2-D microflow generation on superhydrophilic nanoporous substrates using epoxy spots for pool boiling enhancement. (April 2020)

• Record Type: Journal Article
• Authors: Najafpour, S.; Moosavi, A.; Rad, S.V.
• Is Part Of: International communications in heat and mass transfer. Volume 113(2020:Apr.)
• Publication Date: 2020-04
• Subjects: 2-D microflow -- Pool boiling enhancement -- Superhydrophilic nanoporous oxide layer -- Critical heat flux; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Heat -- Transmission; Mass transfer; Periodicals; 621.4022
• DOI: 10.1016/j.icheatmasstransfer.2020.104553
• Languages: English
• ISSNs: 0735-1933

Abstract

Abstract: We conduct an experimental investigation on the pool boiling enhancement in DI water on nanoporous surfaces. The surfaces are modified by anodic oxidation, and cavities with 2 mm diameter and pitches between 2.5 and 5 mm applied on them using EDM method filled with a two-part epoxy with low thermal conductivity properties. The capillary wicking action of the superhydrophilic nanoporous oxide layer enhances the rewetting and spreading of the liquid to dry-spots during boiling. The epoxy disks remain wet and prevent merging bubbles during the pool boiling experiment and a 2-D microflow is induced toward dried regions with synergic effects of nanoporous surface absorption, create a considerable delay in the formation of a vapor blanket. The results indicate that the anodized surface enhances the critical heat flux (CHF) by 33% and the heat transfer coefficient increases by 48% at the CHF compared to the non-coated substrate. It has been shown that for anodized samples with 3 and 4 mm epoxy spot pitches the CHF equals to 144 and 133 W/cm 2, respectively, considerably higher than the coated surface without epoxy parts 125 W/cm 2 .