A review on packing characteristics of explosives: Recent advances and future perspectives

With the increasing demand for high uniformity, high density, high performance, high safety, and automated production in modern weapon systems, the packing properties of explosive powders have garnered widespread attention. This review summarizes strategies for regulating and enhancing the packing properties of explosive powders, as well as methods for graded classification evaluation. The approaches for modulating and improving packing properties primarily focus on three aspects: particle morphology control, particle gradation, and surface modification. These significantly improve the packing characteristics. Regarding evaluation systems, commonly used gradation and classification methods based on flowability and packing characteristics are introduced, such as the angle of repose method, the vibrating funnel method, the Carr index method, and the Hausner ratio method. Although these methods benefit from simple equipment and ease of operation, they predominantly involve single-factor evaluations, which can lead to incomplete assessments and a lack of standardized criteria. Given the current state of research, future efforts should prioritize microscale simulation studies on the mechanisms governing packing properties. Concurrently, there should be a shift from single-parameter evaluation to multi-parameter comprehensive assessment. These advancements are expected to provide the theoretical foundation and technical support necessary for the precise control and high-precision production of next-generation munitions. This paper reviews the research progress of packing characteristics for explosives. The regulation approaches involving particle spheroidization, particle gradation, and surface modification are highlighted, together with typical characterization methods for flowability and packing properties. The current limitations of insufficient evaluation and non-unified standards are discussed, and prospects for microscopic simulation and multi-parameter evaluation, guiding charge optimization. • Progress in regulating the packing characteristics of explosives is systematically reviewed, including particle spheroidization, particle gradation, and surface modification. • Particle gradation significantly influences the flowability and bulk density of powder particles. • Common evaluation methods for flowability and packing properties are compared, revealing the limitations of single-parameter assessment and non-unified standards.