Studies on buoyancy driven two-directional smoke flow layering length with combination of point extraction and longitudinal ventilation in tunnel fires

2013 ◽  
Vol 59 ◽  
pp. 94-101 ◽  
Author(s):  
L.F. Chen ◽  
L.H. Hu ◽  
W. Tang ◽  
L. Yi
Keyword(s):  
Tunnel Fires ◽  
Smoke Flow ◽  
Longitudinal Ventilation

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).

Study on the heat exhaust coefficient and smoke flow characteristics under lateral smoke exhaust in tunnel fires

2019 ◽  
Vol 43 (7) ◽  
pp. 857-867 ◽  
Author(s):  
Zhisheng Xu ◽  
Qiulin Liu ◽  
Lu He ◽  
Haowen Tao ◽  
Jiaming Zhao ◽  
...  
Keyword(s):  
Flow Characteristics ◽  
Tunnel Fires ◽  
Smoke Flow

Study of Fire Smoke Flow of Tunnel at Different Longitudinal Ventilation

2012 ◽  
Vol 226-228 ◽  
pp. 1472-1475
Author(s):  
Pei Pei Yang ◽  
Xiao Lu Shi ◽  
Bi Ming Shi
Keyword(s):  
Flow Resistance ◽  
Reverse Flow ◽  
Ventilation System ◽  
Gas Temperature ◽  
Smoke Control ◽  
Smoke Flow ◽  
Longitudinal Ventilation ◽  
Smoke Spread ◽  
Fire Smoke ◽  
Safety Evacuation

Once the tunnel fires happened, it will cause a major accident. And the smoke control of the runnel is important to fire prevention. A numerical simulation of the fire smoke flow in the tunnel model is presented by using FDS. The influence of different longitudinal ventilation on fire smoke flow of tunnel is obtained. And providing theory basis for tunnel ventilation system design, smoke spread control and safety evacuation. The results shown that in order to avoid reverse-flow and extend the time of smoke at the top of tunnel, the longitudinal speed should be controlled in 3.4 m/s; because of the role of longitudinal ventilation, smoke flow resistance and longitudinal ventilation generated by the effect of smoke flow resistance make the gas temperature first rise and then down.

The maximum temperature of buoyancy-driven smoke flow beneath the ceiling in tunnel fires

2011 ◽  
Vol 46 (4) ◽  
pp. 204-210 ◽  
Author(s):  
Ying Zhen Li ◽  
Bo Lei ◽  
Haukur Ingason
Keyword(s):  
Maximum Temperature ◽  
Tunnel Fires ◽  
Smoke Flow

Study on the smoke stratification length under longitudinal ventilation in tunnel fires

2018 ◽  
Vol 132 ◽  
pp. 285-295 ◽  
Author(s):  
Zhen Zeng ◽  
Kang Xiong ◽  
Xin-Ling Lu ◽  
Miao-Cheng Weng ◽  
Fang Liu
Keyword(s):  
Tunnel Fires ◽  
Longitudinal Ventilation

Smoke movement in tilted tunnel fires with longitudinal ventilation

2015 ◽  
Vol 75 ◽  
pp. 14-22 ◽  
Author(s):  
W.K. Chow ◽  
Y. Gao ◽  
J.H. Zhao ◽  
J.F. Dang ◽  
C.L. Chow ◽  
...  
Keyword(s):  
Smoke Movement ◽  
Tunnel Fires ◽  
Longitudinal Ventilation

Reduced-Scale Model Tests of Fires in Railway Tunnel and Structure Fire Safety

2010 ◽  
Vol 168-170 ◽  
pp. 2473-2476 ◽  
Author(s):  
Hong Li Zhao ◽  
Zhi Sheng Xu ◽  
Xue Peng Jiang
Keyword(s):  
Fire Safety ◽  
Numerical Models ◽  
Scale Model ◽  
Railway Tunnel ◽  
Tunnel Fires ◽  
Tunnel Fire ◽  
Longitudinal Ventilation ◽  
Overall Stability ◽  
Reduced Scale ◽  
Ventilation Velocity

The high-temperature toxic gas released by long railway tunnel fires not only causes great harm to persons, but also damages the structure of the tunnel which will reduce the overall stability of tunnel. In order to diminish the damage to tunnel structure produced by a tunnel fire, on the basis of the first extra-long underwater railway tunnel in China, some reduced-scale tests were carried out to study the distribution of smoke temperature along the tunnel ceiling, the smoke velocity and the backlayering distance with the fire size of 63KW. The longitudinal ventilation velocity and the tunnel gradient varied in these tests. The smoke temperature below the tunnel ceiling in different times and under different longitudinal ventilation velocity, the smoke velocity under the ceiling, and the backlayering distance in the presence of different ventilation velocity are acquired from the tests. The conclusions have the guiding meaning to the disaster prevention design and construction of structure fire safety in tunnel fires, and all the experimental data presented in this paper are applicable for the verification of numerical models.

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