A Study On The Simulation Of Fractal Floc Structure

The paper adopted the Matlab tool, with the help of DLA and DLCA model, the coagulating process is studied through computer simulation. We studied floc structure based on DLA and DLCA model, when the initial diameter of floc particle prensents as a normal distribution, then analysed the fractal dimensionality. We also optimized DLCA model with which initial diameter the floc particle is equal.When the initial particle diameter presents as a equal distribution, the simulation shows that floc structure has typical character in the two-dimensional space. And the fractal dimensionality of floc descends slowly as the number of particle increases, but the trend of steady value is 1.67 or so. Comparing to it, when the initial particle diameter presents as a normal distribution, the fractal dimensionality of floc diminishs obviously as the number of particles increases, but the value of the fractal dimensionality is higher than the value, which the initial particle diameter presents as a equal distribution.When the initial particle diameter presents as different normal distributions, the changing tendency of fractal dimensionality is influenced little by the distribution of initial particle size in the three-dimensional DLCA model. The reason is that particle can be captured easily by floc with opening structure, and joined at branches which floc spread outward, thus the floc structure is more slack.Meanwhile the results of simulation shows that in the floc growing process, the influence of diverse sedimentation on the floc can't be overlooked. As the number of particles gets to a certain degree, the diverse sedimentation has great influence on the coagulation of the floc, which causes the scattering degree of the floc increases. Therefore, the diverse sedimentation affects the changing laws of the floc flactal dimensionality on the whole.