Experimental and numerical investigations on the decomposition and combustion characteristics of composite propellant with Mg/Al particles additives

Experimental and numerical works were carried out to investigate the decomposition and combustion characteristics of composite propellant with magnesium and aluminum particles additives in the near burning surface region. Experiments were performed to film the macro-structures of combustion flame, measure the constant pressure burning rates, and test the temperature distributions of combustion wave. Both of the fitted pressure-burning rate curves match well with experiment results and have good predictive capability under ramjet working conditions. A detailed combustion kinetic model was employed in the in-house computational solver to simulate this typical two-phase flow problem. The combustion phenomenon was analyzed carefully about flame structure, chemical reaction order, and an obvious “double-platform” phenomenon was observed in the temperature distributions of combustion wave on central axis. The simulation results show that on one hand higher ambient pressure restricts the diffusion of primary combustion gases, but on the other it enhances the thermal feedback effect on solid domain and helps the combustion stability of composite propellant. The influences of oxygen concentration on the combustion wave structure in axial direction are negligible before platform 1 position, while the diffusion combustion characteristics in radial direction are obviously changed.