Effect of surface roughness and void fraction on thermal transportation of a solid: A molecular dynamics study

Abstract

Interstitial phenomena functioning as surface roughness, voids and irregularities in nano scale influence the heat transfer and these effects become very significant with the reduction of material size. Non-equilibrium Molecular Dynamics (NEMD) simulation was employed in this study to understand the effects of interfacial thermal resistance named kapitza resistance on solid. Argon like solid was considered in this study and LJ potential model was employed for the calculation of atomic interaction. Surface roughness as well as voids was created in the solid and the void radius was varied. From the simulation, it was observed that a large interfacial mismatch due to these irregularities in homogenous solid causes distortion of phonon frequency causing an increase in thermal resistance. The size of voids has a profound effect on thermal conductivity of solid. Voids positioned perpendicular to heat flow direction causes sharp reduction in thermal conductivity. The reduction of thermal conductivity due to large surface to volume ratio for the generation of surface roughness has also been observed in this study.Interstitial phenomena functioning as surface roughness, voids and irregularities in nano scale influence the heat transfer and these effects become very significant with the reduction of material size. Non-equilibrium Molecular Dynamics (NEMD) simulation was employed in this study to understand the effects of interfacial thermal resistance named kapitza resistance on solid. Argon like solid was considered in this study and LJ potential model was employed for the calculation of atomic interaction. Surface roughness as well as voids was created in the solid and the void radius was varied. From the simulation, it was observed that a large interfacial mismatch due to these irregularities in homogenous solid causes distortion of phonon frequency causing an increase in thermal resistance. The size of voids has a profound effect on thermal conductivity of solid. Voids positioned perpendicular to heat flow direction causes sharp reduction in thermal conductivity. The reduction of thermal conductivity due to larg...