碳/碳材料细观尺度的氧扩散特性与烧蚀分析

将DSMC方法运用在材料细观烧蚀机理分析中，对碳/碳材料在典型烧蚀过程中的简化模型进行了微米量级下的氧扩散特性分析，旨在研究氧分子在材料表面缝隙中的扩散特性及其与壁面的作用规律，计算分析结果验证了纤维烧蚀结构演变特性。结果表明：沿缝隙深度方向，O2与壁面的碰撞频率不断降低；在缝隙入口处烧蚀最快，缝隙深处最慢，碳纤维随着烧蚀过程的进行不断尖化直至达到强度极限产生折断剥离；随着烧蚀过程的不断进行，O2与壁面的碰撞频率增加，材料将烧蚀得更快；在同一烧蚀条件下，O2与壁面发生烧蚀反应的概率越大，将消耗O2越快，致使O2与壁面的碰撞频率降低。

Oxygen Diffusion and Ablation Analysis on Micro-Scale of C/C Composite

A DSMC approach is adopted to analyse oxygen the diffusion property and its action law in an aperture located at the surface of ablation material.The purpose of this study is to investigate and interpret the ablation law discovered in experiments.The results show that the collision frequency between oxygen and aperture wall decreases along the depth direction of the aperture.Mass loss is more serious in the aperture inlet than that in the depth,so fiber will be sharpen as development of the ablation process...