A temperature-profile Study of the Combustion of Black Powder and its constituent binary mixtures

Abstract

An earlier thermo-analytical study of black powder, using small sample masses and slow heating rates, has been extended to an examination of the behaviour of black powder under the less-controlled conditions of ignition and combustion, by simultaneous measurement of temperature profiles and burning rates. Burning-rate against composition curves for various charcoal/KNO3, mixtures (sulphurless black powder) and for charcoal/KNO3, mixtures with various proportions of sulphur, were concave-down-type curves. The compositions of mixtures with maximum burning rates did not correspond with the compositions of mixtures with maximum enthalpy-of-reaction. Maximum temperatures of ∼1400°C were recorded. Burning rates were found to decrease with increasing particle size of the constituents: with increasing compaction of the mixtures, or when inert diluents or subsidiary fuels were added to the mixtures. Burning rates were also affected by moisture contents above 276, and failure of burning occurred at >15% moisture.