Multi‐scale simulations of the thermal degradation of thin wooden plates: Evaluation of two kinetic mechanisms

Abstract

SummaryThis study evaluates two kinetic mechanisms to predict, on matter‐level and material‐level scales, the thermal degradation of thin plates of oak and eucalyptus as representing vegetative fuel involved in wildfires. The lumped mechanism considers four successive steps, whereas the simplified one includes two steps. The kinetic parameters of these mechanisms were identified with thermogravimetric analysis in air for heating rates between 2 and 30 °C min−1. On the matter‐level scale, kinetic mechanisms were tested for heating rates inside and outside the parameters optimization range. The simulations of the mass loss were close to the experimental data. The lumped mechanism gave better results than the simplified one. On the material‐level scale, the mass loss and temperature recorded during thermal degradation of thin wooden plates, with a heating cone, were compared to simulations performed with GPYRO. When only the gasification stage occurred, both mechanisms predicted results close to the experimental data. When char oxidation occurred, the beginning of the gasification stage was well predicted, whereas some differences appeared during the transition between the gasification and char oxidation stages. The performance of both mechanisms indicates that a two‐step mechanism is capable of modeling the thermal degradation of thin wooden plates on a material scale.