Study on the characteristics of blast loads due to two simultaneous detonated charges in real air

Most studies about the air blast loads due to a single explosion have been widely reported based on the assumption that the air is an ideal gas. However, this assumption is not applicable for investigating the blast load due to multiple charge explosions in a realistic environment. In this paper, according to the existing data, the mathematical relationship between the specific internal energy and adiabatic index under high pressure is determined, and a new equation of state(EOS) for the real gas is derived. Then, the new EOS is implemented in LS-DYNA to simulate the reflected procedure of blast waves near the ground, and the average errors of overpressure and positive impulse are less than 10% and 21%, respectively. Finally, the validated model is used to investigate the effects of the total charge weight, scaled distance, and distance between the charges on the characteristics of the blast load due to two simultaneous detonated charges. Numerical simulation results show that under the condition of real gas, the total mass and distances between charges will heavily affect the starting and optimal positions of overpressure and impulse enhancement, which lays a foundation for characterizing the closed flow field of multiple charge explosions.