Drop evaporation on rough hot-spots: effect of wetting modes

Research output: Contribution to journalArticle


  • Accepted manuscript

    Accepted author manuscript, 1 MB, PDF-document

    Embargo ends: 12/08/20



  • Huacheng Zhang
  • Yutaku Kita
  • Dejian Zhang
  • Gyoko Nagayama
  • Yasuyuki Takata
  • Khellil Sefiane
  • Alexandros Askounis

Organisational units


Hot-spots are a common occurrence in power electronics which become increasingly hotter as chips become denser. Novel cooling technologies are emerging to cope with this increasing heat load, which imbed a condenser to supply cooling drops to the hot-spots. Nonetheless, the evaporation process of the drops has been overlooked. Here, we conducted a series of experiments to understand how the evaporation and motion of drops are influenced by the wetting mode of rough hot-spot. We fabricated three different surfaces exhibiting full (Wenzel) or partial (Cassie-Baxter) wetting and the hot-spot is imposed by laser irradiation. We report a direct link between drop motion and wetting mode with the partial wetting drops being highly mobile, attributable to the lowest pinning energy and interpret based on an energy analysis. This work provides a framework for future modifications in hot-spot cooling to account for drop motion which should greatly influence the overall heat removal performance.


Original languageEnglish
JournalHeat Transfer Engineering
Early online date12 Aug 2019
Publication statusE-pub ahead of print - 12 Aug 2019

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