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Published on: December 25, 2015
Coalescence in semiconcentrated emulsions in simple shear flow
A V Korobko1, D van den Ende, W G M Agterof
1Physics of Complex Fluids, Institute of Mechanics, Processes and Control-Twente (IMPACT) and J.M. Burgerscentrum, Department of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. a.korobko@chem.leidenuniv.nl
The Journal of Chemical Physics
|December 15, 2005
Summary
Investigating droplet coalescence in emulsions under shear flow, this study found that droplet size distribution is crucial for predicting coalescence probability. The findings support models with partially or fully immobile interfaces, with critical coalescence radius around 10 micrometers.
Area of Science:
- Fluid dynamics
- Colloid and interface science
- Emulsion science
Background:
- Coalescence frequency in emulsions is critical for stability and processing.
- Droplet size distribution significantly impacts emulsion behavior.
- Understanding droplet interactions in shear flow is essential for industrial applications.
Purpose of the Study:
- To experimentally investigate the coalescence frequency of low-viscosity droplets in simple shear flow.
- To compare experimental findings with theoretical models of two-droplet coalescence.
- To determine the influence of droplet size distribution and shear rate on coalescence probability.
Main Methods:
- Experimental investigation of emulsion coalescence frequency at various volume fractions and shear rates.
- Monitoring droplet size distribution evolution to determine average coalescence probability.
- Theoretical modeling of two-droplet coalescence, averaging probabilities over orientation and size distribution.
Main Results:
- The full droplet size distribution must be considered for accurate prediction of average coalescence probability.
- Experimental results align with partially or fully immobile deformable interface models.
- The ratio of drainage time to collision time scales with coalescence radius and shear rate.
Conclusions:
- Droplet size distribution is a key factor in emulsion coalescence.
- Interface mobility models provide a good description of the observed coalescence processes.
- A critical coalescence radius of approximately 10 micrometers was identified.
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