Molecular Dynamics Study of Droplets on Flat Crystalline Surface during Cooling and Ice formation

TL;DR

This study uses molecular dynamics simulations to investigate how water droplets freeze on crystalline surfaces, revealing how ice formation affects thermal resistance and depends on surface wettability.

Contribution

It provides new insights into the microscopic mechanisms of ice nucleation and thermal resistance changes during freezing on crystalline surfaces.

Findings

Ice nucleation location varies with surface wettability.

Interfacial thermal resistance changes during freezing.

Wettability influences the adsorption layer transformation.

Abstract

Condensation and frost formation degrade the heat transfer performance of air-conditioners and refrigerators. Yet, the frost formation mechanism has not been fully understood. In the present study, we numerically investigated H2O droplets during cooling and ice formation by means of classical molecular dynamics simulations. The mW potential was employed for the H2O molecules. A nanoscale H2O droplet was placed on a flat solid wall consisting of Pt atoms. The fcc (110) crystal plane faced the droplet. We examined where ice nucleation was formed and how the ice formation proceeded inside the droplet, and then evaluated temporal change in interfacial thermal resistance between the H2O molecules and the solid wall. We found that the cooling and ice formation changed the interfacial thermal resistance; however, its tendency differed depending on the solid-wall wettability. It was influenced by the nearest neighbor adsorption layer consisting of H2O molecules transformed during the cooling and ice formation.