摘要
在对冰的物理属性及其力学特性进行完整探讨的基础上,对冰射流中所使用冰粒的温度提出维持在-30℃以下的要求.通过球状液滴冻结过程的传热分析,得出影响结冰时间的主要因素有低温环境温度、液滴表面对流换热系数及液滴直径.依据热量传递的守恒性获得液滴结冰时间的理论计算表达式,该式表明,结冰时间与液滴粒径的平方成正比.基于以上理论分析所得结论,设计出合理的冰粒制备装置以制取冰射流中所需要的冰粒.实验表明,常温水在预冷器中被预冷至0℃,通过该实验装置可以连续稳定的制取出-71℃以下、平均粒径为100μm的低温微细冰粒.
Based on the in-depth analysis of the physical properties and mechanical performance of ice particle, the proper temperature of ice particles for ice jet process should maintain below - 30 ℃. According to the heat transfer analysis of the solidification of a spherical droplet, the key factors influencing freezing time included cryogenic temperature, convective heat transfer coefficient and diameter of the droplet. Considering the conservation of heat transfer, the expression for freezing time was obtained. It shows that the freezing time is directly proportional to the square of the droplet diameter. By reference to the analytical results, a reasonable laboratory-scale apparatus can be designed to produce ice particles needed in ice jet. Experiment results show that -71℃ cryogenic fine ice particles of 100μm diameter can be made from the 0℃ pre-cooled water droplets continuously and steadily by use of this apparatus.
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2009年第1期129-132,共4页
Journal of China Coal Society
基金
教育部科学技术研究重点资助项目(03026)
关键词
冰射流
冰粒制备
液滴
结冰时间
低温
预冷
ice jet
ice particle making
water droplets
freezing time
cryogenic temperature
pre-cooled
