Equation chapter 1 section 1pyrolysis kinetic parameter and thermophysical property identification of charring ablative materials under high heating rate (>100 K/s)

In the paper, a method for identifying pyrolysis kinetic parameters and thermophysical properties of charring ablative materials under high heating rate was proposed, utilizing multi-source information. In the method, the recession depth of the char layer front and internal temperature were used as the observation data. The method leverages the distinct sensitivities of pyrolysis kinetic parameters to the char layer front recession and thermophysical properties to the internal temperature, thereby achieving decoupled identification of these parameters. By using the char layer front measurement sensor in combination with ablation experiments, pyrolysis kinetic parameters under high heating rates (>100 K/s) were identified. The identification results reveal that pyrolysis kinetic parameters, particularly the pre-exponential factor, are influenced by the heating rate. A quadratic model linking these parameters to the heating rate was developed and experimentally validated under a heat flux of 1.8 MW/m². The results demonstrate maximum prediction errors of 4.5% for measurement point temperature and 8.8% for surface recession, which are significantly lower than the errors obtained using traditional thermogravimetric data (12.3% and 68.5%, respectively). The proposed method contributes to more accurate acquisition of pyrolysis kinetic parameters and thermophysical properties under high heating rates, thereby providing beneficial support for the design and reliability evaluation of charring ablative thermal protection materials.