Abstract

The objective of the present work was to simulate three-dimensional drying of wood, based on the concept of the effective diffusion coefficient. For this, we used a conventional drying process of radiata pine in a controlled environment (dry and wet bulb temperatures of 44 and 36 degrees C, respectively). This experiment allowed us to gather data on: a) the spatial distribution of moisture content at different drying times, b) the drying curve, and c) the surface emission coefficient. A differential, partial, non-linear, second-order mathematical model was used, and the exponential functions of the effective diffusion coefficient characterized the three-dimensional orthotropic (radial, tangential, and longitudinal) transport of moisture content in the wood. This mathematical model was integrated numerically through the control volume finite element method, which contemplates: a) tetrahedral elements for discretization, b) implicit Euler method for the time differential, and c) Gauss-Seidel with successive over-relaxation method to resolve the linear equation system. We compared these results for the three-dimensional spatial distributions of moisture content after 22, 44, 66, and 88 (h) of drying, and the resulting drying curves were in good agreement with the experiments.