LFC-R (UMR5150 with CNRS and TOTAL), Université de Pau et des Pays de l'Adour, BP 1155, F-64013 Pau Cedex, France.
J Chem Phys. 2013 Sep 21;139(11):114704. doi: 10.1063/1.4821128.
This work focuses on a possible influence of a nanoporous medium on the thermodiffusion of a fluid "isotopic" mixture. To do so, we performed molecular dynamics simulations of confined Lennard-Jones binary equimolar mixtures using grand-canonical like and non-equilibrium approaches in sub- and super-critical conditions. The study was conducted in atomistic slit pore of three adsorbent natures for various widths (from 5 to 35 times the size of a molecule). The simulation results indicate that for all thermodynamic conditions and whatever the pore characteristics, the confinement has a negligible effect on the thermal diffusion factor/Soret coefficient. However, when considered separately, the mass diffusion and thermodiffusion coefficients have been found to be largely influenced by the pore characteristics. These two coefficients decrease noticeably when adsorption is stronger and pore width smaller, a behavior that is consistent with a simple hydrodynamic explanation.
本工作主要研究纳米多孔介质对流体“同位素”混合物热扩散的可能影响。为此，我们采用巨正则系综和非平衡方法，在亚临界和超临界条件下对受限 Lennard-Jones 二元等摩尔混合物进行了分子动力学模拟。研究在三种不同吸附剂性质的原子狭缝孔中进行，孔径宽度（从分子尺寸的 5 倍到 35 倍不等）。模拟结果表明，对于所有热力学条件和孔特征，受限对热扩散因子/Soret 系数的影响可以忽略不计。然而，当分别考虑时，发现质量扩散和热扩散系数受孔特征的影响很大。当吸附更强且孔径更小时，这两个系数明显下降，这种行为与简单的流体力学解释一致。
