为了研究等温化学气相渗透( ICVI)工艺制备C/C复合材料过程中预制体的致密化过程及流场和温度场的分布,利用COMSOL软件建立预制体致密化过程中传质、传热和孔隙率变化的多场耦合模型。以甲烷为前驱体,将动量和能量守恒方程进行耦合计算,计算结果表明,在传质最初始阶段,前驱体温度迅速升高至设定的沉积温度,且整个反应器内部温度分布均匀。根据以上计算结果,设定温度为定值,耦合质量、动量守恒方程和孔隙率变化方程,通过计算得到在开始致密化阶段预制体最大密度分布在预制体中部,随着致密化进行,该区域向外侧移动。致密化150 h后,不同时间预制体整体平均密度的计算值与实验值吻合较好,验证了致密化模型的可靠性。
In order to investigate the process of the isothermal chemical vapor infiltration( ICVI) and the distribution of velocity and temperature for fabricating carbon/carbon composites, a multi-physical fields coupling models were developed through COM-SOL, including the mass and heat transportation, and the variation of porosity in the densification process. Taking Methane as the precursor, the momentum and energy equations were solved. The results indicate that the temperature rises rapidly to the setting point at the beginning and the distribution of temperature was uniform in the reactor.According to above results, the temperature was set as the constant value in the next step. Then the coupling equations of the mass and momentum conservation and the changing po-rosity equation were calculated to obtain the variation of preform density. The results show that the region of maximum density is dis-tributed in the middle of preform and this region move towards the edge during the densification process. After the preform is infiltra-ted for 150h, the bulk density of simulation agrees well with the experimental data, which demonstrate that the densification model is reliable.