Leidenfrost Self-Rewetting Drops
Résumé
As discovered by Leidenfrost, liquids placed on very hot solids levitate on a cushion of their own vapor. This is also called the calefaction phenomenon, a dynamical and transient effect, as vapor is injected below the liquid and pressed by the drop weight. To account for the film vapor, we consider the surface tension magnitude as well as the Marangoni effect (in particular the thermal one) which arise with imbalance of surface tension forces. For standard liquids, these forces contribute to amplify the thickness of the film layer and the levitation of the droplet. Our findings imply the ability of recent binary mixture liquids, called self-rewetting fluids, to reduce the vapor film thickness and demonstrate the powerful influence exerted by different binary mixtures to enhance the heat transfer at high temperature. Such self-rewetting fluids are presenting a high value of surface tension at high temperature, and in which the Marangoni forces are inversed as from critical temperature. We consider our assay to be a way for improvement in the high temperature mass cooling applications.