Numerical investigation of the influence of the L/D-ratio of propellent grains on the packing density

In this numerical investigation, the influence of the L/D ratio (length-to-diameter ratio) of propellant grains on the packing density was studied. The packing density of propellant grains plays a crucial role in determining the performance and combustion characteristics of solid propellants. A computational model based on the discrete element method was used to simulate the pouring process of propellant grains with different L/D ratios to achieve a more efficient use of space within the combustion chamber. This study provides valuable insights into the optimization of propellant grain design, can contribute to improving the overall performance of granular propellant-based systems, and can be adapted to study solid propellants with arbitrary geometries. A series of propellant diameter and length combinations were selected, and the resulting packing densities for different L/D ratios were calculated. The findings of this study indicate that an L/D ratio between 0.8 and 1 yields the highest packing density. This optimal ratio is dependent on the ratio of propellant and vessel volume.