Study On Energy Output Structure Of DNAN-based Melt-cast Explosive Explosion In Air

Through using the combination of experiments and numerical simulation methods, the problems related to air explosion of DNAN based melt-cast composition explosives were studied.Through the experiment of the air explosion of DNAN based melt-cast composition explosives with different Al contents and different diameters, the air explosion shock wave parameters such as overpressure and positive pressure impulse and time constant which represent the energy output structure were obtained. Firstly, based on the experimental results, the relation of the peak overpressure, positive pressure impulse,time constant and distance was fitted. The results show that with the increase of scaled instance, overpressure and positive pressure impulse reduce,but time constant increases. Secondly, the effects of different Al contents and different diameters on the shock wave parameters were studied. The results show that the explosives with different aluminum content and different diameters have the same scaled distance-pressure curve trend; the peak pressure increases at first and then reduces, but the positive pressure impulse increases all the time by the increasing of scaled distance; the explosives which content aluminum with 5μm diameters are better than another. In addition, different formulations empirical formula coefficient were calculated according to the experimental data.The JWL coefficients which include Miller energy release model with different formulations were demarcated and the simulation results were close to the experimental results at first. And then, the air explosion of DNAN based melt-cast composition explosives was simulated using AUTODYN software. Finally,the influence of different mesh division methods and the different simplified models of calculation results were compared which shows that the cubic model with 10 mm mesh division can reflect the air explosion shock wave.