A Calculation Method of Heat Release Rate Based on Flame Spread Rate: Applied in a High-Speed Train Carriage Fire

Heat release rate (HRR) is an important parameter for the fire safety assessment of high-speed trains and the design of tunnel ventilation systems. However, the existing theoretical calculation methods of the HRR do not consider the fire development process and can not accurately obtain the HRR of high-speed trains. This paper uses a combination of theoretical analysis and numerical simulation to study the HRR of high-speed train fires. Firstly, based on the flame spread rate, a calculation method of the HRR is established, called the spatial time-series superimposed method. The accuracy of the calculation method is verified through a small-scale combustion experiment. Then, the calculation model of the HRR of the high-speed train fire is obtained according to the heat release rate per unit area (HRRPUA) of the carriage material, the flame spread rate in the carriage, and the spatial time-series superimposed method. Afterward, the calculation model is modified according to the change in combustion intensity during the flame spread in the high-speed train carriage. Finally, the calculation method of the HRR established in this paper is compared with several existing calculation methods. The results show that the HRR curve obtained by the calculation model is consistent with that obtained by the FDS simulation. The maximum relative error is less than 25%, and the relative error of the peak heat release rate (PHRR) is 7.4%. Therefore, this study can provide a reference for the fast and accurate calculation of the HRR of the high-speed train carriage fire.