【摘要】 分子量级超薄油膜的润滑特性与流体润滑及边界润滑的都有所不同，而且在超薄油膜中也同样存在着润滑剂的流动。因此，利用分子动力学方法模拟了超薄油膜中的压力流动，模拟中采用了刚性分子流体模型，重点研究固体壁面对流动的影响，结果表明，当油膜厚度远比流体分子“直径”大时，模拟所得速度剖面和流量均与流体力学的理论值基本一致；随着油膜厚度逐渐变薄，压力流动或动压流因受到固体壁面的阻碍作用而不断减小；当油膜厚度减小到几个分子直径量级时，两固体壁面之间的流体分子发生固化或晶体化，由此而导致压力流动消失。这可能是流体动力润滑向边界润滑转化的机理之一。由这些研究结果可见，分子动力学模拟在薄膜润滑研究中具有广阔的应用前景。更多还原

【Abstract】 Molecularly thin lubricating films behave diffetently from both hydrodynamic andboundary lubrication:the lubricant flow still exists in the ultrathin film but the flow will the affected by the solid wall. For this reason ,a Poiseuille flow within ultra thin film has been studiedby molecular dynamics (MD)simulation for simple fluid with rigid molecule. The simulation results show that the velocity profile and flow rate were consistent with the prediction of the Stokesequations when the film thickness is much larger than the molecule “diameter”; the Poiseuille orhydrodynamic folw will be blocked by the solid walls and the effective viscosity increase as the solidwalls come closer; a sharp increase in effective viscosity observed at a film thickness of fewmolecular diameters may correspond to the termination of hydrodynamic flow; the phenomenon ofmolecule ordering near solid-fluid interface was confirmed by the present simulation; and the transition from hydrodynamic to boundary lubrication may be related to the fluid solidification and the growth of the ordering structure throughout entire film thickness. These results show that theMD simulation provides a new and prospective approach in studying thin film lubrication.更多还原