Mathematical model of wood pyrolysis including internal forced convection

Abstract A one-dimensional mathematical model of charring pyrolysis which includes porous and permeable structural effects on the volatile flow has been developed. This model features variable thermal and physical properties, a time-dependent surface radiant flux, a global Arrhenius pyrolysis reaction, and arbitrary boundary conditions. Darcy's law is incorporated in the momentum equation to account for some of the anisotropic effects observed when wood is heated perpendicular or parallel to the grain direction. Comparison of calculated pyrolysis data with experimental data for maple wood indicates good agreement at low surface heating rates (0.53 cal cm−2 sec−1), but poor agreement at fire level heat fluxes (2.0 cal cm−2 sec−1). At fire level heat flux intensities, it appears that both structural effects and the allowance of secondary pyrolysis reactions are necessary to more fully account for the experimental observations.