Download or read book Deflagration to Shock to Detonation Transition of Energetic Propellants written by H. Krier and published by . This book was released on 1984 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is well known that explosive-based propellants are susceptible to detonation from the controlled deflagration mode of combustion. In some instances a confined zone of granulated propellant adjacent to a zone of cast propellant can provide a rapid enough pressure-rise rate to shock initiate the cast material. If the cast propellant has voids, the detonation will initiate at some location ahead of the granulated bed/cast material interface. This report is a summary of the research activities that focus on the analysis and modeling of the physics of such highly transient flows.

Download or read book Modeling of Deflagration to Shock to Detonation Transition DSDT in Porous High Energy Solid Propellants and Explosives written by Herman W. Krier and published by . This book was released on 1982 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: This annual report represents the summary of work done on the modeling of processes leading from deflagration to detonation in porous or granular high energy propellants. Particular attention is paid to the analysis of shock development from compression waves forming ahead of confined burning in the original material. It is summarized that if the shock is sufficiently strong, it will lead to shock to detonation transition (SDT). During the development of the shock wave, the porous material may collapse into a solid plug of void free propellant because the speed at which the wave propagates increases as the material is compressed. The modeling effort presented indicates how two-phase unsteady combustion processes in granular material can couple to the solid mechanics of shock formation and eventually to a steady-state detonation. (Author).

Download or read book Modeling of Deflagration to shock to detonation Transition DSDT in Porous High Energy Solid Propellants and Explosives written by Herman Krier and published by . This book was released on 1982 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Shock Wave Science and Technology Reference Library Vol 5 written by Blaine Asay and published by Springer Science & Business Media. This book was released on 2009-12-16 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: Los Alamos National Laboratory is an incredible place. It was conceived and born amidst the most desperate of circumstances. It attracted some of the most brilliant minds, the most innovative entrepreneurs, and the most c- ative tinkerers of that generation. Out of that milieu emerged physics and engineering that beforehand was either unimagined, or thought to be f- tasy. One of the ?elds essentially invented during those years was the science of precision high explosives. Before 1942, explosives were used in munitions and commercial pursuits that demanded proper chemistry and con?nement for the necessary e?ect, but little else. The needs and requirements of the Manhattan project were of a much more precise and speci?c nature. Spatial and temporal speci?cations were reduced from centimeters and milliseconds to micrometers and nanoseconds. New theory and computational tools were required along with a raft of new experimental techniques and novel ways of interpreting the results. Over the next 40 years, the emphasis was on higher energy in smaller packages, more precise initiation schemes, better and safer formulations, and greater accuracy in forecasting performance. Researchers from many institutions began working in the emerging and expanding ?eld. In the midst of all of the work and progress in precision initiation and scienti?c study, in the early 1960s, papers began to appear detailing the ?rst quantitative studies of the transition from de?agration to detonation (DDT), ?rst in cast, then in pressed explosives, and ?nally in propellants.

Download or read book Analysis of Shock to Detonation Transition SDT of Porous High Energy Propellant from Ramp Wave Compression Loading written by H. Krier and published by . This book was released on 1984 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing the nitramine content of solid rocket propellants increases the overall performance of the system as well as the sensitivity to detonation by shock initiation. In some instances a confined zone of granulated propellant adjacent to a zone of cast propellant can provide a rapid enough pressure-rise rate ot shock initiate the cast material. If the cast propellant is porous, the detonation will initiate at some location ahead of the granulated bed/cast material interface. The work presented here is an effort to numerically model this Deflagration to Shock to Detonation Transition event. Results are presented showing the detonation build up for propellants/explosives with various initial void content and ramp wave compression loads. (Author).

Download or read book Deflagrationo Detonation Transition in HMX Based Propellants written by M. Cowperthwaite and published by . This book was released on 1978 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research on the deflagration-to-detonation transition (DDT) is important to the Air Force because many of the energetic propellants required for present and future long-range delivery systems are explosively filled compositions that are capable of undergoing DDT. HMX-based propellant, for example, usually burns reliably in rocket motors but has detonated and destroyed the motor on several occasions. Possible steps leading to detonation in the rocket motor are fracture of propellant ahead of the flame and the subsequent formation of shock waves produced by the increased burning rate of fractured propellant. But even in this case, the mechanism of DDT and the conditions for its initiation are not adequately understood. The long-range objective of the present research program is to develop a computational capability for assessing the DDT hazard in explosively filled propellants. The program is based on the concept that a basic understanding of the physical and chemical processes involved in DDT is necessary to achieve this objective. Combined theoretical and experimental studies to determine the pressure fields behind and ahead of the flame and to establish mechanisms of DDT are required to develop such understanding. (Author).

