Thermodiffusion or the Ludwig-Soret effect is known as the cross effect between the temperature gradient and induced separation of mixture species in multicomponent mixtures. The performance of the boundary driven non-equilibrium molecular dynamics enhanced heat exchange (eHEX) algorithm was validated by evaluating the sign and magnitude of the thermodiffusion process in methane/n-butane/n-dodecane (nC₁–nC₄–nC₁₂) ternary mixtures. The eHEX algorithm consists of an extended version of the HEX algorithm with an improved energy conservation property. In addition to this, the transferable potentials for phase equilibria-united atom augmented force field was employed in all molecular dynamics (MD) simulations to accurately represent molecular interactions in the fluid. Our newly employed MD algorithm was capable to appropriately reflect the thermophobicity concept and the coupled effect of relative density and mole fraction of the mixture species on the thermodiffusion process. The separation ratio of the ternary mixture for five different compositions (at 333.15 K and 35 MPa) showed good agreement with experimental data and better accuracy in predicting the sign change of the intermediate component (nC₄) as its concentration in the mixture increases, when compared to other MD models.

中文翻译：

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组成对三元混合物疏水性的影响：一种增强的分子动力学方法

热扩散或路德维希-索雷特效应被称为温度梯度与多组分混合物中混合物种类的诱导分离之间的交叉效应。通过评估甲烷/正丁烷/正十二烷（nC ₁ –nC ₄ –nC _12）中热扩散过程的符号和幅度，验证了边界驱动的非平衡分子动力学增强的热交换（eHEX）算法的性能。）三元混合物。eHEX算法由具有改进的节能特性的HEX算法的扩展版本组成。除此之外，在所有分子动力学（MD）模拟中均采用了相平衡单元原子增强力场的可转移势能，以准确表示流体中的分子相互作用。我们新采用的MD算法能够恰当地反映憎热性概念以及混合物种类的相对密度和摩尔分数对热扩散过程的耦合影响。五种不同成分（在333.15 K和35 MPa时）的三元混合物的分离率与实验数据显示出良好的一致性，并且在预测中间组分（nC ₄），因为与其他MD模型相比，其在混合物中的浓度增加了。