Factors Affecting the Primary Combustion Products of Boron-Based Fuel-Rich Propellants

Boron-based fuel-rich propellants with different formulation were prepared, and the condensed-phase products under different chamber pressures were collected in this study. The composition of boride (elemental boron, boron oxide, boron carbide, and boron nitride) in the condensed-phase products was measured by chemical analysis and the particle size distribution was determined using a laser particle size analyzer. Moreover, the burning rate and combustion temperature of the propellants were measured using a strand burner. The experimental results show that both the propellant burning rate and combustion temperature played an important role in the production of boride. There might be large amounts of boron carbide in the condensed-phase products which appear to have a negative effect on the combustion efficiency of the propellants studied in this work. The production of boron carbide could be reduced and combustion efficiency was improved by lowering the combustion temperature while increasing the burning rate. This study also shows that reducing the chamber pressure also causes a decrease in production of boron carbide.