Scaling approach of the convective drying of a porous medium |
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Authors: | P Coussot |
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Institution: | (1) LMSGC (UMR 113 LCPC-CNRS), 2 allée Kepler, 77420 Champs-sur-Marne, France, FR |
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Abstract: | We propose a simplified, theoretical approach of the evolution of liquid distribution during the convective drying of a granular
packing. In the absence of gravity effects three regimes are distinguished according to the relative importance of surface
evaporation, capillarity or evaporation from the interior of the sample. The evolution of the drying rate as a function of
the saturation can be inferred from the characteristic velocities associated to each of these effects. We also carried out
drying experiments of bead packings saturated with ethanol, at four different velocities of the boundary convection current,
and with bead size ranging from 4.5 to 100 μm. The drying curves exhibit different regimes with a scaling as a function of
particle radius and current velocity as predicted by the theory.
Received 7 June 1999 and Received in final form 25 October 1999 |
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Keywords: | PACS 68 10 -m Fluid surfaces and fluid fluid interfaces - 81 05 Rm Porous materials granular materials - 92 40 Je Evaporation |
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