Effect of Black Powder Combustion on High- and Low-Pressure Igniter Systems

Abstract

Abstract : Large-caliber igniter systems have been evaluated using black powder lots which were manufactured with specific defects. The purpose of the program was to determine how the igniter system performance was affected by the black powder. At the same time, several conventional lots from two different black powder manufacturing companies were also tested in the igniters. Igniter action time was found to vary considerably depending on the lot used. Various other tests, including high-speed cinematography, have shown that the igniter performance differences are related to combustion characteristics of black powder which vary from lot to lot. Slow-burning lots form large amounts of liquid droplets at the surface which then move into the flame above the surface. Fast lots burn with very little droplet formation. Particle size and the degree of mixing of the ingredients appear to be related to the combustion properties. However, more factors are involved and are currently under study. Examination of low-pressure igniter performance indicates that there are slow and rapid gas generation rates. The transition from the slow to the rapid rate takes place at low pressure.