Mesoscopic visualization of pyrolysis process in silica fiber phenolic composites

Silica fiber phenolic composites are widely applied in the thermal protection system. In this work, a comprehensive model considering the reaction morphology during the pyrolysis process in silica-phenolic composites at pore scale is proposed. The proposed model couples the chemical process and structure morphology evolution of the composites using Lattice Boltzmann method. The influences of fiber diameters and volume fractions on the temperature and mass loss of the composites are investigated. Results show that the matrix around the silica fiber entirely reacts firstly, then followed by the matrix on the surface of the silica fiber during pyrolysis process. The temperature of the composites increases with a decrease in the silica fiber diameter. The mass loss of the composites reduces when the silica fiber volume fraction decreases. These findings provide basic thermal data for silica-phenolic composites that can contribute to the design of thermal protection structures with a higher reliability.