Growth Mechanism of Ice Crystals with Five-Fold Symmetry by the Phase-Field Method

Abstract

In order to simulate the ice crystal growth with five-fold symmetry, a new phase-field model was established. The finite difference method was used to solve the governing equation, reproduce the growth morphology of ice crystals with five-fold symmetry, and study the influence of interfacial energy anisotropy and undercooling on the growth mechanism of ice crystals. The results indicate that when the strength of interfacial energy anisotropy ( ${\epsilon }_5$ ) is greater than the critical value (1/24), the interface discontinuity and corners form at the tips of the main stem and side branches. The characteristic parameters of the ice crystal tip in the horizontal direction have an extreme value at ${\epsilon }_5$ equal to 0.1. With an increase in undercooling, the main branch becomes slender and side branches appear, which is consistent with the mechanism of crystal continuous growth. When undercooling reaches 0.4, ice crystal growth changes from diffusion control to dynamic control. Therefore, by selecting the quick freezing conditions, undercooling is controlled at around 0.4 and the interfacial energy anisotropy at around 0.1, and the tip radius of curvature is minimized so as to prevent large ice crystals from damaging the cell wall and leading to the decline in the quality of quick-frozen food. The findings of this study can help us have a better understanding of ice crystal growth in the process of quick-frozen food preservation.