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PROCEEDINGS OF THE FIFTH INTERNATIONAL CONFERENCE ON ENGINEERING COMPUTATIONAL TECHNOLOGY
Edited by: B.H.V. Topping, G. Montero and R. Montenegro
Numerical Methods for the Computation of Radiation and Moisture Effects in Fire Spread
L. Ferragut12, M.I. Asensio1 and S. Monedero1
1Department of Applied Mathematics,
L. Ferragut, M.I. Asensio, S. Monedero, "Numerical Methods for the Computation of Radiation and Moisture Effects in Fire Spread", in B.H.V. Topping, G. Montero, R. Montenegro, (Editors), "Proceedings of the Fifth International Conference on Engineering Computational Technology", Civil-Comp Press, Stirlingshire, UK, Paper 200, 2006. doi:10.4203/ccp.84.200
Keywords: fire spread, free boundary, multivalued operators, radiation.
A numerical method is developed for fire spread simulation modelling. The model is a variant of the models in chapter one of reference , Model I in  or the model in  where we have introduced the influence of the moisture content and radiation. We consider the combustion of a porous solid, where a simplified energy conservation equation is applied.
The rate of loss of fuel is given by
Which is coupled to the temperature by the arrhenius law through the term
The effect of the vegetation moisture and endothermic pyrolysis is incorporated in the model by means of a multivalued function representing the enthalpy.
Where the and are the non-dimensional evaporation heat and pyrolysis heat and , the temperatures of evaporation and pyrolysis.
The resolution of this multivalued operator is done using the Yosida approximation of a perturbed multivalued operator
Which gives explicit values of and without the need of an iterative algorithm.
The nonlocal radiation term from the
flames above the vegetable is based on a 3D transfer equation
involving 2D calculations and taking into account the absortion by
We present two ways of computing the approximate solution of the
radiative equation, by use of the characteristic method combined
with a discrete ordinate method, and by the discontinuous
Galerkin method together with a modified Runge-Kutta method .
Finally several representative examples are solved and compared with experimental data .
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