Study on the quasi-isentropic model for aluminized explosive driving the cylinder in the direction perpendicular to detonation wave propagation

Abstract

A cylinder test was designed for the CL-20-based aluminized explosives to study the influence of aluminum (Al) powder properties on the explosives' metal driving performance in the direction perpendicular to detonation wave propagation. The research results showed that: in the direction perpendicular to detonation wave propagation, as the Al powder particle size became larger (in the range of 2–43 μm), the metal driving performance of the explosives grew stronger; the CL-20-based explosive containing 25% Al was much less capable of accelerating the metal than the formulation containing 15% Al. Considering the two-dimensional flow characteristics of the detonation products in the radial and axial directions as the aluminized explosive expands and drives the cylinder, a quasi-isentropic theoretical model for the aluminized explosive driving the cylinder was proposed. In the model, the calculation methods for the variations of the cylinder expansion velocity, Al reaction degree, and detonation product parameters with time, axial space, and radial space were developed. According to the experimental data of the cylinder test, the correctness of the proposed quasi-isentropic theoretical model was verified; the variation laws of the physical parameters, such as the pressure and temperature of the detonation products under different radial distributions in the cylinder with time and axial positions, were calculated. It was found that the pressure and temperature of the detonation products in the non-inner-wall place of the cylinder were significantly higher than those on the inner wall of the cylinder at the same axial position; the pressure and temperature of the detonation products on the inner wall decreased rapidly at the early timeframes; as the Al reaction proceeded, the pressure gradually turned to a constant value, and the temperature dropped slowly; for the CL-20-based explosives with 15% Al, the temperature of the detonation products in the non-inner-wall place rose slightly at first and then decreased slowly; for the formulation with 25% Al, the temperature of the detonation products in the non-inner-wall place kept rising at a small rate.