A Study On The Morphological Characteristics Of Flocculation Of The Yellow River's Loess Particles--Computer Simulation Of Flcos Growth And Flcos Model

This paper studied the flocculation of Yellow River's loess particles from morphological characteristics by fractal theory and computer simulation technique.The contens concluded the formula of macromolecule flocculant dosage and automatical dosing model, computer simulation of particles's aggregation in two dimensional space, morphological characteristics of floes of Yellow River's loess particles and its flocculation kinetics and floes model.On the basis of theory analysis, the average transmitted light intensity (correspond to DC value) was determined as characteristic parameter of raw water using photoelectric method for monitoring the fluctuation of transmitted light and photometric dispersion analyzer(PDA).The DC value was closely related to both particle concentration and surface area of sand clay simultaneously. The experimental results shows that there is an exponential function relation between DC and surface area of sand clay inunit volume water(Sp):DC = aSbp in which a and b are empirical coefficients.Then the formula ofmacromolecule flocculant dosage is found to be D=f(DC) = e(DC)f in which e and / are empirical coefficients and the average correlation coefficient equal to 0.981. So the model of automatical control system of water treatment plant was established using the formula.The particles aggregation was simulated using particle-cluster and cluster-cluster aggregation model.Several type of floes was reached and its morphological characteristics was analyzed The fractal dimension,density and porosity of floes was studied by changing sticking probabilities, sticking position ,particle number,particle concentration,difrusion coefficient and motion trajectory.The parameters by which special floes growth were determined.In the study of morphology, floes of Yellow River's loess particles was observed by TV-microscope.Its morphological characteristics were obtained by image analysis.The effect of fractal dimensions by stirring time strring speed, macromolecule flocculant dosage, flocculant concentration andparticle concentration was studie.Its rule of change was obtained.On the basis of other studies,the flocculation kinetics and floes structure was studied. By making some assumptions, collision frequency were presented.Then the the flocculation kinetics model was established through population balance equation. Comparison of experimental data and modeling results indicate that there are the same trend between the two. So the model can predict floes number and size during flocculation of Yellow River's loess particles without using empirical parameters.The TEM and SEM were used to obsever floes in the study of floe structure.The flocculation was divided as flocculi,floc and floe aggregate.The floes structure model was established by assumption that particles position in floe accords with tetrahedron.The fractal dimension of model and experimental floes was found to be coincidentSo the model can reflect the structure of flocs formed in flocculation of Yellow River's loess particles by macromolecule flocculant at a certain extent...