Nonequilibrium Aerothermodynamics for a Capsule Reentry Vehicle

This paper deals with the aerothermodynamic analysis of a capsule Crew Return Vehicle concept for the low Earth orbit support service. The reentry scenario with the corresponding loading environment is described and analyzed. Real gas aerothermodynamics and catalytic effects on the vehicle forebody heat shield have been taken into account. To this end, several Navier-Stokes computational fluid dynamics analyses have been performed in correspondence with the reentry peak heating conditions by considering the air as a nonequilibrium reacting gas mixture. The effects of chemical nonequilibrium on the vehicle forebody heat shield are pointed out, by assuming its surface alternately as a non-catalytic, partially catalytic and fully catalytic wall. This work confirms that the knowledge of the flow chemical environment is crucial for the exact prediction of the vehicle aeroheating. In fact, the possibility of reducing the heat loads by using a low-catalytic heat shield has been highlighted.