Hatte Sandeep, Pitchumani Ranga
Advanced Materials and Technologies Laboratory, Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061-0238, USA.
iScience. 2024 Sep 27;27(11):111059. doi: 10.1016/j.isci.2024.111059. eCollection 2024 Nov 15.
Surface condensation is ubiquitous in applications such as power generation and desalination. Nonwetting surfaces have been studied extensively for their dropwise condensation potential with reports of dramatic improvements relative to the classical Nusselt equation for film-wise condensation that has long served as a reference theoretical on the condensation heat transfer coefficient. However, a theoretical on the possible condensation heat transfer over a given surface is not available. Considering actual surface topographies as fractal surfaces, we present theoretical upper bounds for gravity-driven and jumping droplet condensation modes in a unified manner. Experimental data on steam condensation from this study as well as the literature on dry nonwetting surfaces are compared to the bounds to identify the opportunity gap to the theoretical maximum. Solid-infused surfaces, introduced recently by the authors, are shown to fall in this opportunity space, closer to the upper bound.
表面冷凝在发电和海水淡化等应用中无处不在。非润湿性表面因其滴状冷凝潜力而受到广泛研究，与长期以来作为冷凝传热系数参考理论的经典努塞尔膜状冷凝方程相比，有显著改进的报道。然而，目前尚无关于给定表面上可能的冷凝传热的理论。将实际表面形貌视为分形表面，我们以统一的方式给出了重力驱动和跳跃液滴冷凝模式的理论上限。将本研究中蒸汽冷凝的实验数据以及关于干燥非润湿性表面的文献与这些上限进行比较，以确定与理论最大值之间的差距。作者最近引入的注入固体的表面被证明处于这个差距范围内，更接近上限。
