MULTICOMPONENT MASS-TRANSPORT IN CHEMICAL-VAPOR INFILTRATION

The effects of multicomponent mass transport on the predictions of che mical vapor infiltration models are investigated. The dusty-gas model is used as basis for describing multicomponent transport in the pore s pace of the preforms. Results are presented over a broad range of cond itions extending from the bulk to the Knudsen diffusion regime using t he full dusty-gas model and a number of variants. These variants are o btained by simplifying the full form of the dusty-gas model and retain ing or omitting the viscous flow terms. The presented results demonstr ate the importance of using the complete form of the dusty-gas model i n most applications and elucidate the implications of some of the simp lifying assumptions that are commonly made in describing gaseous mass transport in chemical vapor infiltration.