絮凝体DLA模型仿真及其废水处理

Simulation on flocs using DLA model and its application on wastewater treatment

以MATLAB为平台,编写二维扩散限制凝聚(DLA)模型程序,模拟絮体的生成,计算分形维数,空隙率等参数。模拟结果表明,随着凝聚粒子数目从200增加到20000,回旋半径法计算的模拟絮体分形维数从1.75下降到1.30,盒子算法的模拟絮体分形维数从1.70下降到1.40,模拟絮体的空隙率则从0.75上升到0.95。分析模拟结果发现,由于已凝聚粒子的屏蔽作用,模拟絮体的结构呈现内部致密,外部疏松的特点。以印钞浓缩废水为例,以硫酸铝作为絮凝剂,发现絮体的实际平均分形维数在1.3647～1.5048之间,且随废水浓度增加而减少,与模拟结果一致。找出了获得致密或疏松絮体的条件,从而有益探索絮凝的机理。

In this study,a two-dimensional square lattices diffusion-limited aggregation(2d-DLA) model program based on MATLAB platform was written and used to simulate the aggregation process of flocs.Parameters such as fractal dimensions and porosity were calculated. Simulation results show that with aggregation particles rising from 200 to 20000,fractal dimensions decreased from 1.75 to 1. 30 using radius of gyration method and from 1.70 to 1.40 using box-counting method,while porosity,believed to be the main cause...