Molecular dynamic simulation of bubble nucleation in a nanochannel with a groove

Abstract

Molecular dynamics methods are used to investigate the effect of wall wettability and initial fluid density on the nucleation and growth of nanobubbles in a nanochannel with a groove. Surface wettability is controlled by adjusting the parameters of the solid-liquid potential energy and the results show that groove wettability greatly influences the bubble nucleation process. In the case of a groove with a weak solid-liquid interaction, fluid atoms in the groove are strongly affected by repulsive forces attributed to solid atoms, the density of the fluid atoms is low, and atomic collision frequency increases. The local activation energy is concentrated in the groove, resulting in bubble nucleation. In the case of a groove with a stronger solid-liquid interaction, the bubble is formed in the center of the nanochannel. In general, the bubble radius of curvature and contact angle remain unchanged during the growth process in the case of a uniform wettability nanochannel with a groove, while significant changes are observed for a nonuniform wettability nanochannel. The radius of curvature for the generated bubble increases with increasing fluid initial density, while the steady contact angle decreases.