Validation of a Multi-Dimensional Model for Unsteady Combustion of AP/HTPB Propellants

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimIn this work, a model for the characterization of unsteady combustion of AP/HTPB composite propellants is benchmarked against experimental data. The model describes a change of phase of the propellant from condensed to gas phase and afterwards its combustion by a simplified chemistry scheme. A Finite Volume approximation is used to solve the system of equations. Firstly, the conservation equations including all source terms but combustion source terms are solved, in this case the numerical fluxes are computed by using Rusanov numerical scheme. Diffusive source terms are solved explicitly. After this, a first order Euler scheme is used to solve the system of ordinary differential equations resulting after considering the combustion source terms. The code is validated with two tests: the burning of a strand composed by AP and HTPB in sandwich configuration and the burning of a strand composed by AP particles uniformly distributed within HTPB. In both cases, simulation results are compared with experimental data. Influence of the pressure in burning rate, AP mass fraction, temperature and gas velocity are examined for sandwich test. For the strand, the effect of the pressure and initial temperature is also analyzed. Results show a good agreement between experimental and numerical data.