C/C复合材料热梯度CVI工艺的数值模拟研究

NUMERICAL SIMULATION OF THERMAL-GRADIENT CVI PROCESS FOR C/C COMPOSITE

TCVI(热梯度 CVI)工艺是一种很有潜力的 C/C复合材料制备工艺 ,它可以在较短的时间内制备出密度均匀性较高的 C/C复合材料制件。本文根据传热、传质理论及 C/C复合材料预制体的结构特点建立了 TCVI过程的动力学模型和几何模型 ,在该模型的基础上利用数值模拟技术对该工艺进行了模拟和分析。模拟结果为 TCVI工艺的开发和应用提供了理论依据。

TCVI (Thermal Gradient CVI) process is a very potential process for C/C composite, by which C/C products with well distributed density can be manufactured in relatively shorter time. In this paper, the dynamic model and geometrical model of the process were established on the basis of theory of heat and mass transfer and structure character of the preform. According to these models, the technology of numerical simulation is applied to simulate and analyze the process. It's indicated by simulation that the preform is densified from interior to exterior during TCVI process so the external pores in the preform will not be sealed too early. The density homogeneity and the speed of deposition can be greatly improved by properly altering the thermal gradient in the preform. The result of simulation can lay the theoretical foundation for the development and application of TCVI process.