Theoretical Prediction of Pressure and Temperature of an Aluminized High Explosive in Underwater Explosion

The blast wave propagation in underwater explosion was studied. The shock propagation in water medium was different from that in air. The blast effect in water lasted longer and offered resistance to the expansion of hot gases and release of energy. A theoretical analysis of the expansion of blast wave in water was carried out and numerical results for pressures and temperatures were obtained as functions of distance and time by analytically solving the governing equations. The initial peak pressures of blast waves, which were required for theoretical analysis were calculated using the blast wave theory. Underwater blasts with different weights (0.045, 0.5, and 1.0 kg) of the aluminized high explosive HBX‐3 were conducted to record pressure as a function of distance and time from the blast point. Theoretical results were compared with experimental data and empirical data for HBX‐3 from literature. Since the measurement of pressure and temperature at close proximity of point of detonation is difficult, theoretical modeling of underwater blast is of significant importance.     

Theoretical and Experimental Studies on Blast Wave Propagation in Air

High pressure and temperature are produced when high explosives are detonated in open air. The heat of detonation of the explosive compound, peak pressure, and temperature of the blast wave are important blast parameters. A blast wave generated due to explosion propagates into the air medium at supersonic speed until the pressure in the blast zone is released completely. The intensity of the impact by the blast wave on any intervening solid object depends on the blast parameters and the speed of propagation of the blast wave. A theoretical analysis is carried out to predict the pressure produced in the expanding blast zone as function of distance and time by analytically solving the governing equations. The initial peak pressure and temperature of blast wave, which are required in the theoretical analysis, were calculated making use of the blast wave theory. For comparison, experiments were conducted by detonating different weights of high explosives, and pressures were recorded at various distances from the blast point. The high explosives used in the experiments were TNT (0.045, 0.5, 1, 15, and 40 kg) and Composition B (0.045, 0.5, 1, and 15 kg). The theoretical results are validated by comparison with the experimental data and empirical equations available in literature.