Experimental Validation of Detonation Shock Dynamics in Condensed Explosives PDF Download
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Author:
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Languages : en
Pages : 29
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Book Description
Experiments on the HMX-based, condensed explosive PBX-9501 were carried out to validate a reduced asymptotically derived description of detonation shock dynamics (DSD). The experiments, coined passover experiments' have embedded disks of lead in right circular cylinders of PBX-9501. A range of dynamically changing states, with both divergent and convergent shock shapes are realized as a detonation front is created on one end of the cylinder and passes over the embedded disk of lead. The time-of-arrival of the detonation shock at the output end of the cylinder is recorded and compared against simulations using the DSD model. The experiment and DSD theory are found to be in excellent agreement and offer a high-fidelity, yet computationally efficient means for complex wave-front tracking in explosive systems.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 29
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Book Description
Experiments on the HMX-based, condensed explosive PBX-9501 were carried out to validate a reduced asymptotically derived description of detonation shock dynamics (DSD). The experiments, coined passover experiments' have embedded disks of lead in right circular cylinders of PBX-9501. A range of dynamically changing states, with both divergent and convergent shock shapes are realized as a detonation front is created on one end of the cylinder and passes over the embedded disk of lead. The time-of-arrival of the detonation shock at the output end of the cylinder is recorded and compared against simulations using the DSD model. The experiment and DSD theory are found to be in excellent agreement and offer a high-fidelity, yet computationally efficient means for complex wave-front tracking in explosive systems.
Author:
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Category :
Languages : en
Pages : 7
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Book Description
Three-dimensional simulation of detonation shock motion in a condensed explosive, modeled with a reactive flow in a moderately complex geometry can require enormous amounts of computer time, since the reaction zone behind the leading shock is extremely thin compared to the overall dimensions of the computational domain. Therefore algorithms such as program burn, pre-compute the detonation shock arrival time, and then essentially use a delta function model to release the heat of detonation into few computations cells near the shock wave. Previous validation efforts that use a program burn algorithm based on detonation shock dynamics (DSD) highlighted the prescription of the initial detonation shock for the simulation, in a manner that is self-consistent with the theory and physical experiment. In this paper, we use a combination of theory, direct multi-material simulation and experiment to determine a critical radius for the starting detonation shock shape.
Author: Roger Cheret
Publisher: Springer Science & Business Media
ISBN: 1461392845
Category : Science
Languages : en
Pages : 442
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Book Description
This work marks a stage in the evolution of a scientific and technical field which has been developed by the Commissariat a l'Energie Atomique (CEA) over several decades. Many members of the staff of the CEA have won re nown in this field, and their work has brought it to the high degree of excel lence for which it is internationally recognized today. These scientists had to consider every aspect of the field, as it concerned: modeling, which has recourse to fluid thermodynamics, molecular phys ics, and chemistry; numerical evaluation, which relies on mathematical analysis and data processing; and experiments in the firing area, which require specific stress generators and instrumentation. Whilst this book is a testament to the activity and success of staff of the CEA, it also reviews a number ofthe advances made in the discipline. How ever, it is not intended to be an exhaustive account of those advances; it is assumed that the reader can, if desired, consult the standard monographs, and more recent, more specialized works (notably W.C. Davis and W. Fickett, and C.L. Mader). The history of the discipline is interesting in itself, and also as an illustra tion of the causes which lead to progress in a coherent body of scientific work. I should like to make some comments on this progress, of which there is a fascinating summary in the introduction, and which will figure largely throughout the work.
Author: Juan A. Saenz
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
We investigate the ignition and dynamics of detonation waves in condensed phase explosives using direct numerical simulations and asymptotic analysis. We develop a model to simulate deflagration to detonation transition in pentaerythritol tetranitrate powders. The model uses a continuum mechanics formulation of conservation laws for a mixture of solid reactants and gas products, written in terms of mixture quantities, plus two independent variables used to account for exothermic conversion of solid reactants into gas products, and compaction associated with pore collapse and grain rearrangement. We propose a simple empirical dependence of the reaction rate on the initial bed compaction that allows us to calibrate the model for a wide range of initial conditions. For the solid reactants we use a wide ranging equation of state. We suggest phenomenological closure relations, consistent with the limit of a compressible inert material and of a solid fully reactive material, such that the equation of state can be posed only in terms of mixture quantities and the reaction and compaction variables. We demonstrate the model's ability to capture deflagration to detonation transition in pentaerythritol tetranitrate powders by matching transients typically observed in experiments, through simulation. We develop an asymptotic formulation to calculate an intrinsic relation between the shock acceleration, velocity and curvature of self-sustained detonation waves in the limit of small time variation and small curvature of the lead shock front in condensed phase explosives. The formulation is developed in terms of a general, incomplete equation of state with composition variables to represent scalar quantities for a general range of phenomena. The results presented here are the first calculations obtained from asymptotic detonation shock dynamics relations for general material models. The formulation is a generalization of an asymptotic theory for a polytropic equation of state and a single step Arrhenius reaction rate model. We discuss the assumptions and justify the generalizations made that allow the use of general form incomplete equations of state. We test the proposed theory by calculating quasi-steady relations between detonation velocity and curvature and the dynamics of ignition events in a reactive hydrogen-oxygen mixture using an ideal equation of state and single step Arrhenius reaction rate model, and compare the results with those obtained using the original asymptotic theory. We find that quasi-steady relations between detonation velocity and curvature calculated using the proposed theory are in better agreement with numerical calculations than the original theory. We also use an equation of state that realistically represents condensed phase explosives, and two composition variables to track reaction and compaction processes, to perform calculations of quasi-steady relations between detonation velocity and curvature, detonation shock acceleration fields as a function of detonation velocity and curvature, and the dynamics of ignition events in solid PBX9501 and in PETN powders. We compare our results with numerical calculations of detonation shock dynamics and direct numerical simulations. We find that the time it takes an ignition wave to become quasi-steady is short, explaining why the quasi-steady relation between the detonation velocity and curvature can sometimes be a good approximation for a speed rule.
