When you dry out a large pile of wood, the moisture actually flows inward toward the center instead of outward toward the heat.
April 17, 2026
Original Paper
INFLUENCE OF THE THICKNESS OF THE DISPERSED WOOD LAYER ON THE MECHANISMS OF INTRAPORE HEAT AND MASS TRANSFER DURING THE DRYING
SSRN · 6584061
The Takeaway
It’s common sense that if you heat something wet, the water evaporates out into the air. But this study shows that once a pile of wood chips gets thicker than 50mm, the physics flips: the vapor actually travels deeper into the pile. This happens because of a weird pressure trap created within the pores of the wood. This 'backward' flow explains why industrial wood drying is so inefficient and often leads to unexpected fires or rot. By understanding this counter-intuitive 'moisture trap,' we can completely redesign how we process biomass for green energy, making it much faster and safer.
From the abstract
This paper presents theoretical and experimental findings on heat and mass transfer processes occurring within dispersed woody biomass confined in a semi-enclosed cubic chamber. Experimental results demonstrate that the thickness of the wood layer plays a decisive role in shaping the mechanisms of the coupled heat and mass transfer processes occurring simultaneously under significant phase transformations during wood dehydration. It is shown that, across the entire investigated range of drying a