Performance sensitivity study on a blowdown nitrous oxide paraffin wax hybrid sounding rocket

A hybrid rocket design methodology is dependent on a number of factors, such as mission requirements and resource availability and thus no single solution exists. An in-house software called the Hybrid Rocket Performance Simulator (HYROPS) was used as the foundation of the design process followed in this paper. The software is based on a one dimensional, unsteady combustion flow model that predicts the performance of a hybrid rocket motor as well as a generic 6-DOF flight dynamics simulator that determines the flight performance of a rocket. Parametric studies using the HYROPS software were conducted to investigate the effects of various design parameters on the performance of a sub-orbital hybrid rocket. The propellant combination used in this trade study was paraffin wax fuel with nitrous oxide. The various design parameters under analysis include chamber pressures, O/F ratio, and grain characteristics. Performance gain and mass saving obtained from the performance simulations reduce costs associated with the development of a hybrid rocket. •Design parameter trade-off study for large-scale hybrid rockets using paraffin wax.•Highlighting the sensitivity of combustion efficiency, chamber pressure and O/F ratio.•The investigation of the effect of aluminised fuel grains.