纳米流体中固-液作用影响界面热阻及导热率的分子动力学研究

Molecular Dynamics Study on Solid-liquid Interaction Affecting Interface Thermal Resistance and Thermal Conductivity of Nanofluids

纳米流体中固-液界面处由于声子散射形成界面热阻,给纳米流体内热量传递带来阻力。为研究界面热阻对纳米流体导热率的影响,以Cu-Ar纳米流体为基础模型,采用非平衡分子动力学方法研究了纳米粒子-流体相互作用强度与界面热阻的定量关系。研究表明,随着纳米粒子-流体相互作用强度增大,界面热阻显著降低,其机制在于流体分子的吸附作用增强了纳米粒子表面原子的振动强度,从而促进了纳米粒子与流体之间的热传递。增大纳米粒子-流体相互作用强度可显著提高纳米流体导热率,且界面热阻对纳米流体导热率的影响程度随纳米粒子尺寸减小而增大。

Due to the phonon scattering at the solid-liquid interface,thermal resistance is formed in nanofluids,which bring a resistance to heat transfer inside the nanofluids.Non-equilibrium molecular dynamics simulations were performed for the Cu-Ar nanofluids to investigate the effect of interface thermal resistance on the thermal conductivity of nanofluids.The results show that the interface thermal resistance decreases significantly with the increase of the inter-atomic interaction strength between nanoparticles and fluids.The mechanism is that the adsorption of fluid molecules enhanced the vibration strength of surface atoms of the nanoparticles,which promoted the heat transfer between the nanoparticles and fluids.The nanofluid has higher thermal conductivity when the interaction strength between nanoparticles and fluids is larger,and the impact of interface thermal resistance can be more obvious with the decrease of nanoparticle size.