Numerical investigation on the smoke behaviour and longitudinal temperature decay in tilted tunnel fire with portal sealing

Li, Jiaxin; Li, Yanfeng; Li, Junmei; Yang, Quan

doi:10.1177/1420326x211034894

Cited by 6 publications

(4 citation statements)

References 41 publications

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“…The program is based on solving the low-speed Navier-Stokes heat flow equations depending on the boundary condition to be solved linked to the solution conditions. The program uses a set of equations that it solves together to get the approximate solution of the numerical model [27] as follows:…”

Section: Fire Dynamic Simulator Modellingmentioning

confidence: 99%

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Smoke Management Characteristics in a Road Tunnel with Different Scenarios of Exhaust Fans and Solid Curtains

Elsaid,

Ali,

Wahba

et al. 2024

Preprint

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The continued condensation of the smoke emitted from the fire arising through the road tunnels leads to many dangers, the most important of which is a loud explosion that may extend outside the tunnels and be a fatal factor for innocent people due to poor design that leads to loss of safety. Also, the increased concentration and level of smoke inside the long tunnels lead to poor visibility for vehicle drivers, in addition to a lack of oxygen and more CO2, causing a catastrophe to increase the number of deaths of tunnel occupants. Also, increasing the concentration and level of smoke inside the long tunnels leads to a lack of visibility, in addition to a lack of oxygen, which is a cause of a catastrophe with the death of the tunnel’s occupants. To overcome these risks, controlling the smoke generated while directing them away from the level of visibility of tanker truck drivers has become an urgent necessity to save lives and reduce the level of environmental pollutants to achieve safety. The present research aims to conduct a numerical investigation of smoke management due to solid curtains and a transverse ventilation system on smoke condensation leading to blowouts inside a road tunnel with tanker trucks. The FDS version 2018 code is used for modeling the numerical simulations with model validation performed through open literature studies. Different important parameters of temperature distribution, visibility level, and carbon monoxide concentration through tunnels have been studied. Four suggested scenarios are developed, simulated numerically, and discussed at a horizontal road tunnel for 600 seconds when achieving steady-state conditions. The road tunnel is a rectangular cross-section area with a 10 m width and 5 m height. A release heat rate of 100 MW fire is considered equivalent to a burning tanker, while a fixed position of generated fire at 300 m from the road tunnel entrance is supposed. Increasing the volumetric flow rate of exhaust fans with the use of solid curtains (Scenario-D) leads to enhancing the visibility level, decreasing the concentration level of CO, and accordingly safe people through tunnels during a fire with a rate of 100 MW.

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Section: Fire Dynamic Simulator Modellingmentioning

confidence: 99%

“…The numerical model of the two way-road tunnels was a rectangular cross-section with a dimension of 10 m (W) X 5 m (H) and a length of 600 m; the height of the smoke exhaust duct was 2 m, which has the same tunnel model width regarding code [27]. The fire HRR was specified as constant 100 MW.…”

Section: Numerical Model Description and Variablesmentioning

confidence: 99%

Smoke Management Characteristics in a Road Tunnel with Different Scenarios of Exhaust Fans and Solid Curtains

Elsaid,

Ali,

Wahba

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…Tao et al 14 established a tunnel model to study the vault temperature of the single-side centralized smoke exhaust tunnel with varying amount of smoke exhaust air volumes and HRR. Based on the variations in the slope, HRR and sealing rate, Li et al 15 used FDS to study the smoke characteristics and longitudinal temperature attenuation law in tunnel fire. Jia et al 16 studied the maximum tunnel ceiling temperature under double fire by combining small-size experimental data and numerical simulation.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on the flame merging and ceiling impingement behavior of transversely located double fire sources in an urban utility tunnel

Zhang

Gao

et al. 2023

Indoor and Built Environment

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The investigation of the fire characteristics and propagation behaviour in the urban utility tunnel is of great practical importance, especially for the conditions with double fire sources. In this work, a 1/8th scaled urban utility tunnel model was built to conduct the experiments to characterize the flame merging and ceiling impingement behaviour of transversely located double fire sources. Two rectangular fire sources with the same dimension were used, and their heat release rate (HRR) and fire source spacings were varied to consider the typical scenarios. Results show that for the smaller HRR, the tunnel ceiling and sidewalls have little influence on the flame merging of double fire sources. With the increase of HRR, the flame gradually impinges on the tunnel ceiling and forms a stable ceiling jet flame extension, and the ceiling and sidewalls of the tunnel can promote the merging of the flames of the double fire sources. Besides, with the increase of the fire source spacings, the flame merging probability P m can be divided into three stages, that is, (i) complete merging stage, (ii) intermittent merging stage and (iii) complete separation stage. On this basis, the predicting relation of P m was obtained by using the piecewise function.

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“…Therefore, smoke characteristics, especially temperature distribution, have been investigated widely as a classical problem [3][4][5][6][7][8][9][10]. However, previous research mostly concentrated on the influences of longitudinal ventilation [11][12][13], sealing ratio [14][15][16] and fire location [17][18][19] on temperature profile in single tunnels. In addition, full-scale fire tests of battery-electric vehicles were conducted to investigate fire behavior, and new approaches to fighting a BEV fire were suggested [20].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Fire Smoke Temperature under Forced Ventilation Conditions in a Bifurcated Tunnel with Fires Situated in a Branch Tunnel

Guo,

Yang,

Zhang

et al. 2023

Fire

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In this work, a number of experiments were conducted in a reduced scale bifurcation tunnel with a ratio of 1:10 to explore the influence of the position of longitudinal fires (placed in branch tunnel) on smoke temperature profile under forced ventilation. Three heat release rates, six ventilation velocities, and three fire locations were considered. The main findings are summarized below, as follows: The temperature of smoke downstream of the main tunnel decreases with the rate of ventilation and longitudinal fire location. In contrast, the smoke temperature downstream of the fire source inside the branch tunnel drops with the ventilation velocity; the maximum temperature of the flame under the ceiling of the tunnel rises with longitudinal fire location. The dimensionless longitudinal smoke temperatures downstream of the main tunnel decrease exponentially with longitudinal distance, and the same observation is found in the branch tunnel. The attenuation coefficient k in the main tunnel increases with longitudinal ventilation velocity according to a power law but does not change significantly with longitudinal fire locations. However, the exponential coefficient k′ in the branch tunnel decreases linearly with ventilation velocity, whereas it increases with longitudinal fire location inside the branch tunnel. Lastly, modified models are established for estimating the longitudinal profile of temperatures downstream of the main tunnel and branch tunnel, where the influence of the rate of ventilation and location of the fire are taken into account.

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Numerical investigation on the smoke behaviour and longitudinal temperature decay in tilted tunnel fire with portal sealing

Cited by 6 publications

References 41 publications

Smoke Management Characteristics in a Road Tunnel with Different Scenarios of Exhaust Fans and Solid Curtains

Smoke Management Characteristics in a Road Tunnel with Different Scenarios of Exhaust Fans and Solid Curtains

Experimental study on the flame merging and ceiling impingement behavior of transversely located double fire sources in an urban utility tunnel

Experimental Investigation on Fire Smoke Temperature under Forced Ventilation Conditions in a Bifurcated Tunnel with Fires Situated in a Branch Tunnel

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