Experimental and numerical studies characterizing the burning dynamics of wildland fuels

Houssami, Mohamad El; Thomas, Jan C.; Lamorlette, Aymeric; Morvan, Dominique; Chaos, Marcos; Hadden, Rory M.; Simeoni, Albert

doi:10.1016/j.combustflame.2016.04.004

Cited by 46 publications

(45 citation statements)

References 64 publications

(114 reference statements)

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“…For example, in some cases, the solid behavior model needs to adapt to the changing thickness of the solid phase, charring process, internal convective heat transfers between the solid/gas phases, and variation of porosity and permeability of the solid phase. Consequently, numerous input parameters are required for conducting a fire simulation with solid material response included . This need for a wide range of input data poses a great challenge for fire modeling, especially, in obtaining accurate input parameters.…”

Section: Introductionmentioning

confidence: 99%

Methodology for material property determination

et al. 2019

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Summary Predicting solid material pyrolysis requires numerous parameters/properties that are time consuming and difficult to measure. Multiobjective optimization techniques have been used to determine these parameters; however, a methodology for the types of tests needed for the optimization and parameters that should be optimized versus measured has not been fully established. This study investigated combinations of testing protocols and parameters for optimization to determine a testing and optimization methodology that results in the accurate parameters. A Shuffled Complex Evolution (SCE) optimization routine was used to determine parameters based on some parameters being known (ie, measured) and others being determined through optimization and different combinations of types of input data. The results indicate that material testing should be done at three different heating rates in a thermogravimetric analyzer (TGA) and at three different heat fluxes in the cone calorimeter. The TGA tests and two cone calorimeter tests are input into the SCE optimization routine to determine the remaining parameters. The third cone calorimeter test is used to validate the parameters determined using the methodology. The method provides parameters within 20% of the actual parameters input into the Fire Dynamics Simulator (FDS) virtual experiment models. This method is applied to Polymethyl methacrylate (PMMA) experimental data to prove effectiveness.

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Section: Introductionmentioning

confidence: 99%

Methodology for material property determination

et al. 2019

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“…The combustion behaviors of porous fuels has been investigated for many years, and considerable achievements have been comprehensively applied to understand the development of wildland forest fires. Pine needles [32,33] and shredded papers [23,34] are commonly-used materials to investigate the flame spread of porous fuel. Among all the examinations, there seems to be a consensus that the increasing bulk density will impose restriction on the burning intensity.…”

Section: Discussionmentioning

confidence: 99%

Effect of Bulk Density on the Combustion Property of Nitrocellulose with Isopropanol Humectant

Liu

Wang

et al. 2018

Propellants Explo Pyrotec

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This paper experimentally examined the effect of bulk density on the combustion behaviour of nitrocellulose with isopropanol humectant. Experimental findings reveal that when the bulk density varies within 120.5∼171.5 kg m−3, the fuel regression rate in the quasi‐steady stage changes slightly, with an average value of 0.41 mm s−1, while it will decrease visibly as the bulk density increases within 171.5∼209.7 kg m−3. The overall regression rate follows the similar variation trend. The measurements of thermocouples mounted inside the sample also support the findings above, and further indicate the flame temperature of nitrocellulose‐isopropanol is about 600∼800 °C. Considering the measured radiative heat flux and flame height determined from flame intermittent contour, the radiation fraction of nitrocellulose‐isopropanol is quantitatively ascertained, i. e. roughly equivalent to 0.3. It is expected that the findings could provide insights into the fire risks of nitrocellulose products with different bulk densities and further offer guidance on their safety management.

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“…Parameters that are used in the numerical simulations are summarised in Table 1 (El Houssami 2016;El Houssami et al 2016).…”

Section: Sub-models and Parametersmentioning

confidence: 99%

“…Indeed, as pointed out by Pickett et al (2010) and McAllister et al (2012), large temperature gradients are observed within fuel particles, with a plateau at ,200-3008C for the particle surface temperature and a plateau at ,1408C for the core temperature, during evaporation (Pickett et al 2010). This behaviour, specific to living fuel, cannot be accounted for using a classical multiphase formulation as in Grishin (1997), Larini et al (1998), Morvan and Dupuy (2001), Séro-Guillaume and Margerit (2002), Mell et al (2009) andEl Houssami et al (2016), because the thermal equilibrium assumption (between the solid and the liquid comprising the fuel particles) and the classical degradation models lead to a plateau at 1008C for the particle temperature. Moreover, the work of Mell et al (2009) does not show comparison between experimental results and numerical simulations for a fuel moisture content (FMC) value higher than 49%, suggesting that this model requires further investigation for high FMC.…”

Section: Introductionmentioning

confidence: 96%

“…Also, these experimental results have been chosen based on our previous studies. Indeed, as shown in El Houssami El Houssami et al (2016), the FPA configuration simulations using ForestFireFOAM can be considered as validated on dead pitch pine needle bed, hence experiments in the FPA with living pitch pine needles seem the best candidate to validate the model presented here. In our study, prediction of ignition time, flaming time and HRR time evolution are compared with a set of two experiments on live fuel with an initial FMC equal to 110%.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An improved non-equilibrium model for the ignition of living fuel

Lamorlette

Houssami

Morvan

2018

Int. J. Wildland Fire

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This paper deals with the modelling of living fuel ignition, suggesting that an accurate description using a multiphase formulation requires consideration of a thermal disequilibrium within the vegetation particle, between the solid (wood) and the liquid (sap). A simple model at particle scale is studied to evaluate the flux distribution between phases in order to split the net flux on the particles into the two sub-phases. An analytical solution for the split function is obtained from this model and is implemented in ForestFireFOAM, a computational fluid dynamics (CFD) solver dedicated to vegetation fire simulations, based on FireFOAM. Using this multiphase formulation, simulations are run and compared with existing data on living fuel flammability. The following aspects were considered: fuel surface temperature, ignition, flaming combustion time, mean and peak heat release rate (HRR). Acceptable results were obtained, suggesting that the thermal equilibrium might not be an acceptable assumption to properly model ignition of living fuel.

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Experimental and numerical studies characterizing the burning dynamics of wildland fuels

Cited by 46 publications

References 64 publications

Methodology for material property determination

Methodology for material property determination

Effect of Bulk Density on the Combustion Property of Nitrocellulose with Isopropanol Humectant

An improved non-equilibrium model for the ignition of living fuel

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