Post Flight Experiments of the SHEFEX I Configuration in the High Enthalpy Shock Tunnel Göttingen (HEG)

Abstract

One important aspect of the SHarp Edge Flight EXperiment (SHEFEX) program of the German Aerospace Center (DLR) is the post flight analysis of the data gathered during the flight of SHEFEX-I. One part of the analysis is the experimental simulation of a flight point at an altitude of approximately 20 km in the High Enthalpy Shock Tunnel Göttingen (HEG). To conduct these experiments a very complex wind tunnel model of the SHEFEX-I configuration has been designed, machined and instrumented by DLR. The experimental campaign performed in HEG included the measurement of surface pressure and surface heat fluxes on the wind tunnel model. Additionally flow visualisation with the Schlieren- and Shadowgraph method has been applied and flow velocity measured by the use of Particle Image Velocimetry (PIV) have been accomplished. As a supplementation to the heat flux measurements with thermocouples, the technique of IR-thermography of the model surface has been tested for the first time in HEG to gain access to the complete flow topology on the surface of the wind tunnel model. To achieve a adequate experimental database an exceptional large number of runs has been performed in HEG and supplementary each experiment has been numerically conducted by applying the DLR Tau code to model the flow in HEG. The comparison between the numerical and experimental data for surface pressure and surface heat flux is the main focus in this paper. The comparison between the wind tunnel results and the data gathered during flight will be discussed conclusively.