Rapid boiling and subsequent cooling of water in ultra-thin vapor chamber: A molecular dynamics study

The interfacial interaction between water (H₂O) molecules and hot/cold surface is of crucial importance to enhance thermal energy transport in ultra-thin vapor chamber. In this regard, a typical case focusing on the rapid boiling of liquid H₂O film on hot surface (900 K) and subsequent cooling of vapor H₂O molecules on cold surface (300 K) is carried out firstly, by tracking the spatiotemporal motion of H₂O molecules and investigating the associated thermal energy transport. The potential energy of H₂O molecules plays a dominant role in conveying thermal energy from the hot surface to the cold surface. Moreover, the impacts of hot surface temperature and surface wettability are studied. It is found that the higher degree of heating at the hot surface above 900 K is detrimental to the overall performance of thermal energy transport. The combination of hydrophilic hot surface and hydrophilic cold surface brings the highest performance of thermal energy transport than the other three combinations (hydrophilic hot surface and hydrophobic cold surface, hydrophobic hot surface and hydrophilic cold surface, hydrophobic hot surface and hydrophobic cold surface). The present work provides atomistic insights into the rapid boiling and subsequent cooling related interfacial interaction between H₂O molecules and hot/cold surface, as well as the impacts of surface heating and wettability, which are informative to the design of ultra-thin vapor chamber in thermal management.