Research on Characteristics of Back Pressure Performance for Constant Area Isolator of a Hypersonic Inlet

To investigate characteristics of constant area isolator under strong back pressures,the flow filed in isolator of a typical hypersonic inlet was simulated with uniform and non-uniform(with oblique shock) inflow.The flow patterns of isolator and shock properties under different back pressures at different inflow Mach numbers were analyzed.The technical terms of the nominal length of shock train and the length of were presented.It was observed that with increase of back pressure shock moved forward and its nominal length reduced while length of pseudo-shock decreased.The calculated values of nominal length of shock showed good agreement with Waltrup-Billig correlation and empirical equations about relationship between length of pseudo-shock and back pressure ratio was attained.It was also observed that when back pressure approached maximum pressure capability,the oblique shock changed into normal shock and pressure rise was close to value through a normal shock.With non-uniform inflow,asymmetric shock was formed near upper wall of isolator and there was no normal shock when back pressure approached maximum pressure capability.