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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Flow inside Evaporating Water Sessile Drop: a Numerical Study

Get access (open in a dialog) DOI: 10.1615/IHTC15.evp.008347
pages 2515-2524

Sinopsis

The liquid flow inside an evaporating water drop of 10 mm3 on an unheated substrate of different nature is investigated by means of a numerical model. It accounts for convective flow inside the drop, heat conduction in the substrate and heat and mass diffusion in the surrounding air. The liquid motion within the drop is due to non-uniform evaporation at the drop surface, to thermal buoyancy as well as to thermo-capillary effect. A finite volume based numerical method is invoked to solve the governing equations for temperature and concentration. The numerical predictions exhibit a negligible thermal buoyancy effect meaning that the flow is mainly controlled by thermo-capillary effect in the core of the drop, except in the near contact line region where it is strongly influenced by local evaporation. Furthermore, it is highlighted that the thermo-capillary flow direction changes according to the substrate thermal conductivity when the contact angle is lower than 10°.