Open AccessNumerical Study of Fire Smoke Exhausting in an Eight-lane Dual-Directional Rectangular Tunnel
Author(s) -
Zhiyu Cao,
Xiao Liu
Publication year - 2019
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.179
H-Index - 26
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/371/2/022092
Subject(s) - smoke , structural engineering , ventilation (architecture) , span (engineering) , engineering , environmental science , waste management , mechanical engineering
In order to obtain the smoke exhausting characteristics of large-span cross section rectangular tunnel under lateral exhaust model, fire numerical simulation calculation was conducted by FDS to analyse the influence of different factors on smoke exhausting efficiency, including the layout, area, and spacing of smoke exhausting valves in immersed tunnels, and the applicability of the different tunnel width under the model of lateral exhaust was studied. The results are as follows: The smoke exhausting efficiency of individual exhausting valve decreases with more exhausting valves opened, but the total smoke exhausting efficiency of immersed tunnel increases. When three smoke exhausting valves are arranged in a group, the increase of distance between groups is conducive to smoke exhausting. The Smoke exhausting efficiency of evenly arranged valves is higher than the ones where three valves are in a group. When the number of exhausting valves opened remains the same, the increase of opening area can increase the total smoke exhausting efficiency because the ventilation resistance reduces. In lateral exhaust model, the increase of the width of immersed tunnel can result in the sharp decrease of smoke exhausting efficiency. In a two-lane, uni-directional immersed tunnel, the smoke exhausting efficiency is 93.7%, and that of a four-lane one is only 45.94%. For the poor applicability of lateral exhaust model in the large-span cross section immersed tunnel fire, it is suggested that additional smoke exhausting measures should be adopted to increase the efficiency of smoke exhausting.