Dropwise Condensation Modeling Suitable for Superhydrophobic Surfaces
Dropwise Condensation Modeling Suitable for Superhydrophobic Surfaces
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DOI：
10.1115/1.4003742
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发表时间：
2011-08-01
影响因子：
--
通讯作者：
Kim, Kwang J.
中科院分区：
文献类型：
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作者：
Kim, Sunwoo;Kim, Kwang J.
开发了一个数学模型来表示和预测具有疏水或超疏水（接触角大于150度）特征的非湿润表面上的滴状冷凝现象。该模型是将单个液滴的传热与液滴尺寸分布综合起来建立的。单个液滴的热传递被分析为汽-液界面阻力、由于通过液滴本身的传导引起的阻力、来自涂层的阻力以及由于液滴的曲率引起的阻力的组合。人口平衡模型是适应发展的小滴，直接冷凝增长的液滴分布函数。由一个著名的经验方程得到的大滴，主要是通过聚结增长的液滴尺寸分布。实验结果表明，接触角对单液滴的传热和液滴分布都有很大的影响。更具体地说，模型的结果表明，一个高的液滴接触角导致增强冷凝传热。强烈的疏水性会产生高接触角，导致由于重力而即将落下的液滴尺寸减小，从而为更多的小液滴提供空间。模拟结果与实验数据进行了比较，这是以前报道。[DOI 10.1115/1.4003742]
A mathematical model is developed to represent and predict the dropwise condensation phenomenon on nonwetting surfaces having hydrophobic or superhydrophobic (contact angle greater than 150 deg) features. The model is established by synthesizing the heat transfer through a single droplet with the drop size distribution. The single droplet heat transfer is analyzed as a combination of the vapor-liquid interfacial resistance, the resistance due to the conduction through the drop itself, the resistance from the coating layer, and the resistance due to the curvature of the drop. A population balance model is adapted to develop a drop distribution function for the small drops that grow by direct condensation. Drop size distribution for large drops that grow mainly by coalescence is obtained from a well-known empirical equation. The evidence obtained suggests that both the single droplet heat transfer and drop distribution are significantly affected by the contact angle. More specifically, the model results indicate that a high drop-contact angle leads to enhancing condensation heat transfer. Intense hydrophobicity, which produces high contact angles, causes a reduction in the size of drops on the verge of falling due to gravity, thus allowing space for more small drops. The simulation results are compared with experimental data, which were previously reported. [DOI: 10.1115/1.4003742]