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  • Journal article
    Wang S, Huang X, Chen H, Liu N, Rein Get al., 2015,

    Ignition of low-density expandable polystyrene foam by a hot particle

    , Combustion and Flame, Vol: 162, Pages: 4112-4118, ISSN: 0010-2180

    Insulating materials are ubiquitous in modern buildings for improving energy efficiency, but their high flammability becomes a significant fire safety issue. Many large fires in high-rise buildings were caused by the ignition of insulating materials by hot particles from fireworks and welding processes. Such ignition event is fundamentally different from the traditional flame or radiation driven ignition assumed in the literature, and still presents significant knowledge gaps. In this work, we study experimentally the ignition of a widely used insulation materials, expandable polystyrene (EPS) foam, by a hot steel particle under different conditions. In the experiments, a small spherical particle (6∼14 mm in diameter) was heated to a high temperature (>900 °C), and then placed on a bench-scale low-density (18 or 27 kg/m3) foam sample. It was observed that flaming ignition could only occur on the foam surface during its rolling process (rolling ignition) or before it was fully embedded (embedding ignition). The measurements suggested that larger particles held lower critical temperatures for ignition, which decreased from 1030 to 935 °C for diameters increasing from 6 to 14 mm. Compared to higher-density forest fuels in the literature, the critical particle temperature of EPS foam is much higher, with a narrower transition region for ignition probability of 5–95% and has a weaker dependence on the particle size. Results also show that both the sample density and thickness have a negligible influence on the ignition probability and mass-loss ratio. Theoretical analysis suggested that the hot particle acts as both heating and pilot sources, and the ignition of EPS foam is controlled by the competition between the gas mixing time and the particle residence time.
  • Book chapter
    Prat-Guitart N, Hadden RM, Belcher CM, Rein G, Yearsley JMet al., 2015,

    Infrared Image Analysis as a Tool for Studying the Horizontal Smoldering Propagation of Laboratory Peat Fires

    , Coal and Peat Fires: A Global Perspective, Pages: 121-139

    Smoldering fires in peatlands can consume large areas of peat and release important amounts of carbon to the atmosphere as they self-propagate. This chapter focuses on the use of infrared images to characterize the horizontal propagation of smoldering fires in laboratory experiments. In these laboratory experiments an infrared camera takes images of the peat surface at regular intervals during the experiment. We present methods to process and analyze these infrared images that identify the shape and position of the smoldering front, quantify the maximum energy flux, the spread rate and direction of the front and its variability to time. To demonstrate our methods we analyze images from experiments that record the smoldering of dry peats (25% moisture content, mass of water per mass of dry peat) and wet peats (100% moisture content). Infrared images are used to quantify the effect of moisture content upon the smoldering fronts. Our methods demonstrate that smoldering combustion in dry peats has a wider front (6.8 ± 1 cm for the dry peat, 2.4 ± 0.7 cm for the wet peat), a faster spread rate (4.3 ± 1 cm/h for dry peat, 2.6 ± 0.7 cm/h for wet peat), and a lower peak of radiative energy flux (7.1 ± 0.7 kW/m2 for dry peat, 10.51 ± 2.1 kW/m2 for wet peat). Our infrared image analysis is a useful tool to characterize peat fires at an experimental scale. These methods can be applied to peats with different characteristics to identify and compare smoldering propagation dynamics.
  • Book chapter
    Rein G, 2015,

    Smoldering-Peat Megafires: The Largest Fires on Earth

    , Coal and Peat Fires: A Global Perspective, Pages: 1-11

    Smoldering megafires are the largest and longest burning fires on Earth. They destroy essential peat land ecosystems and are responsible for 15% of annual global greenhouse gas emissions. This is the same amount attributed to all the combustion engine vehicles in the world, yet it is not accounted for in global carbon budgets. Peat fires also induce surges of respiratory emergencies in the population and disrupt shipping and aviation routes for long periods, weeks, and even months. Despite their importance, we do not understand how smoldering fires ignite, spread, or extinguish, which impedes the development of any successful mitigation strategy. Megafires are routinely fought across the globe with techniques that were developed for flaming fires, and are thus ineffective for smoldering. Moreover, the burning of deep peat affects older soil carbon that has not been part of the active carbon cycle for centuries to millennia, and thus creates a positive feedback to the climate system.
  • Journal article
    Rein G, 2015,

