MULTIDIMENSIONAL TRANSPORT EFFECTS ON FORCED-FLOW CHEMICAL-VAPOR INFILTRATION

A general multidimensional transport and reaction model that was formu lated for the chemical vapor infiltration process in a previous study is used to carry out a comprehensive study of multidimensional transpo rt effects in forced-flow chemical vapor infiltration. Results are obt ained on the effects of the anisotropy and geometry of the preform, th ermal gradients, and the distribution of flow at the face of the prefo rm. For a simple, slab-shaped preform geometry, all these parameters a re found to influence strongly the distance from the entrance of the p reform up to which significant multidimensional transport effects are encountered in the partial pressure and density profiles. The key fact or controlling the appearance and extent of multidimensional transport effects is the distribution of flow over the entrance face of the pre form.