Basic Research Of Indoor Air Stability Theory And Large Eddy Simulation

The methods of environment assessment are increasing constantly nowerdays as the environment requirements of human beings are improved and the quality of indoor air and outdoor air is widely concerned about. But at present the domestic and foreign scholars have not yet studied the similarities between indoor air and outdoor air as well as the characteristics and assessments of the spreading of indoor air pollutants under certain airflow organization condition. Taking these as research background, this paper in-depth studies on the relationship between the indoor temperature distribution and stability and the proliferation and migration of indoor air pollutants.The introduction summarizes indoor environment assessment methods in recent years. It has promulgated the significance of this paper through introducing the atmospheric stability briefly, and analyzing the research background of indoor air stability.In the master's thesis of Basic Research of Indoor Air Stability Theory, it defines that indoor air stability is the amount of the correlation between indoor turbulence flow climatic environment and the pollution transport property, and roughly categorizes indoor air stability into following types: stable type, unstable type and neutral type, which through simulating pollution transport property of ammonia and catbon dioxide in three different indoor air stabilities of horizontal flow.This article has improved two-dimensional flow fields and has simulated three different kinds of cases (casel~case3) of the vertical flow situation which namely simulate the pollutants dissemination characteristic. At the same time we have established a three-dimensional model, using the LES model. Correlation analyses of stability strongly corroborate that under the two absolutely opposite circumstances, i.e., normal distribution with positive temperature lapse rate and inverse distribution with negative temperature lapse rate, pollutant transport property will differ apparently accordingly. If indoor air is unstable type, turbulence flow is intensified and reinforces the pollution diffuse while turbulence flow is restrained compared with unstable type when indoor air is stable. By comparison horizontal flow and vertical flow simulation results showed that: regardless of the horizontal flow or vertical flow,γ> 0 in the indoor air of stability classification air is unstable, and pollutants more easily transverse prolireration.γ<0 in the indoor air of stability classification air is stable, and pollutants more difficult to transverse prolireration. In order to improve indoor air stability evaluation system, it is also necessary to establish a new model and introduce more factors, including the different airflow conditions, space form factors, different obstacles (including moving objects) and the sources of pollutions, etc. we want to study the spread of pollutants dispersion characteristics of strength, and establish a more reasonable stability classification of indoor air.