Comparison of blast mitigation performance between water layers and water droplets

• Published in: Shock waves 2021, Vol.31 (1), p.89-94
• Main Authors: Tamba, T., Sugiyama, Y., Ohtani, K., Wakabayashi, K.
• Format: Article
• Language: English
• Subjects: Acoustics; Blasting (explosive); Bulk density; Condensed Matter Physics; Droplets; Engineering; Engineering Fluid Dynamics; Engineering Thermodynamics; Explosions; Fluid- and Aerodynamics; Heat and Mass Transfer; High speed cameras; High speed photography; Kinetic energy; Mass ratios; Overpressure; Prediction models; Technical Note; Thermodynamics; Transducers; Water drops; Waveforms
• ISSN: 0938-1287; 1432-2153
• DOI: 10.1007/s00193-021-00990-3

An experimental investigation was conducted to compare the blast mitigation performances of water layers, whose mass ratios to an explosive were m W / m E = 12.2 , 44.5 , and 107.2 , with water droplets surrounding the explosive. The blast waveforms were measured using pressure transducers, and the motion of the water layer was recorded using a high-speed camera. When m W / m E was equivalent between the water layer and water droplets, the water layer exhibited less mitigation of the peak overpressure and positive impulse than the water droplets. The results demonstrated high efficiency of the water droplets in blast mitigation and the existence of an optimal apparent density of the water barrier. The velocities of the water layers determined using high-speed photography agreed with the prediction model of the barrier material accelerated by explosion. It suggested that the primary cause of the blast overpressure mitigation by the water layer was the allocation of the explosion energy into the kinetic energy of the water.