A Near-Field Overpressure Estimation Equation of Cylindrical Charge Explosive Air Blast

Abstract

After cylindrical charge air blast, an uneven overpressure field is formed in the near-field space. The near-field overpressure at the same equivalent attenuation distance and different angles can differ by several times or even more than one order of magnitude. The use of spherical charge overpressure model in the near field of cylindrical charge air blast will bring great error, so it is necessary to develop a cylindrical charge overpressure model with near-field description ability. Because of the insufficient experimental data, a quick estimation method was proposed to analyze the effect of intensity and distributing of near-field overpressure in cylindrical charges air blast on the area damage and safety. Based on simulated data fitting, an estimation equation of overpressure was developed for cylindrical charge air blast in less equivalent attenuation distance. First, compared with the experience equation of the spherical TNT charge and the experiment results of cylindrical charge, the believable degree of the simulation results was validated respectively for spherical charge and cylindrical charge. Then, based on quadratic polynomial fitting, an estimation equation of near-field overpressure was obtained for cylindrical charge air blast. And the cylindrical charge air blast simulations with different length-diameter ratios were carried out. Finally, the simulation results of the near-field overpressure of cylindrical charge air blast with 6 different length-diameter ratios were compared with their experimental results. The results show that the estimation equation can be used to estimate the overpressure with less error range for cylindrical charge air blast at any position in near-field space. According to preliminary experimental verification, its suitable application range is that the range of cylinder length-diameter ratio is 0.2～2.0 m/kg1/3.