The effect of technical installations on evacuation performance in urban road tunnel fires

A set of burning experiments were conducted to investigate the effect of vertical shaft geometry on natural ventilation in urban road tunnel fires. Results show that using vertical shafts to discharge smoke leads to a boundary layer separation near the right-angle connection of the shaft and the tunnel ceiling. In a low shaft, the turbulent-boundary-layer separation phenomenon causes relatively large-scale vortexes and restricts smoke from being exhausted, resulting in a negative effect on natural ventilation. Replacing the right-angle connection with the bevel-angle connection was proposed to split one separation point into two separation points, to attenuate the negative effect. The detailed characteristics of the separation phenomenon were analysed and the proposition was verified by Large Eddy Simulation. Results show that there are no relatively large-scale vortexes in shafts with bevel-angle connections, resulting in improved natural ventilation effectiveness. For lower shafts, the advantage of using the bevel-angle connection is more significant, and for shafts of the same height, the mass flow rate of smoke discharged by shafts with the bevel-angle connection increases up to 1.5 times of that by shafts with the right-angle connection. For relatively high shafts, it is about 1.2 times.

Download Full-text

Theoretical and numerical study on mass flow rates of smoke exhausted from short vertical shafts in naturally ventilated urban road tunnel fires

Tunnelling and Underground Space Technology ◽

10.1016/j.tust.2020.103782 ◽

2021 ◽

Vol 111 ◽

pp. 103782 ◽

Cited By ~ 2

Author(s):

Qinghua Guo ◽

Ying Zhen Li ◽

Haukur Ingason ◽

Zhiguo Yan ◽

Hehua Zhu

Keyword(s):

Mass Flow ◽

Numerical Study ◽

Road Tunnel ◽

Flow Rates ◽

Urban Road ◽

Tunnel Fires ◽

Mass Flow Rates

Download Full-text

Large Eddy Simulation of stack effect on natural smoke exhausting effect in urban road tunnel fires

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2013.07.057 ◽

2013 ◽

Vol 66 ◽

pp. 531-542 ◽

Cited By ~ 71

Author(s):

J. Ji ◽

Z.H. Gao ◽

C.G. Fan ◽

J.H. Sun

Keyword(s):

Large Eddy Simulation ◽

Road Tunnel ◽

Urban Road ◽

Stack Effect ◽

Tunnel Fires ◽

Eddy Simulation ◽

Large Eddy

Download Full-text

A numerical study on upstream maximum temperature in inclined urban road tunnel fires

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2015.05.002 ◽

2015 ◽

Vol 88 ◽

pp. 516-526 ◽

Cited By ~ 76

Author(s):

Jie Ji ◽

Huaxian Wan ◽

Kaiyuan Li ◽

Jianyun Han ◽

Jinhua Sun

Keyword(s):

Numerical Study ◽

Maximum Temperature ◽

Road Tunnel ◽

Urban Road ◽

Tunnel Fires

Download Full-text

Should We Expect a Disastrous Fire Accident in an Urban Road Tunnel? Literature Data Review and a Case Study for Selected Tunnels in Poland

Sustainability ◽

10.3390/su13116172 ◽

2021 ◽

Vol 13 (11) ◽

pp. 6172

Author(s):

Krystian Szewczyński ◽

Aleksander Król ◽

Małgorzata Król

Keyword(s):

Time Horizon ◽

Road Traffic ◽

Traffic Intensity ◽

Road Tunnel ◽

Urban Road ◽

Road Tunnels ◽

High Uncertainty ◽

Fire Outbreak ◽

Fire Accident

Urban road tunnels are a reasonable remedy for inconvenience due to congested road traffic. However, they bring specific threats, especially those related to the possibility of fire outbreak. This work is a case study for selected urban road tunnels. Considering tunnel specificity, road traffic intensity, and structure and based on the literature data for vehicle fire probability, the chances of a fire accident were estimated for selected tunnels in Poland. It was shown that low power tunnel fires could be expected in the 10–20-year time horizon. Although such threats cannot be disregarded, tunnel systems are designed to cope with them. The chances of a disastrous fire accident were estimated as well. Such events can occur when an HGV with flammable goods or a tanker are involved. Such accidents are fortunately very rare, but, on the other hand, that is the reason why the available data are scanty and burdened with high uncertainty. Therefore, a discussion on the reliability of the obtained results is also provided.

Download Full-text