Numerical study on the mitigation effect of glass particles filling a partially confined space on a blast wave

Abstract

The interaction of a shock wave and particles filling the inside of a straight tube was numerically investigated to understand the mitigation mechanism on a blast wave outside the tube. A shock wave propagating along the particle layer inside the straight tube induced differences in the velocity and temperature between the particle layer and shocked air, inducing energy transfer through a drag effect, heat transfer, and nozzling term. Because the particle layer hardly moved inside the straight tube, the drag effect and nozzling term were too small to mitigate the blast wave. On the other hand, the heat transfer from the air to the particle layer absorbed several tens of percent of the energy released by the high explosive and was the dominant factor in mitigating the blast wave. To estimate the effect of the heat transfer between the particle layer and shocked air, we proposed a novel index estimated by the shocked-air properties, using the Rankine–Hugoniot relation. The numerical data for the heat transfer rate were simply and adequately estimated by the novel index, which indicated that the shocked-air properties were responsible for the heat transfer rate used to determine the mitigation of the blast wave.