Feature-aware Ablation and Reaction Simulator for Thermal Extremes

Hypersonic vehicles require thermal protection systems (TPS) for protection from high-temperature, strongly shocked air. Carbon-based ablative TPS have received particular attention for Navy applications. Since ground-based testing at flight-like non-equilibrium conditions is limited and costly, physics-based simulation tools, including comprehensive finite-rate gas-gas and gas-surface chemistry models, are essential for designing next-generation TPS materials. The intricate interplay between gases and materials during hypersonic flight induces a degradation process, leading to alterations in surface morphology, and subsequently influencing the ablation dynamics within the TPS material. Moreover, these morphological/surface transformations have the potential to impact the gas-surface interactions throughout the flight. However, the current finite-rate ablation models for these systems are not tuned to chemical and morphological structure of the TPS material and do not account for mesoscale structural changes that occur during a flight. To address these gaps, Spectral Sciences, Inc. (SSI), in collaboration with the University of Colorado Boulder (CU), the University of Minnesota (UMN) and GoHypersonic, Inc. (GHI), proposes to develop an innovative software suite to model ablation of carbon-based TPS materials on hypersonic vehicles, with finite-rate chemistry and mesoscale material physics in the framework of computational fluid dynamics (CFD). Our team combines expertise in both hypersonic vehicle simulations and state-of-the-art experimental gas-surface reaction dynamics. In the Phase I effort, we demonstrated the feasibility of extensions to the state-of-the-art Air Carbon Ablation (ACA) finite-rate model, informed by new experimental data and integrated into the US3D hypersonic CFD code. In the Phase II program, we will implement advanced models of molecular and mesoscale ablation processes, guided by a comprehensive experimental validation campaign on Navy-relevant materials. The final product will meet critical Government and commercial needs to understand and manage gas–material interactions in extreme thermal environments.