蓄冰球内定向凝固过程蓄冷特性的实验研究

Experimental Study on the Characteristics of Cold Storage During Directional Solidification Process in Ice Ball

为了探究球形相变介质动态蓄冷过程的传热特性及冷却边界条件对凝固过程的影响,对蓄冰球中纯水凝固过程进行了实验研究。选取一个半球形蓄冷单元为研究对象,设计并搭建了可视化蓄冷实验系统,通过获取相变过程的实时温度响应和凝固界面推移,以分析球形介质相变凝固过程的换热机理。实验结果表明:蓄冰球纯水凝固过程中,固液相界面随着时间呈圆形逐渐向内推移;不同半径同心球球面的温度响应相同,自然对流影响微弱;冷却边界条件温度越低,蓄冷速率越快,与-7℃时相比,-5、-6℃时可分别缩短凝固阶段用时55%、28.3%,为工程实践中球形蓄冷设备的蓄冷性能提升提供了一定的参考。

To further explore the heat transfer characteristics in dynamic cold storage process of the spherical phase change medium and the influence of cooling boundary condition on the solidification process,the solidification process of distilled water in an ice ball was experimentally studied.A visualized experimental system for cold storage was calibrated and set up.A semi-spherical cold storage unit was selected as the test object,enabling the capture of the transient solidification front.The real-time temperature response of the phase change process and the transition of the solidification interface were obtained.The experimental results showed that the solid-liquid interface gradually moved inward in a circular shape over time.The temperature responses of concentric spheres with different radiuses kept the same.The influence of natural convection was weak and could be ignored.The lower the temperature of the cooling boundary condition was,the faster the transition speed of the phase interface would be.Compared with-5 and-6℃,the temperature of-7℃can shorten the solidification time by 55%and 28.3%,respectively.This work may provide a reference for improvement and optimization of the cold storage performance in engineering practices.