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arXiv · 1111.0435

Drop impact on superheated surfaces

Tuan Tran·Hendrik J. J. Staat·Andrea Prosperetti·Chao Sun·Detlef Lohse
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Abstract

At impact of a liquid droplet on a smooth surface heated above the liquid's boiling point, the droplet either immediately boils when it contacts the surfaces (``contact boiling''), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (``gentle film boiling''), or both forms the Leidenfrost layer and ejects tiny droplets upward (``spraying film boiling''). We experimentally determine conditions under which impact behaviors in each regime can be realized. We show that the dimensionless maximum spreading $γ$ of impacting droplets on the heated surfaces in both gentle and spraying film boiling regimes shows a universal scaling with the Weber number $\We$ ($γ\sim\We^{2/5}$) -- regardless of surface temperature and of liquid properties -- which is much steeper than for the impact on non-heated (hydrophilic or hydrophobic) surfaces ($γ\sim\We^{1/4}$). We also intereferometrically measure the vapor thickness under the droplet.

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Tuan Tran, Hendrik J. J. Staat, Andrea Prosperetti, Chao Sun, Detlef Lohse. 2011-11-02. Drop impact on superheated surfaces. https://doi.org/10.1103/physrevlett.108.036101

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