Experimental and Theoretical Investigation of Longitudinal Temperature Attenuation and Smoke Movement in Urban Utility Tunnel Fires

The urban utility tunnel is an indispensable part of modern engineering construction. However, the fire risk cannot be ignored due to the narrow space and limited ventilation of the utility tunnel. A study of smoke filling is performed in a 1/8-scaled utility tunnel (25 m × 0.5 m × 0.45 m). Five heat release rates (5, 10, 15, 20 and 25 kW) and four positions of fire sources are used for tests. The initial position of the one-dimensional smoke movement of strong plume is determined. Based on the traditional model, the longitudinal temperature attenuation model of tunnel smoke is established with consideration of radiation and convection heat losses. The theoretical value of the longitudinal temperature rise of smoke is in good agreement with the experimental value. A one-dimensional spreading velocity model is established that coincides well with the experimental value, and the relative error is less than 20%. The spreading velocity of smoke is increased by the heat release rate. The velocity of the smoke spreading at the near end is smaller than that at the center, due to the long spreading route. The current conclusions disclosed in this study provide important guidance for the ventilation design of utility tunnels for fire smoke scenarios

Numerical study on the different prevention methods for fire and smoke in utility tunnel fire

Abstract Series numerical simulations of fire in utility tunnel have been performed by Fire Dynamics Simulator (FDS) in this paper. The main purpose is to investigate the smoke prevention effect of fireproof door, water mist curtain, air curtain and ceiling screen. The pressure of water mist, airflow velocity of air curtain and the height of ceiling screen were considered. The results show that once a fire occurs in the pipe corridor, fireproof door has a good effect of smoke preventing and cooling. The water mist curtain, air curtain and smoke ceiling screen systems all have a blocking effect on fire and smoke, and the best fire smoke prevention parameters of water mist curtain and air curtain applied in underground comprehensive pipe gallery are 10 MPa and 10 m/s respectively. Therefore, the fireproof door, water mist curtain and air curtain systems can be set in pipe gallery to prevent fire and smoke, so as to improve evacuation safety and emergency rescue efficiency.</jats:p