Author(s): WU Shixian, ZHU Hui, FU Haiming, KANG Yanming, Department of Building Environment and Energy Engineering, Guilin University of Aerospace Technology, School of Environmental Science and Engineering, Donghua University
Pages: 4738-4746
Year: 2015 Issue:  12
Journal: Journal of Central South University (Science and Technology)
Keyword:  fibrous filtration; particle deposition; convection-diffusion; dust layer;
Abstract: A discrete stochastic model was developed to simulate the convective diffusional deposition of ultrafine particles in a model filter composed of an array of identical parallel fibers placed transverse to the flow. The flow feature in the vicinity of fibers was described by the Kuwabara flow field. Lattice walk method was employed to solve convection-diffusion-migration equation in order to obtain the probability of particle motion in the calculation domain. The local structures of dust layer formed by deposited particles and the relationship between structure of dust layer and mechanisms of particle transport were investigated. The results show that for Pe<10, when the diffusion is a controlling mechanism of particles transport, dust layer is more open and looser structure than that obtained at the higher value of Pe. The whole particles deposition process may be distinguished by three stages of particles adhesion, particles bridging and dust layer growth. According to the change of locate packing density along the dust layer height direction, the structure of dust layer can be divided into three typical parts of substructure, main profile and surface layer.