Maximum Smoke Temperature in Non-Smoke Model Evacuation Region for Semi-Transverse Tunnel Fire

Lou, Bo; Qiu, Yonghai; Long, Xinping

doi:10.18869/acadpub.jafm.73.241.26529

Cited by 13 publications

(12 citation statements)

References 33 publications

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“…Once the tunnel catches fire, the high-temperature smoke generated by the fire will reduce the visibility of the tunnel and increase the difficulty of evacuation. Therefore, a well-designed ventilation system mainly includes mechanical ventilation (longitudinal ventilation [1] , transverse ventilation [2] , semi-transverse ventilation [3] ) system and natural ventilation system, which can ensure the safety of trapped persons. The mechanical ventilation system is less affected by the external environment and has high stability.…”

Section: Intruductionmentioning

confidence: 99%

Numerical study on the effect of shaft position on natural smoke exhaust in tunnels with one closed portal

et al. 2020

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.This paper uses Fire Dynamics Simulator (FDS) to study the effect of the longitudinal distance from the shaft to the fire source on the natural smoke exhaust of the tunnel fire with one closed portal, and analyzes the temperature distribution of the smoke and the shaft’s smoke exhaust efficiency. The results show that when the shaft is located downstream of the fire source (Ds<0), with the increase of the distance from the shaft to the fire source, the smoke exhaust efficiency decreases first and then stabilizes at a fixed value. At this time, the ceiling temperature attenuation’s coefficient at upstream of the fire source is only related to the heat release rate of the fire source (HRR). When the shaft is located upstream of the fire source (Ds>0), the smoke exhaust efficiency increases slightly with the increase of the distance from the shaft to the fire source, but the overall value is relatively small. When HRR is fixed, the shaft located downstream of the fire source has a higher smoke exhaust efficiency. As the distance between the shaft and the fire source increases, the plug phenomenon decreases.

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Section: Intruductionmentioning

confidence: 99%

Numerical study on the effect of shaft position on natural smoke exhaust in tunnels with one closed portal

et al. 2020

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“…Evacuation efforts are impeded, and survival chances are reduced by high temperature and smoke, exacerbating the danger of tunnel fire. 3 To inhibit the burning of asphalt during a tunnel fire, effective flame-retarding measures are taken on asphalt materials. Usually, a flame retardant is incorporated into asphalt pavements to delay asphalt burning.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Formaldehyde solution (37 wt % in H 2 O) is a colorless and pungent liquid. Its density at 25 °C is 1.09 g/cm 3 , melting point −15 °C, and boiling point 95 °C. Anhydrous sodium carbonate is a white powder with a purity superior to 99.5%.…”

Section: ■ Introductionmentioning

confidence: 99%

Development of a Sustainable Biobased Flame-Retardant Microcapsule and Its Flame-Retarding Mechanism on Asphalt Combustion

Dong,

Xia,

2024

Langmuir

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To develop an efficient, sustainable, and eco-friendly biobased flame-retardant microcapsule suitable for the working environments of tunnel asphalt pavement and reveal its flame-retarding mechanism on asphalt combustion, microencapsulated amylopectin (MAMP) was first prepared using an in situ polymerization method. Changes in the basic properties of amylopectin (AMP) and its compatibility with asphalt after microencapsulation were studied. Then, the flame retarding efficiency and improvement effects of MAMP on the flame retardancy of asphalt were investigated. Results show that melamine formaldehyde (MF) resin is evenly coated on the AMP surface without changing the chemical composition of AMP, increasing the thermal stability of AMP and the compatibility between AMP and asphalt. MAMP reacts with ammonium polyphosphate (APP) to release a number of incombustible gases to delay asphalt combustion at early stages and subsequently dehydrates to form a stable starch-based charring layer to suppress heat and mass transfer during asphalt combustion, improving the fire safety of asphalt materials. The added 3% MAMP can reduce the total enthalpy value of all exothermic peaks of the 10% APP-modified asphalt by 43.6%. As a carbonization agent, MAMP produces a charring layer with higher heat capacity during asphalt combustion, exerting an excellent inhibition effect on heat release. This study provides a reference for the application of biobased materials in flame-retarded asphalt pavements.

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“…For example, Lou et al investigated the effects of the heat release rates of fire (10,20,and 30 MW) and exhaust rate (from 0 to 160 m3/h) on the maximum gas temperature in tunnels. They found that the maximum gas temperature rise at tunnel vault is proportional to ¾ power of non-dimensional heat release rate of fire (Lou et al 2017). Li et al analytically and experimentally investigated the maximum temperature of buoyant gases beneath the tunnel ceiling in presence of fire and found that the heat release rate and the tunnel inlet velocity play important rules in the maximum ceiling gas temperature (Li and Ingason 2012;Li et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Effects of False-Ceiling on Critical Ventilation Velocity and Maximum Gas Temperature in Tunnel Fires

2021

JAFM

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In the present study, the effect of the use of false-ceiling on fire-induced smoke flow characteristics in tunnels is investigated using a 3D developed computational fluid dynamics tool. The critical velocity, the minimum required tunnel ventilation velocity to stop the smoke flow from moving toward the tunnel inlet (toward the upstream of the fire source), and the maximum gas temperature beneath the ceiling are selected to evaluate the smoke flow control in presence of the false-ceiling. The hydraulic height of the cross-sectional geometry of the tunnel is used as the characteristic length in order to dimensional analyze and compare the nondimensional results. The results indicate that the use of the false-ceiling reduces the critical velocity and the smoke backlayering, while increases the maximum ceiling gas temperature. Reducing the critical velocity results in ventilation cost reduction (positive impact), while increasing the maximum gas temperature beneath the ceiling increases the risk of instrumental and life damages (negative impact). The detailed results and corresponding physical discussions are presented to clarify the reason for the significant differences between the results of the tunnels with and without false-ceiling.

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Maximum Smoke Temperature in Non-Smoke Model Evacuation Region for Semi-Transverse Tunnel Fire

Cited by 13 publications

References 33 publications

Numerical study on the effect of shaft position on natural smoke exhaust in tunnels with one closed portal

Numerical study on the effect of shaft position on natural smoke exhaust in tunnels with one closed portal

Development of a Sustainable Biobased Flame-Retardant Microcapsule and Its Flame-Retarding Mechanism on Asphalt Combustion

Effects of False-Ceiling on Critical Ventilation Velocity and Maximum Gas Temperature in Tunnel Fires

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