Citation

Xie E, Zhao W, Xu Z, Zhang X, Xu W, Wang T, He L. Fire Mater. 2022; 46(8): 1208-1221.

Copyright

(Copyright © 2022, John Wiley and Sons)

DOI

10.1002/fam.3063

PMID

unavailable

Abstract

When a fire occurs at the lowest point of a V-shaped tunnel, the stack effects on both sides have different directions and will compete with each other. The smoke back-layering can be observed in the side with a smaller angle. In this work, the smoke back-layering length in the V-shaped tunnel was investigated by theoretical analyses and numerical simulations. The different inclination combinations of the V-shaped tunnel and the heat release rates (HRRs) were concerned. The HRRs were set at 3, 5, 8, and 10 MW, respectively. An equivalent longitudinal velocity of the V-shaped tunnel was proposed in this study. Different from the horizontal tunnel fire, the smoke back-layering length decreased with the increase of the HRR in the V-shaped tunnel due to the special smoke movement, and a prediction function was proposed to describe the relationship. After that, the effect of the different inclination combinations on the smoke back-layering length was researched under the same HRR. The dimensionless smoke back-layering length decreased with the rise of the sine difference between the two angles of the V-shaped tunnel. In addition, when the smaller angle was fixed, the dimensionless smoke back-layering length decreases logarithmically with the increase of the sine difference of the tunnel angles on both sides. At last, a semi-empirical formula for smoke back-layering length in V-shaped tunnels was proposed.

Language: en

Keywords

back-layering length; equivalent velocity; inclination combination; stack effect; V-shaped tunnel fire