Heat transfer to bouncing droplets on superhydrophobic surfaces
Heat transfer to bouncing droplets on superhydrophobic surfaces
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DOI：
10.1016/j.ijheatmasstransfer.2019.03.103
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发表时间：
2018-11
影响因子：
5.2
通讯作者：
Chunfang Guo;Daniel Maynes;J. Crockett;Danyang Zhao
中科院分区：
文献类型：
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作者：
Chunfang Guo;Daniel Maynes;J. Crockett;Danyang Zhao
本文从实验和理论两方面研究了加热到沸点以下的超疏水表面上水滴撞击的动力学和传热。与撞击亲水性基底不同，液滴在扩展和收缩阶段之后从表面反弹。实验进行同步高速视频和红外（IR）成像捕捉液滴动态和温度变化的瞬态过程中。热图像允许估计接触期间的整体液滴温度变化，使得可以估计单个液滴的冷却效果。一个相似的解决方案是利用产生一个模型的瞬态热通量在液滴壁界面，液滴内的对流占。冷却效率的实验和理论结果显示出良好的一致性。结果表明，冷却效率随韦伯数的增加而增加，但随液滴直径和表面空穴率（空穴面积与总表面积的比值）的增加而减小。
This study experimentally and theoretically investigates the dynamics and heat transfer to impinging water droplets on superhydrophobic surfaces heated below the boiling temperature. Different from impingement on hydrophilic substrates, the droplets rebound from the surface after the spreading and retraction stages. Experiments are performed using simultaneous high speed video and infrared (IR) imaging to capture droplet dynamics and temperature variation during the transient event. Thermal images allow estimation of bulk droplet temperature change during contact such that the cooling effectiveness for an individual droplet can be estimated. A similarity solution is utilized to yield a model for the transient heat flux at the droplet-wall interface, where convection inside the droplet is accounted for. The experimental and theoretical results for the cooling effectiveness show good agreement. It is revealed that the cooling effectiveness increases with Weber number but decreases with droplet diameter and surface cavity fraction (the ratio of cavity area to total surface area).