Quenching of smoldering: Effect of wall cooling on extinction

Lin, Shaorun; Huang, Xinyan

doi:10.1016/j.proci.2020.05.017

Cited by 44 publications

(28 citation statements)

References 22 publications

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“…In limiting cases, high heat losses can lower smouldering temperatures to the point of extinction [1,4,23,28,49]. In line with the numerical observations from [28], it is postulated here that heat losses in the cooling zone (upstream of reactions, Fig.…”

Section: Resultssupporting

confidence: 71%

“…Smouldering combustion research has traditionally focused on hazards in combustible porous materials (e.g., polyurethane foam, biomass), including within home furniture, spacecrafts, coal mines, and peatland fires [1][2][3][4]. However, smouldering (sometimes called filtration combustion [5][6][7][8]) is also being used as an engineering tool across various disciplines to address a wide range of challenges.…”

Section: Introductionmentioning

confidence: 99%

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Heat losses in applied smouldering systems: Sensitivity analysis via analytical modelling

Rashwan

Torero

Gerhard

2021

International Journal of Heat and Mass Transfer

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Section: Resultssupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Heat losses in applied smouldering systems: Sensitivity analysis via analytical modelling

Rashwan

Torero

Gerhard

2021

International Journal of Heat and Mass Transfer

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“…It is noted that air flux ( Pironi et al, 2009 , 2011 ; Rashwan et al, 2016 ; Zanoni et al, 2019a , 2019b ), bed bulk density ( Hu et al, 2020 ; Huang and Rein, 2017 ; Krause et al, 2006 ; Prat-Guitart et al, 2016 ) and wall heat loss/insulation ( Lin and Huang, 2021 ; Rashwan et al, 2021c , 2021d ; Yermán, 2016 ) have all been considered with respect to their influence on the smouldering reaction. However, the new cooling optimisations reveal how key parameters quantitatively influence the overall efficiency and effectiveness of commercial smouldering systems beyond the smouldering phase.…”

Section: Resultsmentioning

confidence: 99%

Understanding, controlling and optimising the cooling of waste thermal treatment beds including STARx Hottpads

et al. 2022

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STARx (Self-sustaining Treatment for Active Remediation ex situ) is a thermal treatment strategy for contaminated soils and organic wastes. Key to this technology is that organics are embedded in porous matrix beds (e.g. sand). STARx induces a self-sustaining smouldering combustion front that traverses the bed, burning away the embedded contaminants/wastes. The time and cost effectiveness of this technology is largely dictated by the time required for cooling of the hot, clean, porous matrix bed that remains after treatment. This study is the first to explore the cooling of these beds. A suite of novel simulations investigated the influence of key parameters on bed-cooling time. The results reveal that cooling time decreased nearly linearly with decreases of volume-averaged bed temperature and bed bulk density. Increased injection air fluxes led to the non-linear decrease of cooling time. Also, cooling time was negatively impacted by bed temperature inhomogeneity, which influenced preferential air flow through cooler regions of the bed, bypassing hotter regions. From these results, using lower bulk density bed materials, increased air fluxes and enhancing wall insulation to improve bed temperature homogeneity were identified as system optimisations to reduce cooling times. While the aim of this research is to improve the STARx cooling process, the results are also highly applicable to many similar engineering systems that involve hot porous bed cooling.

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“…Two layers of aluminium foil were attached to the outer surface of the insulation board to seal the reactor and reduce the radiative heat loss due to its lower emissivity (Incropera 2007). The test setup had a large internal cross-section of 24 cm × 24 cm to avoid quenching by the cold wall (Lin and Huang 2021;Lin et al 2021aLin et al , 2022. Together with the ceramic insulation and aluminium foil, the wall cooling was minimised and similar to the field condition.…”

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

Deep peat fire persistently smouldering for weeks: a laboratory demonstration

Qin

Musa

Lin

et al. 2022

Int. J. Wildland Fire

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Background. Peatlands are becoming more vulnerable to smouldering fires, driven by climate change and human activities. Aims. This work explores the persistent burning, propagation, and emission of the deep peat fire. Methods. Laboratory experiments are conducted with a 1-m deep peat column, and smouldering fires are initiated at different depths. Key results. We found localised burning and multi-directional smouldering fire spread in deep peat layers. The smouldering temperature first decreases with depths up to −40 cm (from around 550 to 350°C) and then remains at about 300°C in the deeper layers. High moisture content can slow down in-depth fire propagation and reduce the burning duration. Conclusions. Peat fire can burn in deep layers for weeks, and its combustion is incomplete with small mass loss, because of a limited oxygen supply and low smouldering temperature. Measuring the carbon monoxide concentration near the surface can detect underground fire and monitor its intensity. Implications. This work helps reveal the underlying mechanism of the in-depth smouldering wildfires in peatland and supports future larger-scale peat fire experiments in the field.

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Quenching of smoldering: Effect of wall cooling on extinction

Cited by 44 publications

References 22 publications

Heat losses in applied smouldering systems: Sensitivity analysis via analytical modelling

Heat losses in applied smouldering systems: Sensitivity analysis via analytical modelling

Understanding, controlling and optimising the cooling of waste thermal treatment beds including STARx Hottpads

Deep peat fire persistently smouldering for weeks: a laboratory demonstration

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