Author: Alon Gany
Publisher: Springer Nature
ISBN: 9811917744
Category : Science
Languages : en
Pages : 640
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Book Description
This book features selected papers presented at the 2021 International Conference on Development and Application of Carbon Nanomaterials in Energetic Materials. It discusses the latest progress in the field of advance carbon nanomaterials in energetic materials; including the structural design, theoretical calculation, synthesis, properties, and applications of carbon materials. It also presents the new technology and applications of advanced carbon nanomaterials in energetic materials. It can be used as a reference book for researchers in energetic materials and related fields. It is also be useful for undergraduates and postgraduates studying these topics.
Author: Anatoly N. Dremin
Publisher: Springer Science & Business Media
ISBN: 1461205638
Category : Technology & Engineering
Languages : en
Pages : 163
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Book Description
It is known that the Chapman-Jouguet theory of detonation is based on the assumption of an instantaneous and complete transformation of explosives into detonation products in the wave front. Therefore, one should not expect from the theory any interpretations of the detonation limits, such as shock initiation of det onation and kinetic instability and propagation (failure diameter). The Zeldovich-Von Neuman-Doring (ZND) theory of detonation appeared, in fact, as a response to the need for a theory capable of interpreting such limits, and the ZND detonation theory gave qualitative interpretations to the detonation limits. These interpretations were based essentially on the theoretical notion that the mechanism of explosives transformation at detonation is a combustion of a layer of finite thickness of shock-compressed explosive behind the wave shock front with the velocity of the front. However, some experimental findings turned out to be inconsistent with the the ory. A very small change of homogeneous (liquid) explosives detonation velocity with explosive charge diameter near the rather sizable failure diameter is one of the findings. The elucidation of the nature of this finding has led to the discovery of a new phenomenon. This phenomenon has come to be known as the breakdown (BD) of the explosive self-ignition behind the front of shock waves under the effect of rarefaction waves.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
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Book Description
High energy explosives are used in a variety of applications, from military to industrial processes. The use of embedded, inert material "wave shapers" is a primary method to customize the detonation front for desired ex-plosive applications. These systems create detonation states that do not follow the simple line of sight, or Huy-gens model and, hence, advanced detonation physics with associated theory are required. The theory of detonation shock dynamics (DSD) is one such description used to provide high fidelity modeling of complex wave structures. A collection of experiments using ultra-high speed cameras is presented as a means of obtaining spatial and temporal characteristics of complex detonation fronts that validate the DSD descriptions. The method of test, operational conditions and results are given to demonstrate the use of high-rate imaging of detonation events and how this validates our understanding of the physics and the capability of advanced detonation wave tracking models.
Author: Shiro Kubota
Publisher: Springer Nature
ISBN: 9811953074
Category : Science
Languages : en
Pages : 298
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Book Description
This book presents fundamental theory of shock and detonation waves as well as selected studies in detonation research in Japan, contributed by selected experts in safety research on explosives, development of industrial explosives, and application of explosives. It also reports detonation research in Japan featuring industrial explosives that include ammonium nitrate-based explosives and liquid explosives. Intended as a monographic-style book, it consistently uses technical terms and symbols and creates organic links between various detonation phenomena in application of explosives, fundamental theory of detonation waves, measurement methods, and individual studies. Among other features, the book presents a historical perspective of shock wave and detonation research in Japan, pedagogical materials for young researchers in detonation physics, and an introduction to works in Japan, including equations of state, which are worthy of attention but about which very little is known internationally. Further, the concise pedagogical chapters also characterize this book as a primer of detonation of condensed explosives and help readers start their own research.
Author: Wildon Fickett
Publisher: Courier Corporation
ISBN: 9780486414560
Category : Science
Languages : en
Pages : 420
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Book Description
This advanced and specialized introduction to the hydrodynamics of detonation offers a theoretical and observational overview. It explores the "simple theory" and experimental tests of the theory; flow in a reactive medium; steady detonation; the nonsteady solution; and the structure of the detonation front. Many simple cases are worked out for illustration. 1979 edition.
Author: Michael D. Furnish
Publisher:
ISBN:
Category : Condensed matter
Languages : en
Pages : 840
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Book Description
