Jumping Leidenfrost droplets

Abstract: A leidenfrost droplet forms when a liquid droplet is placed on a very hot surface. In the case that there is a thin layer of insulating material as a step on the substrate, under specific conditions Leidenfrost droplets interact with the edge of the step. The result of this interaction is sometimes lateral detachment or jumping from the surface. Specically, the best jumping can be observed when liquid nitrogen droplets move on a brass substrate with a piece of plastic tape as a step. This thesis experimentally studies the specific physics of the jumping process. We examined the effect of the step material, liquid property and the step height on the jumping process. We hypothesize that the Marangoni effect, due to thermal gradients contributes to this type of motion. This is evident by comparing the estimated Marangoni flow and measurement flow rate.