Interaction of shock/boundary layers in a scramjet inlet

Increasing back pressure due to external factors has great impact on the structure and intensity of shock waves,and so affects the induced separation of boundary layers.A 2-D model of a scramjet inlet was developed,simulating the complex flow field of the isolating section in one of the inlets using the RSM turbulence model.The interaction of shock waves and boundary layers of the inlet under different back pressures was calculated.The results show that the separation zone inside the isolating section is larger and the Mach number in the outlet is lower when the back pressure is 0.At this level,shock waves are relatively weak,thereby providing favorable conditions for stable burning in the combustion chamber.With increasing back pressure,the total pressure recovery coefficient increases a bit,but the air flow stability decreases in the tail zone of the isolator.Therefore,it is necessary to properly adjust the back pressure of the isolator of a scramjet engine in order to resolve the contradiction between total pressure loss and stability of the flow field in the tail zone.This research provides a reference for optimal control over the operation of a scramjet inlet.