熱を排出するために設計された表面を使用する、画期的な発見(Virginia Tech researcher’s breakthrough discovery uses engineered surfaces to shed heat)

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2024-05-24 バージニア工科大学(VirginiaTech)

バージニア工科大学のJiangtao Cheng教授の研究チームは、従来230℃以上で発生するライデンフロスト効果を130℃で発生させる方法を発見しました。この効果は、水滴が蒸気の層の上に浮かび、熱伝達の応用に重要です。研究では、マイクロピラーで覆われた表面を使用し、水滴内部に効率的に熱を伝え、低温での浮揚を実現しました。この技術は、産業機械の冷却や核設備の安全性向上に貢献し、蒸気爆発のリスクを低減します。また、表面の自己清浄能力も向上させます。

<関連情報>

微小構造表面上の無柄な液滴の低温ライデンフロスト様ジャンピング Low-temperature Leidenfrost-like jumping of sessile droplets on microstructured surfaces

Wenge Huang,Lei Zhao,Xukun He,Yang Li,C. Patrick Collier,Zheng Zheng,Jiansheng Liu,Dayrl P. Briggs & Jiangtao Cheng
Nature Physics  Published:24 May 2024
DOI:https://doi.org/10.1038/s41567-024-02522-z

熱を排出するために設計された表面を使用する、画期的な発見(Virginia Tech researcher’s breakthrough discovery uses engineered surfaces to shed heat)

Abstract

The Leidenfrost effect—the levitation and hovering of liquid droplets on hot solid surfaces—generally requires a sufficiently high substrate temperature to activate liquid vaporization. Here we report the modulation of Leidenfrost-like jumping of sessile water microdroplets on micropillared surfaces at a relatively low temperature. Compared to traditional Leidenfrost effect occurring above 230 °C, the fin-array-like micropillars enable water microdroplets to levitate and jump off the surface within milliseconds at a temperature of 130 °C by triggering the inertia-controlled growth of individual vapour bubbles at the droplet base. We demonstrate that droplet jumping, resulting from momentum interactions between the expanding vapour bubble and the droplet, can be modulated by tailoring of the thermal boundary layer thickness through pillar height. This enables regulation of the bubble expansion between the inertia-controlled mode and the heat-transfer-limited mode. The two bubble-growth modes give rise to distinct droplet jumping behaviours characterized by constant velocity and constant energy regimes, respectively. This heating strategy allows the straightforward purging of wetting liquid droplets on rough or structured surfaces in a controlled manner, with potential applications including the rapid removal of fouling media, even when located in surface cavities.

0105熱工学
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