Research on Airflow and Pollutant Diffusion by Windows Opening of Street-Facing Building

Abstract

Purposes The typical street canyon-building of the city is researched in this work. Methods On the basis of field measurement and numerical simulation CFD(Computational Fluid Dynamics), the airflow pattern and pollutant distribution in street canyon and indoor the building with windows opening were investigated. Findings The results show that the opening of windows on the outer wall of building disturbs the surrounding air flow, which leads to the enhancements of the vortex flow in the street canyon, and the variation of local wind direction and wind speed in different heights. The turbulence intensity of the street-facing buildings on the leeward side is more obviously affected by the opening of the windows than that of the buildings on the windward side,1~4 floors are 20.6% higher than the case of unopened windows. The change of indoor pollutant concentration on each floor is roughly consistent with the outdoor street canyon pollutant distribution. The indoor pollutant concentration of leeward buildings is much higher than that of windward buildings. Concentrations of indoor pollutants in leeward buildings decrease with the increase of floors, the pollutants on floors 1~4 account for 43.7% of the total pollution. The indoor pollutant concentration of buildings on the windward side first decreases along the building height, but does not show a monotonous trend of decreasing floor by floor. The pollutant concentration value is the smallest near the middle floor of building, then increases under the combined action of window disturbance and street canyon circulation vortex. The whole solution of street canyon-window building overcomes the inconsistency between the inflow level setting of simulated street buildings and the actual working conditions, better solves the problems of complex vortex boundary setting and different window opening positions from floor to floor.

Keywords

• street canyon
• numerical simulation
• window opening
• airflow structure
• turbulent diffusion