Cook-off analysis of a propellant in a 7.62 mm barrel by experimental and numerical methods

Abstract

Cook-off is an involuntary self-ignition phenomenon of a propellant in a cartridge often encountered in multiple sequential firings. In this study, an efficient approach has been used for cook-off analysis of a propellant by experimental and numerical methods. Various firing tests have been conducted with a 7.62mm rifle to determine the temperature distribution in a barrel and the cook-off time. The outer surface temperature at the hottest area on the combustion chamber where the cook-off process was assumed to initiate was measured with a thermal imager as an effective method. For numerical analysis the model of the combustion chamber combined with the cartridge was created and analyzed using the ANSYS 14.5 Academic finite element solver and the temperature distribution of the inner/outer surfaces of the combustion chamber was determined. The numerical results for temperature distribution were observed to be quite close to the temperature values measured by the thermal imager. The numerical analysis was also validated by comparing the numerically determined cook-off time with the experimental measurements. At the end, various parametric analyses have been made that affect the cook-off time of a propellant.