Thermo-structural behaviour of an UHTC made nose cap of a reentry vehicle

Abstract

In the frame of the technology project sharp hot structures (SHS), focused on the assessment of the applicability of ultra-high temperature ceramics (UHTCs) to the fabrication of high performance and SHS for reusable launch vehicles, the nose cap demonstrator named Nose_2 has been tested in the plasma wind tunnel (PWT) facility. In this paper, the FEM based thermo-structural analyses, carried out for the rebuilding of this PWT test are presented. Comparisons with experimental data measured in the PWT have been introduced to validate the FEM model and to help in interpreting the experimental test itself. Synergies between numerical and experimental activities have been finalized to the improvement of knowledge on the physical phenomenon under investigation. The effects on the thermal response due to the assumption of the catalytic condition of the wall, due to the uncertainties related to heat flux and pressure measurements on the probe (which influence the heat flux computation) and due to uncertainties in the determination of some UHTC thermal properties, have been investigated. The experimental temperatures curves falls very close to the numerical envelope (taking in account several sources of error) for all the test duration and the NCW model was found more reliable in reproducing thermal behaviour of the nose cap.