标题： 当壁面滑移胜过剪切流动：一种温度依赖的Eyring滑移定律和用于聚α烯烃油润滑类金刚石碳的热多尺度模型 显示英文标题

标题： When wall slip wins over shear flow: A temperature-dependent Eyring slip law and a thermal multiscale model for diamond-like carbon lubricated by a polyalphaolefin oil

摘要： 润滑剂在纳米尺度通道中的定量描述受到各种有限尺寸效应的复杂影响，这些效应在传统的热弹流润滑（TEHL）模型中未被考虑。 其中一种效应是壁面滑移，这一现象已通过理论和实验进行了广泛研究。 壁面滑移与热效应之间的关系错综复杂，一些作者争论在TEHL区域内观察到的摩擦减小是否可以由滑移或加热润滑剂的粘度降低来解释。 为了理清这些机制，本文在此对剪切流动中4 cSt聚α烯烃（PAO4）基础油在纳米尺度类金刚石碳（DLC）通道中的温度与滑移关系进行了全面的分子动力学研究。 Eyring定律描述了在给定温度和压力下，固-液界面处滑移速度与剪切应力之间的关系。 同一模拟活动提供了DLC与PAO4之间界面热阻（ITR）的压力依赖性定律。 这些本构定律被应用于润滑平行通道的连续介质模型中。 通过考虑热传导，并将滑移和ITR定律与温度和压力相关的Eyring粘度定律结合，可以回答关于滑移和润滑剂热变薄之间竞争的问题。 对于与摩擦学实验和应用相容的DLC膜厚，该模型表明滑移仅在典型的边界润滑条件下非常薄的润滑剂膜中相关，这表明在TEHL区域内热变薄占主导地位。 显示英文摘要

摘要： The quantitative description of lubricant flow in nanoscale channels is complicated by various finite-size effects that are not taken into account in conventional thermo-elasto-hydrodynamic lubrication (TEHL) models. One of these effects is wall slip, a phenomenon that has been extensively studied both theoretically and experimentally. The relationship between wall slip and thermal effects is intricate, and some authors debate whether the friction reduction observed in their experiments in the TEHL regime can be explained by either slip or viscosity reduction in heated lubricants. To disentangle these mechanisms, a comprehensive molecular dynamics study of the relationship between temperature and slip in the shear flow of a 4 cSt polyalphaolefin (PAO4) base oil in a nanoscale diamond-like carbon (DLC) channel is performed here. An Eyring law describes the relationship between slip velocity and shear stress at the solid-liquid interface for a given temperature and pressure. The same simulation campaign provides a pressure-dependent law for the interface thermal resistance (ITR) between DLC and PAO4. These constitutive laws are employed in a continuum model for lubricated parallel channels. By taking heat conduction into account and combining the slip and ITR laws with a temperature- and pressure-dependent Eyring viscosity law, questions about the competition of slip and thermal thinning of the lubricant can be answered. For DLC film thicknesses compatible with tribological experiments and applications, this model shows that slip is only relevant for very thin lubricant films that are typical of boundary lubrication, suggesting the dominance of thermal thinning in the TEHL regime.