Molecular dynamics study on heat conductivity mechanism of silica aerogel

Equilibrium molecular dynamics and nonequilibrium molecular dynamics simulations based on Lennard-Jones pair potential were used to analysis the energy transport characteristics of Argon in silica aerogel. The results indicate that diffusion coefficient of Argon in aerogel with cubic pore of 15 nm in length is only 50.35% of the value in the free space under the same circum-stances. The movements of gaseous molecules are strictly confined and therefore lead to a low thermal conductivity. The thermal insulation performance is promoted with the decrease of pore size in aerogel.