大孔隙率多孔介质渗透率与流动特性的分形理论研究

发布时间：2018-05-05 00:39

本文选题：大孔隙率 + 多孔介质　；参考：《华东交通大学》2016年硕士论文

【摘要】：自然界中许多流体运动问题发生在多孔介质中,例如农作物在土壤中水分及养分吸收迁移,地下水和油气在岩石孔隙中运动,污水在泥砂过滤器中流动等等。由于多孔介质结构的复杂和特殊,因此研究多孔介质渗透率和流动特性是一个富有挑战性的课题。本文运用分形理论,研究多孔介质渗透率和流动特性与结构参数之间的关系。首先,简单介绍大孔隙率多孔介质渗透率和流动特性研究背景和研究现状,总结了其他学者对渗透率的2种传统研究方法(实验直接测量、数值分析法)所做的研究,综述分析了相关的优缺点,并且对学者关于大孔隙率惯性阻力系数的研究也做了总结。其次,介绍了多孔介质结构特性,并且构建了正十二面体模型来研究多孔介质流动特性。根据选取的代表性微单元确定多孔介质的2个重要参数孔隙率?与孔密度PPI建立与结构参数(sd、a)之间的关系,将模型计算值与真实值比较,保证模型的可靠性以及表达式的正确性。该表达式经过严格的数学推导,每个参数都有物理意义,没有经验常数。然后,基于分形理论知识以及第二章建立的正十二面体模型,确定多孔介质的渗透率。用AutoCAD软件和几何分析,计算正十二面体模型不同截面的面孔隙率,运用Origin软件拟合面孔隙率与孔隙率的关联式。通过引入面孔隙率,得到大孔隙率渗透率表达。。正十二面体模型渗透率理论值与文献中渗透率的相应值吻合得比较好,进一步验证了正十二面体模型结构的合理性以及模型结构参数关系式的正确性。并且发现,孔隙率?相同,PPI越大,渗透率dk越小;相同PPI,孔隙率?越大,渗透率dk越大。根据确定的渗透率表达式,可以得到大孔隙率多孔介质惯性阻力系数表达式。运用分形理论,通过严格的数学推导,得到孔隙率表达式和惯性阻力系数的表达式,并且式中每个参数都有具体的物理意义,只需要已知多孔介质的孔隙率?、丝径sd、边长a、孔径pd等参数就可以求出大孔隙率多孔介质渗透率和惯性阻力系数理论值。最后对论文的主要研究内容和创新点作了总结,而且对多孔介质渗透率和流动特性的可以进行的研究工作进行了展望。
[Abstract]:In nature, many fluid movement problems occur in porous media, such as the absorption and migration of water and nutrients in soil, the movement of groundwater and oil and gas in rock pores, the flow of sewage in mud sand filters, and so on. Due to the complexity and special structure of porous media, it is a challenging task to study the permeability and flow characteristics of porous media. In this paper, fractal theory is used to study the relationship between permeability, flow characteristics and structural parameters of porous media. First of all, the research background and research status of permeability and flow characteristics of macroporous media are briefly introduced, and two traditional research methods of permeability (experimental direct measurement, numerical analysis) have been summarized by other scholars. The relative merits and demerits are analyzed, and the research on the inertial resistance coefficient of macroporosity is also summarized. Secondly, the structure characteristics of porous media are introduced, and the normal dodecahedron model is constructed to study the flow characteristics of porous media. The porosity of two important parameters of porous media is determined according to the selected representative microelements. The relationship between the model and the pore density PPI is compared with the real value to ensure the reliability of the model and the correctness of the expression. After strict mathematical derivation, each parameter has physical meaning and has no empirical constant. Then, based on the fractal theory and the normal dodecahedron model established in chapter 2, the permeability of porous media is determined. The surface porosity of the normal dodecahedron model was calculated by AutoCAD software and geometric analysis, and the correlation between surface porosity and porosity was fitted by Origin software. By introducing surface porosity, the expression of macroporosity permeability is obtained. The theoretical values of the normal dodecahedron model permeability are in good agreement with the corresponding values in the literature, which further verifies the rationality of the normal dodecahedron model structure and the correctness of the model structural parameter relationship. And found that porosity? The larger the PPI is, the smaller the permeability dk is. The larger the permeability, the greater the permeability dk. According to the expression of permeability, the expression of inertial resistance coefficient of porous medium with large porosity can be obtained. By means of fractal theory and strict mathematical derivation, the expressions of porosity and inertia resistance coefficient are obtained, and each parameter in the formula has specific physical meaning. The theoretical values of permeability and inertia resistance coefficient of porous media can be obtained only by known parameters such as porosity d, wire diameter SDD, side length a, pore diameter PD and so on. Finally, the main contents and innovations of this paper are summarized, and the possible research work on permeability and flow characteristics of porous media is prospected.
【学位授予单位】：华东交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TV139.1

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