Parametric Study of Bi-Modal Ammonium Perchlorate Composite Propellant Variations on Solid Rocket Motor Performance

This paper presents the effects of varying key composition parameters on the performance of bi-modal ammonium perchlorate composite propellant (APCP) rocket motors. Bi-modal APCP motors are desirable from the standpoint of affordability, safe handling and storage, and resilience to supply chain disruptions. This study outlines the impact of ingredient variations on motor thrust, chamber pressure, burn time, total impulse, specific impulse, and the thrust coefficient. The bi-modal AP distribution was varied from 60% of 400 ��m and 40% of 200 ��m particles to 60% of 400 ���� and 40% of 90 ���� particles. For each AP granular size distribution, copper chromite catalyst was tested at 0.10% and 0.15%, and the aluminum powder content was also varied at 7.5%, 10%, and 12.5% for each AP and copper chromite composition. These different compositions were tested in 2.126 inch diameter, 12.375 inch length motors with a 1/2 inch circular Bates core, utilizing a #29 (29/64 inch) nozzle. Results indicate that the 400 ���� and 90 ���� AP particle distribution with 0.1% copper chromite and 12.5% aluminum content had the highest total impulse. The highest specific impulse was achieved with the same AP granular distribution and aluminum powder content but with 0.15% copper chromite content. The observations from this study will be useful to rocket motor designers to develop more affordable and efficient motors.