Numerical prediction of aerothermodynamic effects on a re-entry vehicle body flap configuration

Within the EXPERT program, funded by European Space Agency, a number of experiments to be performed in the CIRA Plasma Wind Tunnel “Scirocco”, representative of the capsule flight conditions with respect to the shock wave boundary layer interaction phenomenon occurring around the 20-degree open flap, has been designed: PWT driving conditions, model configuration and attitude and model instrumentation have been defined, by means of a massive CFD activity performed by using the CIRA code H3NS, in order to duplicate on a forebody full-scale flap model both pressure and heat flux levels estimated in critical flight conditions. The model that has been designed reproduces the full scale EXPERT 20-degree flap, mounted on a holder composed by a flat plate with rounded leading and lateral edges; it will be built by using the same materials of EXPERT: i.e. PM1000 for the flat plate and C–SiC for the flap. Detailed 3D computations of the flow around the model with proper thermal and catalytic modeling of the surface have been carried out in the selected test conditions, to duplicate either the SWBLI phenomenon around the body flap either the associated thermo-mechanical loads acting on it during the EXPERT re-entry flight. Predicted results have been compared to test design results and test requirements extracted from the EXPERT re-entry flight. Some physical and geometrical effects (surface catalysis of PM1000 and C–SiC, wall temperature of the model leading edge, base flow) have been studied qualitatively through a series of simpler two-dimensional simulations. It can be concluded that the Test Matrix of the PWT experiments defined in the previous phase of the project is confirmed by the present accurate three-dimensional CFD simulations.