不同水力条件下悬浮液絮体分形结构的研究

Research on the Fractal Structure of Floc in the Suspension Liquid with Different Hydraulic Conditions

利用计算机MATLAB软件,在高浓度悬浮液混凝试验的基础上对选煤废水混凝过程中不同水力条件(搅拌速度和搅拌时间)下所拍摄的显微镜絮体图片进行处理,计算其分形维数,从而分析研究不同水力条件下所形成的絮体结构与对应的絮体平均沉降速度及处理出水浊度的关系。试验结果表明,在混凝剂加入的初始阶段,当搅拌速度v1为250r/min、搅拌时间t1为10s时,絮体结构最密实且接近球体,分形维数最大(Df=1.961 6),此时絮体沉降速度最快,混凝沉降效果最好,出水浊度可达170NTU。

By using computer software MATLAB, this paper applies microscope to dealing with the images of flocs in the suspension liquid under different hydraulic conditions（mixing velocities and mixing times） in the process of coagulation,and calculates the fractal dimension,and then analyzes and studies the relation- ships between the structure of flocculent body on the one hand and the average settling velocity of the floc- culent body and the turbidity of treated effluent on the other under different hydraulic conditions. The re- sults show that,in the starting stage of adding coagulant,when mixing velocity Vl is 250 r/min and mixing time tl is 10 s,the body structure of flocs is mostly close to the ball; when the value of fractal dimension is the maximum（ Df is equal to 1. 9616）, flocs have the fastest settlement velocity, the best effect of coagula- tion sedimentation can be obtained, and the turbidity of the effluent can reach 170 NTU.