Eslam Kashi - University of Sistan and Baluchestan
Farhad Shahraki - University of Sistan and Baluchestan
Davood Rashtchian - Sharif University of Technology
Amin Behzadmehr - Sharif University of Technology

Dispersion of heavy gas is much slower than passive gas and as a result involves a more considerable hazard rang It can be arise when the gas is accidentally released at ground level or where are many obstructions in the area . Computational Fluid Dynamic (CFD) models provide us with a potential means for better understanding the factor effcting gas dispersion . At the first stage the commercial CFD code should be validated using the standard experimental results . In this paper Thorney Island and Kit Fox experiments were used as simple and complex experiments respectively in order to validate the Ansys CFX11 code . Wind speed was studied taking time , height and direction into consideration . A combination of 2D and 3D geometry was used in order to reduce the number of elements in computational domain . The vertically temperature gradient at the atmosphere was investigated . The results showed that its temperature gradient had significant effect on gas concentration histories , especially at far distances from the gas source.

hevy gas dispersion , temperature gradient , complax train , CFD