Investigation of a two dimensional Scramjet Inlet Flow Field at Mach 7

Abstract

measurement campaign has been carried out to investigate the viscous flow effects in a fixed geometry two dimensional (2D) Scramjet inlet at Mach 7. The tests have been performed in a hypersonic blow down wind tunnel facility. The existing boundary layer separation due to shock interaction in the inlet throat can lead to inlet un-start. Therefore a optional passive boundary layer bleed has been integrated at the throat. The passive bleed reduces the lip shock induced separation bubble in the throat significantly. The obtained experimental wall pressure distribution and Pitot pressure profiles are discussed and compared to 2D and 3D CFD calculations. To investigate the compression behavior, different back pressure ratios have been applied to the isolator flow and the effects on the internal flow structure are analyzed by means of Shadowgraph pictures, static pressure distribution and Pitot pressure profiles at the exit of the isolator. The heat transfer coefficient to the inner side wall of the isolator is calculated using the time dependent surface temperature, measured with an infrared system. The resulting 2D Stanton number distributions are presented for different configurations and different back pressure ratios. In addition three different Reynolds numbers have been used to investigate the effect on the separation bubble located in the corner of the first and second ramp transition and the resulting change in ramp heat flux.