A Diffusion-based Model for Transient High Temperature Treatment of Wood

Abstract

A three-dimensional (3D) mathematical model describing simultaneous unsteady heat and moisture transfer between a gas phase and a solid phase during high temperature treatment of wood has been developed. The model is based on a diffusion equation with variable diffusion coefficients. The governing equations representing the heating process in a 3D rectangular object are discretized using an explicit finite-difference approach, and a computer code is developed to predict the temperature and moisture distributions inside the wood sample. The sample was subjected to high temperature treatment under different operating conditions. The model predictions are compared with experimental results obtained for temperature and average moisture content during high temperature treatment of birch wood. Satisfactory agreement is obtained over a range of heating conditions. A parametric study was also carried out to determine the effects of several parameters such as initial moisture content, heat and mass transfer coefficients, and the sample thickness on the temperature and moisture content distributions within the samples during heat treatment.