Molecular dynamics simulations and mathematical optimization method for surface structures regarding evaporation heat transfer enhancement at the nanoscale

Abstract Surfaces with nanostructures can significantly enhance the evaporation heat transfer process. Most previous investigations on the designed surface structures using the empirical way to find better geometries. This paper proposes an optimization method for different types of nanostructured surfaces to seek optimal structures mathematically under the given heat transfer area. In this paper, three defined types of nanostructured surfaces are discussed: concave, convex and concave-convex. Firstly, a positive correlation between the evaporation heat transfer performance and the defined sectional area of the liquid phase is obtained by molecular dynamics simulations of the empirically designed nanostructured surfaces. Then, the optimization of the surface geometry converts to a mathematical problem which to solve the maximum sectional area of the liquid phase. This method is used to optimize the geometries of the concave and convex surfaces. Moreover, the molecular dynamics simulation results indicate that the optimal surfaces conduce to better heat transfer performance than the normal concave, convex and concave-convex ones. Finally, to explain the mechanism, the investigations of the atomic potential energy distributions of liquid atoms, the interaction energy between solid and liquid atoms, the solid-liquid interfacial thermal resistance and the morphology of the liquid-vapor interface are done.