环形管填充金属泡沫强化相变蓄热可视化实验

Experimental visualization on thermal energy storage enhancement through metal foam filled annuli

针对管壳式相变蓄热器中换热基本单元——换热管开展了强化换热研究,通过在相变材料侧添加金属泡沫以强化蓄热。为了探索金属泡沫对相变蓄热过程强化的效果,设计搭建了相界面可视化的相变蓄热实验台,采用高清摄像机记录换热管内外侧相界面变化过程;通过在径向和轴向布置热电偶以获取相变过程的实时温度响应。测量了流速0.15 m·s^(-1)下光管和金属泡沫管的蓄热过程,实验结果表明:在相同实验条件(初温、入口流量/温度)下,添加金属泡沫能明显提高蓄热效率,达到相同蓄热效果下纯石蜡管所需时间是金属泡沫管的2.9倍;添加金属泡沫后各测点的温度响应速率均高于对照组,各测试点的温差更小且变化更均匀。

Intensified heat transfer research was carried out for the heat exchange basic unit-heat exchange tube in the tube-and-tube phase change regenerator. The metal foam was added on the side of the phase change material to enhance the heat storage. Phase interface was recorded by a high-definition camera during the charging process. T-type thermocouples were attached separately on the radial and axial sides of the PCM. Charging processes of smooth tube and metal foam tube were quantified under the flow rate of 0.15 m · s^-1. The results demonstrated that the involvement of metal foam can significantly enhance the efficiency of thermal energy storage under the same charging condition (initial temperature, inlet temperature and flow rate). It took over 2.9 more times for the melting time of pure paraffin than that of metal foam under the same condition. The temperature response rate of metal foam tube was much higher and the temperature distribution was more uniform, in comparison with that of smooth tube.