Center of Excellence in Energy Conversion, School of Mechanical Engineering, Sharif University of Technology, Iran, P.O. Box: 11155-9567
Fire is a potential hazard in public transportation facilities such as subways or road tunnels due to its contribution to high number of deaths. To provide an insight into fire development behavior in tunnels which can serve as the basis for emergency ventilation design, model-scale railcar fire is explored numerically in this research. Fire growth and its spread are investigated by analyzing the HRR curve as the representative of fire behavior in different stages. Fire development has been predicted through a new approach using an Arrhenius-based pyrolysis model, established to predict the decomposition behavior of solid flammable materials exposed to heat flux. Using this approach, model-scale railcar fire curve is obtained and compared with experimental data. Reasonable agreement is achieved in two important stages of flashover and fully developed fire, confirming the accuracy of the presented approach. Moreover, effects of railcar material type, amount of available air, and surrounding are also discussed. Detailed illustrations of physical phenomena and flow structures have been provided and justified with experimental findings for better description of railcar fire behavior. The presented approach can be further used in other applications such as investigation of fire spread in a compartment, studying fire spread from a burning vehicle to another and reconstruction of fire incidents.