Abstract:

In order to investigate the difference of heat absorption and melting properties between pure paraffin wax and copper foam/paraffin wax phase change composites, and to investigate the effect of copper foam on melting heat transfer process of paraffin wax, the melting phase change processes of pure paraffin wax and copper foam/paraffin wax composites with 0.98 porosity were studied experimentally by visualization, and the melting processes of pure paraffin wax and copper foam/paraffin wax composites were analyzed by numerical simulation. The results showed that there was an intersection point of the liquid phase rate variations between the composite and the pure paraffin wax called the critical liquid phase rate value, indicating that the composite had the same liquid phase percentage as the pure paraffin wax. The filling of copper foam can significantly improve the problem of low heat transfer coefficient of pure paraffin wax and accelerate the overall melting rate of phase change material. When the heat flux was 1200W/m², the filling of copper foam with a porosity of 0.98 shortened the complete melting time of pure paraffin wax by about 12.5%. It also made the overall temperature distribution more uniform and improved the thermal stratification phenomenon. The maximum temperature difference of the composite material was about 27.5K lower than the maximum temperature difference of pure paraffin.

Key words: copper foam, pure paraffin wax, composites, melting, phase change, numerical simulation

摘要：

为了研究纯石蜡与泡沫铜/石蜡相变复合材料吸热熔化性能的不同，探究泡沫铜对石蜡熔化换热过程的影响，本文对纯石蜡和孔隙率为0.98的高孔隙率泡沫铜/石蜡复合材料的相变熔化过程进行了可视化实验研究，并数值模拟分析了纯石蜡及泡沫铜/石蜡复合材料熔化过程。结果表明：复合材料与纯石蜡的液相率变化出现交点，即临界液相率值，此时复合材料具有的液相占比与纯石蜡液相占比相同；泡沫铜的填充能明显改善纯石蜡传热系数低的问题，加快相变材料的整体熔化速率，当热通量为1200W/m²时，孔隙率为0.98的泡沫铜填充使纯石蜡完全熔化时间缩短了约12.5%，并使整体温度分布更均匀，改善热分层现象，且复合材料最大温差比纯石蜡最大温差低约27.5K。

关键词: 泡沫铜, 纯石蜡, 复合材料, 熔化, 相变, 数值模拟