Transition of Convective Combustion into Low-Velocity Detonation in a Low Porous Stochiometric Mixture of Ammonium Perchlorate with Polymethyl Methacrylate in a Device with Mass Ejection

In this paper, we study the propagation of chemical transformation waves in pressed samples from a stoichiometric mixture of ammonium perchlorate with polymethyl. Combustion is initiated by an electric igniter through a booster of a pressed mixture of TNT with RDX in a ratio of 30/70 placed in the projectile. Together with a photographic recording of the glow through a series of holes in the shell, pressures are recorded at three points along the sample length. The projectile mass and the particle size of ammonium perchlorate vary. Sample dimensions, compaction density, initiation method, and shell properties are the same. In previous studies, it was shown that when the initiator is placed at the closed end, low-velocity detonation was easily excited in the test sample. In this study, it is found that when the mixture is initiated from the projectile the development of the process depends significantly on its mass. In the case of a light body, convective combustion occurs in a sample with large particles of ammonium perchlorate, which propagates along the entire length of the sample. If the projectile mass is increased or the size of the ammonium perchlorate particles is decreased, the combustion is accelerated and turns into a low-speed detonation. The pressure records showed that at an increase in the mass of the projectile body, the pressure produced by the initiator, as well as the rate of the pressure increase and the maximal value in the wave, increase. At the grinding of ammonium perchlorate, the maximal pressure in the wave increases, and the projectile muzzle velocity decreases. The formation of powerful pressure waves of a triangular profile with an amplitude of up to 1–1.2 GPa and a steep leading edge is revealed.