Full-scale experiment on burning behaviors and smoke characteristics of spill fires in road tunnels

doi:10.16265/j.cnki.issn1003-3033.2026.09.0328

Abstract

Abstract:

To reveal the disaster mechanism of spill fires in road tunnels and to address the shortage of full-scale experimental data, spill fire experiments were conducted in a full-scale road tunnel (100 m long, 10.5 m wide, 7.5 m high) using two fuel types (n-heptane and ethanol) and varying discharge rates (34-59 mL/s). The evolution characteristics of burning diameter, flame height, burning rate, ceiling smoke temperature, and smoke spread velocity was analyzed. The results show that the burning diameter exhibits a typical three-stage development process: "spread-shrink-quasi-steady burning". A linear relationship is found between flame height and burning diameter. During the quasi-steady stage, the burning rate of n-heptane spill fires is higher than that of ethanol, ranging from 0.055 to 0.063 mm/s and 0.039 to 0.050 mm/s, respectively. The variation trend of ceiling smoke temperature is consistent with that of the burning diameter. The smoke spread velocity under all test conditions ranges from 0.4 to 0.71 m/s and is positively correlated with the discharge rate. During the quasi-steady stage, the maximum ceiling temperature rise exhibits a linear correlation with the heat release rate. The dimensionless temperature rise decays exponentially with increasing dimensionless distance, with a decay rate slower than that predicted by existing models.

Key words: tunnel spill fire, flame height, burning and spreading behaviors, ceiling smoke temperature, smoke evolution characteristics

CLC Number:

X932爆炸安全与防火、防爆

Ma Hanchao, Zhai Xu, Zhang Yichen, Lyu Junke, Xiao Jianfeng, Huang Hong. Full-scale experiment on burning behaviors and smoke characteristics of spill fires in road tunnels[J]. China Safety Science Journal, 2026, 36(9): 185-192.

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参数	不确定度来源	相对不确定度/%
H	试验测量	±11.6
D	试验测量	±7.4
稳定燃烧速率	D	±7.4
烟气温度	试验测量	±12.6