Plateau Mountain City. Wind Tunnel Experiments And Heavy Gas Leakage And Diffusion Simulation Study

Dense gas leaking experiment can be used to predict diffusion and concentration distribution of air pollutants. It was important for air pollution control, comprehensive environment management and environmental decision. Also, it can be used to improve environmental protection and environmental quality.Gejiu, a mountainous city in the tableland, was researched based on a model of downtown and suburb area with a proportion of 1: 1000. Onsite data of wind profile was used to regulate the wind current of wind tunnel, and to identify the characteristics of wind current in Gejiu city. ADMS-EIA system was discussed and used to simulate the diffusion situation of dense gas leaking in Gejiu city.During research of regional wind current, balloon was used to determine the wind velocity at different height, and it was 0.59 for the exponent of wind profile. Coarse objects situated in the tunnel and regulated velocity of fan can simulate the wind current mentioned above. Determination spots were located to identify the variation of wind velocity in different terrain. Due to the complex terrain and crowded buildings in Gejiu city, there were some differences for wind velocity and exponent of wind profile at the same height. Characteristic of wind of the central axis was used to evaluate the influence of mountain-crossing wind and terrain block on the wind current.ADMS-EIA system, a software with strong capacity of calculation, multi way of drawing and accessible user interface, was selected to simulate the situation of wind current and to forecast diffusion of the dense gas according to the simulated wind velocity in the channel and weather date of 2006 of Gejiu city.Complex terrain, buildings and wind velocity was analyzed and researched to assess their influences on the diffusion of dense gas leakage based on a file of terrain parameter, which was made according to net chorography of Gejiu city.There was a little shift for central concentration as result of influence of wind current and velocity in the mountain which was situated in the west part of the leaking spots. Also, several concentration-equal areas formed in different concentration range diffused toward the central part. Furthermore, because of the influence of characteristic of wind current, there was a variation of diffusion concentration of lower city buildings in thesoutheast part of Gejiu city.