Inverted Leidenfrost-like Effect during Condensation

Ramchandra Narhe; Sushant Anand; Konrad Rykaczewski; Marie-Gabrielle Medici; Wenceslao Gonzalez-Vinas; Kripa K. Varanasi; Daniel Beysens

Inverted Leidenfrost-like Effect during Condensation

Ramchandra Narhe ^{1, 2} Sushant Anand ³ Konrad Rykaczewski ⁴ Marie-Gabrielle Medici ^{1, 5} Wenceslao Gonzalez-Vinas ² Kripa K. Varanasi ³ Daniel Beysens ^{1, 6}

1 PMMH - Physique et mécanique des milieux hétérogenes

2 UNAV - Universidad de Navarra [Pamplona]

3 MIT-MECHE - Department of Mechanical Engineering

4 ASU - Arizona State University [Tempe]

5 LPMC - Laboratoire de physique de la matière condensée

6 SBT - Service des Basses Températures

Abstract : Water droplets condensing on solidified phase change materials such as benzene and cyclohexane near their melting point show in-plane jumping and continuous "crawling" motion. The jumping drop motion has been tentatively explained as an outcome of melting and refreezing of the materials surface beneath the droplets and can be thus considered as an inverted Leidenfrost-like effect (in the classical case vapor is generated from a droplet on a hot substrate). We present here a detailed investigation of jumping movements using high-speed imaging and static cross-sectional cryogenic focused ion beam scanning electron microscope imaging. Our results show that drop motion is induced by a thermocapillary (Marangoni) effect. The in-plane jumping motion can be delineated to occur in two stages. The first stage occurs on a millisecond time scale and comprises melting the substrate due to drop condensation. This results in droplet depinning, partial spreading, and thermocapillary movement until freezing of the cyclohexane film. The second stage occurs on a second time scale and comprises relaxation motion of the drop contact line (change in drop contact radius and contact angle) after substrate freezing. When the cyclohexane film cannot freeze, the droplet continuously glides on the surface, resulting in the crawling motion.

Keywords : Lubricant-Impregnated Surfaces Organic Liquids Drop Motion Coalescence Evaporation Mechanism

Document type :

Journal articles

Domain :

Physics [physics]

Complete list of metadatas

https://hal-cea.archives-ouvertes.fr/cea-01734598
Contributor : Jérôme Planès <>
Submitted on : Wednesday, March 14, 2018 - 6:03:36 PM
Last modification on : Thursday, July 4, 2019 - 11:00:05 AM

Inverted Leidenfrost-like Effect during Condensation

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Inverted Leidenfrost-like Effect during Condensation

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