TY - JOUR
T1 - Numerical simulation on the maximum temperature and smoke back-layering length in a tilted tunnel under natural ventilation
AU - Zhang, Xiaolei
AU - Lin, Yujie
AU - Shi, Congling
AU - Zhang, Jianping
PY - 2020/10/21
Y1 - 2020/10/21
N2 - The present study investigates the maximum temperature and smoke back-layering length S in the downhill direction from the fire source in a tilted tunnel under natural ventilation. Numerical simulations were conducted using FDS to study the smoke flow behaviors for a fire in a tunnel with nine tunnel slopes of 0, 1%, 2%, 3%, 4%, 5%, 6%, 7% and 8%. It was found that, due to the stack effect, the smoke stagnated at a distance from the fire source in the downhill direction. The effects of tunnel slope, , fire source heat release rate, , source-ceiling height H and tunnel width W on the maximum temperature and smoke back-layering length were studied. Results showed that the maximum temperature under the ceiling decreased with the increasing of tunnel slope or the decreasing of tunnel width. However, it increased with the increasing of heat release rate or the decreasing of source-ceiling height. A model was proposed for the maximum temperature rise. The smoke back-layering length S decreased with the increasing of the tunnel slope. Fire source heat release rate and tunnel width had no significant effect on the smoke back-layering length. And the smoke back-layering length decreased with the decreasing of source-ceiling height. Based on dimensional analysis, a simple model including the effects of both the tunnel slope and source-ceiling height H, was proposed to predict the smoke back-layering length.
AB - The present study investigates the maximum temperature and smoke back-layering length S in the downhill direction from the fire source in a tilted tunnel under natural ventilation. Numerical simulations were conducted using FDS to study the smoke flow behaviors for a fire in a tunnel with nine tunnel slopes of 0, 1%, 2%, 3%, 4%, 5%, 6%, 7% and 8%. It was found that, due to the stack effect, the smoke stagnated at a distance from the fire source in the downhill direction. The effects of tunnel slope, , fire source heat release rate, , source-ceiling height H and tunnel width W on the maximum temperature and smoke back-layering length were studied. Results showed that the maximum temperature under the ceiling decreased with the increasing of tunnel slope or the decreasing of tunnel width. However, it increased with the increasing of heat release rate or the decreasing of source-ceiling height. A model was proposed for the maximum temperature rise. The smoke back-layering length S decreased with the increasing of the tunnel slope. Fire source heat release rate and tunnel width had no significant effect on the smoke back-layering length. And the smoke back-layering length decreased with the decreasing of source-ceiling height. Based on dimensional analysis, a simple model including the effects of both the tunnel slope and source-ceiling height H, was proposed to predict the smoke back-layering length.
KW - Tunnel fire
KW - tunnel slope
KW - smoke back-layering length
KW - temperature
KW - FDS
U2 - 10.1016/j.tust.2020.103661
DO - 10.1016/j.tust.2020.103661
M3 - Article
SN - 0886-7798
VL - 107
JO - Tunnelling and Underground Space Technology incorporating Trenchless Technology Research
JF - Tunnelling and Underground Space Technology incorporating Trenchless Technology Research
ER -
