Design and performance investigation of sidewall compression scramjet inlets operating from Mach 4 to Mach 7

Three-dimensional sidewall compression scramjet inlets with fore body compression operating in a large Mach number range from 4 to 7 were designed.The selection principles of the inlet primary design parameters were discussed and a high performance inlet scheme with curved surface compression was given.The complex flow field structure and the global performance of the scramjet inlet were investigated by means of numerical simulations.Results indicate at Mach 4 starting point,the sidewall compression scramjet inlet has a mass capture ratio of 0.753,and can work at above 6 degrees attack angle.At Mach 6,the inlet has a mass capture ratio of 0.945 and a total pressure recovery coefficient of 0.504 at the isolator exit,and 0.388 at Mach 7 cruising point.Numerical simulations also show that with the increasing attack angle,the captured mass flow increases nearly linearly,but the total pressure recovery coefficient decreases dramatically.As the yaw angle increased,the inlet total pressure recovery coefficient also decreases dramatically,but the mass capture ratio only drops slightly.It is also found that a pair of vortex occurre at the bottom of the isolator because of the pressure difference between the upper and lower walls of the isolator entrance,which increase the flow field distortion,and decrease the total pressure along the isolator.