Molecular dynamics simulation study on nanofilm boiling of water with insoluble gas

LF Wu and YZ Tang and LX Ma and SY Feng and Y He, INTERNATIONAL JOURNAL OF THERMAL SCIENCES, 171, 107212 (2022).

DOI: 10.1016/j.ijthermalsci.2021.107212

Insoluble gas in water can remarkably affect the boiling heat transfer performance, which is of great practical importance for many applications. The effect of insoluble nitrogen gas on the boiling of water over copper surfaces with different temperature conditions is investigated through molecular dynamics simulations. Observations on the nanofilm boiling phenomena and insights into the fundamental mechanism are analyzed in terms of the temporal and spatial evolutions of temperature and the instantaneous heat flux curves. Results show that the nanofilm boiling processes change from normal evaporation to explosive boiling by increasing surface temperature owing to the conduction dominating the heat transfer mode. The nitrogen molecules are adsorbed on the copper substrate. This condition makes the explosive boiling of water containing nitrogen to occur easily due to its low substrate temperature and short onset time. Compared with the water boiling on nitrogen adsorption substrate, the boiling of pure water on bare substrate benefits the heat transfer in large superheat range because it has higher heat flux and the normal evaporation still works on a surface with relatively high temperature. This work may benefit the fundamental understanding and practices of boiling heat transfer in many industrial applications.

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