Experimental study on the effect of uneven temperature distribution of horizontal cold surface on 3D ice transparency in vertical ice-making process

Clear ice has been widely used in food preservation and ice sculpture fields due to its excellent transparency. Temperature is a key factor affecting transparency in the process of ice production. To understand and clarify the effect of uneven temperature distribution on ice transparency, three-dimensional ice vertically freezing experiments are carried out under different temperature control strategies. Under even cold source surface temperature distribution, the transparency of the ice body is found negatively correlated with the freezing rate. When the freezing rate increased from 0.57 to 0.70 cm/h, the transparency decreased from 48.41 % to 16.04 %. Under the condition of temperature unevenness, the transparency of the ice body had no obvious correlation with the freezing rate. The larger the temperature difference of the cold surface, the more uneven the temperature distribution, which corresponds to the lower transparency of the ice slices. The transparency of the ice slices is 30.76 % and 12.42 % when the temperature unevenness of the cold surface is 0.22 °C and 2.36 °C, respectively. The results of this study are expected to provide a reference for the optimization of the ice-making process and cold energy storage technology.