Surface charge enhanced kinetically-limited evaporation in nanopores
Surface charge enhanced kinetically-limited evaporation in nanopores
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DOI：
10.1016/j.ijheatmasstransfer.2023.123865
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发表时间：
2023
影响因子：
5.2
通讯作者：
Chu-Yao Chou;Chuanhua Duan
中科院分区：
文献类型：
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作者：
Chu-Yao Chou;Chuanhua Duan
了解纳米孔中动力学限制的水蒸发的基本原理对于提高现代基于蒸发的热管理设备的性能具有重要意义。然而，普遍存在的离子在水溶液中和固体壁上的带电官能团已被忽略传统和表面电荷对纳米孔蒸发的影响仍然难以捉摸。在此，我们考虑了表面电荷对分离压力的影响，并数值求解了单纳米孔蒸发过程中的传热传质方程组，以获得各种工作条件下的最终蒸发。我们的研究结果表明，表面电荷，沿着与孔半径，壁温，和环境空气的相对湿度，起着决定系统的整体性能的关键作用。随着表面电荷密度的增加，或者随着孔半径的减小，扩展的弯月面导致每单位孔面积的更高的净蒸发速率。提高孔壁温度增加了蒸发的驱动力，并导致更好的性能，尽管弯月面收缩。这项工作的结果提供了新的理解纳米相变传热，是有益的应用需要强烈的蒸发，如电子冷却，正渗透，膜蒸馏。
Understanding the fundamentals of the kinetically-limited water evaporation in nanopores is of significant importance to improve the performance of modern evaporation-based thermal management devices. However, the ubiquitous existence of ions in aqueous solutions and charged function groups on solid walls have been ignored traditionally and the effect of surface charges on nanopore evaporation remains elusive. Herein, we consider the effect of surface charges on disjoining pressure and solve the system of equations governing the heat and mass transfer during the evaporation process from single nanopores numerically to yield the ultimate evaporation under various working conditions. Our results reveal that the surface charge, along with pore radius, wall temperature, and the relative humidity of ambient air, plays a critical role in determining the overall performance of the system. As the surface charge density increases, or as the pore radius decreases, the extended meniscus leads to a higher net rate of evaporation per unit pore area. Increasing the pore wall temperature increases the driving force for evaporation and results in a better performance despite the meniscus contracted. Results of this work provide new understanding of nanoscale phase-change heat transfer and is beneficial to applications requiring intensive evaporation, such as electronic cooling, forward osmosis, and membrane distillation.