Molecular dynamics study of the mechanism of explosive boiling on hybrid wettability surfaces

In this work, molecular dynamics (MD) simulation is applied to study the effect of heating surfaces with different hydrophobicity occupancy ratios (the ratio of the surface area of hydrophobic spots to the total area of the heating surface) on the boiling process of the liquid film explosion. At the same time, the mechanism is revealed from the trajectory of argon atoms. The simulation results showed that the onset of explosive boiling was later for purely hydrophilic surfaces than for hybrid wettability surfaces with a hydrophobicity percentage of <11%. The earliest onset of explosive boiling was observed for the heated surfaces with a hydrophobicity ratio of 6%. In addition, it was found that the superheat required for explosive boiling tended to decrease first and then increase with the gradual increase of the hydrophobicity ratio. Hydrophobic spots arranged on the surface provided bubble nucleation earlier for explosive boiling while enhancing convective heat transfer and thermal perturbation. The critical heat flux (CHF) of the heated surfaces with a hydrophobicity ratio of <11% were all greater than that of the purely hydrophilic surfaces, and all reached the CHF before the purely hydrophilic surfaces.