Open Access

ARTICLE

Numerical Simulation of Fire-Smoke Diffusion Caused by Vehicles in a Tunnel

Li Lei^*, Wukai Chen, Huiling Li, Shuai Shi

School of Energy and Power Engineering, Shandong University, Jinan, China

* Corresponding Author: Li Lei. Email:

(This article belongs to the Special Issue: High-Speed and High-Temperature Flows)

Fluid Dynamics & Materials Processing 2020, 16(5), 837-856. https://doi.org/10.32604/fdmp.2020.09631

Received 10 January 2020; Accepted 04 August 2020; Issue published 09 October 2020

Abstract

Urban tunnels are generally narrow and fire smoke can hardly diffuse. In the present study, numerical simulation is used to analyze the diffusion of high temperature smoke produced by fire inside a specific tunnel (the Kaiyuan tunnel). The results are compared with similar data relating to other tests to determine the validity of the numerical method. Moreover, the critical velocity obtained by numerical simulation of 5 MW, 20 MW, and 50 MW fires in curved and linear sections of the considered tunnel is compared with the values obtained using empirical formulas. The results show that, for the tunnel ventilation design, it is necessary to consider the fan pressurization at different sections and the fan pressurization should be higher at curved sections than that at linear sections. The safety of personnel escaping under different critical velocity values in the linear section has also been considered. On the basis of our findings, if only relying on natural ventilation, people can escape safely for the case of small fires, whereas for medium and large fires, it is necessary to turn on mechanical ventilation in time (and in order to avoid the danger caused by rapid diffusion of smoke, the timing of mechanical ventilation should be carefully tuned).

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