Download or read book Deflagration to Detonation Experiments in Granular HMX written by and published by . This book was released on 1998 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper the authors report on continuing work involving a series of deflagration-to-detonation transition (DDT) experiments in which they study the piston-initiated DDT of heavily confined granular cyclotetramethylenetetranitramine (HMX). These experiments were designed to he useful in model development and evaluation. A main focus of these experiments is the effect of density on the DDT event. Particle size distribution and morphology are carefully characterized. In this paper they present recent surface area analysis. Earlier studies demonstrated extensive fracturing and agglomeration in samples at densities as low as 75% TMD as evidenced by dramatic decreases in particle size distribution due to mild stimulus. This is qualitatively confirmed with SEM images and quantitatively studied with gas absorption surface area analysis. Also, in this paper they present initial results using a microwave interferometer technique. Dynamic calibration of the technique was performed, a 35 GHz signal is used to increase resolution, and the system has been designed to be inexpensive for repeated experiments. The distance to where deformation of the inner wall begins for various densities is reported. This result is compared with the microwave interferometer measurements.
Download or read book The Deflagration to detonation Transition in Granular HMX written by and published by . This book was released on 1991 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transition from deflagration to detonation in porous beds of explosive and propellant has received considerable attention both experimentally and theoretically. In many cases, the use of a hot-gas-producing igniter complicates the interpretation and subsequent modeling of experiments because considerable effort is required to account for the effect of the igniter gases on the granular bed. Hot-wire ignition is less intrusive; however, the ignition front is not planar. Thus the early events in these experiments cannot be approximated as one-dimensional. We have studied the deflagration-to-detonation behavior of granular HMX confined in steel tubes with x-radiography, light emission, stress gauges, and various pin techniques. Simplification and consistency of results were obtained by igniting the HMX with a piston (initially at rest and in contact with the HMX) driven into the bed. A gasless igniter is used to stare the burning of the piston propellant (low-density HMX) providing the piston with a smooth initial motion. Analysis of the data gives a detailed picture of the DDT process under these conditions. The qualitative and quantitative experimental results show the transition from the burning to detonation is discontinuous. The results are discussed in terms of a descriptive model.
Download or read book Deflagration to detonation Transition in Granular HMX written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental studies of the deflagration-to-detonation transition (DDT) in chemical explosives, specifically, granular HMX, are reviewed. The picture of the DDT process as presented here results from an attempt to incorporate common experimental observations which have heretofore been puzzling. It differs from that presented by G.B. Kistiakowsky in that the role of convective combustion is terminated and mechanical processes are postulated as the means of continuing the reaction buildup until shock waves are formed. In order to validate this picture it will be necessary both to review the experimental literature for observations which may not be reconcilable with it, and to subject each step in the proposed DDT process to detailed scrutiny. (LCL).
Download or read book Deflagration to detonation in Granular HMX written by and published by . This book was released on 1993 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental studies and analysis of the deflagration-to detonation transition (DDT) in granular HMX are continued. Experiments performed using a direct-gasless igniter exhibit the same phenomenology as those ignited with a piston. Simple kinetics and mechanics describe the formation of the (approximately)100% TMD plug in terms of competing pressurization processes. A mass-conservation analysis of the experimentally observed structures shows how the low velocities characteristic of convective burning are amplified to shock-wave velocities through non-convective processes.
Download or read book Deflagration to Detonation Transition in Granular HMX written by Nathan Burnside and published by . This book was released on 2001 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Deflagration to Detonation in HMX Under High Confinement HMX Confined in Steel Tubes written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The deflagration-to-detonation behavior of HMX confined in steel tubes was studied by means of x radiography, light emission, and various pin techniques. Unlike most reported experiments, the HMX bed was ignited by driving a piston (initially at rest and in contact with the HMX) into the bed with the pressure generated from burning, low-density HMX on the opposite side of the piston. Because a gasless igniter is used to start the burning of the low-density HMX, the piston has a relatively smooth initial motion. Analysis of the data from these experiments gives a rather detailed picture of the DDT process under these conditions. 2 refs., 19 figs.
Download or read book Hydrocode Modeling of Deflagration and Detonation with Dynamic Compaction of a Granular Explosive written by Kelly Susan Mahon and published by . This book was released on 2015 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transition from Deflagration to Detonation in Granular Explosives written by Richard R. Bernecker and published by . This book was released on 1972 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deflagration to detonation transition (DDT) has been observed for 91/ 9 RDX/Wax over the range of 67 - 95% TMD. The initial process monitored was the propagation of a convective flame front through the porous charge. Some time after that a postconvective front was formed; it traveled at a greater speed and overtook the convective front. About 10 - 20 microseconds after this intersection and 10 - 20 mm beyond it, detonation appeared. Details of this proposed mechanism and their variation with compaction are fully described in the report. A few experiments at 70% TMD were also made on 97/3 and 94/6 RDX/ Wax and on ammonium picrate. Only the latter failed to undergo a transition to detonation in the apparatus used.
Download or read book The Deflagration to detonation Transition in PETN and HMX written by Robert H. Dinegar and published by . This book was released on 1983 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Detonation written by Wildon Fickett and published by Courier Corporation. This book was released on 2000-01-01 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
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 Deflagration Experiments in Small HMX Explosive Charges written by David A. Benson and published by . This book was released on 1983 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Deflagration to detonation Transition in Granular Secondary Explosives written by Peter Elliott Luebcke 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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 910 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 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 Proceedings Seventh Symposium International on Detonation written by and published by . This book was released on 1982 with total page 1120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
