A Study of Production Characteristics of Liquid Ice by Liquid Spray

以丙二醇水溶液为喷雾液滴，沿三个水平圆柱体浸泡在冷空气中，研究了液态冰作为一种新型相变材料（PCM）的生产特性。实验在风速、气温、液滴质量流量等多种实验参数下进行。试验截面长800mm，截面为200mm × 200mm。三根直径为25mm的透明玻璃管，上面缠绕着厚度为50mm的不锈钢箔，作为结冰筒。沿圆柱体形成的冰层被广泛地观察到。测量了在风洞中产生的液态冰的重量。通过本实验，得出了最适宜生产液态冰的条件。实验装置主要由风洞制冷系统和喷淋系统组成。风洞的主要组成部分是试验段、制冷系统、风扇、加热器、收集液冰的盒子、相关的测量仪器和管道系统。制冷系统由一台11.3KW交流电机驱动的压缩机、两台蒸发器和盐水冷却冷凝器组成。隧道内安装了7台8.25千瓦的加热器，为制冷系统提供额外的负荷。有了这些制冷系统和加热器，使用温度范围从+20到-20ºC。风洞内采用0.75 KW的离心轴流风机，试验段最大风速可达10 m/s。试验二元水溶液在储层中进行了提前冷却。溶液喷雾由位于试验段上游隧道收缩处的一系列喷嘴产生和控制。研究了风速、空气温度、液滴质量流量等参数对柱体产冰行为的影响。在所调查的参数范围内可以得出下列结论。(1)随着气温的降低和风速的增大，气缸顶部形成的液冰层逐渐变厚，气缸间的堵塞在短时间内逐渐增大。(2)本方法在风速U_a = 6 m/s，空气温度THETA_a = -12 C条件下最适宜生成液态冰。少

An experimental study has been performed to investigate the production characteristics of liquid ice as a new phase change material (PCM) along three horizontal circular cylinders immersed in a cold air stream with spraying droplets of propylene-glycol aqueous solution. The experiments were carried out under a variety of experimental para-meters such as wind velocity, air temperature, and droplet mass flow rate. The test section is 800 mm long and 200 mm X 200 mm in cross section. Three lucite tubes of 25 mm in diameter, on which stainless foil of 50 mum in thickness was wound, were utilized as icing cylinders. The formation of the ice layer along the cylinders were extensively observed. The weight of the liquid ice produced in the wind tunnel were measured. For the present experiments, it was found that the most suitable condition for production of the liquid ice might be obtained.The experimental apparatus consists basically of a wind tunnel with refrigeration system and spray-genera … More tion system. The major components of the wind tunnel are test section, refrigeration system, fan, heaters, a box for collecting liquid ice, associated measuring instrumentations, and ductwork. The refrigeration system was composed of a compressor, driven by a 11.3KW AC motor, with two evaporator and brine-cooled condenser. Seven heaters, which are capable of 8.25 KW, were installed in the tunnel to provide an additional load on the refrigeration system. With these refrigeration system and heaters, the usable temperature range extended from +20 to -20ﾟC. A centrifugal axial fan of 0.75 KW in the wind tunnel was used, which was capable of maximum velocity of 10 m/s in the test section. The test aqueous binary solution was cooled in the reservoir in advance. Solution spray was generated and controlled by a series of nozzles located in the tunnel contraction upstream the test section.The effect of a variety of parameters such as wind velocity, air temperature, and droplet mass flow rate on the liquid ice production behavior along the cylinders were extensively determined. The following conclusions may be drawn within the range of parameters investigated.(1) Liquid ice layer formed on the top of the cylinders grows thicker with both decreasing air temperature and increasing wind velocity, and then blockages between the cylinders tend to grow up in short time.(2) The most suitable condition for production of the liquid ice might be in wind velocity U_a = 6 m/s and air temperature THETA_a = -12ﾟC in the present method. Less