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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

ADHESION ENERGY PER UNIT AREA OF VARIOUS LIQUID DROPLETS ON PMMA, PARYLENE C, AND PPFC COATED FLAT SOLID SURFACES

Get access (open in a dialog) DOI: 10.1615/IHTC16.cod.022837
pages 2377-2384

Resumo

Condensation is a crucial process in heat exchangers with application in power plants, refrigerators, air conditioning systems and heat pumps. Dropwise condensation has larger heat transfer coefficient than filmwise condensation. During dropwise condensation, droplets form on surface and grow rapidly, being removed by gravity, and the process resumes. For the continued dropwise condensation, determination of droplet's adhesion force is still an open problem of the liquid droplets mobility on the solid surface. Most of the previous adhesion models taken into account the length of the wet area periphery, even if all the areas in the wet zone contribute to the adhesion of the droplets. In recent years, the authors considering contact area to define the adhesion force and using various liquid droplets on hydrophobic solid surface proposed the new concept "per unit area of adhesion energy". In this study, experiments were conducted to verify that new concepts could also be applied to hydrophilic surfaces. Results demonstrate that considering the contact area to determine the adhesion force is suitable for describing the movement of liquid on a hydrophilic solid surface as well as on a hydrophobic solid surface.