耐高温炭气凝胶隔热材料微观结构控制及其固体、辐射传热机理研究

项目名称： 耐高温炭气凝胶隔热材料微观结构控制及其固体、辐射传热机理研究

项目编号： No.51302317

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 一般工业技术

项目作者： 冯军宗

作者单位： 中国人民解放军国防科学技术大学

项目金额： 25万元

中文摘要： 炭气凝胶的耐温性高达2000℃以上，居所有种类气凝胶之首，是极有前景的高性能隔热材料。在高温下固体和辐射传热是炭气凝胶中最主要的传热方式，其传热机理目前尚不明确。本项目通过控制制备工艺条件获得不同微观结构（孔径、粒径等）的炭气凝胶，重点研究固体、辐射传热与其微观结构的关系规律，分析能量载子声子和光子在炭气凝胶中的传输机理；为减小炭气凝胶固体传热，首次提出活化微孔增强声子散射的新思想，在炭化工艺之后，采用二氧化碳活化方法增加炭气凝胶的微孔，实现对声子更强烈的散射作用，达到减小声子平均自由程，降低固态热导率的目的。以上研究思想和研究内容目前国内外均无报道。本项目的成功，不仅可丰富微纳米尺度传热学理论，还可获得低热导耐高温炭气凝胶隔热材料，支撑国家新型高速航天飞行器研制，具有重要理论和现实意义。

中文关键词： 炭气凝胶；隔热材料；纳米结构；热导率；传热机理

英文摘要： In all kinds of aerogels that ever known, carbon aerogel has the highest thermal stability, it can be stable at even higher than 2000 ℃, so it has great potential for using as high performance thermal insulation. At high temperature, the main heat transfer regime in carbon aerogels are solid and radiative conductions. However, these two heat transfer mechanisms are not clear now. In this work, series of carbon aerogels with tuned and different microstructures (pore size, particle size, etc.) will be prepared by controlling the preparing processes and parameters. The relationships between solid conduction, radiative conduction and the microstructure of carbon aerogel will be mainly studied, and the transfer mechanisms of energy carriers such as phonon and photon will be analyzed. In order to lower solid conduction, the new concept introduced here is enhancing phonon scattering effect by micropore derived from activation. After carbonization, the carbon aerogel is activated by carbon dioxide to increase the number of micropore, and to get a stronger phonon scattering effect, so that reducing the mean free path of phonon and lowering the solid thermal conductivity. This concept and the research detail mentioned above cannot be found in the open literature by now. This study has significant value in developing nanos

英文关键词： carbon aerogels；thermal insulation；nanostructure；thermal conductivity；heat transfer mechanism