Local water vapor diffusion coefficient when drying Norway spruce [Picea abies] sapwood

• Published in: Journal of wood science Vol. 52; no. 3; pp. 195 - 201
• Main Authors: Danvind, J.(Lulea Univ. of Technology, Skelleftea (Sweden)), Ekevad, M
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer Nature B.V 01-06-2006
• Subjects: ACONDICIONADO DE LA MADERA; ALBURA; AUBIER; CHEMICOPHYSICAL PROPERTIES; Computed tomography; CONDITIONNEMENT DU BOIS; CONTENIDO DE HUMEDAD; Dependence; DIFFUSION; Diffusion coefficient; DIFUSION; DRYING; Finite element method; Mathematical analysis; MOISTURE CONTENT; PICEA ABIES; PROPIEDADES FISICOQUIMICAS; PROPRIETE PHYSICOCHIMIQUE; RADIOGRAFIA; RADIOGRAPHIE; RADIOGRAPHY; SAPWOOD; SECADO; SECHAGE; TENEUR EN EAU; Träfysik; Träteknik; Water vapor; WOOD CONDITIONING; Wood Physics; Wood Technology; Norway
• ISSN: 1435-0211; 1611-4663; 1611-4663
• DOI: 10.1007/s10086-005-0753-4

In this article, a one-dimensional and a two-dimensional approach to the evaluation of local diffusion coefficients for Norway spruce sapwood from measured moisture content (MC) values are presented. A studied wood sample was dried from the initial green condition to about 15% mean MC, but here only the diffusive part of the drying process between approximately 25% and 15% mean MC was treated. Measured local MC values were based on nondestructive X-ray computed tomography data. Finite element calculations were performed with two alternative diffusion coefficients to test the appropriateness of the diffusion coefficients that were evaluated from the measured MC values. The evaluated diffusion coefficients show interesting dependence on MC and distance from the evaporation surface. The advantage of using the methods presented is that the diffusion coefficient is calculated on a local level without having to define a function for the diffusion coefficient’s dependency on other parameters.