BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Leidenfrost temperature(s) - Pierre Chantelot\, Universite of Twen
 te
DTSTART:20230119T113000Z
DTEND:20230119T123000Z
UID:TALK192959@talks.cam.ac.uk
CONTACT:Catherine Pearson
DESCRIPTION:When deposited on a hot solid\, volatile liquids can levitate 
 on a cushion of their own vapour\, without liquid-solid contact\, a phenom
 enon called the Leidenfrost effect. The presence of a vapour layer\, that 
 separates the liquid from the solid\, has two crucial consequences for app
 lications: (i) a dramatic reduction of heat transfer\, and (ii) a reduced 
 friction\, making Leidenfrost drops extremely mobile. In this seminar\, I 
 will tackle a deceivingly simple question: what is the solid temperature n
 ecessary to observe levitation\, the so-called Leidenfrost temperature. Fi
 rst\, I will propose to understand the onset of the Leidenfrost effect as 
 emerging from the ability of the vapour layer to levitate the liquid\, thr
 ough the example of drop impact on superheated substrates. I will then sho
 w the limitations of this approach\, and propose a different definition of
  the Leidenfrost temperature as the critical point of a second order phase
  transition\, by making an analogy with non-equilibrium systems exhibiting
  a directed percolation phase transition. In this framework\, the Leidenfr
 ost temperature does not stem from the hydrodynamic ability of the vapour 
 layer to support the liquid\, but it expresses the resilience of Leidenfro
 st drops to contact. Finally\, I will discuss the implications of this new
  definition of the Leidenfrost temperature on heat transfer in drop impact
  situations.
LOCATION:Open Plan Area\, Institute for Energy and Environmental Flows\, M
 adingley Rise CB3 0EZ
END:VEVENT
END:VCALENDAR