Experimental analysis of the heat transfer induced by thermocapillary convection around a bubble
The surface tension driven flow in the liquid vicinity of gas bubbles on a heated wall and its contribution to the heat transfer are investigated experimentally in a configuration where surface tension force and buoyancy forces oppose one another. This liquid flow caused by the temperature gradient along the interface is called thermocapillary or thermal Marangoni convection. The studies were made with silicone oils of different viscosities so that a wide range of dimensionless numbers were encountered. The velocity fields are determined from the motion of carbon particles in the meridian plane of the bubble. The influence of the temperature gradient, the oil viscosity, and the bubble shape on the profiles along the interface and in the direction normal to the interface is analyzed. The temperature field is determined by holographic interferometry. For the axisymmetric problem, the interferograms are evaluated by solving the Abel-integral equation. From the isotherms, the temperature distribution along the bubble surface and in the liquid beneath the bubble is measured. To quantify the contribution of thermocapillarity to the heat transfer, the heat flux transferred by thermocapillarity is measured. A heat exchange law giving the increase in heat flux due to Marangoni convection in comparison to the conductive regime is proposed.
- Research Organization:
- Univ. de Provence, Marseille (FR)
- OSTI ID:
- 20067710
- Journal Information:
- Journal of Heat Transfer, Vol. 122, Issue 1; Other Information: PBD: Feb 2000; ISSN 0022-1481
- Country of Publication:
- United States
- Language:
- English
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