The Leidenfrost effect as a directed percolation phase transition

TL;DR

This paper models the Leidenfrost effect as a directed percolation phase transition, revealing critical behavior and coexistence regimes through experiments and universality class analysis.

Contribution

It introduces a novel analogy between the Leidenfrost effect and directed percolation, providing new insights into the transition mechanisms.

Findings

Identification of a critical surface temperature for Leidenfrost onset

Observation of spatiotemporal intermittency with wet and dry regions

Statistical properties match directed percolation universality class

Abstract

Volatile drops deposited on a hot solid can levitate on a cushion of their own vapor, without contacting the surface. We propose to understand the onset of this so-called Leidenfrost effect through an analogy to non-equilibrium systems exhibiting a directed percolation phase transition. When performing impacts on superheated solids, we observe a regime of spatiotemporal intermittency in which localized wet patches coexist with dry regions on the substrate. We report a critical surface temperature, which marks the upper bound of a large range of temperatures in which levitation and contact coexist. In this range, with decreasing temperature, the equilibrium wet fraction increases continuously from zero to one. Also, the statistical properties of the spatio-temporally intermittent regime are in agreement with that of the directed percolation universality class. This analogy allows us to redefine the Leidenfrost temperature and shed light on the physical mechanisms governing the transition to the Leidenfrost state.