相变胶囊装填在容器内形成堆积床储热单元是目前相变胶囊典型的应用方式。研究堆积床流道中单个相变胶囊的储热释热特性可以帮助优化中温相变储热系统的设计。因此建立了相变胶囊二维堆积床流道数值模型，对比研究了外部传热流体以顺重力方向、逆重力方向及垂直重力方向流过相变胶囊时胶囊内部的传热与流动特性，并研究了传热流体流速、温度及胶囊直径对相变胶囊融化过程的影响。结果表明：堆积床流道内相变胶囊迎风侧换热速率更快。由于空腔空气热阻与自然对流作用，传热流体逆流流动时完全凝固时间最短。相较于顺流，逆流的完全凝固时间缩短8.9%；相变胶囊直径为12 mm时，PTFE为壁材空腔在中心相变胶囊较304不锈钢相变胶囊融化速度慢1.45%，平均储热速率低1.5%。改性PTFE为壁材空腔在中心的相变胶囊较304不锈钢相变胶囊融化速度快6.9%，平均储热速率高5.8%；提高HTF入口速度和温度可以提高相变胶囊的平均储热速率及缩短相变胶囊的融化时间。胶囊的储释热特性对于胶囊单体及中温相变储热系统的设计优化和实际应用都具有重要的指导意义。

Filling phase change capsules in a container to form a packed bed heat storage unit is a typical applica-tion of phase change capsules. Phase change capsules are usually stacked in a specific layout in the packed bed flow channel. Studying the heat storage and release characteristics of a single phase change capsule in a packed bed flow channel can help optimize the design of a medium-temperature phase change heat storage system. Therefore, a two-dimensional packed bed numerical model of phase change cap-sules was established. The heat transfer and flow characteristics of the external heat transfer fluid flowing through the phase change capsules in the direction of gravity, counter gravity and vertical gravity were compared and studied. The effects of flow rate, temperature and capsule diameter on the melting process of phase change capsules were studied. The results show that the heat transfer rate of the windward side of the phase change capsule in the packed bed channel is faster. Due to the thermal resistance of the cavity air and the natural convection, the complete solidification time is the shortest when the heat transfer fluid flows countercurrently. Compared with the downstream flow, the complete solidification time of the up-stream flow is shortened by 8.9%. When the diameter of the phase change capsule is 12 mm, the melting speed of the phase change capsule with PTFE as the wall material in the center is 1.45% slower than that of the 304 stainless steel phase change capsule, and the average heat storage rate is 1.5% lower. The melting rate of the phase change capsule with modified PTFE as the wall material cavity in the center is 6.9% faster than that of the 304 stainless steel phase change capsule, and the average heat storage rate is 5.8% higher. Increasing the HTF inlet velocity and temperature can increase the average heat storage rate of the phase change capsule and shorten the melting time of the phase change capsule. The heat storage and release characteristics of the capsule have important guiding significance for the design optimization and practical application of the capsule monomer and the medium temperature phase change heat storage system.