Experimental study on flame behavior and heat transfer mechanism of ethanol spill fire in tunnels under upwind and downwind environment

• Published in: International communications in heat and mass transfer Vol. 155
• Main Authors: Ye, Chenghao, Hu, Xuejing, Xia, Meiqing, Guo, Yinliang, Zhang, Peihong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2024
• Subjects: Heat transfer mechanism; Longitudinal wind speed; Spill fire; Upwind and downwind; Spill fire; Longitudinal wind speed; Heat transfer mechanism; Upwind and downwind
• ISSN: 0735-1933; 1879-0178
• DOI: 10.1016/j.icheatmasstransfer.2024.107528

The primary objective of this work was to examine the influence of wind speed and wind direction, specifically upwind and downwind, on the flame characteristics, heat transfer processes, and burning rate laws of ethanol spill fires within a tunnel environment. The findings reveal that the flame height is initially controlled by the by the discharge rate, which ultimately transitions to being controlled by longitudinal ventilation. As wind speed escalates in upwind conditions, the combustion area first decreases and then increases, whereas in downwind scenarios, it first increases and then decreases. Convection emerges as the predominant thermal feedback mechanism for spill fires in windy conditions, particularly exhibiting heightened intensity in downwind environment. It is noteworthy that between 20% and 45% of the heat within the fuel layer dissipates through conduction and convection between the fuel and its substrate, with downwind environments experiencing heightened heat loss; approximately 90% of this heat loss in ethanol spill fires is attributed to conduction. These disparities in heat transfer processes ultimately culminate in a higher burning rate for spill fires in upwind environments compared to downwind counterparts.