Effect of the blockage ratio on the smoke extraction efficiency in tunnel fires with natural ventilation

Wang, Jie; Fan, Yongjie; Wei, Yinqiu; Jiang, Xuepeng; Lu, Kaihua

doi:10.1016/j.tust.2021.104165

Cited by 16 publications

(4 citation statements)

References 29 publications

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“…The smoke extraction efficiency can be expressed as the ratio of the amount of smoke discharged from the inclined shaft to the amount of smoke generated by the fire source per unit time [23]. In this paper, the smoke exhaust efficiency is expressed as the ratio of the total amount of CO discharged from the inclined shaft to the total amount of CO generated by the fire source per unit time.…”

Section: Smoke Exhaust Efficiency Of the Inclined Shaftmentioning

confidence: 99%

“…Due to the existence of natural wind in the tunnel, some tunnels with small lengths can meet the ventilation demand only through natural ventilation, and natural ventilation tunnel fire has attracted the attention of scholars. Wang et al [23] studied the influence of vehicle blockage ratio on the smoke exhaust efficiency of natural ventilation tunnels with shafts through model tests and found that the smoke extraction efficiency decreased first, then increased and finally dropped with increasing blockage ratio. Kashef et al [24] studied the vault temperature distribution and smoke diffusion of natural ventilation tunnel fire through a model test and derived formulas for predicting the temperature distribution and smoke diffusion degree.…”

Section: Introductionmentioning

confidence: 99%

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Study on the Effect of Natural Wind on the Smoke Spread Law of Extra-Long Tunnel Fires with Inclined Shafts for Air Supply and Exhaust

Tan,

Wang,

Zhang

et al. 2024

Buildings

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High-temperature smoke generated by tunnel fires is the most important factor causing casualties. To explore the influence of natural wind on fire smoke movement in an extra-long highway tunnel based on the Taihang Mountain Tunnel, the distribution law of natural wind in the tunnel was obtained by on-site monitoring of the meteorological conditions at the tunnel site. A three-dimensional fire dynamics tunnel model considering an inclined shaft smoke exhaust was established, and the influence of natural wind on tunnel temperature distribution, smoke spread and smoke exhaust efficiency was studied. The results show that the natural wind speed of the Taihang Mountain Tunnel is mainly concentrated at 0~3 m/s. The main wind direction of the natural wind on the left tunnel is opposite to the driving direction, and the distribution probability of the main wind direction in each section is 81.27% and 72.15%, respectively. The main wind direction of the right tunnel is the same as the driving direction, and the distribution probability of the main wind direction in each section is 56.78%, 69.73%, 67.32% and 64.65%, respectively. The negative natural wind can inhibit the smoke spread downstream of the smoke exhaust port, but it is not conducive to the smoke exhaust. The positive natural wind promotes the smoke spread to the downstream of the smoke exhaust port, and the larger the natural wind speed, the longer the spread length. Natural wind reduces the smoke exhaust efficiency. For positive or negative natural wind with a guaranteed rate of 70%, the smoke exhaust efficiency is reduced by 27.76% and 15.59%, respectively, compared with the condition without natural wind. The research results can provide a useful reference for the design of fire smoke exhausts and smoke control schemes in extra-long highway tunnels.

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Section: Smoke Exhaust Efficiency Of the Inclined Shaftmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on the Effect of Natural Wind on the Smoke Spread Law of Extra-Long Tunnel Fires with Inclined Shafts for Air Supply and Exhaust

Tan,

Wang,

Zhang

et al. 2024

Buildings

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“…The three main reasons that the vehicle self-ignition, vehicle collision, and over-turning bring about the tunnel fire lead the fire location of a tunnel fire accident to be random (Wang et al, 2016). The effects of the blockage ratio (Wang et al, 2021;Zhang et al, 2021aZhang et al, , 2021bZhang et al, , 2021c, the transverse fire location (Ji et al, 2012) and the longitudinal fire location (Kong et al, 2021) on the tunnel fire characteristics had been analyzed. Natural ventilation systems and longitudinal ventilation systems are two effective methods of smoke control in tunnels for reducing casualties and economic losses.…”

Section: Introductionmentioning

confidence: 99%

Experimental analysis of the effect of the ramp slopes on the maximum exceedance temperature in a branched tunnel fire

Li²,

Li³

et al. 2023

Tunnelling and Underground Space Technology

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“…1,2 According to statistics, more than 85% of the casualties in tunnel fires are caused by inhalation of toxic smoke caused by suffocation or poisoning. 3 At present, scholars have done a lot of research on tunnel fires, such as the variation of the rule of smoke back-layering length, [4][5][6][7][8][9][10] smoke temperature, [11][12][13][14][15][16] the distribution characteristics of smoke, the critical ventilation velocity in the tunnel, [17][18][19] etc.…”

Section: Introductionmentioning

confidence: 99%

Study on the variation rule of smoke back‐layering length of tunnel ceiling jet induced by strong fire plume

Chen

Zhou

et al. 2022

Fire and Materials

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Tunnel fire is a major research topic in tunnel safety. Because of the tunnel's narrow and enclosed structure, smoke movement plays an important role in the investigation of the tunnel fire. In this paper, the Froude similarity principle is used to study the variation rule of the smoke back-layering length of tunnel ceiling jet induced by strong fire plume with different heat release rates, longitudinal ventilation velocities, and effective heights of fire source analyzed. It is found that the smoke back-layering length of tunnel ceiling jet induced by strong fire plume increases with the increase of effective height of fire source and decreases with the increase of longitudinal ventilation velocity. When the heat release rate is relatively small (Q < 60kW), the smoke back-layering length of the tunnel ceiling jet induced by strong fire plume increases as the heat release rate increases. However, for the larger heat release rate (Q ≥ 60kW), the smoke back-layering length of the tunnel ceiling jet induced by strong fire plume is mainly related to the longitudinal ventilation velocity. Based on Thomas's model and Li's model, by introducing the correction coefficient, correction formulas of the smoke back-layering length of tunnel ceiling jet induced by strong fire plume changing with the effective height of fire source are proposed.

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Effect of the blockage ratio on the smoke extraction efficiency in tunnel fires with natural ventilation

Cited by 16 publications

References 29 publications

Study on the Effect of Natural Wind on the Smoke Spread Law of Extra-Long Tunnel Fires with Inclined Shafts for Air Supply and Exhaust

Study on the Effect of Natural Wind on the Smoke Spread Law of Extra-Long Tunnel Fires with Inclined Shafts for Air Supply and Exhaust

Experimental analysis of the effect of the ramp slopes on the maximum exceedance temperature in a branched tunnel fire

Study on the variation rule of smoke back‐layering length of tunnel ceiling jet induced by strong fire plume

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