基于分级结构骨架相变储热系统强化传热特性OA北大核心CSTPCD

The composite phase change materials with a porous medium metal skeleton can improve the low thermal conductivity of pure phase change materials and further improve the heat transfer rate of composite phase change materials,which has essential research significance.This research uses the finite element method to propose the construction of a two-stage backbone branch hierarchical structure metal skeleton and combines it with a paraffin square cavity.Form composite phase change heat transfer materials with better heat transfer performance and add finned tube structures on this basis to further optimize the heat transfer performance of composite phase change materials.The results show that the finned tube structure has a significant impact on the phase change heat transfer process,and the phenomenon of flow velocity protrusion near the transverse main stem can make the melting front more inclined,and the annular flow heat transfer in the cavity quickly moves towards the lower part of the square cavity.The optimized composite phase change material can shorten the solid-liquid phase transition time by 37.4%compared to the uniform skeleton composite phase change material.The trough of the instantaneous phase transition rate curve in the initial melting stage is increased by 1.88 times,and the temperature uniformity is improved,resulting in a 20.9%reduction in the maximum temperature difference at 800s after melting.This research modified the skeleton structure under a constant porosity and improved the heat storage rate of composite phase change materials through a more reasonable volume distribution of the metal skeleton.