A unified flow-material approach to study the oxidation of carbon-based porous materials.*

In recent decades, space exploration has aimed to visit other planets and sample cosmic bodies within our solar system. As these ambitions increase, new technologies and the development of lightweight materials are needed to design spacecraft Thermal Protection Systems (TPS) that endure the harsh environment of hypersonic atmospheric entry and ensure the safety of the payload. Current methods used to design the TPS decouple the flow phase from the material phase, hindering the physics at the interface and, therefore, not fully capturing the coupling effects between each phase. In this presentation, we present the development of a unified macroscale formulation for the conservation of mass, momentum, and energy for both fluid and material phases, allowing an intrinsic coupling between them. We validate the unified approach against FiberForm flow-tube experiments under an oxidizing environment. The experiment concerns a molecular oxygen flow where carbon oxidation is active, and we compare the numerical material recession with the measured one. The finding of the presentation shows the importance of modeling the flow and material in a unified manner and reveals essential aspects that previous coupling approaches cannot.