Combustion Characteristics of Single Granules of Black Power,
ARMY ARMAMENT RESEARCH AND DEVELOPMENT CENTER DOVER NJ
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A stroboscopic laser, schlieren photographic system was employed to study the combustion processes of single granules of black powder. The system uses s streak camera and a high power modulated argon laser as the light source to provide a dynamic sequence of time resolved, high resolution schlieren photographs of the multi-phase combustion product which consists of hot gases, solid, and liquid parties. Several different types of particles were identified and analyzed within as well as outside of the gaseous flow field, including nonreactive and burning solid particles and molten liquid droplets. The nonreactive particle was the largest, most easily identified particle, with an average effective diameter of 550 micrometers. From the photographic records, velocity-history data was obtained as a function of particle type, size, and orientation. Product cloud behavior was also observed throughout the combustion process and cloud front velocity histories were obtained. Particle number-density and size distribution were analyzed and plotted as a function of time after ignition. The burning rate of particles and their possible role in the grain to grain flame propagation mechanism are discussed.