Effect of trapezoidal groove hydrophobic sites on bubble nucleation: A molecular dynamics study

Abstract

In this study, a bubble nucleation model for different hydrophobic sections within grooved surfaces is developed by molecular dynamics method to explore the effects of different hydrophobic sites on bubble nucleation on the surface of hydrophobic/hydrophilic hybrid wettability grooves. The results indicate that the time for bubble nucleation is delayed with an increase in the hydrophobic surface area. The order of bubble nucleation time from fastest to slowest is as follows: the B_phoS_phi (hydrophobic bottom wall and hydrophilic sidewall) surface, the B_phiSS_pho (hydrophilic bottom wall and hydrophobic single-sidewall) surface, the B_phiDS_pho (hydrophilic bottom wall and hydrophobic double-sidewall) surface, and the A_pho (all-hydrophobic) surface. Additionally, the effect of varying hydrophobic areas at the groove bottom on bubble nucleation is investigated. The results show that the HB_phoS_phi (half hydrophobic bottom wall and hydrophilic sidewall) surface and the B_phoS_phi surface are almost the same, whereas the bubble nucleation time for the QB_phoS_phi (quarter hydrophobic bottom wall and hydrophilic sidewall) surface is significantly later. A slight change in the hydrophobic area at the bottom of the groove has a minimal effect on heat transfer, but an excessively small hydrophobic area is unfavorable for bubble nucleation.