Numerical estimations of heat release from a railcar fire based on varying ventilation speed
To design the ventilation system of a railway tunnel that can handle fire emergencies, the energy released from a railcar fire has to be considered. The maximum heat release rate is particularly important. Traditionally, the Kennedy equation is used to calculate the critical velocity of tunnel fire, which is the minimum ventilation speed required to control smoke and heat originating from the railcar fire. However, in a confined fire such as a tunnel fire, the maximum heat release rate varies with the tunnel ventilation speed. In this study, the heat release rates from a passenger railcar in a tunnel were obtained for different tunnel ventilation velocities using the computation fluid dynamics model, Fire Dynamics Simulator, developed by the NIST. The properties of the interior materials of the railcar were obtained from bench-scale tests and literature. Among these properties, the effective heat of combustion and reaction velocity constants were obtained by carrying out cone calorimeter and thermogravimetric analysis.