Simulation of Particles Diffusion Characteristics in the Ventilation Duct of the Air Conditioning System

PM2.5 and PM10 attach harmful substance easily and they pose a threat to health after being inhaled. Here deposits a large amount of PM2.5 and PM10 in the air conditioning system pipe surface, and they seriously affect the indoor air quality following by air into the room. This article analyzes the diffusion and propagation characteristics of PM2.5 and PM10 in the ventilation duct. The study focus on particles in the viscous sublayer and analyzes its movement. The study shows that the larger the wind speed, the faster particles reaching stable distribution; The velocity change of particles increases sharply, then decreases, remains stable finally; The final velocity ( X direction) of particles of different size is same basically in the same duct with the same initial velocity( X direction); PM2.5 and PM10 are generally deposited on the bottom of the pipe within the range of the allowable wind velocity in the air conditioning system. Therefore, the paper concludes that in order to prevent the PM2.5 and PM10's harm to the human, we should clean the ventilation duct regularly. (C) 2015 Published by Elsevier Ltd.