TY  - JOUR
PY  - 2022//
TI  - A numerical study on smoke back-layering length in V-shaped tunnels under natural ventilation
JO  - Fire and materials
A1  - Xie, En
A1  - Zhao, Wangda
A1  - Xu, Zhisheng
A1  - Zhang, Xiaochun
A1  - Xu, Weiku
A1  - Wang, Tianxiong
A1  - He, Lu
SP  - 1208
EP  - 1221
VL  - 46
IS  - 8
N2  - 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.<p />  <p>Language: en</p>
LA  - en
SN  - 0308-0501
UR  - http://dx.doi.org/10.1002/fam.3063
ID  - ref1
ER  -