Guevara-Carrion Gabriela, Fingerhut Robin, Vrabec Jadran
Thermodynamics and Process Engineering, Technical University of Berlin, Ernst-Reuter-Platz 1, 10587, Berlin, Germany.
Sci Rep. 2021 Jun 10;11(1):12319. doi: 10.1038/s41598-021-91727-w.
The Fick diffusion coefficient matrix of the highly associating quaternary mixture water + methanol + ethanol + 2-propanol as well as its ternary and binary subsystems is analyzed with molecular dynamics simulation techniques. Three of the ternary subsystems are studied in this sense for the first time. The predictive capability of the employed force fields, which were sampled with the Green-Kubo formalism and Kirkwood-Buff integration, is confirmed by comparison with experimental literature data on vapor-liquid equilibrium, shear viscosity and Fick diffusion coefficient, wherever possible. A thorough analysis of the finite size effects on the simulative calculation of diffusion coefficients of multicomponent systems is carried out. Moreover, the dependence of the Fick diffusion coefficient matrix on the velocity reference frame and component order is analyzed. Their influence is found to be less significant for the main matrix elements, reaching a maximum variation of 19%. The large differences found for the cross elements upon variation of the reference frame hinder a straightforward interpretation of the Fick diffusion coefficient matrix with respect to the presence of diffusive coupling effects.
采用分子动力学模拟技术分析了高度缔合的四元混合物水 + 甲醇 + 乙醇 + 2 - 丙醇及其三元和二元子系统的菲克扩散系数矩阵。从这个意义上讲，首次对其中三个三元子系统进行了研究。通过与关于气液平衡、剪切粘度和菲克扩散系数的实验文献数据进行比较（只要有可能），证实了采用格林 - 库博形式和柯克伍德 - 布夫积分采样的所用势场的预测能力。对多组分系统扩散系数模拟计算中的有限尺寸效应进行了全面分析。此外，分析了菲克扩散系数矩阵对速度参考系和组分顺序的依赖性。发现它们对主要矩阵元素的影响较小，最大变化为19%。当参考系变化时，交叉元素存在很大差异，这阻碍了对菲克扩散系数矩阵关于扩散耦合效应存在情况的直接解释。
