Dresden 2020 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 87: Wetting and Liquids at Interfaces and Surfaces I (joint session CPP/DY/O)

CPP 87.9: Talk

Thursday, March 19, 2020, 11:45–12:00, ZEU 255

Drop Impact on Hot Plates: Contact, Lift-Off and the Formation of Holes — •Kirsten Harth^1,2, Sang.Hyeon Lee³, Maaike Rump², Minwoo Kim³, Detlef Lohse², Kamel Fezzaa⁴, and Jung Ho Je³ — ¹Institute of Physics, Otto von Guericke University Magdeburg — ²Physics of Fluid and Max Planck Center, University of Twente, The Netherlands — ³X-Ray Imaging Center, Pohang University of Science and Technology, Korea — ⁴X-Ray Science Division, Argonne Ntnl. Laboratory, USA

Everyone who poured water into a hot pan has experienced the manifold boiling behaviours of drops impacting on a hot plate, a problem which is of high relevance in many technical applications. When the drop is gently deposited, and the surface temperature is sufficiently high, it hovers on a vapour layer (Leidenfrost effect). For impacting drops, this critical temperature for a contact-less rebound is substantially increased, and much harder to determine. In fact, determining contact times between drops and smooth substrates from side view imaging is impossible for most temperatures above the boiling point.

We combine High-Speed Total Internal Reflection and synchrotron X-Ray measurements to reliably determine contact times and the Leidenfrost temperature for drops impacting on smooth hot surfaces. Furthermore, we study the lift-off characteristics. A local minimum in lift-off times correlates with spontaneous lamella rupture and the morphology of the contact.