Foam drainage control using thermocapillary stress in a two-dimensional microchamber
V Miralles1, B Selva2, I Cantat3
1MMN, UMR CNRS Gulliver 7083, PSL research University, ESPCI ParisTech, 10 rue Vauquelin, F-75005 Paris, France.
Physical Review Letters
|June 28, 2014
Summary
Researchers controlled microfoam drainage using temperature gradients to manipulate Marangoni stress. Thermocapillarity can overcome gravity, enabling tunable foam drainage in Hele-Shaw cells.
Area of Science:
- Fluid dynamics
- Materials science
- Surface science
Background:
- Foam drainage is crucial in various industrial processes.
- Controlling foam behavior is challenging due to complex interactions.
- Marangoni stress and thermocapillarity are known to influence fluid interfaces.
Purpose of the Study:
- To investigate the control of 2D microfoam drainage using temperature gradients.
- To analyze the antagonistic effects of thermocapillarity and gravity.
- To understand the interplay of forces governing foam drainage dynamics.
Main Methods:
- Utilizing a vertical Hele-Shaw cell for microfoam experiments.
- Applying a constant temperature gradient in situ to generate Marangoni stress.
- Measuring liquid volume fraction over time to characterize drainage.
- Solving mass balance equations to quantify results.
Main Results:
- Marangoni stress, induced by temperature gradients, effectively controls foam drainage.
- Thermocapillarity can counteract or overcome gravitational effects.
- Foam drainage can be directed upwards or maintained stable for extended periods (≥60s).
Conclusions:
- Temperature-controlled Marangoni stress offers a tunable method for microfoam drainage.
- The study provides insights into the complex interplay between gravity, thermocapillarity, and capillary pressure.
- This research has implications for manipulating foam behavior in confined geometries.
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