Scuola di Scienze e Tecnologie, Università di Camerino, Via Madonna delle Carceri, 62032 Camerino, INFN Perugia, Italy.
J Chem Phys. 2011 Jul 28;135(4):044104. doi: 10.1063/1.3608416.
We present the detailed analysis of the diffusive transport of spatially inhomogeneous fluid mixtures and the interplay between structural and dynamical properties varying on the atomic scale. The present treatment is based on different areas of liquid state theory, namely, kinetic and density functional theory and their implementation as an effective numerical method via the lattice Boltzmann approach. By combining the first two methods, it is possible to obtain a closed set of kinetic equations for the singlet phase space distribution functions of each species. The interactions among particles are considered within a self-consistent approximation and the resulting effective molecular fields are analyzed. We focus on multispecies diffusion in systems with short-range hard-core repulsion between particles of unequal sizes and weak attractive long-range interactions. As a result, the attractive part of the potential does not contribute explicitly to viscosity but to diffusivity and the thermodynamic properties. Finally, we obtain a practical scheme to solve the kinetic equations by employing a discretization procedure derived from the lattice Boltzmann approach. Within this framework, we present numerical data concerning the mutual diffusion properties both in the case of a quiescent bulk fluid and shear flow inducing Taylor dispersion.
我们提出了对空间不均匀流体混合物的扩散输运以及在原子尺度上变化的结构和动力学性质之间相互作用的详细分析。本处理方法基于液体状态理论的不同领域，即动理学和密度泛函理论，并通过格子玻尔兹曼方法将其实现为有效的数值方法。通过结合前两种方法，可以获得每个物种的单峰相空间分布函数的封闭的动理学方程集。粒子之间的相互作用在自洽近似中被考虑，并且分析了所得的有效分子场。我们专注于具有短程硬芯排斥的各向同性系统中的多物种扩散，其中粒子的大小不同且具有较弱的吸引力长程相互作用。结果，势的吸引力部分不会显式地贡献于粘性，而是贡献于扩散率和热力学性质。最后，我们通过采用从格子玻尔兹曼方法导出的离散化程序获得了求解动理学方程的实用方案。在这个框架内，我们给出了关于在静止体相流体和诱导泰勒分散的剪切流的情况下的相互扩散性质的数值数据。
