Analysis of annular plug nozzle performance and thrust vectoring control

Plug nozzles are currently being evaluated as alternatives to conventional, internal expansion bell and conical nozzles for launch vehicles. The primary objective of this research was to develop and verify an engineering level tool to predict the thrust and TVC performance of annular plug nozzles. The Aerospike Design and Performance Tool (ADAPT) was modified and shown to be capable of predicting plug nozzle axial wall pressure distributions within engineering accuracy. The Plug Nozzle Analysis Program (PNAP) code was developed to use ADAPT, CFD, or experimental wall pressures to calculate plug nozzle axial thrust performance and TVC. Combining ADAPT and PNAP predicted axial thrust to within +/-5% of cold flow experimental data. This combination also predicted side load trends for differentially throttled cases. The combination of ADAPT and PNAP saves considerable analysis time compared to Computational Fluid Dynamics.