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2-D microflow generation on superhydrophilic nanoporous substrates using epoxy spots for pool boiling enhancement

Najafpour, S ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1016/j.icheatmasstransfer.2020.104553
  3. Publisher: Elsevier Ltd , 2020
  4. Abstract:
  5. 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/cm2, respectively, considerably higher than the coated surface without epoxy parts 125 W/cm2. © 2020 Elsevier Ltd
  6. Keywords:
  7. 2-D microflow ; Pool boiling enhancement ; Superhydrophilic nanoporous oxide layer ; Anodic oxidation ; Heat transfer ; Porous materials ; Substrates ; Superhydrophilicity ; Critical heat flux (CHF) ; Experimental investigations ; Low thermal conductivity ; Micro-flow ; Nano-porous oxide ; Nano-porous surfaces ; Nanoporous substrate ; Pool boiling ; Heat flux
  8. Source: International Communications in Heat and Mass Transfer ; Volume 113 , April , 2020
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0735193320300786