An Experimental Study on Aerothermal Heating of the IXV Configuration During Reentry

Abstract

In the framework of the ESA FLPP program an experimental investigation of the aerothermodynamic phenomena on the IXV configuration during reentry phase has been conducted in the hypersonic windtunnel H2K at DLR Cologne. To study the control behavior of the vehicle with flaps at different flight conditions, a variation of the flap deflection and the angle of attack have been applied. Tests have been carried out at Mach 8.7 and three different Reynolds number steps. The test duration was up to 20 seconds. The model is made of a material with low thermal conductivity, in order to measure the surface temperature distribution by means of IR thermography and to avoid any heat dissipation inside the structure. Using this data the heat flux rate has been determined taking into account temperature-dependent material characteristics, assuming a semi infinite wall and radiative cooling to the environment. The flow topology has been analyzed using Schlieren images. Depending on the combination of the flap deflection angle and angle of attack the experimental data show a significant influence of the Reynolds number on the shock-shock and shock-boundary layer interactions, flow separation and its re-attachment, which lead to a completely different aerothermal heating on the flap.