Transport phenomena of fire-induced smoke flow in a semi-open vertical shaft

De-Cheng, LI; Zhou, Ting; Liu, Zegong; Wang, Jian

doi:10.1108/hff-12-2017-0514

Cited by 8 publications

(7 citation statements)

References 18 publications

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“…A two-dimensional (2-D) conical radiant heater apparatus (168 mm wide, 65 mm high and 50°) was used as the computational domain to simulate the piloted ignition process of a solid combustible. The direct numerical simulation (DNS) mode in FDS was performed instead of the default large eddy simulation mode, which is normally used to simulate large-scale fire scenarios such as high-rise building fires and tunnel fires (Chen et al, 2015b;Chen et al, 2016;Li et al, 2018). For the ith component of velocity, the DNS momentum equation can be expressed by the following conservative form:…”

Section: Model Descriptionmentioning

confidence: 99%

Numerical study on the effect of oxygen concentration on the piloted ignition of PMMA in reduced pressure atmospheres

Wang

Zhou

Chen

et al. 2020

HFF

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Purpose This study aims to investigate the controlling mechanisms of ambient oxygen and pressure on piloted ignition of solid combustibles under external radiant heating. Design/methodology/approach The numerical simulation method was used to model the influence of ambient oxygen concentration on the piloted ignition of a thermally irradiated solid sample in reduced pressure atmospheres. The solid phase decomposition and gas phase kinetics were solved simultaneously. Findings It was determined that the elevated oxygen atmospheres resulted in a higher flame temperature and a thicker temperature profile over the solid surface. Also, increasing oxygen and reducing pressure had a similar effect in the decrease of the ignition delay time. The shorter ignition time in reduced pressure was mainly because of the decreasing of convective heat losses from the heated solid. As oxygen was reduced, however, ignition occurred later and with a greater mass loss rate because more volatiles of solid fuel at transient ignition were required to sustain a complete reaction under an oxygen-poor condition. Research limitations/implications The results need to be verified with experiments. Practical implications The results could be applied for design and assessment of fire-fighting and fire prevention strategies in reduced pressure atmosphere. Originality/value This paper shows the effect mechanism of ambient oxygen and pressure on piloted ignition of solid combustibles.

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Section: Model Descriptionmentioning

confidence: 99%

Numerical study on the effect of oxygen concentration on the piloted ignition of PMMA in reduced pressure atmospheres

Wang

Zhou

Chen

et al. 2020

HFF

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“…In this study, fire dynamics simulator (FDS) 2018 was used to simulate fire-induced environments, and it includes two models, namely, the direct numerical simulation (DNS) and large eddy simulation (LES) [15,24]. Given that the focus of this work is on buoyancy-driven thermal smoke flow, LES was employed for the simulation.…”

Section: Simulation Setupmentioning

confidence: 99%

“…Then, a train of grids should be set and divided into basic units according to the grid independence; thus, a reliable grid-set can be obtained. Thereafter, general fire parameters, such as the temperature, velocity, visibility, and gas concentration can be monitored and outputted after the computation, which is mainly based on viscous fluid equations, i.e., the Navier-Stokes equations [24].…”

Section: Simulation Setupmentioning

confidence: 99%

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Investigation on Smoke Flow in Stairwells induced by an Adjacent Compartment Fire in High Rise Buildings

et al. 2019

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The aim of this study was to evaluate the transport phenomena of smoke flow and vertical temperature distribution in a 21-story stairwell with multiple fire locations and openings. A large eddy simulation (LES) method was used to model the smoke flow in a stairwell model with a set of simulation parameters, wherein the fire heat release rate (HRR) and fire location were varied. Based on the results, a wall attachment effect was found in three-dimensional figures. Moreover, with an increase in the fire HRR, the effects were more pronounced. The simulation results verified that the vertical temperature distribution is an index model with a natural logarithm, where the pre-finger factor and attenuation coefficient increase considerably in accordance with an increase in the fire HRR. Moreover, there was a decrease in the maximum temperature (Tm) with an increase in the fire location factor (h*) due to the upward thermal smoke. Moreover, heat mainly accumulates in the area above a fire source. However, h* has a slight influence on the time required to reach Tm within the range of 53–64 s. Furthermore, the direction of the airflow at each side opening in the stairwell varied in accordance with the variation in the fire location changes, and a regular calculation was carried out.

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“…The study of natural convection in enclosures with at least one opening can generate the movements of fluid at the level of the opening (s) [1][2][3][4][5]. In this situation we can speak of natural ventilation [6][7][8][9][10][11][12][13][14]. José Luis Fernàndez-Zayas et al [15] have performed an experimental analysis of natural ventilation of an office building in Mexico city.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Pressure Generated by a Linear Heat Source in a Semi–ventilated Enclosure

Anicet¹,

Béatrice²,

Pierre³

2022

EAS

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The objective of this work is to understand and successfully control the phenomena found at the openings when the enclosure is subjected to a linear heat source. The enclosure is not adiabatic. The control and understanding of its phenomena will be carried out by differential static pressure measurements. These measurements were carried out in calm weather using a Furness control micro-manometer in 20 points at positions x+ = 0, y+ = -0.5 and along the vertical z+. We have studied four enclosure configurations. Each configuration has two or four or six openings. The openings have identical characteristics, height h = 34 mm and width l = 210 mm. The height of the enclosure is H = 520 mm and the length is equal to the width L = l = 210 mm. We have shown the influences of the reduced Grashof number (Gr*), the number and the position of the openings on the differential static pressure with and without dimension and compared the experimental results obtained with those of cases 11 and 12 of Koueni Toko (2019). It appears that the values and forms of the static pressure and the values of the neutral height can vary according to Gr* and number and the position of the openings.

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Transport phenomena of fire-induced smoke flow in a semi-open vertical shaft

Cited by 8 publications

References 18 publications

Numerical study on the effect of oxygen concentration on the piloted ignition of PMMA in reduced pressure atmospheres

Numerical study on the effect of oxygen concentration on the piloted ignition of PMMA in reduced pressure atmospheres

Investigation on Smoke Flow in Stairwells induced by an Adjacent Compartment Fire in High Rise Buildings

Experimental Study of the Pressure Generated by a Linear Heat Source in a Semi–ventilated Enclosure

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