Experimental study the effect of differences in heat transfer in different freezing directions on the distribution characteristic of trapped bubbles in ice slices

Icing is common in industry and nature and always has a negative effect. To cope with ice damage, it is necessary to understand the icing mechanisms. The presence of trapped air bubbles in ice is a common phenomenon during icing, and these bubbles affect the thermal, mechanical and other physical properties of ice. To understand the distribution characteristics of trapped air bubbles in ice, a water film freezing experimental setup is built. To clarify the effect of heat transfer on trapped air bubbles, five experiments of water film freezing under different freezing directions are carried out. The results showed that both egg-shaped and needle-shaped bubbles showed a tendency to increase and then decrease as the freezing direction changed from vertically upward to vertically downward. When the freezing direction angle is 135°, the widths of the two types of bubbles reach their maximum values, which are 182.5 μm and 134.3 μm, respectively. The study helps to understand and predict the growth and distribution of trapped air bubbles in ice, which in turn can provide a reference for the optimization of de-icing and ice-breaking techniques.