Modeling of Chemical Vapor Infiltration for Fiber-Reinforced Silicon Carbide Composites Using Meshless Method of Fundamental Solutions

Abstract

In this study, the Method of Fundamental Solutions (MFSs) is adopted to model Chemical Vapor Infiltration (CVI) in a fibrous preform. The preparation of dense fiber-reinforced silicon carbide composites is considered. The reaction flux at the solid surface is equal to the diffusion flux towards the surface. The Robin or third-type boundary condition is implemented into the MFS. From the fibers’ surface concentrations obtained by MFS, deposition rates are calculated, and the geometry is updated at each time step, modeling the pore filling over time. The MFS solution is verified by comparing the results to a known analytical solution for a simplified geometry of concentric cylinders with a concentration set at the outer cylinder and a reaction at the inner cylinder. MFS solutions are compared to published experimental data. Porosity transients are obtained by a combination of MFSs with surface deposition to show the relation between the initial and final porosities.

Modeling for the Fabrication Process of a ϕ1185 mm C/C Composite Thermal Insulation Tube in an Isothermal Chemical Vapor Infiltration Reactor

“…The CVI densification process of the C/C composite thermal insulation tube involves the interaction of multiple physical fields, including chemical reaction fields, thermal flow fields, and material transport fields. At the same time, it is essential to couple the pore evolution process of the preform with these physical fields [16][17][18][19][20]. CVI deposition employed methane (CH 4 ) as the carbon source gas and nitrogen (N 2 ) for dilution and protection [21,22].…”

“…Studies on the densification of largesize C/C composite materials are scarce, with most being two-dimensional modeling and simulations. In the case of large-sized C/C composite components, the generation rate of pyrolytic carbon significantly surpasses the densification rate of the preform, resulting in preferential densification near the surface, leading to surface crust formation and the formation of low-density regions internally [19,20]. Consequently, there is an urgent need to investigate the densification behavior of large-sized C/C composite materials.…”