Voeltzel Nicolas, Giuliani Andrew, Fillot Nicolas, Vergne Philippe, Joly Laurent
Laboratoire de Mécanique des Contacts et des Structures, UMR5259 INSA de Lyon-CNRS, Université de Lyon, 69621 Villeurbanne, France.
Phys Chem Chem Phys. 2015 Sep 21;17(35):23226-35. doi: 10.1039/c5cp03134f. Epub 2015 Aug 18.
This article describes molecular dynamics simulations of an ionic liquid (IL) confined between iron oxide surfaces under relatively high pressure and severe shearing, representative of a typical steel-steel lubricated contact. The simulations reveal the presence of hydrodynamic and thermal slip at the walls, despite the wetting nature of the fluid/wall interface. A crucial consequence of the temperature slip is the subsequent increase of the fluid temperature under shear, which modifies its effective rheology, resulting in saturation of the shear stress at high shear rates. Overall, this article provides a methodology for accurate modeling of tribological contacts lubricated by a nanometer-thick IL film. The results contribute to the debate on the saturation of the shear stress at high shear rates, and reveal the rich phenomenology arising in severe tribological conditions, departing from the traditional understanding of nanofluidic transport, mainly built in the linear response regime and standard thermodynamic conditions.
本文描述了在相对高压和强剪切条件下，限制在氧化铁表面之间的离子液体（IL）的分子动力学模拟，这代表了典型的钢 - 钢润滑接触。模拟结果表明，尽管流体/壁面界面具有润湿性，但壁面仍存在流体动力学滑移和热滑移。温度滑移的一个关键结果是剪切作用下流体温度随后升高，这改变了其有效流变学特性，导致在高剪切速率下剪切应力饱和。总体而言，本文提供了一种对由纳米厚离子液体膜润滑的摩擦学接触进行精确建模的方法。这些结果有助于关于高剪切速率下剪切应力饱和的争论，并揭示了在严苛摩擦学条件下出现的丰富现象学，这与主要基于线性响应区域和标准热力学条件建立的传统纳米流体传输理解不同。
