Study on the reaction rate model for shock initiation of aluminized hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) explosive under shock waves

To investigate the influence of the aluminum (Al) powder sizes on shock initiation of aluminized hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), shock initiation experiments were carried out. The experimental results show that as the Al constituent size decreases, a rapid increase in the propagation velocity of the precursory shock waves enhances the peak pressures, shortens the time intervals between the peak pressures and the arrival times of precursory shock waves, and improves the shock sensitivity of the aluminized RDX. Consequently, to predict and evaluate the stability of aluminized RDX with small-size Al powder, a microscopic reaction rate model for shock initiation was established. This model includes the pore collapse model of a double-layered spherical shell structure composed of an RDX spherical shell and a mixture (of Al powder and binders) spherical shell and the reaction model of Al powder in RDX decomposition products under the effect of shock waves and thermal energy released by RDX. The simulation results show that when the diameter of the Al powder is about 1/5 or less of the size of the base explosive (RDX) particles, the microscopic reaction rate model can accurately simulate the shock initiation process of aluminized RDX. As the Al powder size decreases, the reaction rate and the proportion of the Al involved in the initiation reaction for aluminized RDX increase.