Numerical Study on Smoke Diffusion Distance Induced by a Moving Vehicle in Road Tunnel Using Dynamic Mesh

The occurrence of fire in tunnel results in significant human losses and economic damages. The smoke propagation mechanism in tunnel has attracted a lot of attentions all over the world. Most of the previous studies focus on the stationary fire source scenario. However, few researches consider the transient movement of a burning vehicle and its effect on smoke propagation in tunnel. Therefore, to fill the research gap, this paper studies the influence of the moving vehicle on the smoke diffusion distance in tunnel using the dynamic mesh. Based on the geometrical parameters of an urban road tunnel, a 520 m long tunnel model is established. The dynamic mesh method used in this paper is verified by the experimental results by Kim. Multiple variables including the fire heat release rate and the vehicle speed are considered in the simulation. The results show that the propagation of smoke inside tunnel is mainly affected by the vehicle moving speed. Based on the simulation results, an empirical equation of smoke diffusion length is proposed to be used in the practical engineering application.