Understanding sidewall constraint involving ventilation effects on temperature distribution of fire-induced thermal flow under a tunnel ceiling

Zhou, Ting; Li, Haihang; Chen, Qinpei; Wei, Ruichao

doi:10.1016/j.ijthermalsci.2018.03.018

Cited by 35 publications

(8 citation statements)

References 35 publications

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“…The temperature simulation results of small-scale tunnel are consistent with those of full-scale tunnel. Equation (15) applies only to the HRR of fire sources between 20 and 50 MW, with longitudinal ventilation velocity less than 2 m/s. It is used for predicting temperature distribution taking that the combustible materials are ignited near the fire source into account in tunnel…”

Section: Model Validationmentioning

confidence: 99%

“…Based on the flame theory, Li and Ingason 14 theoretically analyzed the maximum temperature below the tunnel ceiling. In order to study the temperature distribution of the heat flow under the tunnel ceiling, two sets of model-scale tests were conducted, Zhou et al 15 performed a series of full-scale simulations of tunnel fires. Tang et al 16 proposed a normalized equation of the ceiling maximum plume temperature, through the addition of an impact factor for the ceiling smoke extraction rate, of a ceiling jet induced by rectangularsource fires.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and numerical study of maximum ceiling temperature in a tunnel

Bai

2019

Advances in Mechanical Engineering

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Maximum ceiling temperatures in a tunnel with different ventilation velocities with three heat release fires are studied experimentally and theoretically. This article investigates the ventilation velocity effects on maximum ceiling temperature combustible materials around ignition source in tunnel fires. Several fire experimental tests are conducted with longitudinal ventilation velocity changes in a small-scale tunnel (23 m in length, 2 m in width, and 0.98 m in height), where three heat release fires (237, 340, and 567 kW) and their corresponding values in the real tunnel are 20, 30, and 50 MW, respectively. This article modifies the current temperature prediction model taking the ignition materials near the fire source into account in tunnels. Results show that the ceiling maximum temperature increases, corresponding to the burn time when other experimental conditions remain unchanged for a given fire heat level source. The ceiling temperature reduces quickly when the ventilation velocity is increased from 0.5 to 2.0 m/s. Moreover, this article proposes an equation that can be used to estimate the ceiling maximum temperature variation value with three heat release fires in tunnels. Finally, experimental results are also compared with the tunnel ceiling temperature attenuation equations established by Alpert, Heskestad, and Ingason. The equation proposed in this article appears to provide better estimates of ceiling temperature variation than the Kurioka model developed in their scaled experiments. The prediction agrees well with the experimental and measured data by the modified equations of this article.

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Section: Model Validationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study of maximum ceiling temperature in a tunnel

Bai

2019

Advances in Mechanical Engineering

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“…Fire is one of the disasters, which may occur in the tunnel, as the vehicles always carry a lot of solid, liquid, and gaseous combustibles . When a fire occurs in the tunnel, because of its long‐narrow structure, hot smoke will quickly spread throughout the tunnel, and it will be difficult to be discharged in time . The toxic gases produced by fire source will seriously affect the evacuation of stranded persons and rescue work of fire department.…”

Section: Introductionmentioning

confidence: 99%

“…[21][22][23] When a fire occurs in the tunnel, because of its long-narrow structure, hot smoke will quickly spread throughout the tunnel, and it will be difficult to be discharged in time. [24][25][26][27][28] The toxic gases produced by fire source will seriously affect the evacuation of stranded persons and rescue work of fire department. Therefore, an effective smoke exhaust system must be installed.…”

Section: Introductionmentioning

confidence: 99%

A numerical study on the effects of naturally ventilated shaft and fire locations in urban tunnels

Fan

Chen

Mao³

et al. 2019

Fire and Materials

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Summary In more and more tunnels, natural ventilation mode with vertical shafts has been gradually employed. However, there are few studies investigating the influences of fire and shaft positions on natural ventilation performance currently. Therefore, this study investigated the effects of the transverse distance from fire source to tunnel sidewall, the longitudinal distance from fire source to shaft, and the transverse distance from shaft to sidewall on natural ventilation effectiveness in a tunnel fire by using Fire Dynamics Simulator. The typical characteristic parameters of smoke, such as mass flow rate, temperature distribution, and velocity vector were analyzed; besides, the phenomenon of plug‐holing was discussed. The results have shown that the mass flow rate of gas exhausted by the shaft decreases slightly with the increase of longitudinal distance from fire source to shaft. When the longitudinal distance from fire source to shaft is constant, changing the transverse distance from shaft to sidewall will have a more obvious effect on the effectiveness of exhausting smoke than changing the transverse distance from fire source to sidewall; in addition, the phenomenon of plug‐holing is more serious when the shaft is close to the sidewall.

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“…As the number and length of tunnels increase, the driving speed and density of vehicles in the tunnel also increase, so tunnel disasters have occurred more frequently in recent decades, and fire is one of the major disasters that may occur in tunnels . If a fire occurs in the tunnel, due to its long‐narrow structure and the poor internal ventilation capacity, the hot smoke will spread rapidly throughout the tunnel and will be difficult to be discharged . Moreover, the toxic gases in the tunnel will seriously affect the evacuation of stranded persons and rescue work of fire department.…”

Section: Introductionmentioning

confidence: 99%

Effects of fire location on the capacity of smoke exhaust from natural ventilation shafts in urban tunnels

et al. 2018

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Summary Investigation of natural ventilation using shafts in tunnels has been receiving more attentions; however, analyses on how fire position influences the natural ventilation performance have rarely been addressed. This study investigated the influence of different fire positions between two shafts on natural ventilation effectiveness in a tunnel by large eddy simulation. The smoke movement characteristics were studied in detail, with systematically varying the fire position between two shafts and the longitudinal wind speed in the tunnel. The typical smoke characteristic parameters, such as temperature distribution, mass flow rate and CO concentration were emphatically investigated. Some special phenomena, such as plug‐holing and smoke bifurcation, were also discussed.

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Understanding sidewall constraint involving ventilation effects on temperature distribution of fire-induced thermal flow under a tunnel ceiling

Cited by 35 publications

References 35 publications

Experimental and numerical study of maximum ceiling temperature in a tunnel

Experimental and numerical study of maximum ceiling temperature in a tunnel

A numerical study on the effects of naturally ventilated shaft and fire locations in urban tunnels

Effects of fire location on the capacity of smoke exhaust from natural ventilation shafts in urban tunnels

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