Modelling the Absorption Process of Water in Wood in the Transient Regime
Introduction The movement of moisture through is very complex process. Moisture in wood exists in three basic forms: bound water within the cell wall, free water in liquid form, as well as water vapor, in the voids of the wood. In general, water can move through wood in three forms: as water vapor through the cell cavities and permanent pores, as bound water in the wood substance and as free liquid water in the same structure [1-10]. Abstract The process of absorption of water by way of wood in
... 3-dimensions can be described mathematically by analytical solutions, whether initial conditions aren't simples e.g., when there is a profile of concentration at the beginning of a stage of absorption, only numerical model scan be used. The transport of water is then obtained below the fiber saturation point. The potential which drives the transport of the bound-water and the free-water through the wood has been considered by testing a diffusional transport model. The transient diffusion with a constant diffusivity has been tested to describe the process. Analytical solutions have been successfully used to describe the stage of absorption. A model based on numerical method with finite differences has been found to describe the process and especially when the equilibrium of absorption has not been attained and diffusion coefficient parameter in the models was obtained by fitting the model predictions with the experimental data. Finally, water absorption of the studied wood was proved to follow the kinetics of a transient regime.