四极真实流体自扩散系数和二元Maxwell-Stefan扩散系数的分子模拟
Self-diffusion and binary Maxwell-Stefan diffusion coefficients of quadrupolar real fluids from molecular simulation
摘要：
自和二元Maxwell-Stefan扩散系数由平衡分子动力学模拟与Green-Kubo方法确定。本文研究了FPDMATHABMM，NPDMATHABMM，COPDMATHABMM，CSPDMATHABMM，CPDMATHABMMHPDMATHABMN，CPDMATHABMMHPDMATHABMO，$_2$和$_6$八种纯流体在液态下的自扩散系数以及$_2$ + $_2$，N $_2$ +C $_2$ H $_6$和CO $_2$ +C $_2$ H $_6$。流体模型的两个中心的Lennard-Jones加上点四极对电位，从我们的小组以前的工作，这是完全确定的汽液平衡数据的基础上的参数。预测的自扩散系数的统计不确定度小于1%，他们同意在2%至28%的实验数据。由于系统的有限尺寸，模拟数据的校正通常使自扩散系数的值增加10%。如果考虑这种校正，可以预期与实验数据更好的协议，为大多数研究的流体。预测了三种二元混合物的Maxwell-Stefan扩散系数，其统计不确定度约为10%。这些结果被用来测试三个经验公式来估计Maxwell-Stefan扩散系数在二元混合物，即方程的Caldwell和Babb，的Darken，和Vignes。考德威尔和巴布和Vignes的方程显示定性不同的行为的麦克斯韦-斯特凡扩散系数比在模拟中观察到的。与以前的工作一致，在所有情况下，Darken方程都得到了最好的结果。
英文摘要：
Self- and binary Maxwell-Stefan diffusion coefficients were determined by equilibrium molecular dynamics simulations with the Green-Kubo method. This study covers self-diffusion coefficients at liquid states for eight pure fluids, i.e. F$_2$, N$_2$, CO$_2$, CS$_2$, C$_2$H$_6$, C$_2$H$_4$, C$_2$H$_2$ and SF$_6$ as well as Maxwell-Stefan diffusion coefficients for three binary mixtures N$_2$+CO$_2$, N$_2$+C$_2$H$_6$ and CO$_2$+C$_2$H$_6$. The fluids were modeled by the two-center Lennard-Jones plus point-quadrupole pair potential, with parameters taken from previous work of our group which were determined solely on the basis of vapor-liquid equilibrium data. Self-diffusion coefficients are predicted with a statistical uncertainty less than 1% and they agree within 2% to 28% with the experimental data. The correction of the simulation data due to the finite size of the system increases the value of the self-diffusion coefficient typically by 10%. If this correction is considered, better agreement with the experimental data can be expected for most of the studied fluids. Maxwell-Stefan diffusion coefficients for three binary mixtures were also predicted, their statistical uncertainty is about 10%. These results were used to test three empirical equations to estimate Maxwell-Stefan diffusion coefficients in binary mixtures, i.e. the equations of Caldwell and Babb, of Darken, and of Vignes. The equations of Caldwell and Babb and of Vignes show qualitatively different behavior of the Maxwell-Stefan diffusion coefficient than that observed in the simulations. In agreement with previous work, the best results are obtained in all cases with the equation of Darken.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
