ABSTRACT

The vein hierarchical structure has high efficiency of component transportation capacity, it has been widely used in energy storage, solar thermochemical reactions, and photocatalysis. In this paper, the idea of packed-bed latent heat thermal heat storage system (LHTESS) with biomimetic vein hierarchical structure is proposed to improve the heat transfer rate and heat storage efficiency of the packed-bed LHTESS. The size of heat storage unit changes along the axial and radial direction under the same porosity as the conventional uniform structure. The effects of inlet velocity on the completion rate, temperature distribution, pressure drop, and liquid fraction of the conventional structure and biomimetic structure are analyzed. The numerical results indicate that the biomimetic vein hierarchical structure can ameliorate the temperature inhomogeneity, increase the heat transfer area, and improve the thermal response of the packed-bed compared with the conventional uniform structure. The maximum increase of liquid fraction is 25% under different inlet velocities, and the average completion rate of phase change material and system in charge process is increased by 12% and 6%, respectively.

摘要

静脉分层结构具有高效的组分运输能力，已广泛应用于储能、太阳能热化学反应和光催化等领域。在本文中，提出了具有仿生静脉分层结构的填充床潜热蓄热系统（LHTESS）的思想，以提高填充床潜热蓄热系统的传热速率和储热效率。在与常规均匀结构相同的孔隙率下，蓄热单元的尺寸沿轴向和径向变化。分析了入口速度对常规结构和仿生结构的完成率、温度分布、压降和液体分数的影响。数值结果表明，与常规均匀结构相比，仿生静脉分层结构可以改善温度不均匀性，增加传热面积，改善填充床的热响应。不同入口速度下液体分数最大提高25%，装料过程中相变材料和系统平均完成率分别提高12%和6%。