The Large-eddy Simulation About Fitment Pollutants Under Natural Ventilation

People spend more than 80% of their time indoors. Building environment has great effect on people's healthiness and work efficiency. The indoor air pollution has become a large problem in most cities. Natural ventilation, which can provide occupants good indoor air quality and reduce energy costs, is attracting considerable interests from designers. Computational fluid dynamics(CFD), especially large eddy simulation(LES), is becoming popular due to its informative results and low costs of labor and equipment. LES simulation of natural ventilation and dilution of indoor air pollution in whole building that contains several rooms is still scanty.In this paper, large-eddy simulation is used to simulate the process of the dilution of indoor air pollutant with nature ventilation in an apartment in a series of conditions. The numerical simulating results show: in ventilation process, the large scale vortex in the flow field contains most of pollutant; rooms of different conformation results to different fluid field contains most of pollutant; rooms of different conformation results to different fluid field and pollutant movement, the speed of dilution of indoor air pollutant in multi-hatch rooms is 2-10 times more than single-hatch rooms, and the sound layout can benefit the flow field to accelerate the dilution and discharging of in-door air pollutant; commonly, speed of pollutant dilution increases with outdoor wind speed; convection has much more influence on dilution of pollutant than diffusion, so the dilution laws of different pollutant are identical; the changing processes of relative concentration difference of pollutant are same when outdoor pollutant concentration is changed. These conclusions can be used to guide the design of building ventilation.