An extended model for predicting the temperature distribution of large area fire ascribed to multiple fuel source in tunnel

Abstract

Recently, the serious heavy haul railway tunnel fire that always resulted in the enlarger of the fire area have attracted much attention due to its great threat to people's life and property. As to this type of large area fire ascribed to multiple fuel source in tunnel, its burning always controlled by the ventilation, and it could be generally divided into three major regions: fuel-rich and hypoxic central zone, reaction zone, and burned out zone near the entrance due to the lack of the oxygen in the middle of the tunnel, however, the temperature distribution of this type fire in tunnel could not be reflected by the existing empirical models well. In order to predict the temperature distribution induced by the large area fire in tunnel well, an extended three-part model was proposed on the basis of the analysis of the special fire characteristic. And the fitting correlations for ceiling temperature of the continuous multiple fire sources were obtained based on a series of experiments. What’s more, the revised vertical temperature correlations based on the McCaffrey’s model were also obtained. It can be seen that the vertical temperature in the centerline of the tunnel remained nearly constant as the number of fire sources increases.