Analysis of the Potential Advantages of Discharging Water Mist in the Primary Damage Area Immediately Following a Weapon Hit

A water mist system that incorporates a survivable design has the potential to significantly reduce the thermal conditions in the primary damage area (PDA) following a weapon hit. This reduction in thermal conditions would certainly prevent flash over and could potentially prevent fire spread to adjacent compartments. The analysis put forth in this paper demonstrates that the likelihood of the PDA to reach flash over following a weapon hit is a function of the size of the opening to the weather created by the blast. Up to the point where the fire becomes fuel surface limited, the larger the vent opening, the greater the fire size and the higher the resulting compartment temperatures. The increased air flow provided by the larger vent opening also dictates the amount of water vapor required to saturate the gases in the PDA. As a result, the amount of mist required to achieve thermal management is also a function of the size of the vent opening. The results of this analysis demonstrate that the conditions produced by the fire following a typical weapon hit could be mitigated by appropriately discharging a minimal amount of water mist into the PDA.