Mechanism characteristics of carriage fire under coupling effect of ignition position and windows breakage

Abstract

Series numerical simulations of fire in the train carriage have been performed by fire dynamics simulator (FDS) in this paper. The main purpose of this study is to investigate the influence of fire source locations and windows breakage on carriage fire spreading. Four locations of ignition source were considered and the trigger temperature of window rupture was set as 400 °C. Parameters, such as temperature, heat release rate (HRR), time of window breakage and flame propagation were monitored. It was found that fire source locations and window breakage affect fire development by changing the fresh air supply of carriage. When the fire occurs in the middle of carriage, heat release rate and combustion intensity are greater than those in ends fire. High temperature will promote windows breakage, and the increasing open area will aggravate the combustion of carriage. The ventilation factor change rate has been introduced to describe the relationship between heat release rate and window rupture. As ventilation is a key factor in the evolution for carriage fires, air circulation between carriage and outside should be avoided as much as possible. Therefore, it is of importance to enhance the fire detection and alarm in the carriage and improve the fire fighting and emergency ability.

Keywords

carriage fire / windows breakage / ignition position / ventilation factor

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