Numerical simulation for thermal throat mechanism of RBCC in ramjet-mode

For the characteristics of operating together in the same expansion flowpath, three-dimensional numerical simulation has been carried out to study the formation mechanism and law of thermal throat in ramjet mode. The results show that the formation position of thermal throat can be controlled through reasonable heat release and area changes in the flowpath. The cavities that are located in the second combustor play an important role for the formation of a stable thermal throat. The combustion region formed from the cavities shear layer becomes a stable heat source which provides airflow with the transition energy of Mach number. The geometry contraction of cavities rear wall also provides impetus for the formation of congested surface. Airflow behind the cavities gradually becomes stable supersonic flow. Thermal throat is substantially formed behind the second cavities.