Jiang Guochen, Wang Lizhong, Tian Ze, Chen Changhao, Hu Xinyu, Peng Rui, Li Daizhou, Zhang Hongjun, Fan Peixun, Zhong Minlin
Laser Materials Processing Research Center, Key Laboratory for Advanced Materials Processing Technology (Ministry of Education), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China.
Mater Horiz. 2023 Aug 29;10(9):3523-3535. doi: 10.1039/d3mh00548h.
Capillary-fed thin-film evaporation micro/nanoscale structures has attracted increasing attention for its high evaporation flux and pumpless liquid replenishment. However, maximizing thin-film evaporation has been hindered by the intrinsic trade-off between the heat flux and liquid transport. Here, we designed and fabricated nanostructured micro-steam volcanoes on copper surfaces featuring triple-level super-wicking routes to overcome this trade-off and boost water evaporation. The triple-level super-wicking routes enable the continuous formation of a 3D thin film for highly efficient evaporation by continuous self-driven liquid replenishment and extending the thin-film region. The micro-steam volcanoes increased the surface area by 225%, improving the evaporation rate by 141%, with a rapid self-pumping water transport speed up to 80 mm s. A remarkable solar-driven water evaporation rate of 3.33 kg m h under one sun vertical incidence was achieved, which is among the highest reported values for metal-based evaporators. When attached to electric-heating plates, the evaporator realized an electrothermal evaporation rate of 12.13 kg m h. Moreover, it can also be used for evaporative cooling with enhanced convective heat transfer, reaching a 36.2 °C temperature reduction on a heat source with a heat flux of 6 W cm. This study promises a general strategy for designing thin-film evaporators with high efficiencies, low costs, and multi-functional compatibilities.
毛细管供液的薄膜蒸发微纳结构因其高蒸发通量和无泵液体补充而受到越来越多的关注。然而，热通量和液体传输之间的内在权衡阻碍了薄膜蒸发的最大化。在此，我们在铜表面设计并制造了具有三级超级芯吸路径的纳米结构微蒸汽火山，以克服这种权衡并促进水的蒸发。三级超级芯吸路径通过连续的自驱动液体补充和扩展薄膜区域，实现了用于高效蒸发的三维薄膜的连续形成。微蒸汽火山使表面积增加了225%，蒸发速率提高了141%，自抽水输水速度高达80 mm/s。在一个太阳垂直入射下，实现了3.33 kg m² h的显著太阳能驱动水蒸发速率，这是金属基蒸发器报道的最高值之一。当连接到电加热板上时，蒸发器实现了12.13 kg m² h的电热蒸发速率。此外，它还可用于增强对流换热的蒸发冷却，在热通量为6 W/cm²的热源上实现了36.2℃的降温。这项研究为设计具有高效率、低成本和多功能兼容性的薄膜蒸发器提供了一种通用策略。