    Breakthrough in the understanding of flaming wildfires

    , Proceedings of the National Academy of Sciences of the United States of America, Vol: 112, Pages: 9795-9796, ISSN: 1091-6490
  • Journal article
    Ayala P, Cantizano A, Rein G, Vigne G, Gutierrez-Montes Cet al., 2015,

    Fire Experiments and Simulations in a Full-scale Atrium Under Transient and Asymmetric Venting Conditions

    , Fire Technology, Vol: 52, Pages: 51-78, ISSN: 1572-8099
  • Journal article
    Rackauskaite E, Hamel C, Law A, Rein Get al., 2015,

    Improved formulation of travelling fires and application to concrete and steel structures

    , Structures, Vol: 3, Pages: 250-260, ISSN: 2352-0124
  • Journal article
    Chen H, Rein G, Liu N, 2015,

    Numerical investigation of downward smoldering combustion in an organic soil column

    , INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, Vol: 84, Pages: 253-261, ISSN: 0017-9310
  • Journal article
    Belcher CM, Hadden RM, Rein G, Morgan JV, Artemieva N, Goldin Tet al., 2015,

    An experimental assessment of the ignition of forest fuels by the thermal pulse generated by the Cretaceous-Palaeogene impact at Chicxulub

    , JOURNAL OF THE GEOLOGICAL SOCIETY, Vol: 172, Pages: 175-185, ISSN: 0016-7649
  • Journal article
    Hasan T, Gerhard JI, Hadden R, Rein Get al., 2015,

    Self-sustaining smouldering combustion of coal tar for the remediation of contaminated sand: Two-dimensional experiments and computational simulations

    , Fuel, Vol: 150, Pages: 288-297, ISSN: 0016-2361

    This study presents the development and validation of a computational model which simulates the propagation of a smouldering front through a porous medium against unique experiments in coal tar and sand. The model couples a multiphase flow solver in porous media with a perimeter expansion module based on Huygens principle to predict the spread. A suite of two-dimensional experiments using coal tar-contaminated sand were conducted to explore the time-dependent vertical and lateral smouldering front propagation rates and final extent of remediation as a function of air injection rate. A thermal severity analysis revealed, for the first time, the temperature–time relationship indicative of coal tar combustion. The model, calibrated to the base case experiment, then correctly predicts the remaining experiments. This work provides further confidence in a model for predicting smouldering, which eventually is expected to be useful for designing soil remediation schemes for a novel technology based upon smouldering destruction of organic contaminants in soil.
  • Journal article
    Rein G, Jervis FX, 2015,

    Experimental study on the burning behaviour of Pinus halepensis needles using small-scale fire calorimetry of live, aged and dead samples

    , Fire and Materials, Vol: 40, Pages: 385-395, ISSN: 1099-1018

    Limited research has been conducted on the burning characteristics of live fuels, which are commonly assumed to behave like moist dead fuels. We use small-scale laboratory calorimetric experiments to investigate the differences in fire dynamics between live and dead Pinus halepensis needles. The study includes laboratory-aged samples and different moisture conditions (fresh or oven dry). A series of ten fire behaviour parameters are extracted from the measurements to identify and quantify differences. The main parameters are the following: time to ignition; flaming time; mass loss pre-ignition, during flaming, and during smouldering; peak power; effective heat of combustion; mean and peak CO/CO2; and radiative fraction. Using these parameters, we show that the most flammable samples are fresh dead and aged needles, followed by dry dead and dry live needles. The least flammable is fresh live needles. Live needles ignite about four times slower, and burn with ~60% lower power and ~50% lower heat of combustion than dead needles. Aged needles resemble most closely the behaviour of dead needles, but many fire behaviour parameters were significantly different. The results confirm the importance of moisture content in the burning behaviour of pine needles, but the differences between live and dead samples cannot be explained solely in terms of moisture but require consideration of plant chemistry and sample drying.
  • Journal article
    Bal N, Rein G, 2015,

    On the effect of inverse modelling and compensation effects in computational pyrolysis for fire scenarios

    , FIRE SAFETY JOURNAL, Vol: 72, Pages: 68-76, ISSN: 0379-7112
  • Journal article
    Huang X, Rein G, Chen H, 2015,

