受限球腔内缔合Lennard-Jones流体的压力张量及应用

发布时间：2018-01-09 19:43

本文关键词：受限球腔内缔合Lennard-Jones流体的压力张量及应用　出处：《河北大学》2017年硕士论文　论文类型：学位论文

【摘要】：本文以受限球腔内缔合Lennard-Jones(LJ)流体为主要研究对象,通过考虑高阶的密度关联计算了流体的压力张量,进一步探讨了压力张量在计算界面和表面特征时的应用。首先,基于角度平均的方法得到了分子间的二体作用势。其次,根据经典的密度泛函理论分别计算了开放和封闭体系下的平衡密度分布,并在此基础上计算讨论了相关因素(缔合强度、缔合位点的数目、球腔尺寸以及体相密度(平均粒子数密度))对压力分布的影响。再次,作为应用,分别计算了两体系(即开放体系和封闭体系)下相关因素变化时的表面张力和界面张力,进而讨论了这些因素对其的影响。最后,在前述基础上比较了两体系下相关因素对压力张量、表面张力以及界面张力的具体影响情况。本文的研究旨在为揭示受限流体的物理化学性质和聚集态结构提供可能的理论线索。本文共分为四个部分,主要内容如下:第1章:绪论。介绍了受限流体以及经典的密度泛函理论的发展现状,阐述了经典的密度泛函理论计算的一般步骤,并对压力张量、表面张力、界面张力等受限流体的力学特征做以简介。第2章:球腔内Af型缔合LJ流体的压力张量(巨正则系综)。基于Wertheim的一阶微扰理论,通过角度平均法将缔合位点之间的相互作用势转化为分子间的相互作用势,根据经典的密度泛函理论得到了开放体系下流体处于平衡态时的密度分布,在此基础上,研究了不同因素作用下的压力张量,并讨论了这些因素对压力分布的影响。作为应用,计算了开放体系下,不同因素变化时的表面张力与界面张力,并分析了这些因素对其的影响。第3章:封闭球腔内Af型缔合LJ流体的压力张量(正则系综)。采用经典的密度泛函理论,得到了封闭体系下流体的平衡密度分布,进而计算和讨论了封闭体系中压力分布随不同因素变化的情况。作为应用,分别计算了封闭体系中不同条件下的表面张力和界面张力,并讨论不同条件下表面张力和界面张力的变化情况。最后,对开放体系和封闭体系下的压力分布、表面张力、界面张力进行了比较与分析。第4章:本文的不足和展望。
[Abstract]:In this paper, the associating Lennard-Jones LJ fluid in a confined spherical cavity is taken as the main research object, and the pressure Zhang Liang of the fluid is calculated by considering the high order density correlation. The application of pressure Zhang Liang in the calculation of interface and surface characteristics is further discussed. Firstly, the two-body interaction potential between molecules is obtained based on the angular averaging method. Secondly, the two-body interaction potential between molecules is obtained. Based on the classical density functional theory, the equilibrium density distributions in open and closed systems are calculated, and the relative factors (association strength, number of associated sites) are discussed. The influence of spherical cavity size and bulk density (mean particle number density) on the pressure distribution. Thirdly, as an application. The surface tension and interfacial tension of the two systems (i.e. open system and closed system) are calculated, and the influence of these factors on them is discussed. On the basis of the above, we compare the relevant factors under the two systems to the pressure Zhang Liang. The purpose of this paper is to provide possible theoretical clues for revealing the physicochemical properties and aggregation state structure of confined fluids. This paper is divided into four parts. The main contents are as follows: chapter 1: introduction. This paper introduces the development of confined fluid and classical density functional theory, expounds the general steps of classical density functional theory calculation, and describes the pressure Zhang Liang, surface tension. The mechanical characteristics of confined fluids such as interfacial tension are briefly introduced. Chapter 2: pressure Zhang Liang of Af associating LJ fluid in spherical cavity (giant canonical ensemble) based on Wertheim's first-order perturbation theory. The interaction potential between associating sites is transformed into the intermolecular interaction potential by the angular averaging method. According to the classical density functional theory, the density distribution of the fluid in equilibrium state in the open system is obtained. On this basis, the pressure Zhang Liang under different factors is studied, and the influence of these factors on the pressure distribution is discussed. As an application, the open system is calculated. The surface tension and interfacial tension of different factors. Chapter 3: pressure Zhang Liang (canonical ensemble) of Af-type associating LJ fluid in closed sphere cavity. The classical density functional theory is used. The equilibrium density distribution of the fluid in the closed system is obtained, and the pressure distribution in the closed system with different factors is calculated and discussed. The surface tension and interfacial tension in the closed system under different conditions are calculated, and the variation of surface tension and interfacial tension under different conditions are discussed. Finally, the pressure distribution in open system and closed system is discussed. The surface tension and interfacial tension are compared and analyzed. Chapter 4: the deficiency and prospect of this paper.
【学位授予单位】：河北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O35

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