Drop Evaporation on Rough Hot-Spots: Effect of Wetting Modes

Huacheng Zhang; Yutaku Kita; Dejian Zhang; Gyoko Nagayama; Yasuyuki Takata; Khellil Sefiane; Alexandros Askounis

Drop Evaporation on Rough Hot-Spots: Effect of Wetting Modes

Huacheng Zhang, Yutaku Kita, Dejian Zhang, Gyoko Nagayama, Yasuyuki Takata, Khellil Sefiane, Alexandros Askounis^*

^*Corresponding author for this work

Engineering

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Abstract

Hot-spots are a common occurrence in power electronics which become increasingly hotter as chips become denser. Novel cooling technologies are emerging to cope with this increasing heat load, which imbed a condenser to supply cooling drops to the evaporator resting on the hot-spots. Nonetheless, the evaporation process of the drops has been overlooked. Here, we conducted a series of experiments to understand how the evaporation and motion of drops are influenced by the wetting mode of rough hot-spots. We fabricated three different surfaces exhibiting full (Wenzel) or partial (Cassie–Baxter) wetting and the hot-spot is imposed by laser irradiation. We report a direct link between drop motion and wetting mode with the partial wetting drops being highly mobile, attributable to lower pinning energy based on an energy analysis. This study provides a framework for future modifications in hot-spot cooling to account for drop motion which should greatly influence the overall heat removal performance.

Original language	English
Pages (from-to)	1654-1662
Journal	HEAT TRANSFER ENGINEERING
Volume	41
Issue number	19-20
Publication status	Published - 12 Aug 2019

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Accepted_manuscript
This is an Accepted Manuscript of an article published by Taylor & Francis in Heat Transfer Engineering on 12 August 2019, available at: https://www.tandfonline.com/doi/full/10.1080/01457632.2019.1640458
Accepted author manuscript, 1.04 MBLicence: CC BY-NC-ND

Cite this

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title = "Drop Evaporation on Rough Hot-Spots: Effect of Wetting Modes",

abstract = "Hot-spots are a common occurrence in power electronics which become increasingly hotter as chips become denser. Novel cooling technologies are emerging to cope with this increasing heat load, which imbed a condenser to supply cooling drops to the evaporator resting on the hot-spots. Nonetheless, the evaporation process of the drops has been overlooked. Here, we conducted a series of experiments to understand how the evaporation and motion of drops are influenced by the wetting mode of rough hot-spots. We fabricated three different surfaces exhibiting full (Wenzel) or partial (Cassie–Baxter) wetting and the hot-spot is imposed by laser irradiation. We report a direct link between drop motion and wetting mode with the partial wetting drops being highly mobile, attributable to lower pinning energy based on an energy analysis. This study provides a framework for future modifications in hot-spot cooling to account for drop motion which should greatly influence the overall heat removal performance.",

author = "Huacheng Zhang and Yutaku Kita and Dejian Zhang and Gyoko Nagayama and Yasuyuki Takata and Khellil Sefiane and Alexandros Askounis",

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T1 - Drop Evaporation on Rough Hot-Spots: Effect of Wetting Modes

AU - Zhang, Huacheng

AU - Kita, Yutaku

AU - Zhang, Dejian

AU - Nagayama, Gyoko

AU - Takata, Yasuyuki

AU - Sefiane, Khellil

AU - Askounis, Alexandros

PY - 2019/8/12

Y1 - 2019/8/12

N2 - Hot-spots are a common occurrence in power electronics which become increasingly hotter as chips become denser. Novel cooling technologies are emerging to cope with this increasing heat load, which imbed a condenser to supply cooling drops to the evaporator resting on the hot-spots. Nonetheless, the evaporation process of the drops has been overlooked. Here, we conducted a series of experiments to understand how the evaporation and motion of drops are influenced by the wetting mode of rough hot-spots. We fabricated three different surfaces exhibiting full (Wenzel) or partial (Cassie–Baxter) wetting and the hot-spot is imposed by laser irradiation. We report a direct link between drop motion and wetting mode with the partial wetting drops being highly mobile, attributable to lower pinning energy based on an energy analysis. This study provides a framework for future modifications in hot-spot cooling to account for drop motion which should greatly influence the overall heat removal performance.

AB - Hot-spots are a common occurrence in power electronics which become increasingly hotter as chips become denser. Novel cooling technologies are emerging to cope with this increasing heat load, which imbed a condenser to supply cooling drops to the evaporator resting on the hot-spots. Nonetheless, the evaporation process of the drops has been overlooked. Here, we conducted a series of experiments to understand how the evaporation and motion of drops are influenced by the wetting mode of rough hot-spots. We fabricated three different surfaces exhibiting full (Wenzel) or partial (Cassie–Baxter) wetting and the hot-spot is imposed by laser irradiation. We report a direct link between drop motion and wetting mode with the partial wetting drops being highly mobile, attributable to lower pinning energy based on an energy analysis. This study provides a framework for future modifications in hot-spot cooling to account for drop motion which should greatly influence the overall heat removal performance.

UR - https://doi.org/10.1080/01457632.2019.1640458

M3 - Article

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JO - HEAT TRANSFER ENGINEERING

JF - HEAT TRANSFER ENGINEERING

IS - 19-20

ER -

Drop Evaporation on Rough Hot-Spots: Effect of Wetting Modes

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