Wood heating and drying: Effect of grain orientation and moisture content

Heat and mass transfer in wood varies with species, grain orientation, and moisture content. The objectives of this paper were to study the early heating/drying stage at temperatures below 200 °C prior to wood pyrolysis. Five wood species were tested with a cone calorimeter at 4 kW.m −2 , varying grain orientation and moisture content. The grain orientation of the samples was either parallel or perpendicular to the heat flux and the moisture content was varied from 0 % to 30 %. The obtained results contribute to a better understanding of the influence of moisture content and grain orientation on the thermal behavior of wood subjected to a heat flux and provide data to validate models. In-depth temperature measured with thin wire K-type thermocouples showed a difference in heat transfer between parallel and perpendicular grain samples. Mass loss measurements showed that the two grain orientations also behaved differently.