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Thermocapillary Convection Space Experiment on the SJ-10 Recoverable Satellite
Published on: March 11, 2020
Thermocapillary convection in double-layer fluid structures within a two-dimensional open cavity
Nivedita R Gupta1, Hossein Haj-Hariri, Ali Borhan
1Department of Chemical Engineering, University of New Hampshire, Durham, NH 03824, USA.
Journal of Colloid and Interface Science
|July 17, 2007
Summary
Thermocapillary convection in a two-layer system is studied without gravity. A free surface enhances encapsulant convection but reduces melt convection, with interface deformation larger in open cavities.
Area of Science:
- Fluid dynamics
- Heat and mass transfer
- Materials science
Background:
- Thermocapillary convection drives fluid flow due to surface tension gradients caused by temperature differences.
- Understanding convection in multi-liquid systems is crucial for processes like crystal growth and microelectronics manufacturing.
- Previous studies often focused on closed cavities, limiting insights into open systems with free surfaces.
Purpose of the Study:
- To investigate thermocapillary convection in a differentially-heated open rectangular cavity with two immiscible liquid layers.
- To analyze the impact of a free surface on convection intensity and interface deformation.
- To explore methods for suppressing convection in the melt layer.
Main Methods:
- Numerical computation of temperature and flow fields using domain mapping and a finite-difference scheme on a staggered grid.
- Modeling of deformable melt-encapsulant and air-encapsulant interfaces with pinned contact lines.
- Comparison of open cavity results with those of a closed cavity with a rigid top surface.
Main Results:
- A free surface increases convection in the encapsulant but retards thermocapillary flow in the melt.
- Increased encapsulant viscosity or decreased encapsulant thickness reduces convection intensity.
- Interface deformations are larger in open cavities compared to closed ones, with a characteristic dipping shape near hot and cold walls.
Conclusions:
- A free surface is more effective than a rigid top in reducing melt layer convection intensity.
- Selecting an encapsulant with higher surface tension temperature sensitivity can suppress melt convection.
- The study provides insights into controlling fluid behavior in open, multi-layer systems relevant to advanced manufacturing.
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