Heat Transfer Analysis for a Winged Reentry Flight Test Bed

In this paper we deal with the aero-heating analysis of a reentry flight demonstrator helpful to the research activities for the design and development of a possible winged Reusable Launch Vehicle. In fact, to reduce risks in the development of next generation reusable launch vehicles, as first step it is suitable to gain deep design knowledge by means of extensive numerical computations, in particular for the aero-thermal environment the vehicle has to withstand during reentry. The demonstrator under study is a reentry space glider, to be used both as Crew Rescue Vehicle and Crew Transfer Vehicle for the International Space Station. It is designed to have large atmospheric manoeuvring capability, to test the whole path from the orbit down to subsonic speeds and then to the landing on a conventional runway. Several analysis tools are integrated in the framework of the vehicle aerothermal design. Between the others, we used computational analyses to simulate aerothermodynamic flowfield around the spacecraft and heat flux distributions over the vehicle surfaces for the assessment of the vehicle Thermal Protection System design. Heat flux distributions, provided for equilibrium conditions of radiation at wall and thermal shield emissivity equal to 0.85, highlight that the vehicle thermal shield has to withstand with about 1500 [kW/m] and 400 [kW/m] at nose and wing leading edge, respectively. Therefore, the fast developing new generation of thermal protection materials, such as Ultra High Temperature Ceramics, are available candidate to built the thermal shield in the most solicited vehicle parts. On the other hand, away from spacecraft leading edges, due to the low angle of attack profile followed by the vehicle during descent, the heat flux is close to values attainable with conventional heat shield. Also, the paper shows that the flying test bed is able to validate hypersonic aerothermodynamic design database and passenger experiments, including thermal shield and hot structures, giving confidence that a full-scale development can successfully proceed.