Molecular Dynamic Study of Boiling Heat Transfer Over Structured Surfaces

Abstract

A phase change heat transfer from liquid to gas is studied in nanoscopic framework using molecular dynamics. Water on structured Si substrate is observed from molecular viewpoint after employing heat flux at a constant rate. Initially, we observe that water settles down on the substrate occupying the free space within the notch to obtain its static shape maintaining intramolecular configuration based on attractive and repulsive forces in neighboring hydroxyl bonds. Upon applying heat flux, we observe that the molecular vibration increases which repels neighbors to make the packing loose. Molecular dilution initiated at the notch and then proceeds to the rest domain. Progressive loosening of the molecules leads to the formation of vapor bubbles which increase in size with time. The rate of growth of this bubble is studied as a function of surface geometry parameters such as notch height, notch width, notch type, and notch spacing. Present simulations enrich the knowledge of surface characteristics on boiling heat transfer from fundamental principle in the molecular domain.