Influence Of Opening Layout On Pollutant Dispersion Within The Courtyard

With the increasing urbanization and industrialization, air quality in living and working environment is a subject of growing concern during recent years in China. Since courtyards are superior in day-lighting and interior privacy, they are receiving more and more attentions both in civil and public constructions.Courtyards have built a transition space from the out door environment and its air quality can influence the indoor environment as well as people's health directly. Therefore, it is significant to study the pollutant dispersion within the courtyards to provide optimized designing suggestions. Proper designing of the courtyards would improve air quality by defending against the out door pollutants and releasing the in door particles effectively. In this thesis, flow pattern, pressure distribution and particle dispersion are simulated by employing the computational fluid dynamic methods and the impacts of opening layouts, wind force, ground thermal conditions and the pollutant source positions on the particle dispersion within the courtyards are discussed.The numerical results indicate that courtyards can effectively reduce its interior wind velocity and particle concentration; the amount of reduction is decided by opening layouts. The ground thermal conditions would impact the particle dispersion within the courtyards in aerostatic conditions, however, the influence decreases as the wind velocity increases.If the pollutant source is located outside the courtyards, the vertical-opening layout and non-opening layout can bring down the breathing level particle concentration to a lower level. More pollutants would be brought into the courtyards in aerostatic conditions due to the increasing air exchange rate strengthened by the ground heat release. Particle transportation is concentrated in rooms located in upwind areas and the migration amount decreases with the wind velocity.If the pollutant source is located inside the courtyards, the vertical-opening layout is also superior in building better breathing level air quality. The increasing ground heat release would strengthen the air exchange rate within the courtyards, thus lead to the decrease of pollutant concentration. The high particle transportation area is located in the downwind area and the migration amount decreases with the wind velocity.