Internal ballistics simulation study of propellant geometry for optimal combustion and packing density

Abstract

A conventional bullet or projectile, driven by the rapidly expanding gas formed by the combustion of the propellant charge, accelerates in the barrel and reaches a certain muzzle velocity, spin, and propulsion energy. The geometric characteristics of the propellant grains are one of the primary factors which affect the performance of a projectile and its maximum achievable range. The geometric shape of the propellant grains is crucial to ensure simultaneous burnout of the entire charge before the projectile is discharged from the barrel to prevent unburnt propellant from forming residue inside the gun chamber. The geometrical shape of the propellant grains plays a significant role in the performance of a gun system. This also affects the packing density of the charge. In this research, a proposed propellant grain geometry for a 155 mm artillery gun system was investigated and compared to the rosette grain as a reference propellant grain. This was done to investigate and determine the effects of propellant geometry on the grain size, the packing density, the maximum pressure, and the muzzle velocity. the proposed propellant grain is outperformed by the rosette grain in term of performance. However, the developed propellant grain achieves higher packing density than the rosette grain. This research establishes a framework that to be used to develop any new propellant grain.