Explosive fragmentation of liquids in spherical geometry

Milne, A. M.; Longbottom, A. W.; Frost, David L.; Loiseau, Jason; Goroshin, Samuel; Petel, Oren E.

doi:10.1007/s00193-016-0671-y

Cited by 19 publications

(7 citation statements)

References 15 publications

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“…A similar behavior occurs for the explosive dispersal of liquids [2] or liquid/particle mixtures [3,4]. A growing body of photographic and radiographic evidence suggests that the jets form early during the dispersal process, on the timescale of the propagation of the shock and release wave through the particle layer [5].…”

Section: Introductionmentioning

confidence: 65%

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Particle segregation during explosive dispersal of binary particle mixtures

Frost¹,

Loiseau²,

Marr³

et al. 2017

AIP Conference Proceedings

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Abstract. The explosive dispersal of a layer of solid particles surrounding a spherical high explosive charge generates a turbulent, multiphase flow. The shock-compacted particle layer typically fractures into discrete fragments which move radially outwards on ballistic trajectories. The fragments shed particles in their wakes forming jet-like structures. The tendency to form jets depends on the mass-ratio of the particles to explosive and the type of particles. Brittle or soft, ductile particles are more susceptible to forming jets during compaction and dispersal, whereas particles that are comprised of material with moderate hardness, high compressive strength and high toughness are much less prone to forming jets. Experiments have been carried out to determine the degree of particle segregation that occurs during the explosive dispersal of a uniform, binary mixture containing both "jetting" (silicon carbide) and "non-jetting" (steel) particles with various mass fractions of each particle type. During the dispersal of mixtures that contain predominantly non-jetting (steel) particles, the steel particles form a stable layer whereas the jetting (silicon carbide) particles rapidly segregate and form jets which are confined within the shell of steel particles. As the fraction of silicon carbide particles increases, the jet structures dominate the particle motion and the steel particles are entrained into the jet structures.

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Section: Introductionmentioning

confidence: 65%

“…For solid particles, the number of jets scales inversely with the ratio of the mass of the particles to that of the explosive (M/C), or fill/burster (F/B) ratio [2]. Furthermore, the tendency to form coherent jets is dependent on the particle material properties and to a lesser extent on the F/B ratio.…”

Section: Introductionmentioning

confidence: 99%

Particle segregation during explosive dispersal of binary particle mixtures

Frost¹,

Loiseau²,

Marr³

et al. 2017

AIP Conference Proceedings

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“…Let us now compare our engineering model against experimentald ata obtainedt hroughc ollaborations with workers at AWE [ 6],D stl [7],a nd McGill University [8].F igure 9c ompares shell speed experimental data for as pherical sand shell with our porous modela nd the standard Gurney model The datai sn ot well matched by the standard Gurney model but we see good agreement betweeno ur porous model and ar ange of experimental data. Wec an also compare against data in cylindrical geometry.I nF igure 10 we plot the ratio of predicted porous speed to the Gurney speed against data from Ref.…”

Section: V Alidationmentioning

confidence: 82%

Gurney Analysis of Porous Shells

Milne

2016

Propellants Explo Pyrotec

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1IntroductionThere are many applicationa reas where the ability to accurately predict the speed of expansion of fragments from explosively disseminated porous shells is important.F or inert materials (e.g. blast mitigants) this speed, in part, determines the size of the resulting cloud. For reactive materials this speed, in part, determinest he ability to ignite the material and determines the trade-off betweenr eactive and inertial fragment effects.As imple analytical modelf or fragments peed from exploding cased munitions, derived by R. W. Gurney[ 1] during WWII, is still very much in use today.B ya ssuming uniform internal gas density and al inear variationo fg as velocity from the center of axis ofc harge out to the casing, the terminal shell or case material velocity V Gurney was approximated to be af unction both of the explosive properties and the ratio M/C,w here M is the case mass and C the charge mass:Here E (commonly known as the Gurney Energy)i sa n energy per unit mass associated with individual explosives and n varies with the geometry of the system, i.e. plane n = 1, cylinder n = 2, or sphere n = 3. Gurney analysis has been used extensively for many years to approximate the speed of fragmenting solid material shells [2,3].K ennedy gives ad etailed description of the Gurney model as does Cooper,w ho also providesarange of usefule ngineering approximationsf or av ariety of explosives. Reaugha nd Souers [4] extended the Gurney approach to the Cylinder Te st taking account of shell thickness effects. Hutchinson [5] has also considered extensions to Gurney theory for blast and fragment applications.For porouss hells and liquids it is known [6] that the shell breaks up very early in the expansion. It is thus naturalt o ask whether solid shell Gurney theory applies.The aim of this work is to investigate the behavior of HE driven porouss hells in spherical and cylindrical geometry and to identify any appropriate factorso ne can use to multiply the solid shell Gurney velocity by to predict the speed of aporousshell. 2B asic Model and ResultsOur approach in this work will be to consider the effect of replacing as olid case surroundinga ne xplosivew ith ap orous material. We use the EDEN hydrocode to study these effects numerically.T he effect of changing explosive type with the Gurney equation has beene xhaustively studied and Refs.[2] and [3] give good summaries of this work. We thus are free to choose any ideal High Explosive as our baseline. We have recently undertaken some experiments using COMP A4 explosive, which we will compare with in this work so choose this for use in our basic numerical model. The detonations peed for the A4 used in calculations was 7026 ms À1 .C ooper [3] has recorded an engineer-Abstract:T here are manya pplication areas, where the ability to accurately predict the speed of expansiono ff ragments from explosively disseminated porous shells is important. For inert materials this speed in part determines the size of the resultingc loud. For reactive materials this speed in part de...

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“…For example, when a sample of a solid metal is subjected to a high-power laser beam, the large negative pressures created in the metal lead to its instant melting followed by micro-spalling [9]. In an underwater explosion, the detonation of an unconfined charge leads to the growth of a stable gas bubble [10]. In the design of liquid blast mitigants, the detonation of a confined explosive surrounded by a liquid layer leads to the jetting of finger-like structures or instabilities [11].…”

Section: Introductionmentioning

confidence: 99%

An All-Mach Number HLLC-Based Scheme for Multi-Phase Flow with Surface Tension

et al. 2021

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This paper presents an all-Mach method for two-phase inviscid flow in the presence of surface tension. A modified version of the Hartens–Lax–van Leer Contact (HLLC) solver is developed and combined for the first time with a widely used volume-of-fluid (VoF) method: the compressive interface capturing scheme for arbitrary meshes (CICSAM). This novel combination yields a scheme with both HLLC shock capturing as well as accurate liquid–gas interface tracking characteristics. It is achieved by reconstructing non-conservative (primitive) variables in a consistent manner to yield both robustness and accuracy. Liquid–gas interface curvature is computed via height functions and the convolution method. We emphasize the use of VoF in the interest of interface accuracy when modelling surface tension effects. The method is validated using a range of test-cases available in the literature. The results show flow features that are in sensible agreement with previous experimental and numerical work. In particular, the use of the HLLC-VoF combination leads to a sharp volume fraction and energy field with improved accuracy.

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Explosive fragmentation of liquids in spherical geometry

Cited by 19 publications

References 15 publications

Particle segregation during explosive dispersal of binary particle mixtures

Particle segregation during explosive dispersal of binary particle mixtures

Gurney Analysis of Porous Shells

An All-Mach Number HLLC-Based Scheme for Multi-Phase Flow with Surface Tension

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