Erosion of Hypersonic Warhead by Nuclear Dust Cloud Impact

Abstract

A hybridized Eulerian-Lagrangian solver was built in the open-source computational fluid dynamics code OpenFOAM. This solver was developed as a starting point for higher fidelity combined abrasion-ablation effects modeling for hypersonic vehicles in OpenFOAM. A preliminary study, evaluating the erosion of a hypothetical hypersonic reentry body by a nuclear dust cloud composed of non-ionized silicone dioxide, was conducted. The thermal protection system material of primary interest was TACOT, Theoretical Ablative Composite for Open Testing. Heat of ablation calculations were used as a simplistic methodology to estimate the recession of vehicle by thermochemical means. Due to a lack of erosion models for high porosity materials, the erosion models of legacy materials were used in addition to some custom-developed models for TACOT. The predicted abrasion to ablation ratio was found to vary with Eulerian and Lagrangian refinements anywhere from 10-20% depending on the resolution combinations being examined.

Overall the abrasion to ablation ratio for TACOT, as predicted by the two-thirds-energy extrapolation method, was in the same order of magnitude as the correlations for legacy materials. While this is a good starting point it is believed by the author that this ratio should be much larger than those of the legacy materials. Given the high porosity of TACOT, when compared to legacy materials, it is believed that its char layer would be more susceptible to abrasive erosion. Unfortunately there is limited to no experimental data available for high porosity TPS erosion analyses. As new descriptive models are developed for high porosity TPS materials, both from experimental and numerical data sources, they will be incorporated into this tool.

Future work expanding on this modeling capability will focus on the incorporation of high particle Reynolds and Knudsen number drag correlations, the incorporation of finite-rate chemistry modeling and in-depth ablation modeling. Pending access to computational resources, simulations with thermally and radiatively coupled particles will also be conducted in order to assess the impact that the incorporation of radiation has on the solution and performance of the tool.