Numerical investigation of particle–blast interaction during explosive dispersal of liquids and granular materials
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Experiments show that when a high-explosive charge with embedded particles or a charge surrounded by a layer of liquid or granular material is detonated, the flow generated is perturbed by the motion of the particles and the blast wave profile differs from that of an ideal Friedlander form. Initially, the blast wave overpressure is reduced due to the energy dissipation resulting from compaction, fragmentation, and heating of the particle bed, and acceleration of the material. However, as the blast wave propagates, particle–flow interactions collectively serve to reduce the rate of decay of the peak blast wave overpressure. Computations carried out with a multiphase hydrocode reproduce the general trends observed experimentally and highlight the transition between the particle acceleration/deceleration phases, which is not accessible experimentally, since the particles are obscured by the detonation products. The dependence of the particle–blast interaction and the blast mitigation effectiveness on the mitigant to explosive mass ratio, the particle size, and the initial solid volume fraction is investigated systematically. The reduction in peak blast overpressure is, as in experiments, primarily dependent on the mass ratio of material to explosive, with the particle size, density, and initial porosity of the particle bed playing secondary roles. In the near field, the blast overpressure decreases sharply with distance as the particles are accelerated by the flow. When the particles decelerate due to drag, energy is returned to the flow and the peak blast overpressure recovers and reaches values similar to that of a bare explosive charge for low mass ratios. Time–distance trajectory plots of the particle and blast wave motion with the pressure field superimposed, illustrate the weak pressure waves generated by the motion of the particle layer which travel upstream and perturb the blast wave motion. Computation of the particle and gas momentum flux in the multiphase flow generated during explosive particle dispersal indicates that the particle momentum flux is the dominant term in the near field. Both the gas and particle loading must be taken into account when determining the damage to nearby structures following the detonation of a high-explosive charge surrounded by a material layer.
KeywordsExplosive particle dispersal Blast–particle interaction Momentum exchange Hydrocode simulation
Assistance with the EDEN hydrocode calculations by Leo Crozes at Fluid Gravity Engineering is gratefully acknowledged as well as the Defense Threat Reduction Agency for funding under Project HDTRA1-11-1-0014. The authors would also like to thank the reviewers for their many constructive comments.
- 1.Allen, R.M., Kirkpatrick, D.J., Longbottom, A.W., Milne, A.M., Bourne, N.K.: Experimental and numerical study of free-field blast mitigation. In: AIP Conference Proceedings, vol. 706, pp. 823–826 (2004). https://doi.org/10.1063/1.1780363
- 2.Pontalier, Q., Loiseau, J., Goroshin, S., Frost, D.L.: Experimental investigation of blast mitigation and particle-blast interaction during the explosive dispersal of particles and liquids. Shock Waves 28(3) (2018). https://doi.org/10.1007/s00193-018-0821-5
- 3.Frost, D.L., Ornthanalai, C., Zarei, Z., Tanguay, V., Zhang, F.: Particle momentum effects from the detonation of heterogeneous explosives. J. Appl. Phys. 101, 113529 (2007). https://doi.org/10.1063/1.2743912
- 4.Loiseau, J., Pontalier, Q., Milne, A.M., Goroshin, S., Frost, D.L.: Terminal velocity of liquids and granular materials dispersed by a high explosive. Shock Waves 28(3) (2018). https://doi.org/10.1007/s00193-018-0822-4
- 7.Ling, Y., Haselbacher, A., Balachandar, S.: Importance of unsteady contributions to force and heating for particles in compressible flows. Part 2: Application to particle dispersal by blast waves. Int. J. Multiph. Flow 37(9), 1013–1025 (2011). https://doi.org/10.1016/j.ijmultiphaseflow.2011.07.002 CrossRefGoogle Scholar
- 9.Zarei, Z., Frost, D.L., Timofeev, E.V.: Numerical modelling of the entrainment of particles in inviscid supersonic flow. Shock Waves 21(4), 341–355 (2011). https://doi.org/10.1007/s00193-011-0311-5
- 15.Lee, E.L., Hornig, H.C., Kury, J.W.: Adiabatic Expansion of High Explosive Detonation Products. Technical Report UCRL-50422, Lawrence Radiation Lab, University of California, Livermore (1968)Google Scholar
- 17.Pontalier, Q.T., Lhoumeau, M.G., Frost, D.L.: Non-ideal blast waves from particle-laden explosives. In: 31st International Symposium on Shock Waves, Nagoya, Japan (2017)Google Scholar
- 20.Gurney, R.W.: The initial velocities of fragments from bombs, shells, and grenades. Technical Report (45), BRL, Aberdeen Proving Ground, Maryland, USA (1943)Google Scholar
- 21.Pontalier, Q., Lhoumeau, M., Frost, D.L.: Blast wave mitigation in granular materials. In: 20th Biennial APS Conference on Shock Compression of Condensed Matter (SCCM), St. Louis, MO, USA. AIP Conference Proceedings (2017)Google Scholar