Blast wave mitigation in granular materials

Pontalier, Quentin; Lhoumeau, M. G.; Frost, David L.

doi:10.1063/1.5044933

Cited by 4 publications

(2 citation statements)

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“…In the far field, the peak blast overpressure recovers almost to the same value as the base explosive charge for 50 wt% addition of glass and even exceeds the baseline case for 10 wt% and 30 wt% addition, by up to 22.8% even though the charges with added glass have a reduced amount of explosive. This behavior is consistent with the earlier results from Pontalier et al [10][11][12][13], who attributed the near-field reduction in blast pressure to the energy transfer from the detonation products to the kinetic energy and heating of the inert particles, and the later time blast pressure recovery to the pressure perturbations induced by the particle-flow interactions.…”

Section: Effect Of Particle Materials and Mass Loading On Blast Decay In The Mid-to-far Field (Videography)supporting

confidence: 92%

“…For inert particles, as they are accelerated by the expanding combustion products, and subsequently decelerate, the particles exchange momentum with the surrounding gas and perturb the local pressure field non-uniformly as the particles typically form particle jets or filaments [9]. This effect leads to a reduction in peak blast overpressure in the near field as the particles accelerate and to a corresponding augmentation farther from the charge as the particles decelerate and return energy to the flow [10][11][12][13]. In the case of reactive particles, the contribution of the energy release from the particle reaction to the local pressure field is more complex.…”

Section: Introductionmentioning

confidence: 99%

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Blast enhancement from metalized explosives

et al. 2021

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Experiments are carried out to determine the effects of particle size and mass loading on the free-field blast wave from spherical, constant volume metalized explosive charges. The charges are comprised of gelled nitromethane with uniformly embedded aluminum, magnesium, or glass particles. Particle sizes are varied over an order of magnitude with particle mass fractions up to 50%. Peak blast overpressures are directly measured within the fireball with piezoelectric pressure gauges and outside the fireball are inferred by tracking the velocity of the blast wave and using the Rankine–Hugoniot relation. With the addition of inert particles, the peak blast overpressure is initially mitigated, but then recovers in the far field. For charges with reactive particles, the particles react promptly with oxidizers in the detonation products and release energy as early as within the first few hundred microseconds in all cases. The particle energy release enhances the peak blast overpressures in the far field by up to twice the values for a constant volume charge of the baseline homogenous explosive. By plotting the peak blast overpressure decay as a function of energy-scaled distance, it is inferred that at least half of the particle energy release contributes to the blast overpressure in the far field of higher mass loadings, and nearly all of the particle energy for a particle mass fraction of 10%. For aluminum, the blast augmentation is not a systematic function of particle size. This observation implies that conventional models for particle combustion that depend on particle surface area are not appropriate for describing the rapid aluminum reaction that occurs in the extreme conditions within the detonation products, which influences the blast wave propagation.

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Section: Effect Of Particle Materials and Mass Loading On Blast Decay In The Mid-to-far Field (Videography)supporting

confidence: 92%