Speaker
Description
During atmospheric hypersonic re-entry, the heat distribution within the thermal protection system (TPS) is dampened by the in-depth chemical degradation of materials - called pyrolysis -, and by a surface physico-chemical degradation - called ablation. The aim of this work is to enhance pyrolysis modeling by considering solid deformations in order to describe more accurately the solid geometry variations resulting from swelling and ablation. The further aim of this study is to ensure mass and energy conservation during the pyrolysis-thermal coupling of heat shield under deformations. First, an overview of macroscopic modeling of pyrolysis is done. Arrhenius laws are employed for the density variation prediction. Then, thermal expansion, swelling and shrinkage are investigated as a consequence of material degradation, in addition to ablation. This analysis explores a pyrolysis-thermal model preserving mass and energy conservation during deformation and a number of numerical resolution maintaining numerical conservation. Finally, the model and methods are validated on ablation and swelling test cases from the literature and then applied to in-house experimental cases. The simulation results are in reasonable agreement with reference data and experimental data. Including swelling provides a closer approximation of wall evolution during hypersonic re-entry simulation.