Journal
APPLIED THERMAL ENGINEERING
Volume 149, Issue -, Pages 325-331Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.applthermaleng.2018.12.049
Keywords
Nucleate boiling; Organic fluids; Wettability patterning; Hydrophobic coating; Heat transfer enhancement
Ask authors/readers for more resources
Due to the considerably reduced boiling point, organic fluids such as ethanol provide an attractive alternative to water as the working fluid in two-phase thermal management systems for high-heat-flux applications. The state-of-the-art enhancement methods for ethanol boiling normally involve surface structure engineering. Here we report, for the first time, enhancement of nucleate boiling of ethanol using wettability-patterned surfaces. By depositing onto a polished copper surface an array of circular spots of superamphiphobic coating of modified halloysite nanotubes (HNT) with fluoropolymer, which was shown to repel low-surface-tension fluids, we managed to create a meaningful biphilic pattern of alternating hydrophobicity (with ethanol contact angle exceeding 100 degrees) and hydrophilicity (with contact angle close to 0 degrees) on the surface. Boiling heat transfer was found to be improved dramatically on the coated surface. Specifically, the onset of nucleate boiling was found to drop by more than 35%. Moreover, at 20 K surface superheat (above the boiling point), a maximum heat transfer enhancement over 300% compared with a plain copper surface occurred on the surface with a pitch-to-spot ratio close to 2.5. The significantly increased heat transfer rate of the biphilic surfaces could be attributed to facilitated bubble nucleation and stronger agitation effect.
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