Thermal diffusion in micropores by molecular dynamics computer simulations
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- 作者：Guillaume Gallié ; ro ; Jean Colombani ; Philippe A. Bopp ; Bernard Duguay ; Jean-Paul Caltagirone and Franç ; ois Montel
- 关键词：Thermal diffusion ; Molecular dynamics ; Slit pore ; Lennard– ; Jones ; Adsorption
- 刊名：Physica A
- 出版年：2006
- 出版时间：1 March 2006
- 年：2006
- 卷：361
- 期：2
- 页码：494-510
- 全文大小：363 K
文摘
This work focuses on the identification of the main microscopic processes that influence thermal diffusion (the Soret effect) in a fluid mixture confined in an uncorrugated slit pore. To achieve this purpose, a boundary driven nonequilibrium molecular dynamics scheme is applied on binary mixtures of super-critical Lennard–Jones (LJ) spheres representing methane and n-decane. Following previous work, we perform a systematic study of the influence of the parameters used to describe a model slit pore on an effective thermal diffusion factor. Among these parameters are: The nature of the reflection of the diffusing particles on the walls (specular or diffusive), the pore width with respect to the particle size and the fluid-wall potential strength. Simulations were run both on equimolar and non-equimolar mixtures. The results indicate that thermal diffusion is effectively lowered only for strong fluid–wall interactions. It is shown that the general trends, which are different under sub- and super-critical conditions, can be explained by a careful analysis of the relative sorption energies of the two compounds.