The numerical simulation of thermal-gradient CVI process on positive pressure condition

Normally, carbon/carbon (C/C) composites are manufactured by negative pressure CVI process. The products manufactured by this process may have higher density, but it takes a very long time and the reaction gases cannot be utilized adequately. The experimental results indicated that the densification rate of C/C composites can be greatly increased and the reaction gas can be utilized more adequately by applying positive pressure chemical vapor infiltration (CVI) process. However, the density homogeneity of the products manufactured by this process is relatively lower. To solve this problem, numerical simulation technology is applied to analyze the characters and feasibility of thermal-gradient CVI (TCVI) process on positive pressure condition. The result indicates that the thermal-gradient CVI process can increase the density homogeneity and densification rate of C/C composites greatly.