Analysis of a Three-Dimensional, High Pressure Ratio Scramjet Inlet with Variable Internal Contraction

We conducted an extensive experimental examination of the operational behavior of a three-dimensional scramjet inlet featuring a movable cowl to adapt the internal contraction according to the respective operation conditions. The experiments were conducted in the H2K wind tunnel of the DLR Cologne at Mach 7. The parameters investigated include different flight path angles (both angle of attack and angle of yaw), internal contraction ratio and Reynolds number. The critical internal contraction for inlet starting was found to agree well with common relations for starting of 3D-inlets. With increasing internal contraction, the inlet performance was found to improve and the inlet operated more stable. It was successfully tested for angles of attack up to ± 6° and angles of yaw up to 6°. Reynolds-Number had rather small effects on the performance and starting behavior of the inlet. Infraredthermography also gave some insight into the flow structure in the external part of the inlet.