Abstract:In order to investigate the effect of wall wettability and initial fluid density on the nucleation and growth of nanobubbles in the grooves, molecular dynamics method are used to study the nucleation boiling process of liquid argon in microchannel. The wettabilities are changed by adjusting the parameters of the solid-liquid potential energy. The results show that the nano-groove wettability has an important influence on the bubble nucleation process. On the one hand, when the solid surface is a hydrophobic wall, the fluid in groove is affected by the repulsive force, thus the atomic density is sparse, the atomic collision frequency increases, and the local activation energy is concentrated, resulting in bubbles in the nano-groove. On the other hand, when the solid wall is a hydrophilic surface, the bubble is formed in the center of the microchannel. In addition, the bubble curvature radius and contact angle kept unchanged for homogeneous wettability microchannel, which are significantly different from the heterogeneous wettability microchannel with nanostructure. When the wall wettability remains unchanged, the radius of the bubble curvature increases as the initial density of the fluid increases. Conversely, the steady state contact angle decreases.