Abstract
Numerical simulations are carrier out for the temperature distribution, the specie concentration profile, and the matrix deposition distribution in a forced-flow, temperature-gradient chemical vapor infiltration (FCVI) process for forming ceramic matrix composites. In this analysis, the SiC matrix material is obtained from the thermal decomposition of the methyltrichlorosilane (MTS) vapor in excess hydrogen and the reinforcement in the form of three-dimensional fibrous mat is considered. A quasi-steady state approach is adopted to simulate the consolidation of the ceramic composite. The process parameters studied include the applied boundary conditions (pressure and temperature) as well as the reactant concentration. The first order reaction mechanism for pyrolysis of MTS vapor is used to calculate the deposition rate of SiC matrix. In order to enhance the uniformity of the matrix deposition, a `pause and rotation' method is applied in this work. The analysis concludes that the matrix deposition is influenced significantly by the arrangement of the heating elements and the adopted processing temperature. Furthermore, the application of pause and rotation method improve the uniformity of the deposited matrix very significantly.