基于传热机理的氧化铝纳米孔材料隔热性能优化

氧化铝纳米孔隔热材料耐温高、热导率低，在航天飞行器热防护系统、高温节能、新型能源等领域具有重要的应用前景。从材料传热机理出发，设计具有最佳隔热性能的氧化铝纳米孔隔热材料，确定材料组分与微观结构参数，是建立材料热设计理论，指导材料研制、提升材料性能的有效途径。本项目主要研究氧化铝纳米孔隔热材料的传热机理，分析气固耦合传热行为，构建基于材料真实结构特征的传热计算模型，发展材料气相热导率计算方法；建立氧化铝纳米孔隔热材料遮光剂辐射特性的理论计算方法，揭示遮光剂形状、尺寸、分布等对材料隔热性能的影响规律。实现氧化铝纳米孔隔热材料表观热导率的理论计算，获得具有最低热导率的材料组分、结构参数，指导材料设计研制。

Nanoporous alumina thermal insulator with good heat-resistance and low thermal conductivity is potential for thermal protection system of aerospace vehicles, energy-saving and novel energy devices. In order to produce nanoporous alumina thermal insulator with the best heat insulation performance, the composition and microstructure of the material have to be optimized. It is a reasionable way to improve the thermal insulation property by analyzing the thermal transfer process in the nanoporous structure of the alumina insulator. Therefore, the aim of the research is to study the heat transfer mechanism of the nanoporous alumina thermal insulator and calculate the gsaeous thermal conductivity by developing a thermal transfer model based on the solid framework and porous structure of the material. Another goal of the research is to develop a theoretical method to descibe the radiation property of the opacifiers used in the insulator and understand the relationship between the characteristics of the opacifier, such as morphology, size and distribution, and the rediative properties. The effective thermal conductivity of the nanoporous alumina thermal insulator would be calculated and the composition and micrstructure of the material with the lowest thermal conductivity would be obtained. It is believed the results will give valuable instructions to the design and synthesis of the nanoporous alumina thermal insulator.