    Computational smoldering combustion: Predicting the roles of moisture and inert contents in peat wildfires

    , Proceedings of the Combustion Institute, Vol: 35, Pages: 2673-2681, ISSN: 0082-0784

    Abstract Smoldering combustion is the slow, low-temperature, flameless burning of porous fuels and the most persistent type of combustion. It is the driving phenomenon of wildfires in peatlands, like those causing haze episodes in Southeast Asia and Northeast Europe, but is poorly understood. In this work, we develop a comprehensive 1-D model of a reactive porous media, using the open-source code Gpyro, to investigate smoldering combustion of natural fuels with an emphasis on the roles of the moisture and inert contents. The model solves the species, momentum, and energy conservation equations and includes heterogeneous chemical reactions. A previously developed 5-step reaction scheme for peat, including evaporation of water, is adopted to describe the drying, thermal and oxidative degradation during the smoldering combustion. The model predicts the transient temperature, species, and reaction profiles during ignition, spread, and extinction. The predicted smoldering thresholds related to the critical moisture and inorganic contents for ignition show a good agreement with the experimental results in the literature for a wide range of peat types and organic soils. The influences of the kinetic parameters, physical properties, and ignition protocol are investigated. This is the first time that a physics-based model of smoldering peat fires is developed, thus helping to understand this important natural and widespread phenomenon.
  • Journal article
    Turetsky MR, Benscoter B, Page S, Rein G, van der Werf GR, Watts Aet al., 2015,

    Global vulnerability of peatlands to fire and carbon loss

    , NATURE GEOSCIENCE, Vol: 8, Pages: 11-14, ISSN: 1752-0894
  • Journal article
    Li K-Y, Huang X, Fleischmann C, Rein G, Ji Jet al., 2014,

    Pyrolysis of Medium-Density Fiberboard: Optimized Search for Kinetics Scheme and Parameters via a Genetic Algorithm Driven by Kissinger's Method

    , Energy & Fuels, Vol: 28, Pages: 6130-6139, ISSN: 1520-5029

    The pyrolysis kinetics of charring materials plays an important role in understanding material combustionsespecially for construction materials with complex degradation chemistry. Thermogravimetric analysis (TGA) is frequently usedto study the heterogeneous kinetics of solid fuels; however, there is no agreed method to determine the pyrolysis scheme andkinetic parameters for charring polymers with multiple components and competing reaction pathways. This study develops a newtechnique to estimate the possible numbers of species and sub-reactions in pyrolysis by analyzing the second derivatives ofthermogravimetry (DDTG) curves. The pyrolysis of a medium-density fiberboard (MDF) in nitrogen is studied in detail, and theDDTG curves are used to locate the temperature of the peak mass-loss rate for each sub-reaction. Then, on the basis of the TGdata under multiple heating rates, Kissinger’s method is used to quickly find the possible range of values of the kinetic parameters(A and E). These ranges are used to accelerate the optimization of the inverse problem using a genetic algorithm (GA) for thekinetic and stoichiometric parameters. The proposed method and kinetic scheme found are shown to match the experimentaldata and are able to predict accurately results at different heating rates better than Kissinger’s method. Moreover, the searchmethod (K−K method) is highly efficient, faster than the regular GA search alone. Modeling results show that, as the TG dataavailable increase, the interdependence among kinetic parameters becomes weak and the accuracy of the first-order modeldeclines. Furthermore, conducting TG experiment under multiple heating rates is found to be crucial in obtaining good kineticparameters.
  • Journal article
    Zaccone C, Rein G, D'Orazio V, Hadden RM, Belcher CM, Miano TMet al., 2014,

    Smouldering fire signatures in peat and their implications for palaeoenvironmental reconstructions

    , GEOCHIMICA ET COSMOCHIMICA ACTA, Vol: 137, Pages: 134-146, ISSN: 0016-7037
  • Journal article
    Huang X, Rein G, 2014,

    Smouldering combustion of peat in wildfires: Inverse modelling of the drying and the thermal and oxidative decomposition kinetics

