Investigation of evaporation and diffusion phenomena in porous media

R. Bennacer*, K. Sefiane

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Many industrial and biological phenomena involve the evaporation of liquids in porous media. In drying processes the evaporation of a liquid meniscus from the solid is the key mechanism in the process and its efficiency. After a first steady stage of evaporation the meniscus becomes unsteady and recedes inside the pore. Diffusion of vapour becomes the controlling mechanism for evaporation in a later stage. In this work an experimental investigation is undertaken to Study the various stages of evaporation of different liquids in capillary tubes (pores) of various sizes. The analysis of the data obtained from this investigation reveals some interesting behaviours and emphasizes the role played by vapour diffusion in the case of unsteady interface. The preliminary transient regime allowing the thermal field establishment, is followed by the first stage of evaporation is found to be dominated by thermocapillary effects associated with non-uniform evaporation and temperature gradients. The laste stage is a molecular diffusion-limited mode. The liquid volatility and the effect of the size of the tube (ranging from 200 to 900 mu m) are also analysed to show the interaction between the various effects at different scales.

Original languageEnglish
Title of host publicationDIFFUSION IN SOLIDS AND LIQUIDS: HEAT TRANSFER - MICROSTRUCTURE & PROPERTIES
EditorsA Ochsner, J Gracio
Place of PublicationSTAFA-ZURICH
PublisherTRANS TECH PUBLICATIONS LTD
Pages215-222
Number of pages8
ISBN (Print)978-0-87849-438-5
Publication statusPublished - 2007
Event2nd International Conference on Diffusion in Solids and Liquids - Aveiro, Portugal
Duration: 26 Jul 200628 Jul 2006

Publication series

NameMaterials Science Forum
PublisherTRANS TECH PUBLICATIONS LTD
Volume553
ISSN (Print)0255-5476

Conference

Conference2nd International Conference on Diffusion in Solids and Liquids
Country/TerritoryPortugal
Period26/07/0628/07/06

Keywords

  • evaporation
  • diffusion
  • thermocapillary convection
  • heat transfer

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