Novel combustion flame luminosity methodology to track gun propellant combustion progress in closed vessel and semi-closed vessel

Abstract

This research project investigated a novel technique aiming to evaluate the performance of gun propellant combustion. The voids between propellant particles cause some difficulties in accurately measuring the performance of powder propellants. Closed vessels and strand burners are methods capable of measuring propellant burn rate, however, cannot consistently control the non-linear progression of gun propellants due to the voids. Combustion models have been employed to solve this problem; however, several models still produce unrealistic predictions, hence the necessity for an experimental technique. The combustion parameters commonly associated with propellant combustion were recorded and their correlation with the luminosity was investigated. A novel technique was designed intended to contribute to the knowledge obtained during certain combustion processes. The luminosity generated by the combustion flame is associated with the chemistry of the propellants and can be measured by cameras from safe distances. A camera was utilised to record the luminosity generated by the combustion and the data was compared to the pressure and combustion time. Several modes of operation were utilised in the form of closed vessel, vented vessel, and open vessel to study the difference between these modes on the parameter’s correlation. It was observed that the luminosity data was closely correlated to the pressure, especially the peak luminosity to the peak pressure, obtained when the burn rate was at its highest conditions. Despite individual variation between firings, the average luminosity for any propellant loading density generated a reproducible and consistent rise, indicating the correlation hypothesised exists. Despite making useful observations, the luminosity technique requires improvements to more accurately describe the correlations. The usefulness of this technique does rely on the ability of the propellant to produce a smokeless burn, generally a requirement for several military weapon systems for safety purposes.