Effect of bifurcation angle and fire location on smoke temperature profile in longitudinal ventilated bifurcated tunnel fires

Lu, Xin-Ling; Weng, Miaocheng; Liu, Fang; Wang, Fei; Han, Jiaqiang; Cheung, Sherman Chipok

doi:10.1016/j.tust.2022.104610

Cited by 13 publications

(4 citation statements)

References 43 publications

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“…The arithmetic mean value of nine measuring points is taken as the average velocity of the measuring plane. The uncertainty of _u_u 0 can be calculated as (Lu et al, 2022):…”

Section: Credit Authorship Contribution Statementmentioning

confidence: 99%

A study of the critical velocity and the confinement velocity of fire accident in a longitudinally ventilated underground train with different door opening scenarios

Li²,

Feng³

et al. 2023

Tunnelling and Underground Space Technology

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“…The arithmetic mean value of nine measuring points is taken as the average velocity of the measuring plane. The uncertainty of _u_u 0 can be calculated as (Lu et al, 2022):…”

Section: Credit Authorship Contribution Statementmentioning

confidence: 99%

A study of the critical velocity and the confinement velocity of fire accident in a longitudinally ventilated underground train with different door opening scenarios

Li²,

Feng³

et al. 2023

Tunnelling and Underground Space Technology

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“…The average velocity of the measuring plane is determined by taking the arithmetic mean value of nine measuring points. The uncertainty of u0¯ can be calculated as follows: 43 where u i,j means the j th measured value of u i , and n is the number of measurements of the i th measuring point. The maximum uncertainty of the velocity in this study is 1.8 × 10 −2 , and the maximum uncertainty in Test 17 is ± 4.7%.…”

Section: Error and Uncertainty Analysismentioning

confidence: 99%

Investigation of the fire hazard of underground space fire scenarios in urban metro tunnels under natural ventilation: Analysis of the impact of tunnel slope on smoke back-layering length

Su,

Li,

Zhong

et al. 2023

Building Services Engineering Research and Technology

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The smoke back-layering length is a crucial parameter for evacuating people in both road and subway tunnel fires. This study investigates the fire hazard induced by carriage fire in inclined metro tunnels under natural ventilation. The parameter ‘transition slope’ is defined to measure the smoke flow from the carriage head in the upstream direction to the tunnel or not due to the stack effect of the tunnel slope. The aim of this paper is to analyse the effects of changes in cross-section, downstream length, tunnel slope, and carriage side-door coupling on smoke behaviour characteristics by experiment and simulation methods. A piecewise function expression between dimensionless smoke back-layering length, downstream length, and tunnel slope for carriage fires in an inclined tunnel under natural ventilation is proposed by theoretical analysis. At the same time, a 1:15 scale model experiment was conducted to initially analyse the characteristics of smoke movement. Following this, full-scale numerical simulations were employed to complement the model experiment and quantify the principles governing smoke movement. The experimental results show that the tunnel slope has a significant effect on the smoke back-layering length. In contrast, the influence of the heat release rate was found to be relatively minor. In addition, simulation results show that the tunnel slope has no significant effect on the smoke back-layering length when the fire location is approximately 20 m from the train head, and the tunnel slope is in the range of 2.29° ∼ 3.43° (4% ∼ 6%). For small tunnel slopes, smoke spreads in the tunnel, and the smoke back-layering length produced by the virtual fire source shows a different law from the previous study model. Finally, the correlation coefficient of the piecewise function in theoretical analysis is fitted by combining the experimental and numerical simulation results. Practical application This study provides valuable insights into the practical implications of controlling and mitigating the impact of fires in inclined metro tunnels. By understanding the critical role of tunnel slope and providing a quantitative tool for smoke spread law assessment, this study contributes to the enhancement of safety measures and the protection of lives in tunnel environments during fire incidents.

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“…Gannouni et al [20,21] investigated the effect of obstacles on the back-layering length and the critical velocity in single-line tunnel fires by using Fire Dynamic Simulator (FDS) and developed the model to calculate the back-layering arrival time. Lu et al [22] researched the longitudinal temperature distribution and maximum ceiling temperature by experimentation and the simulation method and proposed a mathematical model to predict the maximum rise in ceiling temperature and the longitudinal temperature distribution in the bifurcated tunnel. Liu et al [23] studied the effect of longitudinal fire location on temperature distribution in bifurcated roadways and developed empirical models of the maximum temperature in the main tunnel and temperature decay in the branched tunnel.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Smoke Distribution Characteristics in a T-Shaped Roadway

Ding,

Chang,

Sun

et al. 2024

Fire

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This paper numerically analyzes the influence of heat release rate (HRR) and longitudinal ventilation velocity on smoke distribution characteristics in a T-shaped roadway when the fire source was located upstream of the T-junction. The back-layering length, critical ventilation velocity, smoke temperature, and CO concentration in the main and branched roadway were investigated and analyzed. The results showed that the ventilation velocity is the key factor influencing back-layering length, while the effect of HRR on back-layering length is gradually weakened as HRR increases. The critical ventilation velocity in the T-shaped roadway is higher than in a single-tube roadway, and the predicted model of dimensional critical ventilation velocity in a T-shaped bifurcated roadway is proposed. The correlation between average temperature (Z = 1.6 m) (both in the main roadway I and the branched roadway) and ventilation velocity fits the power function, and the variation in average temperature (Z = 1.6 m) according to HRR fits the linear formula. The relation between average concentration of CO (Z = 1.6 m) (both inside the main roadway I and the branched roadway) and longitudinal ventilation velocity follows the power relation, and the variation in average concentration of CO (Z = 1.6 m) according to HRR follows the linear function.

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Effect of bifurcation angle and fire location on smoke temperature profile in longitudinal ventilated bifurcated tunnel fires

Cited by 13 publications

References 43 publications

A study of the critical velocity and the confinement velocity of fire accident in a longitudinally ventilated underground train with different door opening scenarios

A study of the critical velocity and the confinement velocity of fire accident in a longitudinally ventilated underground train with different door opening scenarios

Investigation of the fire hazard of underground space fire scenarios in urban metro tunnels under natural ventilation: Analysis of the impact of tunnel slope on smoke back-layering length

Numerical Simulation of the Smoke Distribution Characteristics in a T-Shaped Roadway

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