Mass Transfer from Wooden Surfaces and Internal Moisture Non-Equilibrium
作者:
Jarl-Gunnar Salin,
期刊:
Drying Technology
(Taylor Available online 1996)
卷期:
Volume 14,
issue 10
页码: 2213-2224
ISSN:0737-3937
年代: 1996
DOI:10.1080/07373939608917204
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The transfer of moisture from a wooden surface and the corresponding mass transfer coefficient in relation to the heat transfer coefficient are considered. Experimental data are reviewed that show that the mass transfer coefficient often is one order of magnitude smaller than what could be expected from the analogy between heat and mass transfer. The nature of this deviation and its influence on wood drying models is discussed.It has been suggested by Wadsö.that moisture flow inside the wood exhibits non–Fickian behaviour and that this may be due to a slow desorptiodabsorption by the wood fibre. A model is thus developed where the normal assumption of internal local equilibrium between the vapour and bound phases is replaced by a mass transfer resistance. The model is applied to one–dimensional moisture flow in a body of finite thickness and solved analytically.Numerical values calculated with the model are analysed in order to establish whether “apparent” non–Fickian behaviour of the kind observed could be explained by such a model. It is also analysed whether the model could explain an apparent decreased mass transfer coefficient at the surface.
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