LAUSR

Abstract This experimental study focused on fire source combustion characteristics and the distribution law of fire temperature field in the utility tunnel caused by side wall constraint effect. The oil pans are placed at 0 m, 0.15 m, 0.3 m, 0.45 m from the side wall and the center of the model to study the influence of the side wall of the utility tunnel on the flame height, flame shape and temperature distribution of the ceiling. The flame height increases with the fire source gradually approaching the side wall from the center line. According to the flow path of the fire plume, the effective height of the ceiling is corrected. It is found that the longitudinal attenuation of temperature in the center of the ceiling shows a power exponential attenuation law. The temperature distribution under the tunnel ceiling near the fire source area is asymmetrical. When the distance from the fire source center to the side wall increases to 0.4 m and the longitudinal distance increases to 1.2 m, the temperature distribution tends to be symmetrical.