Transient three-dimensional simulation of densification process of carbon fibre preforms via chemical vapour infiltration of carbon matrix from methane

Chemical vapour infiltration (CVI) is widely used for fabricating carbon fibre-reinforced carbon materials for aircraft brake disks. This study aims at developing a numerical simulation method for predicting densification of the material during the CVI. Based on the multi-step reaction and deposition models, including the hydrogen inhibition model of pyrocarbon growth, transient 3D simulations of the CVI using methane as a precursor of the pyrocarbon were carried out via the finite element method coupling the mass transfer (by convection and diffusion) and the evolutive porous structure model with gas-phase and surface chemical reactions. The CVI of two different types of preforms was studied. The pore structure evolution models were derived not analytically but numerically with the aid of a computational tool for visualizing the fibre structures. An acceptable agreement was found between the predicted densification profiles and the experimental data obtained using a laboratory CVI reactor at a temperature of 1343 K, a methane pressure of 30 kPa and a total deposition time of 120 h.