Experimental Study of the Linear Diffusion of Water in Clonal Eucalyptus Wood

Abstract

For wood, water diffusivity is an important factor that influences its mechanical and physical properties. In this experimental study, the water absorption and desorption were investigated in linear directions for woods of two Eucalyptus clones; Eucalyptus grandis and Eucalyptus camaldulensis. The diffusion model based on Fick’s second law was applied to assess both water absorption and desorption processes on cubic wood samples of (20 × 20 × 20) mm3. The diffusion coefficient, absorption coefficient, surface emission and diffusivity resistance were estimated. The study of sorption kinetics was carried out at ambient temperature about 25 °C and desorption kinetics at 30 °C for 12 h. The obtained results indicate that the sorption and desorption kinetics as well as the diffused quantities of water in the wood of these two clones were greater in the longitudinal direction than in the radial direction and that they were the lowest in the tangential direction. Wood samples of E. grandis exhibit higher average values of diffusion coefficient, absorption coefficient, and surface emission coefficient in both absorption and desorption processes in the linear directions than those of E. camaldulensis. However, they display lower average values of resistance diffusivity in all directions than those E. camaldulensis in both absorption and desorption processes.