The blast mitigation mechanism of a single water droplet layer and improvement of the blast mitigation effect using multilayers in a confined geometry

The blast mitigation mechanism of a water droplet layer was numerically studied, considering convective heat transfer and quasi-steady drag. The propagation of a one-dimensional blast wave in a shock tube was modeled, leading to momentum and energy transfer between the water droplets and the air. Convective heat transfer absorbed part of the energy, thereby directly mitigating the blast wave. Although the quasi-steady drag transferred less energy than the convective heat transfer, it exhibited greater blast mitigation. Thus, a parametric study using characteristic values and describing the water droplet layer was conducted to examine the blast mitigation mechanisms involved in the quasi-steady drag, aside from the energy absorption effect. It was determined that each time the shock wave reached the air/water droplet interface, the quasi-steady drag divided the wave into transmitted and reflected waves. Because the one-dimensional blast wave helped to carry some of the energy, the division reduced the energy carried by the incident blast wave, resulting in its mitigation. Finally, the blast mitigation effect of multilayers was compared with that of a single layer. The result showed that increasing the number of layers synergistically improved the blast mitigation effect by dividing the shock wave multiple times.