Recent studies have indicated that droplet evaporation heat transfer can be substantially enhanced by fabricating a thin nanoporous superhydrophilic layer on a metal substrate. Such surfaces have immense potential to improve spray cooling processes however little durability testing of the surface has been performed. In spray cooling applications, as water evaporates any impurities in the water will be deposited onto the surface. Primarily, this investigation serves to demonstrate how minerals in hard water deposit on the surface and interact with the ZnO nanopillars of the superhydrophilic surface. Quantifying the effects of mineral scale on droplet spreading and vaporization heat transfer on the surface is important in determining implementation requirements to advance the surface into industry applications. Micrographs of the surface demonstrate minerals deposit nonuniformly and quickly fill the nanostructure. This deposition within the nanostructure reduces the extent of droplet spreading and reduces the droplet vaporization rate from that of the clean nanostructure. However, because the scale nanostructure remains slightly porous, the nanostructure even with mineral deposits still shows improvement when compared to the uncoated, smooth copper surface. Future implementation would likely require reducing the ions and contaminants present in the water to extend the life and performance of the nanostructured surface.


Nanoscale and Macroscale Effects of Mineral Deposition During Water Evaporation on Nanoporous Surfaces

Division / Sponsors: 
Heat Transfer Division (HTD), Fluids Engineering Division (FED)

Heat Transfer Summer Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/HT/HT2020/volume/83709

18th International Conference on Nanochannels, Microchannels, and Minichannels
Paper Proceedings: https://asmedigitalcollection.asme.org/ICNMM/ICNMM2020/volume/83693

Fluids Engineering Division Summer Meeting
Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2020/volume/83716

HT-ICNMM2020 - Virtual Conference, SHTC - Virtual Conference, FEDSM2020 - Virtual Conference

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