TY - JOUR
T1 - Critical ventilation velocity for multi-source tunnel fires
AU - Tsai, Kuang Chung
AU - Chen, Hon Hsiang
AU - Lee, Shin Ku
N1 - Funding Information:
The authors would like to thank the National Science Council of the Republic of China , Taiwan for financially supporting this research under contract no. NSC 96-2221-E-327-015-MY3 . Tsun-Tse Huang is appreciated for his carrying out data and Ted Knoy for his editorial assistance.
PY - 2010/10
Y1 - 2010/10
N2 - Ventilation is an effective method for controlling smoke during a fire. The "critical ventilation velocity" ucr is defined as the minimum velocity at which smoke is prevented from spreading under longitudinal ventilation flow in tunnel fire situations. All previous studies on this topic have simulated fire scenarios in which only one fire source exists. This study conducted small-scale experiments and numerical simulations to investigate ucr for cases in which two tunnel fires occur simultaneously. The tunnel was 4m long, 0.6m wide and 0.6m tall. Three cases of two variously separated fires were experimentally explored and six cases were examined numerically. Both the experimental and simulation results indicated that for two identical fires, ucr declines with separation. When the two fire sources are separate completely, ucr can be determined by considering only a single fire. When the larger fire is upstream of the smaller downstream fire, ucr also decreases with the separation. When two such fires sources are completely separate, ucr can be evaluated by considering only the larger fire. The concurrent ventilation flow and flow of downstream smoke from the larger fire are strong enough to suppress the smoke flow from the smaller fire. However, when the smaller fire is upstream of the larger fire, the decrease in ucr becomes insignificant as distance increases and the flow at ucr must overcome the flow from both fires.
AB - Ventilation is an effective method for controlling smoke during a fire. The "critical ventilation velocity" ucr is defined as the minimum velocity at which smoke is prevented from spreading under longitudinal ventilation flow in tunnel fire situations. All previous studies on this topic have simulated fire scenarios in which only one fire source exists. This study conducted small-scale experiments and numerical simulations to investigate ucr for cases in which two tunnel fires occur simultaneously. The tunnel was 4m long, 0.6m wide and 0.6m tall. Three cases of two variously separated fires were experimentally explored and six cases were examined numerically. Both the experimental and simulation results indicated that for two identical fires, ucr declines with separation. When the two fire sources are separate completely, ucr can be determined by considering only a single fire. When the larger fire is upstream of the smaller downstream fire, ucr also decreases with the separation. When two such fires sources are completely separate, ucr can be evaluated by considering only the larger fire. The concurrent ventilation flow and flow of downstream smoke from the larger fire are strong enough to suppress the smoke flow from the smaller fire. However, when the smaller fire is upstream of the larger fire, the decrease in ucr becomes insignificant as distance increases and the flow at ucr must overcome the flow from both fires.
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U2 - 10.1016/j.jweia.2010.06.006
DO - 10.1016/j.jweia.2010.06.006
M3 - Article
AN - SCOPUS:77954953409
SN - 0167-6105
VL - 98
SP - 650
EP - 660
JO - Journal of Wind Engineering and Industrial Aerodynamics
JF - Journal of Wind Engineering and Industrial Aerodynamics
IS - 10-11
ER -