Effect of afterburning effect of aluminum powder on shockwave and bubble behavior of CL-20 explosive in deep-water explosion

Aluminized explosives are widely used in underwater explosives, and their energy release follows a typical time-varying process involving two stages: explosive detonation and afterburning of aluminum powder. Simulated deep-water explosion experiments of hexanitrohexaazaisowurtzitane (CL-20)-based explosives were conducted using a deep-water explosion pressure tank to study the effect of aluminum powder combustion on the shockwave propagation and bubble pulsation of deep-water explosions. The distribution mechanism of aluminum powder afterburning energy in the process of shockwave propagation and bubble pulsation under a high hydrostatic pressure was clarified, and the effect of aluminum contents on the bubble behavior of deep-water explosion was obtained by the proposed calculation method of bubble behavior. The results showed that the pressure of the shockwave of the CL-20-based aluminized explosive was lower, and the energy released by the combustion of aluminum powder increased the pressure in the middle and end of the shockwave’s trailing edge, reduced the shockwave attenuation rate, and increased the first bubble pulse pressure and pulse period. The afterburning phenomenon of aluminum powder in the CL-20 aluminized explosive in explosion bubbles under high hydrostatic pressures was captured in the simulated deep-water explosion experiment for the first time. It was proven that the combustion time of the micro-aluminum powder was at the millisecond level, and the maximum radius of the bubble increased with the afterburning of aluminum powder. The characteristic parameters of the first pulsation of the CL-20-based explosive with different aluminum content in deep-water explosions calculated by the second-order Mach accuracy bubble dynamics equation and the equation of state of the explosion products were within 7% of the experimental values. The change of the afterburning process of the aluminum powder caused by the aluminum content has a great influence on the bubble behavior, and through the design of aluminum content, ideal deep-water explosion bubble characteristic parameters can be obtained.