Aziz Babapour - Department of Chemical Engineering, Faculty of Engineering, Ahar branch, Islamic Azad University- Ahar- Iran
Vahid Bab - Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
Mehdi Ahmadi Sabegh - Department of Chemistry, Faculty of Science, Ahar branch, Islamic Azad University- Ahar- Iran

Tunnel fire is challenging problem all over the world. Properties damage, injuries, or even fatalities are the most typical consequence of fire event in tunnel. A computational fluid dynamics (CFD) code, FDS (Fire Dynamic Simulator), was utilized for the simulation of a pool fire generated after the release of chemicals as a consequence of a hypothetical accident in a tunnel. The FDS code was used to assess the effectiveness of ventilation systems in a 328 m long tunnel where a car incident evolved in a severe Gasoline pool fire. Predictions of the temperatures, visibility, pollutants and smoke concentrations during a time interval of 3 min from the fire start up were obtained for both the cases of natural ventilation and of forced ventilation. Influence of the ventilating system on tunnel fire dynamic and development has been investigated under different ventilation modes throughout the tunnel. The results showed that the only natural ventilation was not sufficient to assure safety conditions for escape and rescue operations and that, forced ventilation systems proved to be very effective for immediately creating upstream the fire a safe route for evacuation and rescue, although very unsafe conditions took place downstream the fire.

Tunnel fire, CFD, FDS, Ventilation system