Effect of Ultrasonic Field on Crystallization of Supercooling Aqueous Solution

Dynamic ice-making technology using supercooling water is expected to realize large-scale applications. In industry, the ultrasonic field is often used to release the supercooling state of supercooling water and generate ice slurry. In this study, the effect of different ultrasonic fields on the supercooling characteristics of crystallization, the size of the ice crystals, and the particle size distribution of ice crystals of 3% sodium chloride solution, were studied experimentally. The results showed that the introduction of an ultrasonic field of a certain power and frequency can quickly release the supercooling state. It was also found that the solution nucleation temperature was close to the ultrasonic irradiation temperature, and the ultrasonic field with high power and low frequency was more conducive to nucleation. The power, frequency and irradiation temperature were varied from 10.0 W to 40.0 W, 28 kHz to 40 kHz, and 0 ℃ to 4 ℃, respectively. The optimal ultrasonic field scheme was set as the power at 40.0 W, the frequency 28 kHz, and the irradiation temperature 2.0 ℃. An ultrasonic field can significantly reduce the crystal size. With the extension of the ultrasonic irradiation time after nucleation, the size of the ice crystals first increased and then leveled off. The changes in ultrasonic power and frequency had no obvious effect on the size of the ice crystals.