Explosive Venting Technology for Cook-Off Response Mitigation
ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ ENERGETICS WARHEADS AND MANUFACTURING TECHNOLOGY DIRECTORATE
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Small and large scale explosive venting experiments were conducted using highly controlled thermal cook-off test fixtures. These experiments allowed us to characterize the explosive violence as a function of a known vent area and controlled heating rate. The required venting area was experimentally determined at different heating rates. Large scale hardware was used to investigate scaling effects. Tests results indicate that some explosives PAX-28 and PBXN-109 intrinsically require less vent area to achieve a non-violent response than others Comp B. However, the results also indicate that for solid explosives, a violent reaction commonly occurred when the samples were heated without the use of a melt out liner, which allows gaseous products to reach the vents. This is in contrast to melt cast explosives that may respond in a non-violent manner without the use of a liner. Thermal modeling, including explosive kinetics, was also conducted using ALE-3D and for some solid explosives PBXN-109 shows close agreement with actual test results. However, very limited modeling is available for melt pour explosives. Slow cook-off experiments were conducted at 27.8 deg Chr 50 deg Fhr and 3.3 deg Chr 6 deg Fhr heat rates. At the lower rate, the ignition normally occurred near the center of the billet. In this case, gas products can be confined, resulting in a violent reaction. Recent work has concentrated on concepts for using energetic materials to force the reaction to the billet surface during 6 deg Fhr heating in order to produce a non-violent reaction.
- Ammunition and Explosives