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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

Development of an Empirical Model for Convective Evaporation of Sessile Droplets of Volatile Fluids

Get access (open in a dialog) DOI: 10.1615/IHTC15.fcv.008711
pages 3215-3225

要約

Despite the fact that evaporation dynamics of sessile droplets has been study for almost half a century, the scientific community struggles with the creation of an accurate quantitative description of evaporation flux rate. The classically used description considers evaporation as a quasi-steady process controlled by the diffusion of vapour into the air, and the whole system is assumed to be isothermal at the ambient temperature. However, when two type of fluids (alcohols and alkanes) are let to evaporate on heated substrates while a side view camera measures their evaporation flux rate with accuracy, droplets tend to see their evaporation flux rate underestimated by this model mostly due to convection. This experimental study aims to understand how atmospheric convective transport in the vapour phase influences evaporation in order to developed an empirical model that describes with accuracy the evaporation flux rate. The Rayleigh number is used to analysed the contribution of natural convection and an empirical is developed combining diffusive and convective transport for each type of fluid. The influence of the molecular chain length (and the increasing number of carbon atoms) is also being discussed.