Bubble nucleation on various surfaces with inhomogeneous interface wettability based on molecular dynamics simulation

In this paper, non-equilibrium molecular dynamics simulation is performed to study the bubble nucleation behaviors on smooth and nanostructured surfaces with inhomogeneous interface wettability. The bubble nucleus turns up after the substrate temperature is set up to be 250 K. The atomic trajectory, argon density profiles and bubble nucleus volume are computed to compare the processes of bubble nucleation on different surfaces. First of all, comparisons are made between weak-hydrophilic smooth surfaces with different area of strong-hydrophilic region in the center. Results show that larger area of strong-hydrophilic region is beneficial for the formation and growth of bubble nucleus. Then, the strong-hydrophilic smooth region is replaced by introducing strong-hydrophilic nanostructure. Results show that the nanostructure surface is favorable for bubble nucleation and can improve the efficiency of nucleate boiling. Finally, the common strong-hydrophilic nanostructures of cylinder, cuboid and cone are constructed to explore their effects on bubble nucleation. Both the strong-hydrophilic area and the height of these nanostructures are the same. It is found that the nanostructure morphology has little influence on the efficiency of bubble nucleation.