Prediction of CO Distribution in Zand Tunnel of Shiraz Using Computational Fluid Dynamics (CFD) Model

Three-dimensional flow and dispersion of gas pollutant carbon monoxide in a two-way underground tunnel in the center of Shiraz in Iran was modeled using standard k-􀄰 turbulence model, which was numerically solved by the commercial CFD code FLUENT. To validate the model and the concepts used in finding the distribution of CO concentration, the concentration of CO was experimentally measured at different locations inside the tunnel at different times. The results indicate a good agreement between the experimental data and model. To check the ventilation system of the tunnel, model was run at different metrological, traffic level and ventilation operation conditions. The results show that exist ventilation system of Zand tunnel cannot work truly and CO concentration is higher than Indoor Air Quality (IAQ) international standards.