Abstract

Formulating wood drying models with predictive capabilities is still a challenge. Traditionally, the wood drying process is studied macroscopically, with pore-level physics lumped into effective transport properties. However, microvisual experiments in 2-D transparent porous media (known as micromodels) can improve our understanding of the drying process and add to current theories. Here, we make etched glass micromodels with the pore morphology of softwoods and carry out simple drying experiments, thereby proving the potential of this experimental tool on the wood science field. We develop a procedure to generate the random morphology of softwood with a computer program based on known probability distribution laws. In particular, we generate the tracheid cell microfeatures of a softwood longitudinal-tangential section. The wood morphology is etched onto glass using a photolithographic technique, creating softwood glass micromodels. Good agreement is seen between the morphology of microtome sections and our computer-generated softwood. During wood drying, liquid flow is driven by capillary instabilities. Sudden liquid redistribution, know as a Haines jump, spontaneously drains the liquid contained in cell cavities. Viscous flow occurs mainly through liquid films in partially dry cells.