Experimental study of air entrainment mode with natural ventilation using shafts in road tunnel fires

Fan, Chuangang; Ji, J.; Gao, Zihe; Han, Jiaqiang; Sun, Jinhua

doi:10.1016/j.ijheatmasstransfer.2012.09.047

Cited by 158 publications

(43 citation statements)

References 29 publications

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“…Many experimental and CFD studies, over the world, have been conducted in order to evaluate the impact of the airflow on temperature and smoke distributions during the fire in tunnels [7][8][9][10][11][12][13]. The results have proven the direct influence of the airflow on smoke and temperature behavior.…”

Section: Air Velocity Boundary Conditionmentioning

confidence: 99%

Numerical Simulation of a Full Scaled Fire Test of the Tunnel with Natural Ventilation

Rafiei¹

2015

IJCA

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A mechanical ventilation system plays a major role in tunnels safety. Over the world, different ventilation systems regarding to the tunnel geometry and other parameters are used for tunnel ventilation in the normal and fire operations. However, in short tunnels depending on the tunnel geometry and traffic condition, there is the possibility of passing traffic through a tunnel without mechanical ventilation. Normally, natural ventilation is applied in short tunnels. In longer tunnels, additional measures in geometry such as openings or shafts are necessary to support natural ventilation. Due to the high costs of the electro-mechanical installations, maintenance and electricity power consumption for mechanical ventilation, having tunnels with natural ventilation system will be the best option. But, reliability of such ventilation systems in case of emergency must be substantiated before applying to tunnels. The main concern is a proper smoke evacuation in a fire case. In this survey, in order to set up a suitable CFD model, numerical simulation of a pre-conducted fire test by using same boundary conditions is done. These simulations were further extended to fires with higher capacities to show smoke and temperature behavior during the higher fires. The newest version of the FDS software (Fire Dynamic Simulator 6) was employed for simulations.

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Section: Air Velocity Boundary Conditionmentioning

confidence: 99%

Numerical Simulation of a Full Scaled Fire Test of the Tunnel with Natural Ventilation

Rafiei¹

2015

IJCA

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“…It is well-known that smoke is the most fatal factor in fires, and about 85% of people killed in building fires were killed by toxic smoke [4,5]. Smoke and heat control systems are an essential part of fire protection in the fire safety design of buildings.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of the effectiveness of air curtains of variable width and injection angle to block fire-induced smoke in a tunnel configuration

Liu

Beji

et al. 2018

International Journal of Thermal Sciences

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Small-scale experiments have been conducted to study the sealing effect of an air curtain for fire-induced smoke confinement in a tunnel configuration. The processed data confirmed the results obtained earlier from blind Computational Fluid Dynamics (CFD) simulations [1] using the Fire Dynamics Simulator (FDS) 6.5.3 [2, 3]. Furthermore, the CFD simulations provided complementary information on the detailed flow and temperature fields which are difficult to obtain in experiments with the available techniques. A parametric study is performed, covering a range of air curtain velocities, slot widths, injection angles and total fire heat release rates (HRRs). The momentum ratio R, defined as the ratio of the vertically downward air curtain momentum to the horizontal smoke layer momentum at the position of the air curtain, is confirmed to be a key parameter for the air curtain performance. A ratio R ≈ 10 is recommended for the optimum sealing effect in terms of smoke confinement. In addition, two other important parameters that determine the performance of air curtains for smoke confinement are presented. The first parameter is the dimensionless Preprint submitted to International Journal of Thermal Sciences https://doi.org/10.1016/j.ijthermalsci.2018.07.044 2 shape factor AR (AR=Width/Length) that characterizes the dilution effect of the air curtain jet. The second parameter is the injection angle θ that characterizes the horizontal force of the air curtain. The air curtain sealing effectiveness increases with both the increase of slot width (shape factor AR) and injection angle (θ). The air curtain width has a limited influence on the performance of the air curtain whilst the injection angle has a more significant influence on the sealing effectiveness of the air curtain for the scenarios considered in this study.An optimal injection angle of 30 o inclined to the fire source is recommended in the engineering design of the air curtain for smoke confinement for situations where the fire location can be pre-determined to be only at one side of an air curtain.

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“…In recent years, more attention on the study (Fan et al 2013;Chow and Li 2011;Chow and Gao 2009) of tunnel fire is the smoke spread under the natural ventilation. Chen et al (2015) reveals the effect of the distance between ceiling extraction (opening) distance and heat source on the thermally-driven smoke back-layering flow length beneath the ceiling in a tunnel with combination of ceiling extraction and longitudinal ventilation.…”

Section: ．Introductionmentioning

confidence: 99%

Maximum Smoke Temperature in Non-Smoke Model Evacuation Region for Semi-Transverse Tunnel Fire

Lou

Qiu

Long

2017

JAFM

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Smoke temperature distribution in non-smoke evacuation under different mechanical smoke exhaust rates of semi-transverse tunnel fire were studied by FDS numerical simulation in this paper. The effect of fire heat release rate (10MW 20MW and 30MW) and exhaust rate (from 0 to 160m 3 /s) on the maximum smoke temperature in non-smoke evacuation region was discussed. Results show that the maximum smoke temperature in non-smoke evacuation region decreased with smoke exhaust rate. Plug-holing was observed below the smoke vent when smoke exhaust rate increased to a certain value. Smoke spreading distance can be divided into three stages according to changes of smoke exhaust rate. The maximum smoke temperature model concluded that the peak temperature rise at tunnel vault is proportional to 0.75 power of dimensionless fire power. The maximum temperature in non-smoke evacuation region decays exponentially with the increase of smoke exhaust rate. However smoke vent interval influences the dimensionless maximum temperature in nonsmoke evacuation region slightly. Smoke vent interval influences the dimensionless maximum temperature in non-smoke evacuation region slightly.

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Experimental study of air entrainment mode with natural ventilation using shafts in road tunnel fires

Cited by 158 publications

References 29 publications

Numerical Simulation of a Full Scaled Fire Test of the Tunnel with Natural Ventilation

Numerical Simulation of a Full Scaled Fire Test of the Tunnel with Natural Ventilation

Experimental study of the effectiveness of air curtains of variable width and injection angle to block fire-induced smoke in a tunnel configuration

Maximum Smoke Temperature in Non-Smoke Model Evacuation Region for Semi-Transverse Tunnel Fire

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