Dropwise condensation on superhydrophobic surfaces with two-tier roughness

2007 ◽  
Vol 90 (17) ◽  
pp. 173108 ◽  
Author(s):  
Chuan-Hua Chen ◽  
Qingjun Cai ◽  
Chialun Tsai ◽  
Chung-Lung Chen ◽  
Guangyong Xiong ◽  
...  
Keyword(s):  
Superhydrophobic Surfaces ◽  
Dropwise Condensation

Three dimensional aspects of droplet coalescence during dropwise condensation on superhydrophobic surfaces

Soft Matter ◽  
2011 ◽  
Vol 7 (19) ◽  
pp. 8749 ◽  
Author(s):  
Konrad Rykaczewski ◽  
John Henry J. Scott ◽  
Sukumar Rajauria ◽  
Jeff Chinn ◽  
Amy M. Chinn ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Superhydrophobic Surfaces ◽  
Dropwise Condensation ◽  
Droplet Coalescence

Resistant Energy Analysis of Dropwise Condensation on Superhydrophobic Surfaces With Hierarchical Roughness

2017 ◽  
Author(s):  
Jiangtao Cheng
Keyword(s):  
Contact Line ◽  
Growth Dynamics ◽  
Adhesion Energy ◽  
Superhydrophobic Surfaces ◽  
Dropwise Condensation ◽  
Textured Surfaces ◽  
Biomimetic Surfaces ◽  
Molecular Kinetic Theory ◽  
Submicron Scale ◽  
Second Tier

Recently there have appeared multiscale lotus-leaf-like superhydrophobic surfaces that can enhance dropwise condensation in well-tailored supersaturation conditions. However, designs of most biomimetic surfaces were not driven by the understanding of underlying physical mechanisms. We report energy-based analysis of growth dynamics of condensates from surface cavities. As observed in condensation experiments, these textured surfaces with two tier roughness are superior to flat or solely nanotextured surfaces in spatial control of condensate droplets. To understand the role of condensate state transition in enhancing condensation heat transfer, we considered adhesion energy, viscous dissipation and contact line dissipation as the main portion of resistant energy that needs to be overcome by the condensates formed in surface cavities. By minimizing the energy barrier associated with the self-pulling process, we optimized first tier roughness on the hierarchically textured surfaces allowing condensates to grow preferentially in the out-of-plane direction. The nano-roughness of the second tier plays an important role in abating the adhesion energy in the cavities and contact line pinning. From the perspective of molecular kinetic theory, the dual scale engineered surface is beneficial to remarkably mitigating contact line dissipation. This study indicates that scaling down surface roughness to submicron scale can facilitate self-propelled condensate removal.

Dewetting Transitions of Dropwise Condensation on Nanotexture-Enhanced Superhydrophobic Surfaces

ACS Nano ◽  
2015 ◽  
Vol 9 (12) ◽  
pp. 12311-12319 ◽  
Author(s):  
Cunjing Lv ◽  
Pengfei Hao ◽  
Xiwen Zhang ◽  
Feng He
Keyword(s):  
Superhydrophobic Surfaces ◽  
Dropwise Condensation

Scale Effect on Dropwise Condensation on Superhydrophobic Surfaces

2014 ◽  
Vol 6 (16) ◽  
pp. 14353-14359 ◽  
Author(s):  
Ching-Wen Lo ◽  
Chi-Chuan Wang ◽  
Ming-Chang Lu
Keyword(s):  
Scale Effect ◽  
Superhydrophobic Surfaces ◽  
Dropwise Condensation

scholarly journals Superhydrophobic Surfaces: Nanograssed Micropyramidal Architectures for Continuous Dropwise Condensation (Adv. Funct. Mater. 24/2011)

2011 ◽  
Vol 21 (24) ◽  
pp. 4597-4597
Author(s):  
Xuemei Chen ◽  
Jun Wu ◽  
Ruiyuan Ma ◽  
Meng Hua ◽  
Nikhil Koratkar ◽  
...  
Keyword(s):  
Superhydrophobic Surfaces ◽  
Dropwise Condensation

scholarly journals Effect of Surface Structure Complexity on Interfacial Droplet Behavior of Superhydrophobic Titanium Surfaces for Robust Dropwise Condensation

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4107
Author(s):  
Je-Un Jeong ◽  
Dae-Yun Ji ◽  
Kwon-Yeong Lee ◽  
Woonbong Hwang ◽  
Chang-Hun Lee ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Surface Structure ◽  
Surface Structures ◽  
Superhydrophobic Surfaces ◽  
Dropwise Condensation ◽  
Exchange Performance ◽  
Droplet Behavior ◽  
Titanium Surfaces ◽  
Structure Complexity

In general, the dropwise condensation supported by superhydrophobic surfaces results in enhanced heat transfer relative to condensation on normal surfaces. However, in supersaturated environments that exceed a certain supersaturation threshold, moisture penetrates the surface structures and results in attached condensation, which reduces the condensation heat transfer efficiency. Therefore, when designing superhydrophobic surfaces for condensers, the surface structure must be resistant to attached condensation in supersaturated conditions. The gap size and complexity of the micro/nanoscale surface structure are the main factors that can be controlled to maintain water repellency in supersaturated environments. In this study, the condensation heat exchange performance was characterized for three different superhydrophobic titanium surface structures via droplet behavior (DB) mapping to evaluate their suitability for power plant condensers. In addition, it was demonstrated that increasing the surface structure complexity increases the versatility of the titanium surfaces by extending the window for improved heat exchange performance. This study demonstrates the usefulness of DB mapping for evaluating the performance of superhydrophobic surfaces regarding their applicability for industrial condenser systems.

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