Abstract: To analyze the evaporation characteristics of single water droplet in low temperature and low humidity ratio air in ice production system with evaporative supercooled water,a mathematical model of evaporative supercooling process of single water droplet was proposed.The evaporation process of droplet in supercooling stage was simulated with theoretical model and the results are basically consistent with the experiment on suspended single water droplet,so it is feasible to predict the evaporative supercooling characteristics of small water droplet by the mathematical model.The influence of initial diameter and temperature of water droplet,air temperature,humidity ratio of air,and air velocity on the temperature of water droplet during its evaporative supercooling process was analyzed.The numerical results show that smaller diameter and lower temperature of water droplet and larger air velocity can increase the cooling rate of water droplet and shorten the supercooling time reaching steady state evaporation stage.Additionally,lowering the temperature or humidity ratio of air can not only improve the cooling rate of water droplet,but also increase the supercooling degree of water droplet reaching steady state evaporation stage.The investigation of evaporative supercooling process of water droplet can provide a foundation for improving the efficiency of ice production and optimal design for ice-making system with evaporative supercooled water.

Key words: water droplet, evaporation, supercooled water

摘要： 为分析蒸发式过冷水制冰中单个水滴在此低温低湿空气环境中的蒸发特性,建立了水滴蒸发过冷过程的数理模型。通过悬挂水滴实验与模拟结果的对比,验证了模型的有效性。因此利用该数学模型预测微小直径水滴的蒸发特性是可行的。通过模拟计算获得了水滴初始直径、初始水温、空气温度、空气含湿量和空气流速对水滴蒸发过冷过程的影响。结果表明,水滴初始直径越小、温度越低或空气流速越大,水滴的冷却速率就越大,达到稳态时的过冷时间就越短。另外,通过降低空气温度或含湿量不仅提高了水滴的冷却速率,而且增加了水滴达到稳态时的过冷度。通过水滴蒸发过冷特性的分析,可为制冰系统的优化设计及提高系统制冰效率提供理论参考。

关键词: 水滴, 蒸发, 过冷水