一种离子液体的热弹流润滑数值模拟

离子液体因微观结构与普通润滑油不同,使其具有较低的黏压系数。采用光干涉油膜测量技术标定一种离子液体的黏压系数,并通过等温数值计算验证其可靠性。使用标定的黏压系数,对该离子液体进行膜厚、温升、摩擦因数和接触区中心黏度等热弹流润滑数值计算,并与具有相同黏度的普通润滑油的算例进行比较。计算结果显示,离子液体与同黏度润滑油相比具有突出的摩擦学性能,体现在离子液体在较宽速度和滑滚比范围内有非常低的温升和摩擦因数,而膜厚仍保持在同黏度润滑油的40%以上。离子液体的这种热弹流特性主要归因于其较低的黏压系数。

Numerical Simulation of Thermo-elastohydrodynamic Lubrication of an Ionic Liquid

Compared with regular lubricants,the unique microstructures of ionic liquids(ILs)impart their lower viscous-pressure coefficients(VPC).By measuring film thickness via optical interferometry,the VPC value of an IL was obtained.The availability of the VPC value was confirmed through isothermal elastohydrodynamic lubrication(EHL)simulation.Using this VPC value,numerical simulations of thermoelastohydrodynamic lubrication(TEHL)of IL was conducted to analyze the film,temperature rise,friction coefficient and viscosity.The numerical results were compared with a common lubricating oil which has the same viscosity as the IL.The results show that IL has outstanding tribological properties compared with lubricating oil of the same viscosity,which is reflected in its very low temperature rise and friction coefficient in a wide range of speed and slip roll ratio,while the film thickness still remains more than 40%of the same viscous lubricating oil.The excellent TEHL properties of IL are mainly attributed to its low VPC.