Ignition model for solid propellants under low temperatures involving the effect of aluminum

The specific impact of aluminum powder on solid propellant ignition remains unclear. Therefore, this study investigated the ignition performance of hydroxyl-terminated polybutadiene/aluminum/ammonium perchlorate composite propellants at low temperatures. Based on a solid-phase reaction, a propellant ignition model was developed by modifying aluminum, and the ignition delay times of the propellants at different initial temperatures were calculated. A reduced initial temperature of the propellant from 283 to 213 K increased the theoretical ignition delay time from 0.144 to 0.303 s, respectively. The results were confirmed by comparing the ignition delay times of the propellants at various initial temperatures obtained from laser ignition, with a deviation of ˂9.14%. The key reason for the increased ignition delay time was the increase in inert heating time, whereas the decrease in the chemical reaction rate due to the low temperature was negligible. Subsequent analyses revealed that the presence of aluminum significantly increased the thermal conductivity of the propellant, heat loss from the burning surface, and inert heating time of the propellant, thereby significantly increasing the ignition delay time of the propellant. This study provides a practical theoretical ignition model for composite propellants under low-temperature conditions.