Effects of surface temperature and wettability on explosive boiling of nanoscale water film over copper plate

Surface temperature and wettability can synergistically affect the performance of explosive boiling which is important for many industrial processes. This work investigated the explosive boiling of water film over copper surfaces with different wettability under various surface temperature conditions. The results show that the water molecules on the hydrophilic surfaces have higher temperature gradient and initial heat flux, shorter onset time of boiling, and lower Kapitza resistance than those on the hydrophobic surface. Meanwhile, the temperature gradient, the heat flux in the water films, and the onset time of explosive boiling are promoted by elevating the surface temperature. These indicate that the hydrophilic surface under high surface temperature conditions is most favorable for enhancing the explosive boiling heat transfer. Analysis of the onset of boiling reveals that the effect of wettability on the explosive boiling is more prominent under low surface temperatures but is limited under high surface temperatures. This work provides insights into the mechanisms of liquid molecules behaviors on plate surfaces with different wettability and surface temperatures for phase-change heat transfer enhancement and process intensification. (C) 2020 Elsevier Ltd. All rights reserved.