Effect of Shear on Pumped Capillary Foams
Omotola Okesanjo1, J Carson Meredith1, Sven Holger Behrens1,2
1School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Industrial & Engineering Chemistry Research
|May 16, 2023
Summary
Stable capillary foams, utilizing oil-particle films and particle networks, resist collapse under stress. These foams remain stable at high flow rates but separate at low rates, with shearing enhancing network strength and foam stability.
Area of Science:
- Colloid and Surface Science
- Materials Science
- Fluid Dynamics
Background:
- Stable foams are crucial for applications like firefighting and oil recovery.
- Foam collapse, driven by drainage and coarsening, limits foam efficacy.
- Synergistic stabilization of foams by colloidal particles and immiscible liquids offers a novel approach.
Purpose of the Study:
- To investigate the flow dynamics and stability of capillary foams.
- To understand the impact of the unique oil-particle film and particle network architecture on foam behavior.
- To analyze how stress and aging affect capillary foam stability.
Main Methods:
- Pumping capillary foams through millimeter-sized tubing (790 μm ID) at varying flow rates.
- Analyzing foam stability under different flow conditions and aging.
- Observing the role of the particle network in foam stabilization.
Main Results:
- Capillary foams demonstrated stability at higher flow rates.
- Foams underwent phase separation when subjected to low flow rates.
- The particle network was identified as the key structural element for foam stability.
- Shearing was found to increase particle network strength and overall foam stability.
Conclusions:
- The unique architecture of capillary foams, featuring oil-particle films and interconnected particle networks, enhances foam stability.
- Flow rate significantly influences capillary foam stability, with higher rates promoting stability.
- Shearing is a viable method to reinforce the particle network and improve foam longevity and performance.
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