Download or read book Analysis of Deflagration to Detonation Transition in High energy Solid Propellants written by Patrick Barry Butler and published by . This book was released on 1984 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings written by and published by . This book was released on 1989 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: Papers presented in this publication cover special problems in the field of energetic materials, particularly detonation phenomena in solids and liquids. General subject areas include shock-to-detonation transition, time resolved chemistry, initiation modeling, deflagration-to-detonation transition, equation of state and equation of state and performance, composites and emulsions, and composites and emulsions/underwater explosives, reaction zone, detonation wave propagation, hot spots, detonation products, chemistry and compositions, and special initiation.

Download or read book Raising the Flag of Truth written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Demystifying Explosives written by Sethuramasharma Venugopalan and published by Elsevier. This book was released on 2015-01-09 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: Demystifying Explosives: Concepts in High Energy Materials explains the basic concepts of and the science behind the entire spectrum of high energy materials (HEMs) and gives a broad perspective about all types of HEMs and their interrelationships. Demystifying Explosives covers topics ranging from explosives, deflagration, detonation, and pyrotechnics to safety and security aspects of HEMS, looking at their aspects, particularly their inter-relatedness with respect to properties and performance. The book explains concepts related to the molecular structure of HEMs, their properties, performance parameters, detonation and shock waves including explosives and propellants. The theory-based title also deals with important (safety and security) and interesting (constructive applications) aspects connected with HEMs and is of fundamental use to students in their introduction to these materials and applications. Explains the concept of high energy materials in simple language and down-to-earth examples Worked examples and problems are given wherever required Demystifies the concept of explosives Limited use of big and complex equations Questions and Suggested Reading are given at the end of each chapter

Download or read book Shock Wave Science and Technology Reference Library Vol 5 written by Blaine Asay and published by Springer. This book was released on 2010-02-05 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: Los Alamos National Laboratory is an incredible place. It was conceived and born amidst the most desperate of circumstances. It attracted some of the most brilliant minds, the most innovative entrepreneurs, and the most c- ative tinkerers of that generation. Out of that milieu emerged physics and engineering that beforehand was either unimagined, or thought to be f- tasy. One of the ?elds essentially invented during those years was the science of precision high explosives. Before 1942, explosives were used in munitions and commercial pursuits that demanded proper chemistry and con?nement for the necessary e?ect, but little else. The needs and requirements of the Manhattan project were of a much more precise and speci?c nature. Spatial and temporal speci?cations were reduced from centimeters and milliseconds to micrometers and nanoseconds. New theory and computational tools were required along with a raft of new experimental techniques and novel ways of interpreting the results. Over the next 40 years, the emphasis was on higher energy in smaller packages, more precise initiation schemes, better and safer formulations, and greater accuracy in forecasting performance. Researchers from many institutions began working in the emerging and expanding ?eld. In the midst of all of the work and progress in precision initiation and scienti?c study, in the early 1960s, papers began to appear detailing the ?rst quantitative studies of the transition from de?agration to detonation (DDT), ?rst in cast, then in pressed explosives, and ?nally in propellants.

Download or read book Shock Wave Science and Technology Reference Library Vol 5 written by Blaine Asay and published by Springer. This book was released on 2012-05-04 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: Los Alamos National Laboratory is an incredible place. It was conceived and born amidst the most desperate of circumstances. It attracted some of the most brilliant minds, the most innovative entrepreneurs, and the most c- ative tinkerers of that generation. Out of that milieu emerged physics and engineering that beforehand was either unimagined, or thought to be f- tasy. One of the ?elds essentially invented during those years was the science of precision high explosives. Before 1942, explosives were used in munitions and commercial pursuits that demanded proper chemistry and con?nement for the necessary e?ect, but little else. The needs and requirements of the Manhattan project were of a much more precise and speci?c nature. Spatial and temporal speci?cations were reduced from centimeters and milliseconds to micrometers and nanoseconds. New theory and computational tools were required along with a raft of new experimental techniques and novel ways of interpreting the results. Over the next 40 years, the emphasis was on higher energy in smaller packages, more precise initiation schemes, better and safer formulations, and greater accuracy in forecasting performance. Researchers from many institutions began working in the emerging and expanding ?eld. In the midst of all of the work and progress in precision initiation and scienti?c study, in the early 1960s, papers began to appear detailing the ?rst quantitative studies of the transition from de?agration to detonation (DDT), ?rst in cast, then in pressed explosives, and ?nally in propellants.

