Designing air-independent slippery rough surfaces for condensation
Designing air-independent slippery rough surfaces for condensation
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DOI：
10.1016/j.ijheatmasstransfer.2019.06.035
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发表时间：
2019-09
影响因子：
5.2
通讯作者：
G. Sirohia;X. Dai
中科院分区：
文献类型：
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作者：
G. Sirohia;X. Dai
强化冷凝换热对发电、换热器、集水、空调等行业具有重要意义。虽然超疏水表面(SHS)被广泛研究用于冷凝，但这种表面存在几个缺点：(1)疏水表面化学不利于成核，(2)空气润滑剂的导热性能较差，(3)空气腔在湿度升高或过冷时可能会移位。图案化的SHS可以增强亲水结构域中的汽相成核，但超疏水结构域仍然依赖于空气润滑剂，导致了与SHS相同的弱点。最近，通过用液体润滑剂取代空气润滑剂，液体注入表面得到了发展，从而产生了更坚固的润滑性以实现液体排斥。然而，最初设计的液体注入表面是平坦的润滑剂-水界面，这不能提供大的接触面积来进行换热。在这里，我们利用共形液体润滑法在粗糙的固体表面上成功地设计和制造了与空气无关的光滑粗糙表面(SRS)。表面化学成分是由液体润滑剂决定的，而不是由固体织构决定的，表面粗糙度由润滑的微观织构决定。在没有空气润滑剂的情况下，液滴在这种与空气无关的光滑粗糙表面上具有高度的流动性。我们的综合模型为冷凝换热中非常需要的与空气无关的光滑粗糙表面提供了合理的设计和优化。
Enhancing condensation heat transfer is significant for power generation, heat exchangers, water harvesting, and air-conditioning. While superhydrophobic surfaces (SHS) are widely studied for condensation, this type of surface suffers from several weaknesses: (1) the hydrophobic surface chemistry does not favor nucleation, (2) the air lubricant has poor thermal conductivity, and (3) the air pocket may be displaced at an elevated humidity or subcooling. Patterned SHS can enhance vapor nucleation in the hydrophilic domains, but the superhydrophobic domains still rely on the air lubricant, resulting in the same weakness as SHS. Recently, the liquid infused surfaces have been developed by replacing the air lubricant with liquid lubricant, leading to more robust lubrication for liquid repellency. However, the original design of liquid infused surfaces shows a flat lubricant-water interface, which cannot provide a large contact area for heat transfer. Here, we successfully designed and manufactured the air-independent slippery rough surfaces (SRS) by conformal liquid lubrication on the rough solid surfaces. The surface chemistry of the SRS is governed by the liquid lubricant, not the solid textures, and the roughness is determined by the lubricated microtextures. Droplets are highly mobile on this air-independent slippery rough surface in the absence of air lubricant. Our comprehensive models provide rational design and optimization for the air-independent slippery rough surface that is highly desired in condensation heat transfer.