Ignition Transfer Effectiveness from Primers to Physically Separated Pyrotechnic Boosters

摘要

Current issues of interest including pyrovalve ignition train effectiveness, pyrotechnic ignition transfer margin testing methodology, effects of ballistic pressure oscillation phenomenon, BKNO3 aging effects and ignition time prediction are identified and assessed. Historical evolution of booster charge design is reviewed. Gas-rich output type primers represented by ZPP and solid-to-solid reaction type primers represented by Ti/CuO thermite were studied in several output modes/scenarios. Detailed descriptions and theoretical analyses focused on the transfer efficiency are reported. It was found that the Ti/CuO type primer is more efficient in the booster ignition due to its large attainable heat production. ZPP type primer can be efficient if continuous output plume flow is maintained in relation to the booster. Close proximity between the reacting primer and direct physical contact of the primer plume with the booster charge are essential for ignition transfer effectiveness. Several methods for effectiveness enhancements from existing art are discussed. Using primer charge weight, initiator to booster adapter closure disc gap width, assembly void volume and booster input closure disc thickness as variables for transfer margin evaluation are assessed. New methods for pyrotechnic ignition time prediction in HBW initiation and modeling of ballistic pressure oscillation in closed bomb are presented.