    , Combustion and Flame, Vol: 161, Pages: 1633-1644, ISSN: 0010-2180

    Abstract Smouldering combustion is the driving phenomenon of wildfire in peatlands, like those causing haze episodes in Southeast Asia and Northeast Europe. These are the largest fires on Earth and an extensive source of greenhouse gases, but poorly understood, becoming an emerging research topic in climate-change mitigation. In this work, a series of multistep heterogeneous kinetics are investigated to describe the drying and decomposition in smouldering combustion of peat. The decomposition schemes cover a range of complexity, including 2, 3 or 4-step schemes, and up to 4 solid pseudo-species. The schemes aim to describe the simultaneous pyrolysis and oxidation reactions in smouldering fires. The reaction rates are expressed by Arrhenius law, and a lumped model of mass loss is used to simulate the degradation behaviour seen during thermogravimetric (TG) experiments in both nitrogen and air atmospheres. A genetic algorithm is applied to solve the corresponding inverse problem using TG data from the literature, and find the best kinetic and stoichiometric parameters for four types of boreal peat from different geographical locations (North China, Scotland and Siberia). The results show that at the TG level, all proposed schemes seem to perform well, with a high degree of agreement resulting from the forced optimization in the inverse problem approach. The chemical validity of the schemes is then investigated outside the TG realm and incorporated into a 1-D plug-flow model to study the reaction and the species distribution inside a peat smouldering front. Both lateral and in-depth spread modes are considered. The results show that the drying sub-front is essential, and that the best kinetics is the 4-step decomposition (one pyrolysis, and three oxidations) plus 1-step drying with 5 condensed species (water, peat, α -char, β -char, and ash). This is the first time that the smouldering kinetics and the reaction-zone structure of a peat fire are explained and
  • Journal article
    Switzer C, Pironi P, Gerhard JI, Rein G, Torero JLet al., 2014,

    Volumetric scale-up of smouldering remediation of contaminated materials

    , JOURNAL OF HAZARDOUS MATERIALS, Vol: 268, Pages: 51-60, ISSN: 0304-3894
  • Journal article
    Boulet P, Parent G, Acern Z, Collin A, Forsth M, Bal N, Rein G, Torero Jet al., 2014,

    Radiation emission from a heating coil or a halogen lamp on a semitransparent sample

    , INTERNATIONAL JOURNAL OF THERMAL SCIENCES, Vol: 77, Pages: 223-232, ISSN: 1290-0729
  • Conference paper
    Uadiale S, Urbán É, Carvel R, Lange D, Rein Get al., 2014,

    Overview of problems and solutions in fire protection engineering of wind turbines

    , Pages: 983-995, ISSN: 1817-4299

    The wind energy industry is one of today's leading industries in the renewable energy sector, providing an affordable and sustainable energy solution. However, the wind industry faces a number of challenges, one of which is fire and that can cast a shadow on its green credentials. The three elements of the fire triangle, fuel (oil and polymers), oxygen (wind) and ignition (electric, mechanical and lighting) are represent and confined to the small and closed compartment of the turbine nacelle. Moreover, once ignition occurs in a turbine, the chances of externally fighting the fire are very slim due to the height of the nacelle and the often remote location of the wind farm. Instances of reports about fires in wind farms are increasing, yet the true extent of the impact of fires on the energy industry on a global scale is impossible to assess. Sources of information are incomplete, biased, or contain non-publically available data. The poor statistical records of wind turbine fires are a main cause of concern and hinder any research effort in this field. This paper aims to summarise the current state of knowledge in this area by presenting a review of the few sources which are available, in order to quantify and understand the fire problem in wind energy. We have found that fire is the second leading cause of catastrophic accidents in wind turbines (after blade failure) and accounts for 10 to 30% of the reported turbine accidents of any year since 1980's. In 90% of the cases, the fire leads to a total loss of the wind turbine, or at least a downtime that results in the accumulation of economic losses. The main causes of fire ignition in wind turbines are (in decreasing order of importance): lighting strike, electrical malfunction, mechanical malfunction, and maintenance. Due to the many flammable materials used in a wind turbine (eg. fiberglass reinforced polymers, foam insulation, cables) and the large oil storage used for lubrication of mechanical components, the fue
  • Journal article
    Rein G, 2014,

    Even Greater than the Sum of Its Parts

    , FIRE TECHNOLOGY, Vol: 50, Pages: 1-1, ISSN: 0015-2684

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