Effects of passenger blockage on smoke flow properties in longitudinally ventilated tunnel fires

Wang, Yan; Wu, Fan; Wu, Peihong

doi:10.1002/fam.2801

Cited by 3 publications

(2 citation statements)

References 30 publications

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“…Additionally, many scholars [22][23][24][25][26][27][28] have studied the influence of blockage on the smoke back-layering length. Haddad et al [29] reviews recent research advances relating to critical velocity and the back-layering length of tunnel fires, mainly analyzing the experimental and theoretical studies on the effects of blockage, inclination, and fire source location.…”

Section: Hmentioning

confidence: 99%

Effect of the Metro Train on the Smoke Back-Layering Length under Different Tunnel Cross-Sections

et al. 2022

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Smoke back-layering length is an important aspect of tunnel fire research, and the influence of metro train blockage cannot be ignored. In previous studies, less attention has been paid to the phenomenon of back-layering caused by the same train blocked in tunnels with different cross-sections. This paper investigates this point through dimensionless analysis and fire dynamic simulator (FDS) numerical simulation. Several full-scale model tunnels (300 m in length), with different tunnel cross-sections, were constructed in FDS. According to the FDS simulation result, the smoke back-layering length was compared and analyzed. To investigate the effect of the tunnel cross-sections on smoke back-layering length under metro train blocking, the headroom ratio ε was proposed. Then, the influence of the tunnel cross-section on the smoke back-layering length was discussed in detail. Based on the dimensional analysis and FDS simulation results, a new model for predicting the smoke back-layering length was proposed. The prediction model obtained in this paper was compared with the FDS simulation results and the prediction model proposed by our predecessors. It is proven that the proposed model can better predict the length of smoke back-layering when metro trains are blocked in tunnels with different cross-sections. The outcomes of this work are expected to provide theoretical guidance for fire smoke control in metro tunnels with different cross-sections.

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Section: Hmentioning

confidence: 99%

Effect of the Metro Train on the Smoke Back-Layering Length under Different Tunnel Cross-Sections

et al. 2022

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“…Blockage ratio is another important factor affecting critical velocity. 24,25 Kang et al 26 conducted numerical simulation to investigate the effect of blockage ratio on critical velocity by using the hydraulic diameter as the characterized length. Their results indicated that the critical velocity decreased when the blockage ratio was increased.…”

Section: Introductionmentioning

confidence: 99%

Effect of metro train on the critical driving force for preventing smoke back‐layering in tunnel fires

et al. 2021

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Summary Preventing smoke back‐layering in longitudinal‐ventilated tunnels is an important topic in handling with fires safety issues. Previous studies focused on the critical velocity, while only very few of them paid attention to how to realize this parameter, that is, in a critical state, to overcome the resistance of the tunnel and the fire source to the airflow, the required driving force provided by the ventilation equipment installed in the tunnel. This study addressed this problem in the situation where the coupling effect of blockage and throttling effect was highlighted by conducting theoretical analysis and numerical simulations. The results showed that the presence of metro train blockage reduces the effective cross‐sectional area of the tunnel near the fire source and decreases the critical velocity. On the other hand, the blockage of trains also increases the resistance to the ventilation airflow and exacerbates the throttling effect, leading to the increase of the critical driving force. In such conditions, a stronger driving force to approach the critical velocity was needed. Besides, the length of train blockage was verified to exert limited influence on the value of critical velocity while it significantly affected the critical driving force. Furthermore, the calculated formula for the critical driving force was proposed with the prevention of smoke back‐layering considering the blockage effect to be emphasized.

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Effects of passenger blockage on smoke flow properties in subway station fires

Wang

Zhou

et al. 2022

Environ Sci Pollut Res

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Effects of passenger blockage on smoke flow properties in longitudinally ventilated tunnel fires

Cited by 3 publications

References 30 publications

Effect of the Metro Train on the Smoke Back-Layering Length under Different Tunnel Cross-Sections

Effect of the Metro Train on the Smoke Back-Layering Length under Different Tunnel Cross-Sections

Effect of metro train on the critical driving force for preventing smoke back‐layering in tunnel fires

Effects of passenger blockage on smoke flow properties in subway station fires

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