The Leidenfrost effect: from quasi-spherical droplets to puddles

TL;DR

This paper develops a theoretical model for the Leidenfrost effect, deriving equations for droplet and puddle geometries that align with experimental data across different size regimes.

Contribution

It introduces a new set of equations based on lubrication approximation to describe the steady bottom profile of Leidenfrost drops and puddles, providing scaling laws for their geometry.

Findings

Model agrees with experimental observations for small droplets

Model accurately predicts puddle geometries for larger radii

Provides unified description across different droplet sizes

Abstract

In the framework of the lubrication approximation, we derive a set of equations describing the steady bottom profile of Leidenfrost drops coupled with the vapor pressure. This allows to derive scaling laws for the geometry of the concave bubble encapsulated between the drop and the hot plate under it. The results agree with experimental observations in the case of droplets with radii smaller than the capillary length Rc as well as in the case of puddles with radii larger than Rc.