三维炭纤维预制体孔隙模型与气体传质计算  

Modeling of pore structures and calculation of gas transport for three dimensional carbon fabric structure perform

作　　者：熊翔[1] 龙莹[1] 肖鹏[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2008年第2期209-215,共7页Journal of Central South University:Science and Technology

基　　金：国家重点基础研究发展计划资助项目(2006CB600904)

摘　　要：通过建立三维正交结构炭纤维预制体宏观孔隙网络结构几何模型和化学气相渗透(CVI)工艺过程中反应气体在孔隙网络中的数学传质模型,研究预制体的孔隙网络结构对CVI工艺过程中气体的比渗透率和复合材料最终致密度的影响。研究结果表明:三维正交结构炭纤维预制体的宏观孔隙结构在空间上可以看成是由呈周期性排列的体心立方"晶胞"构成;X,Y和Z3个方向纤维束直径大小及比例关系决定三维正交结构炭纤维预制体宏观孔隙网络的结构和形状,也是决定反应气体在孔隙中的比渗透率和复合材料最终致密度的重要因素;当X,Y和Z3个方向纤维束直径的比例关系一定时,不同预制体在CVI增密过程中比渗透率随孔隙率变化的趋势相同;复合材料的最终致密度一定;比渗透率随纤维束直径增大而略有增大。On the base of the establishment of the geometry model of the three dimensional orthogonal woven carbon fabric structure perform and the relative calculation model of reactant gases transportation during the chemical vapor infiltration （CVI） processing, effects of the pore structure of the performs on the permeability of reactant gases and the densification of the composites were studied. The results show that the microscopical pore structure of the three dimensional orthogonal woven carbon fabric structure perform is composed of body-centered cubes which arranged periodically at spaces. The net structure and shape of the pores of perform are determined by the size and proration of the fasciculns diameter, which are key factors influencing the gaseous permeability and final density of composites. Once the proration of the fasciculns diameters of different directions is determined, the trend of diversification of the permeability followed by pore rate during CVI process and the density of composites are stated, and the permeability increases with the increase of the fasciculns diameter.

关 键 词：化学气相渗透(CVI) 气体传质 孔隙网络模型 比渗透率 致密度 

分 类 号：TB332[一般工业技术—材料科学与工程]