Molecular dynamics simulation on flow boiling heat transfer characteristics

Abstract

In this paper, a flow boiling model consisting of an argon liquid and a copper solid wall has been developed using a molecular dynamics method to understand the effects of driving force and substrate temperature on the flow boiling characteristics at the nanoscale. The variation of parameters such as the morphology of liquid argon, the near-wall liquid temperature and heat flux are analyzed for different driving forces and substrate temperatures. The results show that the boiling onset time at lower substrate temperatures is mainly determined by the driving force, and the boiling onset time is gradually delayed as the driving force increases. The main mechanism is nucleation boiling, and the heat flux in the stabilization stage decreases with increasing driving force. In contrast, the boiling onset time at higher substrate temperatures is determined by both the substrate temperature and the driving force. At higher substrate temperature and lower driving force, atoms near the substrate are more likely to gain energy to break away from the surface, and therefore film boiling occurs, which produces a vapor film near the substrate during heating, leading to deterioration of heat transfer and a decrease in the average heat flux instead.