Physics of Fluids - Publications

Origin of spray formation during impact on heated surfaces

Soft Matter 13, 7514–7520 (2017)

Authors

	Michiel van Limbeek
	Paul Hoefnagels
	Chao Sun
	Detlef Lohse

BibTeΧ

@Article{C7SM00956A,
author ="van Limbeek, Michiel A. J. and Hoefnagels, Paul B. J. and Sun, Chao and Lohse, Detlef",
title  ="Origin of spray formation during impact on heated surfaces",
journal  ="Soft Matter",
year  ="2017",
volume  ="13",
issue  ="41",
pages  ="7514-7520",
publisher  ="The Royal Society of Chemistry",
doi  ="10.1039/C7SM00956A",
url  ="http://dx.doi.org/10.1039/C7SM00956A",
abstract  ="In many applications{,} it is crucial to control the heat transfer rate of impacting drops on a heated plate. When the solid exceeds the so-called Leidenfrost temperature{,} an impacting drop is prevented from contacting the plate by its own evaporation. But the decrease in the resulting cooling efficiency of the impacting drop is yet not quantitatively understood. Here{,} we experimentally study the impact of such water drops on smooth heated surfaces of various substances. We demonstrate that{,} in contrast to previous results for other liquids{,} water exhibits spray in the vertical direction when impacting sapphire and silicon. We show that this typical spray formation during impact is a result of the local cooling of the plate. This is surprising since these two materials were considered to remain isothermal during the impact of mm-sized droplets. We conclude and explain that the thermal time scale of the system is not solely determined by the thermal properties of the solid{,} but also by those of the liquid. We also introduce a dimensionless number comparing the thermal time scale and the dynamic time scale with which we can predict the spraying behaviour at impact."}