A Study of Production Characteristics of Liquid Ice by Liquid Spray

对一种新型相变材料--液冰在三个水平圆柱体上的产生特性进行了实验研究。实验是在各种实验参数下进行的，如风速、空气温度和液滴质量流量。试验段长800 mm，横截面200 mm×200 mm。采用3根直径为25 mm的辉光石管作为结冰圆筒，在其上缠绕有厚度为50微米的不锈钢。沿着圆柱体的冰层的形成被广泛地观察到。测量了风洞中产生的液态冰的重量。在本实验中，得到了产生液态冰的最合适的条件。实验装置基本上由一个带有制冷系统和喷雾的…的风洞组成更多的信息系统。风洞的主要组成部分是测试部分、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网。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。隧道内安装了七个功率为8.25千瓦的加热器，为制冷系统提供额外的负荷。使用这些制冷系统和加热器，可使用的温度范围从+20ﾟC扩展到-20 KW。风洞中使用了0.75KW的离心式轴流风机，试验段的最大风速可达10m/S。将测试的二元水溶液预先在储存池中冷却。溶液喷雾是由位于试验段上游的隧道收缩段内的一系列喷嘴产生和控制的，并广泛地确定了风速、气温和液滴质量流量等各种参数对圆柱体上液冰产生行为的影响。在所研究的参数范围内，可以得出以下结论：(1)随着气温的降低和风速的增加，圆柱体顶部形成的液态冰层变厚，圆柱体之间的堵塞在短时间内趋于增大.(2)在本方法中，最适合产生液态冰的条件是风速U_a=6 m/S，气温Theta=-12ﾟC。较少

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