宏观封装的相变材料（phase change material, PCM）胶囊是构成填充床储热罐的核心部件，为强化填充床储罐的储热速率，优化单个PCM胶囊的蓄放热速率是必要的。在保证单个PCM胶囊体积一致的情况下，建立了4种不同封装形状的PCM胶囊。将胶囊置于阻塞率为0.5的流场中，充分考虑实际应用过程中的重力方向及换热流体流动方向，对不同封装形状下PCM的熔化及凝固过程进行了分析。结果表明：胶囊内液态PCM的自然对流可加速PCM的熔化与凝固过程，提高蓄／放热速率；相比于球形封装胶囊，圆柱形封装胶囊单位体积下的换热面积提高了14.47%，PCM的熔化时间缩短了42.50%。因此，圆柱形封装胶囊具有最佳的热性能，在未来的研究中可将圆柱形胶囊应用于填充床储罐中，从而优化其储热性能。

Macro-encapsulated phase change material (PCM) capsules are the core components that form the heat storage tank of the packed bed. In order to enhance the heat storage rate of the packed bed tank, it is necessary to optimize the heat storage and discharge rate of individual PCM capsules. Four different encapsulated shapes of PCM capsules were established while ensuring the uniform volume of individual PCM capsules. The capsules were placed in a flow field with an obstruction rate of 0.5, and the melting and solidification processes of PCM under different encapsulation shapes were analyzed with full consideration of gravity direction and heat transfer fluid flow direction in practical applications. The results show that the natural convection of liquid PCM inside the capsule can accelerate the melting and solidification process of PCM and increase the rate of charging and discharging; compared with the spherical encapsulation capsule, the heat transfer area per unit volume of cylindrical encapsulation capsule is increased by 14.47% and the melting time of PCM is shortened by 42.50%. Therefore, the cylindrical encapsulated capsule has the best thermal performance, and the cylindrical capsule can be applied to the packed-bed storage tank in future research to optimize its thermal storage performance.