scholarly journals A Study of Droplet-Behavior Transition on Superhydrophobic Surfaces for Efficiency Enhancement of Condensation Heat Transfer

ACS Omega ◽  
2020 ◽  
Vol 5 (43) ◽  
pp. 27880-27885
Author(s):  
Jeong-Won Lee ◽  
Dae-Yun Ji ◽  
Kwon-Yeong Lee ◽  
Woonbong Hwang
Keyword(s):  
Heat Transfer ◽  
Condensation Heat Transfer ◽  
Superhydrophobic Surfaces ◽  
Efficiency Enhancement ◽  
Droplet Behavior

Condensation heat transfer on two-tier superhydrophobic surfaces

2012 ◽  
Vol 101 (13) ◽  
pp. 131909 ◽  
Author(s):  
Jiangtao Cheng ◽  
Aref Vandadi ◽  
Chung-Lung Chen
Keyword(s):  
Heat Transfer ◽  
Condensation Heat Transfer ◽  
Superhydrophobic Surfaces

scholarly journals Vibration-enhanced condensation heat transfer on superhydrophobic surfaces: An experimental study

AIP Advances ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 095123
Author(s):  
Mostafa Moradi ◽  
Seyed Farshid Chini ◽  
Mohammad Hassan Rahimian
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Condensation Heat Transfer ◽  
Superhydrophobic Surfaces

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.

Condensation Heat Transfer on Two-Tier Superhydrophobic Surfaces

2012 ◽  
Author(s):  
Jiangtao Cheng ◽  
Aref Vandadi ◽  
Chung-Lung Chen
Keyword(s):  
Heat Transfer ◽  
Hydrophobic Surface ◽  
High Heat ◽  
Condensation Heat Transfer ◽  
Superhydrophobic Surfaces ◽  
Environmental Scanning ◽  
High Heat Flux ◽  
Textured Surface ◽  
Wenzel State ◽  
Moisture Condensation

Superhydrophobic surfaces exhibit large contact angle (> 150°) and small hysteresis (< 5°) which facilitate liquid transport and are expected to enhance condensation heat transfer on the surfaces. By growing short carbon nanotubes (CNTs) on an array of microposts etched on a silicon wafer, we formed a two-tier multiscale texture mimicking the surface structure of lotus leaves. Compared to one-tier microtexture which energetically favors the Wenzel state, the two-tier texture with micro/nano-scale roughness favors the Cassie state, the desired superhydrophobic state. Using an environmental scanning electron microscope (ESEM), we investigated moisture condensation on the fluoropolymer-coated two-tier texture and we have observed continuous dropwise condensation on the engineered superhydrophobic surface. However, in a customer-designed vapor chamber our condensation measurements indicate that a film layer of condensate in Wenzel state was formed on the textured surface. In particular, due to the filmwise condensation, the condensation heat transfer coefficient of the lotus-leaf-like surface is lower than that of a smooth hydrophobic surface especially under high heat flux situations.

scholarly journals Condensation heat transfer on superhydrophobic surfaces

MRS Bulletin ◽  
2013 ◽  
Vol 38 (5) ◽  
pp. 397-406 ◽  
Author(s):  
Nenad Miljkovic ◽  
Evelyn N. Wang
Keyword(s):  
Heat Transfer ◽  
Condensation Heat Transfer ◽  
Superhydrophobic Surfaces ◽  
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