Basic research on the freezing phenomena of the supercooled water for the effective ice thermal energy storage

为了提高冰蓄热的性能，对几个子课题进行了基础研究。即：(1)通过非均质成核使过冷水冻结的统计条件；(2)通过提供电触发器启动过冷水瞬时冻结的方法；(3)过冷水流经管道冻结的瞬态热力和流体力学过程。在第一副标题的研究中，利用冰的形成温度、冷却速率、固体的表面性质、表面积和表面条件之间的实验关系，讨论了控制非均质成核情况下过冷水冻结的单个表面特有的物理参数。结果表明，利用上述参数，冻结起始可以用一般公式表示。在第二部分的研究中，对不同电压、电极间距、电极形状和过冷程度的过冷水进行了瞬间冻结实验。通过一系列的实验，证明了电触发器对过冷水有冻结作用。同时，通过引入过冷度与电流、时间关系的统计概念，阐明了冻结发生的条件。在第三课题的研究中，通过精确的观测和测量，研究了过冷水管内冰核形成后枝晶的生长和固体冰的发展过程。根据实验和分析结果，给出了决定固体冰传播速度的一般物理关系。以及流动过冷水弛豫过程的机理，其中过冷度的分布、固体冰的发育、枝晶的生长和消失相互影响。少

To improve the performance of the ice thermal energy storage, basic researches were performed concerning a few subtopics. That is, (1) the statistical condition to freeze the supercooled water through the non-homogeneous nucleation, (2) the method to initiate the instantaneous freezing of supercooled water by supplying an electric trigger and (3) the transient thermal and fluid mechanical process of the freezing of supercooled water flowing through a pipe.In the research of the first subtopic, a physical parameter particular to the individual surfaces, which control the freezing of the supercooled water, was discussed for the case of a non-homogenous nucleation, using the experimental relation among the temperature of the ice appearance, the cooling rate, the surface properties of the solid, the surface area and the surface conditions. From the results, initiation of the freezing was confirmed to be expressed by a general formula, using the above parameter.In the research of the second … More subtopic, experiments to freeze the supercooled water instantaneously were performed varying the voltage supplied, the distance between the electrodes, the shape of the electrode and the degree of the supercooling. From a series of experiments, the electrical trigger was proved having an effect to freeze the supercooled water. At the same time, the condition of the initiation of the freezing was clarified by introducing a statistical concept concerning the relation of the degree of the supercooling, the electrical current and the time.In the research of the third topic, the processes of the dendrite growth and the development of the solid ice after the appearance of the ice nucleation in a pipe flow of the supercooled water was investigated through precise observations and measurements. Based on the experimental and analytical results, a general physical relation deciding the propagation velocity of a solid ice was shown. And the mechanism of the relaxation process of a flowing supercooled water, where the distribution of the degree of the supercooling, the development of the solid ice, the growth and the disappearance of the dendrite effect each other. Less