Role of mesoscopic features on thermochemical ablative behavior of 3D C/C braided composites

The mesoscopic features (i.e. the geometry structures of the braid yarns and the matrix, the pores in the carbon matrix and the reaction parameters) of 3D C/C braided composites can greatly influence their thermochemical ablative behaviors. A mathematical model describing the diffusion/reaction coupling problem for the thermochemical ablation is established and numerically solved on the basis of the volume-of-fluid method and the finite volume method using MATLAB codes. The numerical results are validated solving the surface ablation compared to the analytical results. The braided angle, the pores in the matrix and the reactivity distinction between matrix and yarns play important roles in determining the thermochemical ablative behavior of the 3D braided composites. The predicted ablation performances by the macroscopic model should be corrected due to the discrepancies between the ablative behaviors of the braid yarns and the matrix. Some suggestions are provided for design and manufacturing of the 3D C/C braided composites.