Design and numerical simulation of a two-dimensional RBCC variable-geometry inlet with a central strut

A variable-geometry RBCC inlet scheme in the form of two-dimensional mixed-compression with a central strut inside was put forward for a TSTO vehicle using RBCC engine as the first stage power. The inlet can operate from Mach number 0 to 7 and the design point Mach number is 5. The geometry configuration of the inlet could be changed through adjusting the angle of cowl lip and the height of throat. The results of numerical simulation indicate: (1) the inlet self-starting can be realized at Ma=2.4 by changing its configuration and bleeding, which provides a necessary condition for the transition from ejector mode to ramjet mode; (2) the change of inlet's geometry can greatly widen the Mach number range in which the inlet operate normally at starting mode; (3) the performance parameters of the inlet are moderate at typical flight Mach numbers in ramjet and scramjet mode, which could meet the requirement of RBCC engine combustor for entrance air parameters; (4)adjusting its geometry configuration can also improve the inlet's resistance to back pressure.