Numerical Simulation Of The Deposition Characteristics Of Indoor Fine Particles On Vertically Wrinkled Surfaces

Particle deposition is effective in reducing indoor concentrations of particulate matter and the health hazards they pose.In modern home environments,the wrinkled surfaces formed by interior-like textiles(curtains,clothing,etc.)account for a large proportion of the interior surfaces in a room and are important surfaces where indoor particulate matter has a high probability of being deposited.Given that the presence of wrinkles increases the complexity of particle deposition,the study of the deposition characteristics of particulate matter on wrinkled surfaces is important for the enrichment of control strategies related to particle deposition and for the development and preparation of functional textiles.Therefore,this paper investigates the laws that influence the geometrical parameters of indoor wrinkled surfaces on the distribution of the movement of fine particles and their deposition characteristics based on CFD-DPM simulation methods.The main studies are as follows:(1)A three-dimensional physical model and a CFD-DPM mathematical model were selected and built and verified to be correct.Steady simulations of flow fields containing different wrinkled surfaces have been carried out,The results show that,The presence of wrinkles increases the degree of turbulence in the flow field;The area of vortex at the wrinkle trough increases with the amplitude of the wrinkle and increases and then decreases with the number of wrinkles;The position of the vortex gradually moves towards the crest of the wrinkle as the number of Wrinkles and the amplitude of the wrinkle increase.(2)The unsteady particle tracking based on the DPM model was used to simulate the motion distribution characteristics of the particles under the influence of different wrinkled surfaces.Research has found that,Particles first accumulate on the windward slope of the wrinkle,then some particles move along the slope towards the wrinkle crest with the airflow,and some particles move down the slope under the influence of the vortex,and as the number of wrinkles and the wrinkle amplitude increase the particle accumulation point moves closer to the wrinkle crest,and the corresponding high concentration distribution zone is formed further away from the wave trough;An increase in both the number of folds and the wave amplitude leads to an increased diffusion effect and a more dispersed distribution of particles,with the smaller the particle size the more significant the effect.(3)Based on the steady particle tracking of the DPM model,the amount of particulate matter deposited on the different wrinkled surfaces was calculated and counted.The results show that,The deposition of particles of the same particle size on the wrinkled surface at the same air speed is greater than that on the flat surface;The number of particles deposited on the same wrinkled surface all decreases with increasing particle size;The deposition of different particle sizes on the wrinkle surface tends to increase and then decrease with the number of wrinkles,and both particle size and air speed significantly affect the maximum deposition and the number of wrinkles corresponding to it;The wrinkle amplitude is always positively correlated with the change in deposition volume for different grain sizes and wind speeds.(4)The influence of changes in geometric parameters(wavelength,amplitude)of the wrinkled surface on the deposition characteristics of the particles is more significant than for a single area expansion;When the extension area is the same,the number of wrinkles(wavelength)has a more significant effect on the deposition characteristics of the particles compared to the amplitude.