基于有限差分方法的C/C复合材料CVI过程的数值模拟

摘要

Reduced multi-step method was used to simulate C/C composites CVI (Chemical vapor infiltration) process by finite difference method, integrating gas flow, diffusion, gas-phase reaction and surface reaction. Because of hydrogen inhibition, the CVI process simulation using methane with additional hydrogen as precursor gas was researched, which was verified by experiment results. Under the partial pressure 20kPa of methane, through adjusting partial pressure of hydrogen(0kPa,0. 4kPa, 4kPa), the result of numerical simulation shows the distribution of density inside of preform. Also it shows availability of simulation by finite difference method and influence of hydrogon on CVI process.%碳/碳(C/C)复合材料CVI过程数值模拟采用简化的多步模型(Reduced multi-step),将气体流动和扩散、气相反应、表面反应等相结合,使用有限差分方法进行模拟.由于氢气对CVI过程有着很强的抑制作用,研究了甲烷加入氢气后作为前驱气体模拟的情况.在固定甲烷分压为20kPa的条件下,通过对氢气的分压(0kPa、0.4kPa、4kPa)的控制,计算得到沉积结束时预制体内部的密度分布,通过结果的对比验证有限差分方法在此过程中的有效性以及氢气对CVI过程的影响.