Understanding the distribution of micro-scale egg-shaped trapped air bubbles during thin water film solidification

Icing and frosting are common phenomena in daily life and industry. Air bubbles are a common substance trapped in ice during the icing process and can have an effect on the physical properties of ice. To better utilize and control the icing process, an experimental study is conducted to investigate the effect of freezing temperature on the distribution characteristics of egg-shaped trapped air bubbles in horizontal ice slices. The results show that lowering the freezing temperature prolongs the growth time and length of the egg-shaped bubble regions and egg- and needle-shaped bubble regions, but does not change their proportions of 17.71 %, 82.29 % and 41.89 %, 58.11 %, respectively. The width and length of the bubbles decrease gradually with the decrease of freezing temperature, and their growth rate also decreases gradually. Additionally, the bubbles volume gradually increases as the freezing temperature decreases, both being proportional to the 7/6th power of formation time. The results contribute to a better understanding of icing and to extending the use of ice containing trapped air bubbles.