Title: Computational modelling and simulation of forward-smouldering of porous media in a fixed bed

Authors: Chekib Ghabi, H. Benticha, M. Sassi

Addresses: Laboratoire d'Eudes des Systemes Thermiques et Energetiques, Ecole Nationale d'ingenieurs de Monastir 5000, Tunisie. ' Laboratoire d'Eudes des Systemes Thermiques et Energetiques, Ecole Nationale d'ingenieurs de Monastir 5000, Tunisie. ' The Petroleum Institute, P.O. Box 2533, Abu Dhabi, UAE

Abstract: In order to evaluate the performance and optimal operating conditions of forward smouldering in a cylindrical porous medium, a numerical code has been developed that permits prediction of the smouldering propagation (slow-burning) of foam insulation materials in bi-dimensional configuration. The finite volume discretisation and the bi-conjugate gradient stabilised method are used to solve the system of governing equations. The chemical kinetics model is based on a first order pyrolysis reaction, followed by oxidation of the porous fuel and the carbonaceous residual. This second reaction of oxidation might promote the transition from smouldering to flaming, and thus, fire initiation. The gas and solid temperature, the oxygen and the char mass fraction temporal evolutions are computed, based on the adopted chemical kinetics model, and the assumed heat and mass transfer coefficients. The smoulder propagation velocity is then determined. The developed code featured a CPU time, of the simulated phenomena, of the order of 47 hours on a typical Pentium 4 configuration, which represents a significant improvement compared to many previously applied algorithms. The developed code is able to simulate any smouldering and/or reacting front propagation through a fixed bed.

Keywords: smouldering propagation; slow burning; foam insulation; cylindrical porous medium; FVM simulation; fixed bed; finite volume discretisation; chemical kinetics modelling; first order pyrolysis; oxidation; flaming; fire initiation; heat transfer; mass transfer; simulation; reacting front propagation.

DOI: 10.1504/PCFD.2007.013889

Progress in Computational Fluid Dynamics, An International Journal, 2007 Vol.7 No.5, pp.283 - 293

Published online: 01 Jun 2007 *

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