Inferring thermal conductivity of a dual-layer woven thermal protection system using cross-validation

Abstract

Abstract Thermal response modeling is performed for the Heatshield for Extreme Entry Environment Technology (HEEET), a dual layer woven thermal protection system. The 3-D material response code, Icarus, is used for modeling the multi-dimensional thermal response of HEEET in the Laser Hardened Materials Environmental Laboratory, where a flat-top fiber laser is used to generate radiative heating representative of atmospheric entry. Discrepancies between simulation predictions and experimental measurements are suggestive of several uncertainties in the magnitude and spatial distribution of the incident laser radiative boundary condition, as well as the material properties, particularly for the thermal conductivity. By reconstructing the magnitude and spatial distribution of the applied radiative heating, the measurements are used to infer the conductivity of HEEET through constrained optimization and cross-validation. The inference shows that a reduction in thermal conductivity from nominal values is necessary for simulations to achieve improved agreement with experimental data.