Abstract

GENEVIEVE, B.; PITOT DE LA BEAUJARDIERE, J.F.  and  BROOKS, M.J.. A computational tool for predicting hybrid rocket motor performance. R&D j. (Matieland, Online) [online]. 2017, vol.33, pp.56-65. ISSN 2309-8988.

A model is described to aid in the design of hybrid rockets and in the prediction of motor performance, specifically with respect to the University of KwaZulu-Natal's Phoenix-1A vehicle. The Hybrid Rocket Performance Code (HRPC), programmed in MATLAB, is segregated into two individual models: i) a preliminary motor design code to analyse and design hybrid rocket motors, and ii) a predictive motor performance code to compute the instantaneous motor performance for a targeted burn time. The predictive motor performance code is based on a one-dimensional unsteady gas flow model through the nozzle and, on a zero-dimensional model of the combustion chamber capturing only the filling and emptying dynamics. The zero-dimensional model is linked to a self-pressurising delivery tank model obtainedfrom literature to simulate the changes in physicochemical properties of nitrous oxide in the tank. HRPC is coupled with NASA-CEA equilibrium chemistry program to determine the thermodynamic properties of the combustion products necessary for solving the governing ordinary differential equations. As such, different propellant combinations can be analysed for motor performances. The HRPC application is validated against hot-fire test data of Phoenix-lA's PV-1 flight motor and against reported performance data from the literature.

Keywords : Hybrid rocket propulsion; nitrous oxide; paraffin-wax; computational model.

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