Analysis of the Rocket Plug Nozzle Combined Cycle Propulsion System

A new type of Rocket Based Combined Cycle Propulsion System is being researched at the University of Alabama in Huntsville. The Rocket Plug Nozzle Combined Cycle (RPNCC) configuration integrates an air-breathing propulsion system within the base of a rocket-driven plug nozzle. Current research is focused on assessing the feasibility of the RPNCC for space access and high-speed atmospheric flight. Preliminary analysis of this unique propulsion system is presented using analytical and computational methods combined with experimental data to predict plume interaction characteristics. Modifications to an analytical method-of-characteristics code are formulated to model the air-breathing engine plume exhausting through the plug base. The modified code will become part of a suite of codes to design and optimize RPNCC propelled flight vehicles at a variety of flight conditions and thrust levels. The methods used to modify the analytical code are described and compared to preliminary CFD results.