Burning Rate Characteristics of Ammonium Perchloarte-Based Composite Propellant Using Bimodal Ammonium Perchlorate

It is well known that the burning rate of the ammonium perchlorate-based composite propellant depends on the mean particle diameter of ammonium perchlorate. Recently, it was reported that the packing fraction of ammonium perchlorate in the propellant matrix influences the burning rate. The mean particle diameter of the bimodal ammonium perchlorate system decreases by increasing the fine ammonium perchlorate content, and the packing fraction is a maximum when the coarse ammonium perchlorate content is approximately 0.8. The detailed experimental data on the burning rate characteristics of the propellants with bimodal ammonium perchlorate systems were investigated in this study. The burning rates of the ammonium perchlorate-based propellants at a constant mean diameter would not be identical when the packing fractions of the ammonium perchlorate particles were not constant. The burning rate of the bimodal ammonium perchlorate propellant is influenced not only by the mean particle diameter of the ammonium perchlorate, but also by the coarse ammonium perchlorate content and the diameter ratio of the coarse ammonium perchlorate to the fine ammonium perchlorate. The coarse ammonium perchlorate particles play an important role in the combustion of the bimodal ammonium perchlorate propellant even when the coarse particles are loosely dispersed in the fill region consisting of the fine particles and hydroxyl terminated polybutadiene. The combustion characteristics of the coarse ammonium perchlorate particles and the fill region would be the dominant factors influencing the burning rate of the bimodal ammonium perchlorate propellant.