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ISSN Online: 2377-424X

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

Curvature and contact angle measurements in an unstable evaporating extended meniscus

Get access (open in a dialog) DOI: 10.1615/IHTC12.2520
6 pages

Resumo

A novel loop Constrained Vapor Bubble (CVB) heat exchanger system was used to study instabilities in an evaporating extended meniscus of ethanol. To simultaneously measure the curvature and apparent contact angle of the unstable liquid film, an image analyzing technique was used. The film's motion was first characterized by a small amplitude and high oscillation frequency. During this period the contact angle was relatively constant but curvature doubled. In the second phase, the film spread out to flood the surface and both the curvature and contact angle decreased. Finally the spreading film receded, leaving the first two fringes on the flat surface ahead of the main meniscus for thin film evaporation. We found that this kind of unstable film can increase heat transport capacity.