Download or read book Prediction of Detonation Transition in Porous Explosives from Rapid Compression Loadings written by and published by . This book was released on 1985 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing the nitramine content of solid rocket propellants increases the overall performance of the system as well as the sensitivity to Shock to Detonation Transition (SDT) and Deflagration to Detonation Transition (DDT). This report deals primarily with the analysis and numerical modeling of a combined SDT/DDT event. The results show that in some instances a zone of burning granulated propellant, confined and adjacent to a zone of cast propellant, can provide a rapid enough pressure-rise rate to shock initiate the cast material. This type of detonation hazard scenario is a real possibility in any high-energy rocket motor environment. The modeling study also indicates areas where important assumptions need to be further researched. These include: (a) relations for dynamic (transient) collapse of the voids or pores; (b) relations for setting the volume percent of hot spots based on initial porosity; (c) the evaluation and expression for the chemical rate of decomposition of the reactive, shocked material; and (d) the assessment of two-phase mixture equilibrium. The predicted run-to detonation distance as a function of porosity for HMX explosive compares favorably with limited shock initiation experiments. There is no data available to check whether the predictions of ramp-wave compressions (where rise times exceed several microseconds) presented here are valid.

Download or read book Investigation on Deflagration to Detonation Transition in Porous Energetic Materials Final Report written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Deflagration to Detonation Transition in Heteorogeneous Solids A Bibliography written by E. W. Price and published by . This book was released on 1980 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication contains a list of 341 references relating to the mechanism of transition to detonation in heterogeneous high energy solids, with particular reference to solid rocket propellants and granular propellant charges for guns. Because of the important role played by porosity, many of the references pertain to flow, flame spread and pressure rise in porous materials, and to the mechanics of formation cracks and propagation under dynamic loading. This partial list of references was developed primarily from lists contained in papers presented at the 1978 ONR/AFOSR Workshop on Deflagration-to-Detonation Transition (CPIA Publication 229, September 1978), and from reports received subsequent to that Workshop. A subject coding was developed and used to classify each reference. (Author).

Download or read book A Thermal Mechanical Model of Deflagration to Detonation in Granular Energetic Materials written by M. R. Baer and published by . This book was released on 1984 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work we present a multiphase, reactive flow model, based on the theory of mixtures and utilize it to describe deflagration-to-detonation transition in granular explosives and propellants. This nonequilibrium model treats each phase as fully compressible and incorporates a dynamic compaction model for the granular reactant. Formulation of the constitutive models include a pressure-dependent burn rate and experimentally-determined porous bed permeability. Numerical solutions of the one-dimensional Eulerian equations are obtained using an implicit method-of-lines solver. The model has examined two exlosives: CP and HMX. Predictions with this model agree with existing experimental observations and demostrate that a thermodynamically-consistent multiphase model can describe the flame-spread processes of convective burning and detonation.

Download or read book Modeling and Numerical Simulation of Deflagration to detonation Transition in Porous Energetic Materials written by Shaojie Xu and published by . This book was released on 1996 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: An understanding of the deflagration-to-detonation transition (DDT) in porous energetic materials is important for various engineering applications. Safety issues for damaged explosives is one example. In this work, two topics related to multi-dimensional simulation of DDT in energetic materials are presented. The objective of the first part is to develop a simple and predictive model for multidimensional simulations. Models constructed by two-phase mixture theory usually have complicated mathematical formulation, and admit complex dispersive wave structures. Three simplified single-velocity models, named BKS, SVG and GISPA, are considered in this work. The BKS model was derived--using asymptotic theory--from the two-phase theory by assuming a large interphase drag. The SVG model is newly developed, based on solid-void-gas three-phase formulation. The GISPA model is a new single-phase model which utilizes two independent rate processes for compaction and reaction. In addition to model simplification, a new reaction rate law is developed which describes the slow and the fast energy-release processes during DDT. A comparative study is carried out and the study shows that the SVG and GISPA models are able to predict all the events measured in 1-D DDT-tube experiments. The second part of the study describes the development of a high-quality numerical method for two-dimensional DDT simulations. The new fourth-order method integrates total variation diminishing and essentially non-oscillatory schemes with an extension to a general equation of state. In order to handle complex geometry, an internal boundary algorithm is developed on a structured grid, which allows a two-dimensional, non-deformable body of an arbitrary shape to be inserted in a flow field. A DDT simulation is carried out for cases of both blunt-body and sharp-body impact on porous energetic materials. The radius effect (in the case of blunt-body impact) and the angle effect (in the case of sharp-body impact) on detonation properties are studied.