Propulsion aspects of hypersonic turbo-ramjet-engines with special emphasis on nozzle/aftbody integration

For hypersonic transport vehicles with combined turboramjet engines operating in the Mach 0 to 6+ regime the exhaust nozzle/aftbody configuration is one of the most important areas. The variable and controllable hot gas single expansion ramp nozzles coupled with different bypass and boundary layer flows represent highly integrated propulsion/airframe-systems. These exhaust systems influence considerably the vectorial force and moment balance of the total aircraft. This paper presents examples of some concept studies of generic nozzle configurations calculated by different computational fluid dynamic methods for selected flight regimes. The following aspects are mainly discussed: Bookkeeping system of the single expansion ramp nozzle and aircraft aftbody, the application of different CFD-codes, a critical comparison of typical examples and calculation methods and finally some considerations about future investigations and experimental correlation.