Burning Characteristics of AP/HTPB Propellants Supplemented with Low Thermal Conductivity Powders

Thermal conduction in solid propellants is a dominant process of solid propellant combustion and influences the burning characteristics of the propellants. Fine, high thermal conductivity materials do not affect the burning characteristics of propellants, while low thermal conductivity materials improve them. This study is part of a series of studies on the influence of variations in solid-phase thermal conduction on the burning characteristics of propellants. ZrO2, steatite, and SiO2 were used as low thermal conductivity materials. These additives increased the burning rate by the hot spot effect. In addition, the influence of these additives on the burning rate was dependent on the ammonium perchlorate particle size. For the propellant with coarse ammonium perchlorate particles, the enhancement in the burning rate was dependent on the particle size or the specific surface area of the additives.