球形封装颗粒球填充床储热系统仿真研究

Simulation Study of a Spherically Encapsulated Phase Change Material Packed-Bed Thermal Energy Storage System

摘要: 本研究选取相变填充床储热体系作为研究对象，采用熔融盐作为储热介质、导热油作为传热媒介，基于孔隙尺度对单层、双层变径及三层变径三维储热结构进行储热特性的系统分析。首先探讨了相变微胶囊尺寸与不同排列方式对单层储热效果的影响，并量化评估了储热时长、液相含量变化、温度分布特征、总储热量以及传热流体出口温度等关键性能指标；随后进一步考察了分段分区布局策略对储热过程的优化作用。结果表明，在中高温工况下，较小直径的相变微胶囊展现出更高的熔融速率，但会导致储热持续时间缩短；相较于常规直线排列，交错式堆叠显著减少了热边界层效应，提升了热量传递的整体均匀性。三层分级渐变结构较传统单一固定截面方案表现更优，其储热时长分别比对照组缩减约19.8%和27.5%，为相关领域的储热系统设计提供了理论支撑与实践依据。

Abstract: This study employs a phase change packed bed thermal energy storage system, using Solar Salt as the storage medium and thermal oil as the heat transfer fluid (HTF). Based on a pore-scale approach, the thermal storage performance of three-dimensional systems with single-layer, double-layer variable-diameter, and triple-layer variable-diameter configurations is studied. Firstly, the effects of phase change capsule diameter and different arrangement patterns on the thermal storage characteristics of the single-layer system were examined. Key performance parameters such as thermal storage time, liquid fraction, temperature distribution characteristics, heat storage capacity, and HTF outlet temperature were obtained. Building on this, the optimization effect of the segmented and zoned layout strategy on the thermal storage process was further investigated. The results indicate that under medium-high temperature conditions, the melting rate of the PCM in the system increases as the capsule diameter decreases, leading to a shorter thermal storage time. Compared to the in-line arrangement, the staggered arrangement not only mitigates the thermal stratification effect but also enhances the overall thermal uniformity of the system. The thermal performance of the layered variable-diameter systems was superior to that of the single-layer system. Specifically, the heat storage time for the double-layer and triple-layer variable-diameter systems was reduced by approximately 19.8% and 27.5%, respectively, compared to the single-layer system. The research results provide theoretical support and practical basis for the design of heat storage systems in related fields.