Experimental Investigation on the Influences of Different Horizontal Fire Locations on Smoke Temperature Stratification under Tunnel Ceiling

The increased probability of fire occurrence in urban tunnels has led researchers to investigate this issue extensively. Although fire can occur at any point in a tunnel, the effect of fire source position on temperature distribution has not received considerable attention in most of previous investigations. In this research, the influences of varying horizontal fire source locations on temperature diffusion in particular maximum smoke temperature stratification beneath the ceiling has been investigated. A set of scale-down experiments was performed in a model tunnel [3 m (length) × 0.6 m (width) × 0.96 m (height)]. n-Heptane and gasoline were used as fuels in rectangular pools to generate a heat source. The analysis reveals that typical temperature curves have a similar trend when the fire source location changes. Furthermore, the temperature profile tip (maximum smoke temperature) is located between the burner and the origin of the tunnel. The modified model of maximum temperature, which considers the horizontal fire source location, is defined. The results here complement existing literature where the effects of variable fire position in a tunnel have not been considered.