Effects of Various Additives on the Characteristics of Bubbles Originating from the Combustion of Pyrotechnic Mixtures

The bubbling behaviour originating from the combustion of pyrotechnic mixtures of KClO4/Mg-50%Al alloy, and with additives such as nitrocellulose (NC) and urotropine, were studied by high speed photography. The results revealed that with the addition of the additives the combustion pressure and the gas flow rates increased in the order KClO4/Mg-50%Al/NC (3) > KClO4/Mg-50%Al/urotropine (2) > KClO4/Mg-50%Al (1). Additionally, it is confirmed that the bubbling phenomena can be classified into various stages, i.e. single bubbling, pairing and single coalescence, double coalescence and so on.