As an efficient method of seawater desalination, multi-stage solar distillation based on interfacial heat localization is facing to the problems of salt ions accumulation and crystallization that hard to discharge, which makes it difficult to obtain scalable and sustainable water production. Here we proposed and explored a fully passive and extra efficient discharge mechanism of concentrated brine based on open siphoning flow. Nano fiber is used as the super-hydrophilic membranous wick to analyze open siphoning flow. It is found the siphoning flowrate tends to the same value when each of suction height and short transverse flow length is large enough, which makes it possible to match the siphoning flowrate and heat capacity among multiple evaporation-condensation interfaces. A three-stage solar distiller was constructed and studied theoretically and experimentally. Under one sun (1000 W/m²), the water productivity is 238 g/h, which is nearly 82% of the total seawater flowing in, and the remaining 18% flows out as strong brine with a salinity of 19.6%. In addition, a water production of 940 g is obtained with an average gained-output ratio of 1.5 in a whole-day test, namely, 11.99 kg/(d·m²). This study may improve large-scale interfacial evaporation with efficient salt rejection.

作为一种高效的海水淡化方法，基于界面热定域的多级太阳能蒸馏面临着盐离子积累结晶难排放的问题，难以获得规模化、可持续的产水。在这里，我们提出并探索了一种基于开放虹吸流的完全被动和超高效的浓盐水排放机制。使用纳米纤维作为超亲水膜芯来分析开放虹吸流。发现当吸入高度和短横流长度各自足够大时，虹吸流量趋于相同的值，这使得多个蒸发-冷凝界面之间的虹吸流量和热容匹配成为可能。构建了一个三级太阳能蒸馏器，并进行了理论和实验研究。在一个阳光下 (1000 W/m² )，产水量为238 g/h，占流入海水总量的近82%，其余18%以盐度19.6%的浓盐水流出。此外，全天试验平均产水量为1.5，即11.99 kg/(d·m ² ) ，产水量为940 g 。这项研究可以通过有效的脱盐来改善大规模界面蒸发。