Research of evolution of shock train in scramjet isolator

Wave structures in the isolator play an important role in the starting of scramjet inlet;it is the bridge to connect inlet and combustor.Two-dimensional coupled implicit NS equations and RNG k-e viscid models were used to simulate the flow field of two-dimensional scramjet isolator,the evolution of shock train was investigated.Results show that the improvement of back pressure makes the shock train move forward along the flow field of the isolator;eddy appears in double near the wall of isolator with the mach disk;with the increasing of back pressure,intensity of shock train will be greater,oblique shock wave will become normal shock train,then λ normal shock wave,and the shock train will be pushed out of the entrance of isolator,the inlet will be unstart.Isolator with equal section can resist the influence of back pressure more easily than that with one side expanded and that with both sides expanded,it can insulate the effect of pressure of combustor on the working condition of inlet more efficiently.