Development of Finite-Rate Ablation Toolset for Hypersonic Vehicles

The Navy seeks a novel and validated toolset for modeling finite-rate ablation effects on thermal protection systems (TPSs) for hypersonic vehicles. Current, state-of-the-practice ablation tools rely mostly on equilibrium BÆ tables to model TPS ablation which are known, in general, to overpredict recession in comparison to ground test and flight data. Despite known deficiencies, the simplicity and heritage of the BÆ table approach continues to be widely used in current hypersonic TPS analysis. Work in the last decade has focused on moving away from this assumption by leveraging advanced numerical and ground testing techniques to develop more fundamental ablation models which can model the finite-rate nature of the competing surface effects which result in what is commonly referred to as ablation. The current state-of-the-art finite-rate oxidation model is developed from data using molecular beam experiments, which probe individual molecular collisions. Development of these modern finite-rate ablation models, such as the air carbon ablation (ACA) model, now necessitates rigorous validation and evaluation against realistic TPS architectures and hypersonic environments. To this end, Corvid Technologies, in partnership with the University of Kentucky (UK), proposes development and validation of an improved finite-rate ablation model for the systems and environments of interest to the Navy (such as 2D and 3D carbon carbon). Under this Phase I effort, Corvid and UK will integrate improvements to our existing implementation of the ACA model, carry out an initial evaluation effort to assess the performance of the ACA model, and develop an optimization framework to further improve the ACA modelÆs correlation with test data. Also, we will plan a follow-on ground test campaign during the Phase I option period.