SIMULATION AND NOZZLE AFTERBODY INTEGRATION OF HYPERSONIC PROPULSION SYSTEMS

The integration of combined turbo-ramjet engines for hypersonic aircra ft operating in the Mach 0 to 6+ regime is an important development ta sk. The complex interaction between the flow fields of the exhaust sys tem and the airframe considerably influences the vectorial force and m oment balance of the total aircraft. Using different numerical codes ( Euler code, Navier-Stokes code) the flow field in a Single Expansion R amp Nozzle (SERN) for a hypersonic aircraft is studied. Comparisons be tween experimental data and CFD calculations for certain components of the integrated exhaust system (cold 2D nozzle flow and 2D nozzle flow with external flow) are presented. To show the sensitivity of the con sidered components to off-design operating conditions, comprehensive n umerical studies have been carried out. For the determination of nozzl e performance a detailed 2D analysis from transonic to hypersonic flig ht Mach numbers has been performed. A direct optimization method has b een used to investigate the influence of the lower nozzle flap shape o n the thrust vector.