Aerothermodynamic Analysis of Faceted Aeroshell at Hypersonic Speed

Abstract: This study explores the aerothermal behaviour of a rigid mechanically deployable aeroshell developed at Imperial College London for high payload atmospheric entry missions. The multiphysics CFD software STAR-CCM+ is used to perform a Conjugate Heat Transfer analysis on the aeroshell's faceted geometry. Results are presented for four different geometry models tested in air at Mach 5 with angles of attack 0{\deg}, 5{\deg} and 10{\deg}. The predicted surface heat transfer reveals areas of elevated heat loads at the ribs between facets and at the aeroshell shoulder, due to local boundary layer thinning. The increase in heat transfer at the ribs depends on the sharpness of the rib: more rounded shapes result in lower heat fluxes. Comparison with high-speed wind tunnel tests shows good agreement with experimental data. Stanton number and temperature profiles agree within 8% and 2%, respectively. The discrepancies between experiments and simulations are largest at the sharp ribs of the aeroshell. The sources of error can be associated with three-dimensional effects neglected in the heat flux derivations from temperature measurements as well as experimental uncertainties.