Study on the effect of tunnel dimensions on the smoke layer thickness in naturally ventilated short tunnel fires

2021 ◽  
Vol 112 ◽  
pp. 103941
Author(s):  
Lu He ◽  
Zhisheng Xu ◽  
Frank Markert ◽  
Jiaming Zhao ◽  
En Xie ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Tunnel Fires ◽  
Smoke Layer ◽  
Short Tunnel

Multi-Cell Concept for Simulating Fires in Big Enclosures Using a Zone Model

1996 ◽  
Vol 14 (3) ◽  
pp. 186-198 ◽  
Author(s):  
W.K. Chow
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Temperature Distribution ◽  
Physical Properties ◽  
Flow Pattern ◽  
Layer Thickness ◽  
Zone Model ◽  
Smoke Layer

The multi-cell concept is applied to simulate fire in a big com partment with the zone model CFAST. The predicted physical properties of the smoke layer are used to justify the results, including the smoke layer tempera ture, smoke layer thickness and flows between each cell. Microscopic pictures of the flow pattern and smoke temperature distribution similar to the results pre dicted by the Computational Fluid Dynamics technique can be obtained. This idea is recommended to study fires in big enclosures.

scholarly journals Experimental Investigation on the Discharge of Pollutants from Tunnel Fires

2020 ◽  
Vol 12 (5) ◽  
pp. 1817
Author(s):  
Lihua Zhai ◽  
Zhongxing Nong ◽  
Guanhong He ◽  
Baochao Xie ◽  
Zhisheng Xu ◽  
...  
Keyword(s):  
Laser Sheet ◽  
Longitudinal Velocity ◽  
Release Rates ◽  
Layer Height ◽  
Tunnel Fires ◽  
Smoke Flow ◽  
Longitudinal Ventilation ◽  
Toxic Gases ◽  
Smoke Layer ◽  
Series Of Experiments

Many pollutants are generated during tunnel fires, such as smoke and toxic gases. How to control the smoke generated by tunnel fires was focused on in this paper. A series of experiments were carried out in a 1:10 model tunnel with dimensions of 6.0 m × 1.0 m × 0.7 m. The purpose was to investigate the smoke layer thickness and the heat exhaust coefficient of the tunnel mechanical smoke exhaust mode under longitudinal wind. Ethanol was employed as fuel, and the heat release rates were set to be 10.6 kW, 18.6 kW, and 31.9 kW. The exhaust velocity was 0.32–3.16 m/s, and the longitudinal velocity was 0–0.47 m/s. The temperature profile in the tunnel was measured, and the buoyant flow stratification regime was visualized by a laser sheet. The results showed that the longitudinal ventilation leads to a secondary stratification of the smoke flow. In the ceiling extract tunnel under longitudinal ventilation, considering the research results of the smoke layer height and the heat exhaust coefficient, a better scheme for fire-producing pollutants was that an exhaust velocity of 1.26–2.21 m/s (corresponding to the actual velocity of 4.0–7.0 m/s) should be used. The longitudinal velocity should be 0.16–0.32 m/s (corresponding to the actual velocity of 0.5–1.0 m/s).

DECAY OF BUOYANT SMOKE LAYER TEMPERATURE ALONG THE LONGITUDINAL DIRECTION IN TUNNEL FIRES

2004 ◽  
Vol 13 (1) ◽  
pp. 53-77 ◽  
Author(s):  
L. H. HU ◽  
R. HUO ◽  
W. K. CHOW ◽  
H. B. WANG ◽  
R. X. YANG
Keyword(s):  
Longitudinal Direction ◽  
Tunnel Fires ◽  
Smoke Layer

scholarly journals Analysis of smoke stratification and smoke layer thickness in underground car parks

2018 ◽  
Vol 22 (5) ◽  
pp. 1963-1972
Author(s):  
Zeljko Spiljar ◽  
Daniel Schneider ◽  
Miodrag Drakulic
Keyword(s):  
Numerical Modelling ◽  
Layer Thickness ◽  
Time Interval ◽  
Building Structure ◽  
Smoke Movement ◽  
Evacuation Time ◽  
Smoke Layer ◽  
Car Park ◽  
Fire Accidents ◽  
Fire Design

Fire accidents in underground car parks have a significant impact on the building structure and lives of people and firefighters. Different methods are used to obtain a reliable estimation of fire and hot smoke influence on the building structure. Numerical modelling is crucial in the fire design and is a useful tool to determine smoke stratification and clear layers for safe human evacuation and firefighter access. Smoke stratification can be checked separately for any time interval in any section of an underground car park, regardless of the underground car park architecture complexity. This paper describes numerical modelling of smoke stratification and movement in an underground car park. The results show smoke movement and smoke layer thickness during the evacuation time, and how they can help reduce the harmful influence of fire on the underground car park structure.

On the Smoke Propagation of a Fire in a Tunnel With Concentrated Exhaust Ventilation

2011 ◽  
Author(s):  
Futoshi Tanaka ◽  
Masahiro Kato ◽  
Shouhei Majima ◽  
Nobuyoshi Kawabata ◽  
Tomoki Kikumoto ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Scaling Law ◽  
Experimental Results ◽  
Exhaust Ventilation ◽  
Tunnel Fire ◽  
The People ◽  
Fire Smoke ◽  
Smoke Layer ◽  
Fire Accidents ◽  
Real Scale

In recent years, tunnel fire accidents of about 20 occur every year in Japan. The Nihonzaka and the Sakai tunnel fire accidents are as famous typical examples. When concentrated exhaust ventilation device is activated in such a tunnel fire, it is of concern that the people who take shelter receive damage from the fire smoke. When a tunnel fire occurs, the concentrated exhaust ventilation device is stopped in Japan. Therefore, the research on the use of concentrated exhaust ventilation device at a tunnel fire has not advanced in Japan. The purpose of this study is to clarify the smoke propagation when concentrated exhaust ventilation device is activated. The model tunnel in the scale of 1/5 was used in this study. Froude scaling law was used to make the experimental results of the model tunnel correspond to the real scale tunnel. The concentrated exhaust ventilation device installed on the model tunnel extracts the fire smoke from a chimney. The smoke distribution in the model tunnel was measured with smoke concentration meters. In the case that the exhaust ventilation device was activated, the smoke layer thickness of the downstream of the chimney thinned. However, in the upstream of the chimney, the smoke layer thickness did not change though the exhaust ventilation device was activated.

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