纳米流体导热系数和强化机理的分子动力学模拟

杨鹏志++廖立

摘 要：納米流体的导热系数是影响其传热特性的重要热物性参数，本文采用非平衡分子动力学方法，对纳米流体的导热系数进行了分子动力学模拟和计算。纳米流体的导热系数相比于基础液体有了明显的提高，此外纳米流体的导热系数还会受到纳米颗粒体积分数、材料属性、形状、以及系统温度的影响。纳米流体的导热系数与纳米颗粒、基液、以及基液和纳米颗粒之间的相互作用息息相关。通过探索和分析纳米流体内部粒子的迁移过程和动力学机理，研究纳米流体内部的能量传递过程以及纳米流体导热系数强化的微观作用机理。纳米流体微观结构的改变以及纳米颗粒的微运动是强化纳米流体导热系数的主要微观原因。

关键词：非平衡分子动力学模拟；纳米流体；导热系数；微观机理

The thermal conductivity and strengthening mechanism of nanofluids by molecular dynamics Simulation

Yang Pengzhi， Liao Li

（Key Laboratory of Low-grade Energy Utilization Technologies and Systems of Ministry of Education， College of Power Engineering， Chongqing University， Chongqing 400044， China）

Abstract：The thermal conductivity of nanofluids plays an important role in heat transfer， non-equilibrium RNEMD molecular dynamics method is used to calculate the thermal conductivity of nanofluids in this article. The thermal conductivity of nanofluids is enhanced to a very large degree compared to the base fluid. In addition， the volume fraction of nanopartice， the material properties， the shape of nanoparticle and the temperature are significant factors to the thermal conductivity of nanofluids. Nanopartice and the base fluid influence each other as well as the thermal conductivity of nanofluids. Researches on the energy transfer process of nanofluids and the micro mechanism of thermal conductivity enhancement of nanofluids by analyzing the migration process of nanoparticle and the dynamic mechanism of nanoparticle suggest that the change of micro structure of nanofluids and the micro motion of nanoparticle are the main reasons to affect the thermal conductivity of nanofluids.

Keywords：non-equilibrium molecular dynamics simulation；nanofluids； thermal conductivity； micro mechanism