Numerical Study on Blast Mitigation by a Water Mist: Impact of the Mean Droplet Diameter and Volume Fraction

Abstract

The ability of water mist to mitigate blast loads has been widely recognized. However, the effects of the mean droplet diameter and volume fraction of water mist on the blast mitigation effect and underlying mechanisms have not been comprehensively examined. In this study, a three-dimensional numerical simulation based on the Euler-Lagrangian approach was carried out to study the dissipation process of blast wave energy and momentum by water mist, as well as the impact of varying mean droplet diameters (255-855 μm) and volume fractions (2.4×10-3-5.4×10-3) on blast mitigation. The numerical model incorporates interphase mass, momentum, and energy exchanges, as well as droplet breakup and size distribution. The results showed that the most efficient transfer of momentum and energy between the blast wave and water mist occurred at the air/water mist interface. Subsequently, the efficiency of momentum and energy transfer decreased as the blast wave propagated within the water mist due to the blast wave mitigation. The reduction in the mean droplet diameter and the increase in the volume fraction result in an increase in both the total the surface area and number of water droplets, thereby enhancing the efficiency of energy and momentum absorption by droplets and improving their ability to mitigate blasts.

Keywords

• blast mitigation
• water mist
• euler-lagrangian approach
• size distribution
• volume fraction