摘要
Abstract
To address the limited engineering applicability of phase change material capsule(PCMC)structural optimization schemes caused by high large-scale production costs,a three-dimensional unsteady enthalpy model was established in this study using Fluent.The model was applied to analyze the cold storage process of PCMCs with shapes suitable for industrial production and with the inscribed sphere center coinciding with the geometric center,including sphere,cylinder,cube,cone,triangular prism,and regular tetrahedron.Based on the liquid fraction,temperature field,cold storage capacity,cold storage rate,and Fourier-Stefan number,the effects of capsule shape on cold storage performance were systematically compared,and the intrinsic influencing factors governing the cold storage process were investigated.The results indicate that capsule shape has a significant effect on the cold storage performance of PCMCs by influencing the heat transfer process through the inscribed sphere radius.A decrease in the inscribed sphere radius leads to improved cold storage performance.Among the investigated geometries,the regular tetrahedral phase change material capsule(RTPCMC)exhibits the best performance and the smallest inscribed sphere radius,whereas the spherical phase change material capsule(SPCMC)shows the poorest performance and the largest inscribed sphere radius.Compared with SPCMC,the solidification time,cold storage completion time,and inscribed sphere radius of RTPCMC decrease by 34.29%,29.33%,and 36.2%,respectively,while the average Fourier-Stefan number and average cold storage rate increase by 261.81%and 29.44%,respectively.In addition,the filling rate of PCMCs shows a slow linear decrease with decreasing inscribed sphere radius,whereas the specific surface area exhibits a rapid linear increase.Under conditions of identical volume,wall thickness,and coincident inscribed sphere and geometric centers,reducing the inscribed sphere radius is an effective approach for enhancing the cold storage efficiency of PCMCs.关键词
相变材料/胶囊/形状/蓄冷/内切球半径Key words
phase change material/capsule/shape/cold storage/inscribed sphere radius分类
能源科技
