Influence of Heat Capacity Ratio on the Interaction between the External Flow and Nozzle Flow of a Scramjet

Abstract

As part of a graduate college financed by the German National Research Council (DFG), an experimental study on nozzle flows was carried out at the German aerospace center (DLR). The tests were performed at a free-stream Mach number Ma∞ = 7 in the H2K wind tunnel of the wind tunnel department in Cologne. The Reynolds number was varied in order to simulate the influence of different flight altitudes of a scramjet vehicle. The effects of different heat capacity ratios have been investigated by using gases with higher and lower heat capacity ratios than air. The obtained experimental results are discussed and compared with CFD calculations. Furthermore, an analysis on the effect of a Reynolds number and Mach number variation was carried out with a complete scramjet model. In both cases pressure measurements and Schlieren photographs were used in order investigate the flow properties.