【作者】 余振勋；

【导师】 谭凯旋；

【作者基本信息】 南华大学 ， 市政工程， 2007， 硕士

【摘要】 本课题将分形理论运用到对混凝法去除无机悬浮液浊度的过程分析中。由于絮凝体成长随机性,具有非线性的特征,在不考虑絮凝体破碎的话,常规的絮凝过程是由初始粒子结成小的集团,小的集团又结成大的集团,然后结成更大的集团,这样一步一步成长为大的絮凝体。这一过程决定了絮凝体在一定范围内具有自相似性和标度不变性,这正是分形的两个重要特征。也就是说,絮凝体是一个分形体。本文就近些年分形理论在混凝领域的应用,以及对分形絮凝体之间的碰撞频率函数计算公式进行了详细的介绍;并对絮体的生长进行了模拟,得到了多种形态的絮体,并分析了模拟絮体的性质,且通过试验考察了其混凝特性。应用软件模拟技术对絮体的生长进行模拟,通过不同条件参数的设置,得到了多种形态的絮体,并结合分形特点对不同形态的絮体的特征进行了分析。在模拟中,我们改变模拟参数对影响絮体形态和分形维数的各种相关因素进行了分析。通过模拟我们可以得出,随着总体吸附表面几率的升高,模拟中所得到的絮体逐渐开放;絮体随着吸附距离的增大而越来越密实,分形维数随着吸附距离的增大而增大;絮体随着填充空间的增大,变得越来越密实。通过混凝实验技术对无机悬浮液浊度的去除率与絮体沉淀后所形成形状的分形结构间的关系进行了讨论。主要结论有:投药量对浊度的去除是一个先增大后减小的过程,最大去除率出现在投药量为3ml时,此时的去除率为97%,此时维数的变化也是一个先增大后减小的过程;当pH值小于6的情况下,去除率是呈上升趋势的,在值为6时去除率降为最低,去除率为63.4%;从6开始,去除率随着pH的增大而提高;絮体分形维数随原水浊度的增加而增大,实验所测的范围内,去除率也保持着增加的趋势。更多还原

【Abstract】 With the fractal theory, we analyzed the process of removal of inorganic suspended particles by coagulation. The pullulation of flocs is a random process and it has nonlinear character. If the fragmentation of flocs is not considered,the routine flocculation process is to form the small group from initial particle and the big group from small groups. Finally the biggest group is formed from those big groups. In this way thick and big flocs are formed. This process decides that flocs have self-similarity and dilation symmetry in a certain extent, and they are two important characteristics of the fractal. In the paper, the application of fractal theory in flocculation and some basic formula describing characteristics of flocs and some calculation formula with collision frequency function among fractal flocs are demonstrated .In addition, the particles aggregation was simulated. Several type of flocs was reached and its morphological characteristics was analyzed.The particles aggregation was simulated using model. Several type of flocs was reached and its morphological characteristics was analyzed. By changing kinds of parameter which affect the formation of the flocs, we studied the relation between the parameter and characteristics of the flocs. The model result suggested that flocs become open with increasing sticking probability. And flocs was denser with the increase of distance of attraction in cells and increase of fill gaps. So the fractal dimension increased.We studied the relationship between the removal of inorganic suspending liquid turbidity and the fractal structure of shape formed by the settled flocs. The results demonstrated that obvious effect of dosage was found on the removal of turbidity. It increased by 97% when the dosage is 3ml and it decreased later. The fractal dimension varied like the process of the removal of turbidity. The removal increased when the pH value is below 6. And the removal of turbidity is minimum at 63.4% when the pH value is 6. In the other aspect, the removal increased with the increasing pH value which start from 6. The fractal dimension is boosted when the concentration of raw water is raised and the removal of turbidity increased with a similar tendency.更多还原