Finite Diffusion Limited Cluster Agglomeration Of Ferromagnetic Particles

As a result of industrial production,automobile exhaust and coal combustion and so on,a large number of particles and harmful gases have been produced in recent years which have brought serious environmental pollution problems.Fine particles in the air often carry poisonous substances,which can enter the human body through the nasal cavity and pose a threat to human health.At present,the main purification methods of air particles are the installation of industrial waste gas purification equipment,vehicle exhaust purifiers,indoor air purifier and so on.By using these devices,the air quality can be improved to a certain extent,but the fine metal particles in the air can not be effectively purified.The fine metal particles in the air are often magnetic,which is harmful to the human body.So it is an urgent problem to study how to reduce the fine particles in the air,especially reduce the magnetic small metal particles in the air.In this thesis,under two conditions of no magnetic field and magnetic field,the diffusion limited cluster aggregation(DLCA)simulation of ferromagnetic particles with power function interaction is studied by using the fractal theory.The variation of morphology and magnetization of the aggregates was analyzed under different dynamic parameters,different initial particle spacing,different magnetic field strengths,and different magnetic field directions,which have great significance for understanding the mechanism of diffusion and agglomeration of ferromagnetic particles and improving the sedimentation technology of particles.The main researching content is as follows:1.Based on the DLCA model,the spin degree of freedom of the particles is introduced.In this thesis,we study the diffusion and condensation behavior of ferromagnetic particles with the power function interactions and analyzed the evolution of the morphology of fractal clusters of ferromagnetic particles under long-range interaction forces and near-range interaction forces and other dynamic parameters.Lastly,the physical characteristics of agglomerate clusters of ferromagnetic particles are studied in terms of fractal dimension and magnetization.2.This thesis studies the diffusion and condensation behavior of ferromagnetic particles in a magnetic field and analyzes the influence of magnetic field strength and magnetic field direction on the morphology and magnetization of ferromagnetic particle agglomerates.3.Based on DLCA model of non-magnetic particles,DLCA model of ferromagnetic particles without magnetic field,DLCA model of ferromagnetic particles in magnetic field,using Visual Studio and Matlab mixed programming,a particle diffusion condensate interaction simulation software based on DLCA model was designed and developed.The simulation software extracts the input parameters in the Matlab program and displays them in the Visual Studio interface.It can simulate the aggregation behavior of finite diffusion limited clusters with non-magnetic particles,magnetic particles,magnetic particles and non-magnetic particles mixed under different parameters.This simulation software intuitively shows the simulation results of fractal shapes,fractal dimensions,number of spin-on particles,number of spin-down particles,and magnetization of aggregates.