Liu Yawei, Ganti Raman, Frenkel Daan
Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
J Phys Condens Matter. 2018 May 23;30(20):205002. doi: 10.1088/1361-648X/aabd58. Epub 2018 Apr 11.
We present numerical simulations of diffusio-osmotic flow, i.e. the fluid flow generated by a concentration gradient along a solid-fluid interface. In our study, we compare a number of distinct approaches that have been proposed for computing such flows and compare them with a reference calculation based on direct, non-equilibrium molecular dynamics simulations. As alternatives, we consider schemes that compute diffusio-osmotic flow from the gradient of the chemical potentials of the constituent species and from the gradient of the component of the pressure tensor parallel to the interface. We find that the approach based on treating chemical potential gradients as external forces acting on various species agrees with the direct simulations, thereby supporting the approach of Marbach et al (2017 J. Chem. Phys. 146 194701). In contrast, an approach based on computing the gradients of the microscopic pressure tensor does not reproduce the direct non-equilibrium results.
我们展示了扩散渗透流的数值模拟，即沿固液界面由浓度梯度产生的流体流动。在我们的研究中，我们比较了为计算此类流动而提出的多种不同方法，并将它们与基于直接非平衡分子动力学模拟的参考计算进行比较。作为替代方案，我们考虑了从组成物种的化学势梯度以及与界面平行的压力张量分量梯度来计算扩散渗透流的方案。我们发现，将化学势梯度视为作用于各种物种的外力的方法与直接模拟结果一致，从而支持了Marbach等人（2017年《化学物理杂志》146卷194701期）的方法。相比之下，基于计算微观压力张量梯度的方法无法重现直接非平衡结果。
