Experimental and numerical investigations of the effect of pressure and oxygen concentration on combustion characteristics of Al/Mg fuel-rich propellants

Abstract

Experimental and numerical investigations are carried out to analyse the effect of pressure and oxygen concentration on combustion characteristics of Al/Mg fuel-rich propellants. In the present study, a small-scale sealed laser ignition experimental system is set up to obtain the experimental measurements in the combustion process of Al/Mg fuel-rich propellants. The result shows that, as the pressure and oxygen concentration increase, the combustion wave temperature increases and presents two platforms. It is conducive to the convective heat transfer and radiant heat feedback of the flame to the burning surface, thus leading to an increase in the burning rate. When the percentage of Al is increased and the percentage of Mg is reduced, the burning rate is increased. In order to understand the distribution of combustion products, a two-dimensional axisymmetric simulation program is developed. The simulated results show that the diffusion of the pyrolyzed gas is inhibited as the pressure increases, resulting in the rapid consumption of the oxidizing gas, a lower oxygen content and a higher cyanide content nearing burning surface. Due to the higher temperature required, carbides and alumina are produced in the far field region of the flow field. Conversely, the oxygen concentration has a small effect on the combustion wave temperature, but has a greater influence on the mass distribution of combustion products.