The Numerical Simulation Of The Wind Effect On The Size Evolution Of Aerosol Particles

People living in northern cities generally feel the increasing incidence of the haze in atmosphere in recent years.Especially in 2013,the frequency of haze occurrence,its duration and strength have set a historical record.Faced with the severe challenges from the atmospheric environment,we must pay attention to the research on the haze problem.It is clear that the removal of haze from the wind,which is mainly caused by ventilation and coagulation growth.In this paper,aerosol particles were selected for numerical simulation,and the effects of wind on the growth and removal of aerosol particles were studied.This study simulates the uniform and continuous injection of aerosol particles in a confined space,and the particle size of the injected particles changes with time due to the coagulation of the particles.The Hounslow coagulation model is used in this study.Fuchs transition zone coagulation nucleus was used for Brown coagulation.MATLAB software was used in the simulation.First of all,numerical simulations of the number distribution of the particles were compared with previous studies,by this way we prove the rationality of the solution methods and the validity of the computation program.Then,the size distribution of spherical particles and fractal particles under different conditions is simulated,and the law of particle size evolution under pure Brownian action is obtained.The injection source plays a role in promoting the growth of spherical particles and fractal particles.Also,the emission source has a more significant effect on the growth of fractal particles.Furthermore,the effects of wind on the particle size of spherical particles are discussed.The shearing action accelerates the coagulation process of the particles,while shear and ventilation combined effect on particle size growth will eventually reach a stable value.And then,in a certain range,as the ventilation rate increases gradually,the shorter the time the particle size increases to the steady value.The reason is the wind on the haze of the level of handling.