Journal
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
Volume 129, Issue -, Pages 86-95Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.ijheatmasstransfer.2018.09.100
Keywords
Dropwise condensation; Superhydrophobic surface; Long-term operation; Droplet removal; Failure
Categories
Funding
- National Natural Science Foundation of China [51436004]
- China Postdoctoral Science Foundation [2017M620712]
- Fundamental Research Funds for the Central Universities [JB2014005]
Ask authors/readers for more resources
Dropwise condensation heat transfer (DWC) on superhydrophobic nanograsses surface (NGS) was investigated for long-term operation. For DWC of pure water-vapor on fresh NGS, two heat transfer regimes are identified: higher heat transfer coefficients with droplet jumping, and constant heat transfer coefficients with droplet rolling. The one-week operation not only deteriorates heat transfer performance, but also changes jumping or rolling mode to sliding mode. The condensation heat transfer coefficients are apparently decreased from first to third day, but they approach a limit value since the third day. In order to identify if the single-molecule-layer of polymer (SML) modified on nanograsses was destroyed, DWC on a smooth single-molecule-layer of polymer surface (SSML) was tested to display stable heat transfer with drop sliding for one-week operation, concluding no failure of the polymer layer. The collapse and breakage of nanograsses were observed to explain the decayed heat transfer versus time on NGS. Compared with SSML, the NGS has smaller droplet departure size but lower heat transfer coefficients, indicating positive and negative effects after introducing nanostructures. Three nanostructure failure mechanisms are proposed. This work suggests a new research field of the nanoscale fluid-wall interaction. (C) 2018 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available