A nonlinear characteristic line model of the detonation process of aluminized explosives

Abstract

Aiming at the non-ideal properties of aluminized explosive, a local isentropic hypothesis of the expansion of aluminized explosive detonation product was proposed, and a nonlinear characteristic line model for aluminized explosive detonation was established, which provides a new theoretical analysis method for studying the non-isentropic flow and the expansion of detonation products. A lot of studies have shown that for micron aluminum powder, the reaction mainly occurs in the expansion zone of detonation products. The aluminum powder was treated as inert in the detonation reaction zone in the model. Considering the reaction rate of the aluminum powder is relatively slow, the expansion process of the detonation products of aluminized explosive was divided into finite time regions. The energy released from the reaction of aluminum powder has a relaxation effect on the state of the products. Based on the relaxation effect, it was assumed that the detonation products flow was approximately isentropic in each time region. Due to the reaction of aluminum powder, the entropy in each time region was different. Based on the theory of isentropic flow of ideal explosive and local isentropic hypothesis, the non-isentropic expansion process of the detonation products of aluminized explosives can be analyzed theoretically. To verify the correctness of the model, metal plate experiments were conducted. Experiments on aluminized explosives and LiF explosives with a particle diameter of 5μm and 50μm to drive 0.5 mm and 1 mm metal plates were designed. The velocity history of the metal plate was measured by a laser displacement interferometer, and then the reaction degree of aluminum powder in the detonation products was calculated from the experimental results. Combined with the nonlinear characteristic line model of the detonation products of aluminized explosives, the velocity of the metal plate driven by aluminized explosives was calculated theoretically. Compared with the experimental results, the non-isentropic model can well describe the contribution of the secondary reaction of aluminum powder to the work ability of explosives, which verifies the correctness of the model for aluminized explosives (micron aluminum powder).