Use of X‐ray computed tomography for validation of random packs of composite solid propellants

Abstract

This paper presents a comparison of actual solid propellants with a computationally generated propellant pack, which is intended for use in combustion modelling studies. X-ray computed tomography (XCT) was used to obtain a 3D reconstruction of an actual propellant sample. Random distribution of spherical particles of ammonium perchlorate (AP) has been used to model a composite solid propellant (random pack). The simulated random pack and 3D reconstructed propellant are compared based on three parameters capturing volume, area and length metrics, viz., density, exposed AP area and AP/binder intercept lengths. The density match is within 1.5 % between the actual propellant and the simulated propellant pack. The exposed AP surface area lies in the range 53–63 % for the 80–86 % solid loaded non-aluminized propellants considered in the study. The histogram of the intercept lengths matched reasonably as well capturing the variation in particle size and solid loading of the propellant. However, the comparison between simulated and XCT reconstructed packs was found to be limited by the resolution of the XCT reconstruction of actual propellant samples.