Numerical Simulation Of Aerosol Distributions In A Displacement Ventilated Room

As people spend more time indoors, heating, ventilating and air-conditioning systems that provide high thermal comfort and indoor air quality become more and more important. Compared with the traditional mixing ventilation, displacement ventilation, as a new type of air-conditioning strategy, has showed remarkable advantages on many occasions. However, in China, the research and application of this system is still in beginning up to now, especially in the aspect of indoor particle dispersion. So the numerical simulations are carried out in the present paper to investigate and analyze the airflow and particle dispersion in a displacement ventilated room.A typical office room with displacement ventilation was used as research object. Simulation is performed to study the change of contaminant sources locations, in-air temperature and positions. The impact of these factors on indoor airfield was compared and analyzed to make further research on particle concentration distribution. The characteristics of particle concentration variations in room length and width at breathing zone are also investigated in detail. Numerical results show that the height of pollutant source has great influence on indoor particle concentration. When the pollutant source is located around floor, particle concentration in the breathing zone is relatively low; however, when pollutant source is located at taller place, the particle concentration in the breathing zone is much higher which can't be negligible.In addition, it can be seen that various supply parameters have great effects on indoor particle distribution. Contrast to the case of lower supply temperature difference, Particle concentration under higher supply temperature difference system in room length and room width at breathing zone is smaller. So it will result in lower risk to human health. It also can be concluded that particle dispersion characteristics under two diffuser location type is obviously different. When the contaminant source is located at none-heat source area, Vertical diffuser supply system has appreciably better indoor air quality, on the opposite, when the contaminant source is located at near-inlet area and away-inlet area, indoor air quality under vertical diffuser supply system was much worse than the case of horizontal diffuser supply system.