度较小时振幅下降反而较大。其次，在等温落球问题的基础上，运用多重网格法和多重网格积分法以及温度逐列扫描法对粗糙表面冲击热弹流问题进行了分析。首先对表面余弦波纹对考虑热效应的重力落球问题进行分析。接着将热解与对应的等温解比较，随后分别研究了冲击高度和初始油膜厚度对冲击热弹流问题的影响。研究发现，表面粗糙波纹使压力、膜厚及油膜中层温度发生剧烈波动。最高温升和中心温升随着冲击高度的增加均增大。随着初始油膜厚度的增加，第一温升峰和中心温升均减小。最后，采用数值分析方法研究冲击载荷作用下偏心轮-挺杆副的微热弹性流体动力润滑问题。分析中假设平面挺杆表面分布有余弦波纹，探讨了偏心距和余弦波波长对润滑油膜变化的影响。数值模拟计算结果表明，在偏心轮-挺杆副工作的一个周期里，表面波纹度的存在会导致油膜压力和温度上升。在不同的滑滚比条件下，表面波纹的弹性变形程度不同。在两表面反向运动的半个周期内，随偏心距的增加，滑滚比也增加，导致表面波纹的变形程度降低。
[Abstract]:In this paper, the impact elastohydrodynamic problem of isothermal rough surface is numerically simulated by multi-grid method and multi-grid integration method. The influence of surface rough ripple wavelength on isothermal gravity drop was studied. The effects of the initial falling height of the ball, the initial oil film thickness and the ball quality on the impact oil film pressure and film thickness are also analyzed. It is found that the increase of impact height, the increase of initial oil film thickness and the increase of ball mass will increase the first pressure peak of the center pressure. The central film thickness increases with the increase of the impact mass and the initial oil film thickness, while the minimum film thickness increases with the increase of the impact height, and remains basically unchanged with the increase of the initial oil film thickness. As the wavelength increases, the amplitude decreases with each instant. The amplitude of the initial lubricating oil film decreases greatly when the film thickness is small. Secondly, based on the isothermal drop problem, the impact thermal elastohydrodynamic problem of rough surface is analyzed by using multi-grid method, multi-grid integration method and temperature sequential scanning method. Firstly, the gravity ball drop problem considering the thermal effect is analyzed for the surface cosine ripple. Then, the effects of impact height and initial oil film thickness on the impact thermal elastohydrodynamic problem are studied by comparing the pyrolysis with the corresponding isothermal solution. It is found that the surface roughness ripples make the pressure, film thickness and oil film temperature fluctuate sharply. The maximum temperature rise and the center temperature rise increase with the increase of impact height. With the increase of the initial oil film thickness, the first temperature rise peak and the center temperature rise decrease. Finally, the micro-thermoelastic hydrodynamic lubrication of eccentric wheel-tappet pair under impact load is studied by numerical analysis method. The influence of eccentricity and cosine wave length on the variation of lubricating oil film is discussed. The numerical simulation results show that the existence of surface ripple will lead to the increase of oil film pressure and temperature during a period of work between eccentric wheel and tappet pair. The elastic deformation degree of surface ripple is different under different sliding ratio. With the increase of eccentricity, the slip / roll ratio increases during the half period of the reverse motion of two surfaces, which results in the decrease of the deformation degree of the surface ripple.
【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH117.2

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