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Proceedings of the 27th National and 5th International ISHMT-ASTFE Heat and Mass Transfer Conference December 14-17, 2023, IIT Patna, Patna-801106, Bihar, India
December, 14-17, 2023, Bihar, India

Bouncing Dynamics of a Binary Solution Droplet in the Leidenfrost State

Get access (open in a dialog) DOI: 10.1615/IHMTC-2023.220
pages 129-135


A liquid droplet placed on a substrate which is at a significantly higher temperature compared to the saturation temperature of the liquid hovers over a thin film of vapor. This film boiling regime of the droplet is termed as the Leidenfrost (LF) state and is detrimental to heat transfer due to the low thermal conductivity of the vapor. Leidenfrost water droplets with size larger than the capillary length scale (~ 2.7 mm) show behaviors ranging from star-shaped oscillations to underdamped bouncing and trampolining as the droplet evaporates. Here, we report on the dynamics of a Leidenfrost droplet comprising of a binary solution of glycerol and water on a slightly concave stainless-steel substrate. A LF droplet with size (radius ~ 1 mm) less than the capillary length scale initially demonstrates underdamped bouncing and trampolining on the heated substrate until it evaporates and reaches a hovering state where the amplitude of bouncing becomes negligible, which is again followed by bouncing. High-speed visualizations show that the diameter corresponding to the transition from bouncing to hovering state of the droplet is a characteristic of the fluid properties, which can be altered by changing the concentration of glycerol in the solution. Depending on the concentration of the solution, the droplet either continues to bounce on the substrate with gradually increasing amplitude till it explodes or completely evaporates.