The ice accretion on metal surfaces in cold environments occurs through the process of water droplets freezing, which spans a wide range of length scales necessitates a multiscale computational analysis that can link the atomic-scale activities to its micrometer-level behavior.
Firstly, in this work, with aim of understanding the structure of grain boundary of polycrystal ice, we establish a computational protocol for measuring the energy on the grain boundary of bi-crystal ice by performing a coarse-grained atomistic simulation. Secondly, we apply this procedure to the bi-crystal ice in a complex chemical environment. Results show that the microstructure of the grain boundary of the ice is sensitive to the concentration of Na+ and Cl-. Then, to determine the parameter among several, droplet size, metal surface roughness, and chemistry, that controls the grain structure, product phases (cubic or hexagonal ice) in polycrystalline ice accreted on metal surfaces, coarse-grained atomistic simulations of water droplet freezing on an oxidized aluminum substrate are also conducted. By tracking the contact line position and the contact angle throughout the image sequences of the snapshots from the simulations, the contact angle change during a water droplet freezing can be monitored as a function of the real time. It is qualitatively shown that the contact angle decreases when the volume fraction of the ice crystals in a water droplet increase.