Kinetic Rates for Gas-Phase Chemistry of Phenolic-Based Carbon Ablator in Atmospheric Air

A comparison between three chemistry models used for the aerothermodynamic modeling of carbon-based phenolic ablative heat shields in atmospheric air is presented. The differences between the models, as well as the results they produced for the boundary-layer composition and prediction of convective and radiative heat fluxes, are put forward. A new model, built by optimizing and reducing a baseline model constructed using kinetic rates from a combustion database, is presented. Some of the important reactions, such as the CN/CO exchange, are highlighted, and their effects on surface heating are discussed. The resulting model comprises an extensive set of reactions that are relevant to carbon-phenolic ablators in high-enthalpy re-entry environments. The analysis presented in this paper shows that this model preserves the important features of the three existing chemistry models while correcting their deficiencies for a more accurate description pertinent to re-entry conditions.