Experimental Study of Smoke Deposition in the Case of Leakage Joint at the Bottom of Circular Utility Tunnel

Abstract

In order to obtain the relationship between the height of smoke layer and time in the case of fire with small leak at the bottom of circular utility tunnel. In this paper, diesel was used as fuel to conduct three small-size experiments in the utility tunnel. Based on the work of predecessors, the formula for the deposition of smoke suitable for circular utility tunnel was obtained. The results of the study are as following: 1) The highest temperature appears near the ceiling directly above the fire source. The temperature below the location of the hydraulic jump was very low and the temperature presents an obvious stratification phenomenon; 2) By comparing the calculating value with the experimental value, it is suggested that the equation can predict the change of smoke stratification height with time; 3) The horizontal spreading process of smoke in the ceiling is neglected, and the lower air cross-section area is treated approximately, which is the main reason for the difference between the calculating value and the experimental value.