Investigation of a RBCC 2D variable-geometry inlet scheme

In ejector and ramjet modes, working over a wide Mach number range is very important for the RBCC inlet, so the 2D RBCC inlet should be variable-geometry. In this paper, the effect of internal convergent ratio on performance of the mixed-compression inlet is investigated by theretical analysis and numerical simulation, then an variable-geometry 2D inlet scheme, combining the internal contraction ratio adjustment and the boundary layer flow control, is presented. Results show that the variable-geometry scheme attains the improvement of inlet intergrated performance, including decreases of starting Mach number and drag force, and the increase of total pressure recovery coefficient, on the premise of smaller flow loss during a narrow lower Mach number range.