Simulation of Leaking Gas Diffusion in an Urban Using 3D Map Sketch Up

To study air pollution diffusion in an urban, 3D model of city geography is made by utilizing Google Sketch Up to extracting the maps of the building elevation and latitude and longitude from Google Earth. The flow field and pollutant diffusion in urban areas were researched by numerical simulation with Fluent according to the turbulence theory and the gas equation of motion. Evolutionary regularity of air pollution diffusion and the danger zone are discussed based on the simulation results. The simulation results show that the pollution concentrates below the leakage. The high concentration of gas zone presents to be a long and narrow elliptic area and expands over time, but after a long time it tends to be stable. Based on air pollution concentrate distribution, maps of danger zone are made in the urban maps from Google Earth, which can be useful to make emergency decisions.