Research on the influence of vacuum degree on the shock wave in pit type explosion containment vessel

In order to explore the effect of different vacuum degrees on the evolution of the shock wave in a completely confined space, this paper designed a pit type explosion containment vessel and carried out three ground explosion experiments, the signals of impact load were collected by four pressure sensors arranged on the upper cover of this container. The finite element analysis program ANSYS/AUTODYN was applied to simulation the propagation of shock waves in the container, and the reliability of the results was verified by comparing the experimental results with the numerical simulation results. Through analysing the characteristics of the blast impact loads obtained at the cover of explosion containment vessel, it is shown that the peak values and the specific impulses of the impact loads are weakened obviously with the gradual decrease of the vacuum inside the container. According to the analyses of the numerical simulations, although the peak value and the specific impulse of the impact load at 0.12 atm are higher than those at 0.3 atm, the specific impulse at the overall peak position is still small and shows a trend of decline with the decrease of vacuum degree, which is consistent with the experimental conclusion. It is found that the peak values and specific impulse of the impact loads at the center and edge of the seal are both larger, and this law does not change with the vacuum degree.