A new algorithm to determine geometric properties of propellant grains from computer tomographic images

To simulate propellant combustion in guns and to evaluate the burn rate from closed vessel experiments the geometry of the propellant grains has to be known with high precision. In multiperforated propellant grains the web thickness and perforation diameter are the most important properties to be determined with high accuracy. Even small geometric deviations can lead to a different gas production rate or to deviations in determined burn rate parameters. To acquire precise geometric data from whole propellant grains a novel algorithm was defined and implemented. It uses computer tomographic cross sections of the propellant grain and extracts the geometric properties like web thickness. The algorithm was tested on synthetic images and it is shown that it is possible to determine the preset geometric properties with high precision. Furthermore the algorithm is tested on real CT images of JA2 propellant with 7 perforations (7PF) and the results are compared to a traditional method.