Reshaping and Capturing Leidenfrost drops with a magnet

TL;DR

This paper investigates how paramagnetic liquid oxygen drops deform and are manipulated by magnetic fields during the Leidenfrost effect, revealing new ways to control and trap such drops.

Contribution

It introduces a model for drop deformation under magnetic forces and demonstrates magnetic trapping of Leidenfrost drops, a novel approach for manipulating paramagnetic liquids.

Findings

Deformation of oxygen drops can be described by an effective capillary length including magnetic effects.

Magnetic fields significantly slow down and trap Leidenfrost drops.

Critical velocity for trapping is determined from deformation analysis.

Abstract

Liquid oxygen, which is paramagnetic, also undergoes Leidenfrost effect at room temperature. In this article, we first study the deformation of oxygen drops in a magnetic field and show that it can be described via an effective capillary length, which includes the magnetic force. In a second part, we describe how these ultra-mobile drops passing above a magnet significantly slow down and can even be trapped. The critical velocity below which a drop is captured is determined from the deformation induced by the field.