On thermal diffusion in binary and ternary Lennard-Jones mixtures by non-equilibrium molecular dynamics
On thermal diffusion in binary and ternary Lennard-Jones mixtures by non-equilibrium molecular dynamics
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DOI：
10.1080/0141861031000107935
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发表时间：
2003-06-11
影响因子：
1.6
通讯作者：
Montel, F
中科院分区：
文献类型：
--
作者：
Galliéro, G;Duguay, B;Montel, F
分子模拟似乎是一种替代实验来估计流体混合物的输运和热力学性质，这在评价油藏的初始状态中是至关重要的。本研究将非平衡分子动力学算法应用于Lennard-Jones球的混合物中，以计算热扩散过程。这种方法对于简单的烷烃混合物是有针对性的。然后总结了分子特征在二元等摩尔混合物中对热扩散的单独影响。对二元非等摩尔混合物也进行了模拟。结果表明，随着最轻组分摩尔分数的增加，热扩散过程增加。此外，这一增加随着两种烷烃之间碳数差异的增大而增强。然后，提出了一种简单的方法，只从等摩尔值开始预测整个摩尔分数范围内的热扩散，其结果与模拟一致。最后，对于三元混合物，当采用适当的混合规则时，对应态定律是有效的，它允许从等效的二元混合物中估计这种混合物中的热扩散。
Molecular simulation appears to be an alternative to experiment for the estimation of transport and thermodynamics properties of fluid mixtures, which is of primary importance in the evaluation of the initial state of a petroleum reservoir. In this study, a non-equilibrium molecular dynamics algorithm has been applied to mixtures of Lennard-Jones spheres in order to compute the thermal diffusion process. The pertinence of such an approach to simple alkane mixtures is shown. The separate influences on the thermal diffusion of the molecular features in binary equimolar mixtures are then summarized. Simulations on binary non-equimolar mixtures have been performed as well. The results indicate an increase in the thermal diffusion process with increasing molar fraction of the lightest component. Moreover, this increase is enhanced with increasing difference in the number of carbons between the two alkanes. Then, a simple method, which yields results consistent with simulations, is proposed to predict thermal diffusion for the whole range of molar fractions starting only from the equimolar value. Finally, for ternary mixtures, the law of the corresponding states is shown to be valid when the appropriate mixing rules are applied, which allows the estimation of thermal diffusion in such mixtures from equivalent binary mixtures.