Droplet trampolining on heated surfaces in the transitional boiling regime

Agrawal, P and Dash, S (2022) Droplet trampolining on heated surfaces in the transitional boiling regime. In: International Journal of Heat and Mass Transfer, 190 .

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Abstract

Droplet dynamics on a heated surface plays an important role in applications ranging from spray cooling to solidification and pharmaceuticals. Here, we show that in the transitional boiling regime, an unconstrained droplet exhibits trampolining where the droplet bounces to higher heights with each consecutive contact with the substrate. A water droplet of volume 1 μL bounces to a height as high as 6-7 times of its diameter and the height of bounce increases to 18�20 times the diameter as the volume reduces to � 0.1μL. The dynamics of the droplet in the transitional boiling regime results in a non-monotonic variation in the total evaporation time of the droplet with an increase in substrate temperature � an observation that is absent for a constrained droplet. We develop a force-based model to explain the trampolining behavior of the droplet and propose that the gain in momentum of the droplet that results in trampolining is caused by bubble nucleation and escape at the liquid-substrate interface prior to droplet takeoff. © 2022

Item Type:	Journal Article
Publication:	International Journal of Heat and Mass Transfer
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to the Elsevier Ltd
Department/Centre:	Division of Interdisciplinary Sciences > Interdisciplinary Centre for Energy Research Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	16 May 2022 06:36
Last Modified:	16 May 2022 06:36
URI:	https://eprints.iisc.ac.in/id/eprint/71678

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