Gas-liquid-solid multiphase interface evolution of 2.5D woven quartz/phenolic composites undergoing ablation: Experiment and modeling

2.5D woven quartz/phenolic composites exhibit heterogeneous ablation of fibers and matrix during ablation. However, homogenized macroscopic ablation models may not adequately capture the mesoscale heterogeneity, limiting the ability to predict ablation behavior and surface morphology evolution. The mesoscopic ablation behavior of the material is investigated using combined experimental and numerical approaches. An arc-jet wind tunnel ablation test was performed for in situ observation of surface morphology evolution and molten silica flow, while microscopic characterization techniques were used to elucidate microstructural development and underlying mechanisms. A mesoscopic surface ablation model is developed to achieve quantitative prediction of mesoscopic ablation behavior by interface capturing approach and ablation governing equations. The interface capturing approach combines the Volume of Solid method with the Piecewise Linear Interface Calculation method to track the gas–liquid–solid multiphase interface evolution, including quartz fiber melting (solid-to-liquid), subsequent evaporation (liquid-to-gas), and matrix pyrolysis and oxidative ablation (solid-to-gas). The ablation governing equations for fibers and matrix are derived from mass and energy conservation to describe heterogeneous ablation. The accuracy of the model was validated against arc-jet measurements of surface roughness, temperature distribution, and ablation rate. By correcting the limitations in macroscopic ablation models, the proposed mesoscopic ablation model improves the accuracy of ablation prediction and provides guidance for redesigning woven architectures to optimize thermal protection materials for different thermal environments.