Molecular Dynamics Studies of Thin-Film Evaporation: The Effect of Graphene-Coated Silicon on Water Evaporation Behavior
Date of Award
Master of Science (MS)
Conventional single-phase air or liquid cooling methods are insufficient to dissipate the high heat flux of next-generation electronic systems. Thin-film evaporation is one of the most promising solutions, because it takes advantage of the large amount of latent heat in the phase change process. It is important to understand the relationship between interfacial thermal resistance, surface wettability, and thin-film evaporation behavior. In this study, non-equilibrium molecular dynamics simulations are used to study mass and heat transfer in thin-film evaporation of water on a silicon substrate, and equilibrium molecular dynamics simulations are used to study the surface wettability by measuring contact angle. The surface wettability is changed by coating a layer of graphene on the silicon substrate. The observed evaporation process is characterized by evaluating its mass and heat transport flux, density, and temperature. The simulation results demonstrate a direct relationship between surface wettability and the interfacial thermal transport property for an evaporating thin-film liquid. Moreover, increased surface hydrophilicity is shown to correlate with increased heat transfer and evaporation. Compared to the silicon substrate, the additional graphene coating increases the thermal resistance by 65\% and reduces the evaporation rate by 31\%. These findings and methods can provide guidance for designing coating in thin-film evaporation applications.
Damena Agonafer Katharine Flores Swami Karunamoorthy