Understanding the ignition/combustion processes of pyrotechnic pellets and the product-gas pressurization and venting behavior inside the flash tube of an ignition cartridge is very useful for supporting model formulation and design improvements for mortar propulsion systems. This study provides the pressure-time data for flash tubes using both black powder (BP) and moisture resistant black powder substitute (MRBPS) pellets for characterizing the mass and energy fluxes discharged from the vent holes into the granular propellant bed in the M1020 ignition cartridge. Combustion processes in instrumented ignition cartridges using these two types of pellets in the flash tube were studied. Results for both pyrotechnic pellets showed highly non-uniform venting of products from the flash tube vent holes. This can lead to significant pressure wave phenomena in the combustion of ball propellants in the granular bed. The highly transient pressurization process produced by combustion of granular propellants caused non-uniform discharge of products in both gas phase and condensed phase to the mortar tube. MRBPS pellets produced much higher and smoother P-t traces due to its generation of higher percentage of gas-phase combustion products. They also exhibited greater reproducibility than black powder pellets and had a faster average time from ignition to depressurization of the granular bed. However, since both pellets produced a highly non-uniform discharge of product gases and particles from the flash tube into the granular bed, modification of the vent-hole pattern is recommended.
|Original language||English (US)|
|Number of pages||15|
|Journal||International Journal of Energetic Materials and Chemical Propulsion|
|State||Published - Dec 1 2009|
All Science Journal Classification (ASJC) codes
- Materials Science(all)