Drop penetration into porous powder beds

Hapgood, K. P., Litster, J. D., Biggs, S. R. and Howes, T. (2002) Drop penetration into porous powder beds. Journal of Colloid And Interface Science, 253 2: 353-366. doi:10.1006/jcis.2002.8527

Author Hapgood, K. P.
Litster, J. D.
Biggs, S. R.
Howes, T.
Title Drop penetration into porous powder beds
Journal name Journal of Colloid And Interface Science   Check publisher's open access policy
ISSN 0021-9797
Publication date 2002-01-01
Year available 2002
Sub-type Article (original research)
DOI 10.1006/jcis.2002.8527
Open Access Status
Volume 253
Issue 2
Start page 353
End page 366
Total pages 14
Place of publication U.K.
Publisher Elsevier
Language eng
Subject C1
290699 Chemical Engineering not elsewhere classified
670199 Processed food products and beverages not elsewhere classified
670403 Treatments (e.g. chemicals, antibiotics)
Abstract The kinetics of drop penetration were studied by filming single drops of several different fluids (water, PEG200, PEG600, and HPC solutions) as they penetrated into loosely packed beds of glass ballotini, lactose, zinc oxide, and titanium dioxide powders. Measured times ranged from 0.45 to 126 s and depended on the powder particle size,viscosity, surface tensions, and contact angle. The experimental drop penetration times were compared to existing theoretical predictions by M. Denesuk et al. (J. Colloid Interface Sci. 158, 114, 1993) and S. Middleman (Modeling Axisymmetric Flows: Dynamics of Films, Jets, and Drops, Academic Press, San Diego, 1995) but did not agree. Loosely packed powder beds tend to have a heterogeneous bed structure containing large macrovoids which do not participate in liquid flow but are included implicitly in the existing approach to estimating powder pore size. A new two-phase model was proposed where the total volume of the macrovoids was assumed to be the difference between the bed porosity and the tap porosity. A new parameter, the effective porosity (epsilon)eff, was defined as the tap porosity multiplied by the fraction of pores that terminate at a macrovoid and are effectively blocked pores. The improved drop penetration model was much more successful at estimating the drop penetration time on all powders and the predicted times were generally within an order of magnitude of the experimental results. (C) 2002 Elsevier Science (USA).
Keyword Chemistry, Physical
Drop Penetration
Porous Powder Beds
Effective Porosity
Pore Size
Dynamic Contact-angle
Capillary Penetration
Radial Capillary
Wet Granulation
Q-Index Code C1
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Chemical Engineering Publications
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Citation counts: TR Web of Science Citation Count  Cited 109 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 15 Aug 2007, 04:04:07 EST