Dynamic nonisothermal transport in hygroscopic porous media: Moisture diffusion in wood

✍ Scribed by Stavros Avramidis; Peter Englezos; Thanasis Papathanasiou

• Publisher: American Institute of Chemical Engineers
• Year: 1992
• Tongue: English
• Weight: 766 KB
• Volume: 38
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690380813

✦ Synopsis

A model that predicts heat and moisture transfer in the hygroscopic range of a complex porous material such as wood, was evaluated with unsteady-state nonisothermal diffusion experimental data. Water chemical potential gradient was taken as the driving force for diffusion, and the derivation of the temperature-gradient phenomenological coefficient in the mass balance equation was based on the principles of nonequilibrium thermodynamics. The results reveal an excellent prediction of the specimen's average moisture content during desorption in the hygroscopic range. Moreover, a very good agreement was also shown between the specimen's center temperature and the model predictions. The model revealed the existence of a thermal-diffusion phenomenon during the initial stages of the desorption process. This phenomenon was not predicted by Fick's equation for diffusion.