ORIGINAL RESEARCH article
Front. Built Environ.
Sec. Fire Resistant Engineering
Experimental Modeling Study on Mechanical Smoke Exhaust System during Tunnel Fire
Provisionally accepted
- 1China Fire and Rescue Institute, Beijing, China
- 2Shanghai Zanrui Industrial Co., LTD, Shanghai, China
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
With the rapid development of transportation infrastructure, highway tunnels have become vital transportation arteries. However, due to their enclosed and narrow structure, they face severe fire risks. Mechanical smoke extraction systems are core fire protection technologies in highway tunnels, among which the unilateral large-spacing point-type system is widely used in long tunnels. The efficiency of this system depends heavily on key parameters such as the distance between smoke vents and the fire source, and the installation position of longitudinal ventilation fans. However, there is insufficient research on the synergistic effects of these parameters and their performance under high-power fires. To address this gap, this study optimized the key smoke extraction system by focusing on these two parameters. Based on the Froude similarity criterion, a scaled tunnel model was constructed. Experiments were conducted under both natural and mechanical ventilation conditions, analyzing the smoke exhaust effect with different vent positions and fan locations. The results showed that under mechanical ventilation, the smoke flow velocity and temperature increase monotonically decreased with the distance from the vent to the fire. The optimal fan position was found to be around 20 cm upstream of the fire, which maximizes the coupling synergy with near-field smoke. Increasing the fan distance flattened the attenuation of flow velocity and temperature in mid-to-distal vents. This study provides theoretical support for optimizing tunnel smoke extraction systems and aids efficient fire rescue, thereby contributing to the reduction of casualties and property losses.
Keywords: Experimental study, Flue gas control, scaled-down model test, smoke exhaust system, Tunnel fire
Received: 30 Dec 2025; Accepted: 16 Feb 2026.
Copyright: © 2026 Liu, Zhao and Yu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Rongxuan Zhao
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.