Influence of Vent Area on Aluminized Explosive Behavior in Fast Cook‐off

ABSTRACT This study investigates the effect of the venting ratio on the responding intensity of aluminized explosives using a fast cook‐off test vessel with adjustable venting areas. The venting ratio is defined as the ratio of vent area to explosives surface area, and is represented by the variable R . Using a polymer‐bonded explosive TB‐1 (RDX/Al/KP/Binder = 55/35/5/5) as the test subject, we recorded overpressure, reaction temperatures, heating times, and optical signals generated during the tests. The damage to the vessel and the residue of explosives were also analyzed. The recorded results indicated that heating time and reaction intensity exhibit similar patterns. As the R increased, both firstly decreased sharply and then increased gradually. The minimum values for both occur when R is 0.012. At this point, the ignition of the charge damages the explosive matrix, causing the aluminum powder to melt and accumulate at the sidewalls. This quickly compromised the vessel shell in these areas. Reducing the R ‐value exacerbated the matrix damage, significantly speeding up the reaction to a high consumption rate. Enlarging the R ‐value mitigated matrix damage, which was insufficient to concentrate the aluminum powder, resulting in longer heating times and a greater amount of explosive participating in the reaction. Reactions were classified as combustion based on shock wave overpressure, optical signal strength, and shell damage when the R ‐value exceeded 0.012. The non‐monotonic relationship between the vent hole area and the intensity of the explosive reaction is crucial for the design of thermally insensitive munitions.