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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Marangoni effects on natural convection in a small cavity

Get access (open in a dialog) DOI: 10.1615/IHTC12.3630
6 pages

要約

Natural convection in a small cavity (2.8mm × 4.9mm) heated and cooled from sidewalls has been studied. In order to investigate the effect of Marangoni convection, experiments were conducted with and without a lid of a cavity. Without the lid, the top boundary was a free surface and the temperature gradient at the surface caused surface tension force. Silicon oil and water were used as working fluids. Two dimensional velocity fields were measured using a particle image velocimetry. Silicon oil in a cavity clearly showed Marangoni effects and convective velocity increased intensively. The temperatures of sidewalls were set around 4°C because the density of water has a maximum value at 4°C. Therefore, the direction of flow due to natural convection at the surface depends on the temperature although surface tension always drives flow from hot to cold side. When the temperature of water was less than 4°C, Marangoni convection was expected to occur in the opposite direction to natural convection. However, the Marangoni effect was not observed for water because of the sensitivity to a contamination.