Niu Dong, Gao Hongtao
Institute of Refrigeration & Cryogenics Engineering, Dalian Maritime University, Dalian 116026, China.
Materials (Basel). 2021 Apr 26;14(9):2221. doi: 10.3390/ma14092221.
Heat transfer in a porous solid-gas mixture system is an important process for many industrial applications. Optimization design of heat insulation material is very important in many fields such as pipe insulation, thermal protection of spacecraft, and building insulation. Understanding the micro-mechanism of the solid-gas coupling effect is necessary for the design of insulation material. The prediction of thermal conductivity is difficult for some kinds of porous materials due to the coupling impact of solid and gas. In this study, the Grand Canonical Monte Carlo method (GCMC) and molecular dynamics simulation (MD) are used to investigate the thermal conductivity for the ordered porous structures of intersecting square rods. The effect of gas concentration (pressure) and solid-gas interaction on thermal conductivity is revealed. The simulation results show that for different framework structures the pressure effect on thermal conductivity presents an inconsistent mode which is different from previous studies. Under the same pressure, the thermal conductivity is barely changed for different interactions between gas and solid phases. This study provides the feasibility for the direct calculation of thermal conductivity for porous structures coupling gas and solid phases using molecular dynamics simulation. The heat transfer in porous structures containing gas could be understood on a fundamental level.
多孔固体 - 气体混合体系中的热传递是许多工业应用中的一个重要过程。隔热材料的优化设计在管道保温、航天器热防护和建筑保温等许多领域都非常重要。了解固 - 气耦合效应的微观机制对于隔热材料的设计是必要的。由于固体和气体的耦合影响，某些种类的多孔材料的热导率预测很困难。在本研究中，采用巨正则蒙特卡罗方法（GCMC）和分子动力学模拟（MD）来研究交叉方棒有序多孔结构的热导率。揭示了气体浓度（压力）和固 - 气相互作用对热导率的影响。模拟结果表明，对于不同的骨架结构，压力对热导率的影响呈现出与以往研究不同的不一致模式。在相同压力下，气固相间不同相互作用时热导率几乎不变。本研究为利用分子动力学模拟直接计算气固耦合多孔结构的热导率提供了可行性。含气多孔结构中的热传递可以在基本层面上得到理解。
