Investigation of the Performance of a Scramjet Inlet at Mach 6 with Boundary Layer Bleed

Abstract

As part of the graduate college financed by the German National Research Council (DFG), an experimental study has been carried out on a fixed geometry scramjet inlet operating at Mach 6 in the hypersonic wind tunnel H2K at the German Aerospace Center (DLR) in Cologne. To reduce the risk of inlet un-start, a passive boundary layer bleed has been integrated at the throat and successfully tested. The passive bleed reduces the lip shock induced separation bubble on the ramp significantly. The obtained experimental results are discussed and compared with CFD calculations. To investigate the compression behavior, different back pressures have been applied and the effects on the internal flow structure are analyzed by means of Schlieren pictures and Pitot pressure profiles at the exit of the isolator. The heat transfer coefficient to the inner sidewall of the isolator is calculated using the time dependent surface temperature, measured with an infrared system.