真空搅拌法流态冰制备特性的实验研究

Experimental Study of Ice Slurry Production Characteristics by Vacuum Stirring Method

本文设计了一套真空搅拌法流态冰制取装置,对冰浆的生成全过程进行了观测,通过实验研究了乙二醇添加剂、溶液体积、搅拌速度等因素对冰浆形成过程过冷状态的影响。结果表明:真空状态下冰浆的制取需经历溶液蒸发、沸腾、过冷及冰晶生成这四个阶段;冰晶生成瞬间系统的压力会发生突增,压力的升值即过冷结晶压差可用于表征过冷程度的高低;平均过冷结晶压差随乙二醇添加剂浓度的增大而减小,当乙二醇浓度从3%提高至6%时,过冷结晶压差从58.9 Pa降至49.4 Pa,降低了16.1%;溶液体积的增大会使平均过冷结晶压差减小,40 m L溶液的平均过冷结晶压差较20 m L溶液的平均过冷结晶压差下降了12.9%;搅拌速度对过冷程度几乎无影响。

The process of ice slurry preparation is observed with the ice slurry preparation equipment based on vacuum stirring method,and the effects of ethylene glycol additive,solution volume and stirring speed on the supercooling degree of ice slurry preparation are investigated experimentally. The results indicate that the procedure of ice slurry preparation under vacuum can be divided into four stages,including solution evaporation,boiling,supercooling,and ice crystal generation. The system pressure increases at the instant of ice crystal generation and the pressure variation which is defined as supercooling crystallization pressure difference can characterize the supercooling degree. The higher the concentration of ethylene glycol additive,the smaller the average supercooling crystallization pressure difference,which is down to 49. 4 Pa from 58. 9 Pa when the concentration of ethylene glycol additive is varied from 3% to 6%. Furthermore,the increase of solution volume can also reduce the average differential pressure which is dropped by 12. 9% when the solution volume is varied from 20 m L to 40 m L. The stirring speed has little influence on supercooling crystallization pressure difference.