Investigation of particle size effects on aluminized solid rocket motor performance

The aluminum particles in the propellant cause a lot of effects on the solid rocket motor working process, for example, increasing propellant energy, causing loss induced by two-phase flow, and affecting unstable combustion. Existing studies mainly focus on the effect of aluminum content, thus this paper shall discuss the particle size on the motor performance. Firstly, experimental studies with laser diagnosis methods to determine the particle size distributions during realistic operation of the engine are carried out. The numerical simulation model is established afterwards, and its availability is verified by the experimental data. After that, a systematic investigation of inert particles with single sizes within the range of distribution tested shows that the loss of two-phase flow decreases with the increase of particle size. Finally, on the basis of this simulation model, the effect of incomplete particle combustion on the motor performance is studied. The results show that the particle combustion efficiency is not negligible, and the specific impulse loss of engine increases with the size of combustion particles.