Aerothermal loads analysis of ReFEx by coupled fluid–structure simulations

Abstract The Reusability Flight Experiment (ReFEx) is an experimental vehicle developed by the German Aerospace Center (DLR). It simulates the reentry of a reusable booster stage. After being launched with a VSB30 rocket to an altitude of about 139 km, it will perform an autonomous reentry. This paper focuses on the analysis of the aerothermal loads during the ascending and reentry phases. Different approaches are applied and compared for investigating thermal heating: from a very conservative worst-case analysis to a fully coupled simulation via the DLR CoNF $$^\text {2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mtext>2</mml:mtext> </mml:mmultiscripts> </mml:math> aS $$^\text {2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mtext>2</mml:mtext> </mml:mmultiscripts> </mml:math> tool chain (Coupled Numerical Fluid Flight Mechanic And Structure Simulation). In the context of a numerical flight test, CoNF $$^\text {2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mtext>2</mml:mtext> </mml:mmultiscripts> </mml:math> aS $$^\text {2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mtext>2</mml:mtext> </mml:mmultiscripts> </mml:math> is an integrated fluid–structure interacting coupled process chain, allowing the combination of various flow solvers, such as DLR Tau, with commercially available structural solver codes, as well as simple heating evaluations. The focus of the presented work is the heat conduction within the structure induced by the surrounding atmosphere during launch and reentry on the experimental ReFEx vehicle itself, excluding the sounding rocket motor.