水基纳米液压液抗磨减摩特性的分子动力学模拟

Molecular Dynamic Simulation on Anti-wear and Friction Reducing Properties of Water-based Nano Hydraulic Fluid

为探究纳米颗粒对于水基纳米液压液抗磨减摩特性的影响机制,以水基Cu纳米液压液为例,构建纳米流体在平板间做剪切流动的动力学模型,采用Lennard-Jones势函数、嵌入原子势(EAM)、MCY建立原子间势能模型,研究不同压力、不同纳米颗粒含量、不同剪切速度下水基纳米液压液的抗磨减摩特性和承载能力。结果表明:水基纳米液压液的承载能力随着纳米颗粒数量的增加而增大;在一定范围内,摩擦力会随着纳米颗粒含量的增大而减小,但过大的纳米颗粒含量将导致摩擦加剧。借助分子动力学模拟的方法,探索在剪切作用下纳米颗粒的运动状态,结果发现纳米颗粒绕不同坐标轴的角速度分量存在较大的差异,表明纳米颗粒在模拟区域的上下金属壁面之间起到类似滚珠轴承中“滚珠”的作用。

In order to explore the influence of nanoparticles on the anti-wear and friction reducing properties of water-based nano hydraulic fluid,a dynamic model of nano fluid between plates under shear flow conditions was built by taking water-based Cu nano hydraulic fluid as an example.The Lennard-Jones potential function,EAM(embedded atom model)and MCY were adopted to build potential model between atoms.The bearing capacity,anti-wear and friction reducing properties of water-based nano hydraulic fluid under different loads,different content of nanoparticles and different shear rates were studied.The results show that the bearing capacity increases with the increase of the content of nanoparticles.The friction between the walls decreases with the increase of the content of nanoparticles within certain range,however,the excessive content of nanoparticles leads to increased friction.The movement of nanoparticles under shear flow was explored by the molecular simulation.It is found that nanoparticles action is similar to the ball effect of ball-bearings between the upper and lower metal walls in the simulation region.