arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.12247cond-mat.soft
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硬球流体在无序多孔介质中的扩散:Enskog理论描述

Diffusion of hard sphere fluids in disordered porous media: Enskog theory description

M. F. Holovko, M. Ya. Korvatska

摘要:

本文用Enskog理论描述了无序多孔介质中硬球流体的自扩散系数。使用我们以前开发的用于描述硬球流体的热力学性质的标度粒子理论,得到流体-流体和流体-矩阵对分布函数的接触值的简单解析表达式,并用作Enskog理论的输入。所获得的接触值的表达式仅由几何孔隙度描述,并且不包括对其他类型的孔隙度的依赖性,这对于热力学性质的描述是重要的。它示出,这样的接触值的应用忽略了由矩阵和至少探针颗粒孔隙度$ϕ$的流体颗粒的捕获的效果应包括在Enskog理论的矩阵的影响的正确描述。在本文中,我们扩展了Enskog理论通过改变接触值的流体矩阵和流体-流体对分布函数的新的性质,其中包括依赖于不仅对几何孔隙率,而且对探针粒子的孔隙率$ϕ$。结果表明,这种半经验改进的Enskog理论对应于SPT 2b 1近似的热力学性质的描述,它预测正确的趋势多孔介质上的硬球流体在无序多孔介质中的扩散系数的影响。良好的协议与计算机模拟示出。讨论了流体密度、流体与基体球尺寸比、基体孔隙率和基体形貌对硬球流体自扩散系数的影响。

英文摘要:

We use the Enskog theory for the description of the self-diffusion coefficient of hard sphere fluids in disordered porous media. Using the scaled particle theory previously developed by us for the description of thermodynamic properties of hard sphere fluids, simple analytical expressions for the contact values of the fluid-fluid and fluid-matrix pair distribution functions are obtained and used as the input of Enskog theory. The expressions obtained for the contact values are described only by the geometric porosity and do not include the dependence on other types of porosity that are important for the description of thermodynamic properties. It is shown that the application of such contact values neglects the effects of trapping of fluid particles by a matrix and at least the probe particle porosity $ϕ$ should be included in the Enskog theory for a correct description of the matrix influence. In this paper we extend the Enskog theory by changing the contact values of the fluid-matrix and the fluid-fluid pair distribution functions with new properties which include the dependence not only on geometric porosity but also on probe particle porosity $ϕ$. It is shown that such semi-empirical improvement of the Enskog theory corresponds to SPT2b1 approximation for the description of thermodynamic properties and it predicts correct trends for the influence of porous media on the diffusion coefficient of a hard sphere fluid in disordered porous media. Good agreement with computer simulations is illustrated. The effects of fluid density, fluid to matrix sphere size ratio, matrix porosity and matrix morphology on the self-diffusion coefficient of hard sphere fluids are discussed.

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。

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