Model Predictions of Pressurization of Ordnance Magazines by Inadvertent Ignition of Energetic Material
NAVAL AIR WARFARE CENTER WEAPONS DIV CHINA LAKE CA
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For this study, high fidelity computations were performed on a simple fortified ordnance magazine with different levels of confinement and energetic material reaction rates. Pressurization rates versus time were calculated for the different confinementreaction rate combinations. Calculations were then done to determine the effect of the pressurization rate on the magazine structure. For the pressurization calculations, it was assumed that the energetic material came from a mixed system with a small amount of hazard division HD 1.1 energetic material and enough HD1.3 energetic material to fill the magazine to capacity. For comparison with the pressurization computations, calculations were also made with the HD1.3 system energetic material detonating and the effect of a detonation on the ordnance magazine was compared with the effect of the pressurization due to deflagration. Simulations were performed that calculate the pressure rise inside an RC Freloc Stradley 33-15-74 earth-covered magazine ECM from the burning of M10 gun propellant. Simulation data argue the potential for the safety standards in DoD 6055.09 to be inadequate in some instances of HD1.3 storage, but this argument cannot be responsibly made until structural simulations can be run to on the simulation data to calculate damage effects. Calculated pressures predict that pressurization occurs for weights of M10 between 100,000 pounds and one million pounds, but to an extent that is dependent on the mass burn rate via the reaction surface area. At surface areas higher than the arbitrarily-defined nominal area, pressurization occurs severely enough that the ECM is likely to rupture due to stresses on ECM surfaces. Structural simulations must be conducted to calculate whether the magazine ruptures. Future studies will investigate lower weights of M10 in the magazine as well as other reaction surface areas.
- Safety Engineering
- Ammunition and Explosives