Behavior of self-propelled acetone droplets in a Leidenfrost state on liquid substrates

Abstract

It is demonstrated that non-coalescent droplets of acetone can be formed on liquid substrates. The fluid flows around and in an acetone droplet hovering on water are recorded to shed light on the mechanisms which might lead to non-coalescence. For sufficiently low impact velocities, droplets undergo a damped oscillation on the surface of the liquid substrate but at higher velocities clean bounce-off occurs. Comparisons of experimentally observed static configurations of floating droplets to predictions from a theoretical model for a small non-wetting rigid sphere resting on a liquid substrate are made and a tentative strategy for determining the thickness of the vapor layer under a small droplet on a liquid is proposed. This strategy is based on the notion of effective surface tension. The droplets show self-propulsion in straight line trajectories in a manner which can be ascribed to a Marangoni effect. Surprisingly, self-propelled droplets can become immersed beneath the undisturbed water surface. This phenomenon is reasoned to be drag-inducing and might provide a basis for refining observations in previous work.

References in corpus (3)

• Drop impact on superheated surfaces
• The Geometry of the Vapor Layer Under a Leidenfrost Drop
• The Leidenfrost effect: from quasi-spherical droplets to puddles

Cited by in corpus (5)

• Self-propulsion of inverse Leidenfrost drops on a cryogenic bath
• Culinary fluid mechanics and other currents in food science
• Asymptotic theory for a Leidenfrost drop on a liquid pool
• Unexpected Suppression of Leidenfrost Phenomenon on Superhydrophobic Surfaces
• Effect of a surface tension imbalance on a partly submerged cylinder