An experimental study on gas temperature characteristic in tunnel fires: The influences of sidewall restriction and sealing effect

• Published in: International journal of heat and mass transfer 2023-11, Vol.214, p.124385, Article 124385
• Main Authors: Li, Qing, Kang, Jianhong, Xu, Xiangyu, Feng, Yiling, Wang, Yanan
• Format: Article
• Language: English
• Subjects: Gas temperature characteristic; Sealing effect; Sidewall restriction; Tunnel fires
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2023.124385

•A series of combustion tests are conducted in a reduced tunnel.•The process of smoke spread and heat transfer under different scenarios is analyzed.•The influences of sidewall restriction and sealing effect on the gas temperature characteristic are investigated.•The proposed model can provide reasonable predictions for different fire scenarios. This work provides a comprehensive experimental study on the influence of fire source position on gas temperature characteristics during the sealing process. A function correlating the ceiling maximum gas temperature and transverse fire source position factor and the sealing ratio was proposed based on theoretical analysis. Then, a series of methanol pool fire experiments were conducted in a reduced tunnel, considering three fire source positions and five sealing ratios, to investigate the influence of sidewall restriction and sealing effect on the maximum gas temperature and longitudinal distribution pattern. The results demonstrate that the maximum gas temperature does not increase continuously as the fire source moves toward the sidewall. There exists a position in which the lowest gas temperature beneath the ceiling is generated as a result of the combined effect of the flame on air entrainment and the enhanced radiation of the flame to the sidewall. Moreover, the maximum gas temperature rise is found to linearly increase with the sealing ratio and vary as a quadratic function of the transverse fire source position factor. Finally, the calculation model for the longitudinal distribution pattern of ceiling gas temperature rise is developed, which can provide reasonable predictions for different fire scenarios considering fire locations, sealing ratios as well as fire sizes.