Solid phase modelling coupled to gas phase combustion of volatiles helps to investigate the flame spread over solids. The present work focuses on the solid phase. Numerical simulations of pyrolysis of wet charring materials are performed. When the solid is exposed to an external heat flux, the model is such that the moisture present first flows out, leaving behind dry solid. This solid then further heats up and finally generates a mass flow rate of combustible volatiles during the 'pyrolysis' process, i.e. the degradation of the solid. Evaporation and pyrolysis, possibly occurring at the same time, are assumed to take place in infinitely thin fronts. Pyrolysis is thus modelled as an infinitely fast, irreversible endothermic process at the 'pyrolysis temperature' (Tpyr) and as such, all kinetics are ignored. The cases considered are one-dimensional in nature, in order to focus on the principal model performance. Enthalpy is the basic model variable. The temperature distribution inside the material, along with the evaporation and pyrolysis front positions, are related to the distribution of enthalpy. A piecewise linear temperature field representation is adopted.
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