Numerical Analysis on the Mechanism of Blast Mitigation by Water Droplets

Hydrogen has a high risk of ignition owing to its extremely low ignition energy and wide range of flammability. Therefore, acquiring parameters relating to safe usage is of particular interest. The ignition of hydrogen generates combustion processes such as detonation and deflagration, which may produce a blast wave. The severity of injuries sustained from a blast wave is determined by its strength. To reduce the physical hazards caused by explosion, there is a need for some concepts for attenuating explosions and blast waves. In the present study, we used water droplets as a material to reduce the blast wave strength. Numerical analysis of the interaction between blast waves and water droplets in a shock tube was conducted to understand the mitigation mechanism of blast wave. In this report, we numerically modelled the experiment conducted by Mataradze et al. [1] to understand the main factor of blast mitigation by water droplets. In order to quantitatively clarify the mitigation effect of water droplets on the blast wave especially by quasi-steady drag, here we conducted parameter studies on water droplet sprayed region. From this calculation, it was suggested that the location of water droplet sprayed layer did not affect the blast mitigation effect at far side of the high explosives.