Combustion Efficiencies of Aluminum and Boron in Solid Propellants

A closed-type strand bomb was used to trap all species participating in solid propellant combustion to measure combustion efficiencies of aluminum (Al) and boron (B) using titration techniques. Variations of combustion efficiencies (17) of Al and B with pressure and oxidizers of propellants were investigated. In order to improve B combustion, effects of the addition of Al, granulated propellants, and oxidizers were also investigated. It was found that burning of B particles could be enhanced by using fine powders. Boron particles granulated with potassium nitrate had the highest r/B (40%) in the strand burner. Burning of Al was found to be hindered by B burning when Al and B particles coexisted. These observations could be interpreted by considering the agglomeration and ignition processes of metal particles.