Predicting the burning of wood using an integral model

Spearpoint, Michael; Quintiere, James G.

doi:10.1016/s0010-2180(00)00162-0

Cited by 212 publications

(152 citation statements)

References 13 publications

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“…An exception is the asymptotic analysis of Wichman and Atreya [57] wherein approximate formulas are developed for the mass loss rate of a charring solid in the limit of large activation energy. In the simplest class of numerical models for charring pyrolysis, it is assumed that an infinitely thin reaction zone (or pyrolysis front) separates the char layer from the virgin material [58][59][60][61][62][63][64][65][66][67][68], analogous to the Stefan problem where phase change occurs at a thin interface. This is a reasonable approximation at high heat 23 flux levels, but can become questionable at lower heat fluxes.…”

Section: Comprehensive Pyrolysis Models: Charring Materialsmentioning

confidence: 99%

Generalized pyrolysis model for combustible solids

Lautenberger

Fernandez-Pello

2009

Fire Safety Journal

307

259

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This dissertation presents the derivation, numerical implementation, and verification/validation of a generalized model that can be used to simulate the pyrolysis, gasification, and burning of a wide range of solid fuels encountered in fires. The model can be applied to noncharring and charring solids, composites, intumescent coatings, and smolder in porous media. Care is taken to make the model as general as possible, allowing the user to determine the appropriate level of complexity to include in a simulation. The model considers a user-specified number of gas phase and condensed phase species, each having its own temperature-dependent thermophysical properties.Any number of heterogeneous (gas-solid) or homogeneous (solid-solid or gas-gas) reactions can be specified. Both in-depth radiation transfer through semi-transparent media and radiation transport across pores are considered. Volume change (surface regression or swelling/intumescence) is handled by allowing the size of grid points to change as dictated by mass conservation. All volatiles generated inside the solid escape to the ambient with no resistance to mass transfer unless a pressure solver is invoked; the resultant flow of volatiles is then calculated according to Darcy's law. A gas phase 2 convective-diffusive solver can be invoked to determine the composition of the volatiles.Oxidative pyrolysis is simulated by modeling diffusion of oxygen from the ambient into the pyrolyzing solid where it may participate in reactions. Consequently, the mass flux and composition of volatiles escaping from the solid can be calculated. To aid in determining the required input parameters, the model is coupled to a genetic algorithm that can be used to estimate the required input parameters from bench-scale fire tests or thermogravimetric analysis.

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Section: Comprehensive Pyrolysis Models: Charring Materialsmentioning

confidence: 99%

Generalized pyrolysis model for combustible solids

Lautenberger

Fernandez-Pello

2009

Fire Safety Journal

307

259

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“…The second peak is due to the so called 'back effect' [8]. Note that the first peak is quasi-identical for all thermally thick materials, as they behave as infinitely thick materials during that stage.…”

Section: Influence Of Solid Thicknessmentioning

confidence: 94%

“…During the past two decades, several numerical models were developed for pyrolysis, of charring materials with different levels of complexity, such as: Arrhenius-type models [5]; 'integral' models [6][7][8][9]; an 'extended' integral model [10]; a moving mesh model [11]; a dual mesh model [12]. Reviews on pyrolysis modelling have been provided in e.g.…”

Section: Introductionmentioning

confidence: 99%

Application of a simple enthalpy‐based pyrolysis model in numerical simulations of pyrolysis of charring materials

et al. 2009

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A new, simple pyrolysis model for charring materials is applied to several numerical and experimental test cases, with variable externally imposed heat fluxes. The model is based on enthalpy. A piecewise linear temperature field representation is adopted, in combination with an estimate for the pyrolysis front position. Chemical kinetics are not accounted for: the pyrolysis process takes place in an infinitely thin front, at the 'pyrolysis temperature'. The evolution in time of pyrolysis gases mass flow rates and surface temperatures are discussed. The presented model is able to reproduce numerical reference results, which were obtained with the more complex moving mesh model. It performs better than the integral model. We illustrate good agreement with numerical reference results for variable thickness and boundary conditions. This reveals that the model provides good results for the entire range of thermally thin and thermally thick materials. It also shows that possible interruption of the pyrolysis process, due to excessive heat losses, is automatically predicted with the present approach. Finally, an experimental test case is considered.

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“…The CO 2 production curve has two peaks and the wood specimens began to release CO 2 quickly after 100 s. The first peak appeared for the ignition period of wood from heating process. The second peak was generated by the back effect increased burn rate of the test specimen as the thermal waves to the entire surface of the test piece was reflected by the rear of the test piece (36) . Afterwards, the concentration of CO 2 decreased, which can be accounted for by the hindered access of O 2 to the specimens due to the high concentration of CO 2 generated in advance and to the barrier of the char layer formed (37) .…”

Section: Toxic Gases Productionmentioning

confidence: 99%

Evaluation of Combustion Gas for Carbon Oxide of Wood Coated with Bis-(dialkylaminoalkyl) Phosphinic Acids Additives

Jin¹,

Chung²

2016

Fire Science and Engineering

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요 약 이 연구는 비스-(디메틸아미노메틸) 포스핀산(DMDAP), 비스-(디에틸아미노메틸) 포스핀산(DEDAP) 과 비스-(디부틸 아미노메틸) ABSTRACTThis study examined the generation of combustion toxic gases of pinus rigida specimens processed with bis-(dimethylaminomethyl) phosphinic acid (DMDAP), bis-(diethylaminomethyl) phosphinic acid (DEDAP), and bis-(dibutylaminomethyl) phosphinic acid (DBDAP). Each pinus rigida plate was coated three times with 15 wt.% flame retardants in an aqueous solution. The specimens were then dried at room temperature. The production of combustion toxic gases was investigated using a cone calorimeter (ISO 5660-1). The first time to peak mass loss rate (1 ) for the processed specimens was decreased 1.8% for DMDAP and 5.3% for DBDAP and increased 1.8% for DEDAP. The peak carbon monoxide (CO p e a k ) production was 1.5 to 2.0 times higher than that of the unprocessed plate. The peak carbon dioxide (CO 2 p e a k ) production was reduced 0.01 times for DMDAP and increased 1.15 to 1.19 times for DEDAP and DBDAP compared with the unprocessed specimens. In particular, the oxygen concentration was much higher than 15%, which can be fatal to humans and the resulting hazard can be eliminated. Overall, the combustion toxicity of flammable gas were increased partially by the chemical additives compared with those of the unprocessed plate.

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Predicting the burning of wood using an integral model

Cited by 212 publications

References 13 publications

Generalized pyrolysis model for combustible solids

Generalized pyrolysis model for combustible solids

Application of a simple enthalpy‐based pyrolysis model in numerical simulations of pyrolysis of charring materials

Evaluation of Combustion Gas for Carbon Oxide of Wood Coated with Bis-(dialkylaminoalkyl) Phosphinic Acids Additives

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