Sample records for accidental detonations dangerous

  1. Accidental Nuclear War: The Growing Peril. Part I [and] Part II.

    ERIC Educational Resources Information Center

    Newcombe, Alan, Ed.

    1984-01-01

    Two volumes designed to increase awareness of accidental nuclear war dangers are presented. The first of 5 sections in volume I proposes that although accidental war is preventable, the current arms race and secrecy about accidents and false alarms increase the possibility of an accidental war. Section 2 posits that decreased decision-making time…

  2. Confined Detonations and Pulse Detonation Engines

    DTIC Science & Technology

    2003-01-01

    chemically reacting flow was described by the 2D Euler equations &q OF(q) +G(q) W (1) 75 CONFINED DETONATIONS AND PULSE DETONATION ENGINES where q = (p...DETONATIONS AND PULSE DETONATION ENGINES 5 CONCLUDING REMARKS Numerical investigations of RR and MR in a supersonic chemically reacting flows have...formalism of hetero- geneous medium mechanics supplemented with an overall chemical reaction was 141 CONFINED DETONATIONS AND PULSE DETONATION ENGINES

  3. Detonation control

    DOEpatents

    Mace, Jonathan L.; Seitz, Gerald J.; Bronisz, Lawrence E.

    2016-10-25

    Detonation control modules and detonation control circuits are provided herein. A trigger input signal can cause a detonation control module to trigger a detonator. A detonation control module can include a timing circuit, a light-producing diode such as a laser diode, an optically triggered diode, and a high-voltage capacitor. The trigger input signal can activate the timing circuit. The timing circuit can control activation of the light-producing diode. Activation of the light-producing diode illuminates and activates the optically triggered diode. The optically triggered diode can be coupled between the high-voltage capacitor and the detonator. Activation of the optically triggered diode causes a power pulse to be released from the high-voltage capacitor that triggers the detonator.

  4. Risk assessment for stonecutting enterprises Accidental risks in the course of petroleum production and stone extraction

    NASA Astrophysics Data System (ADS)

    Aleksandrova, A. J.; Timofeeva, S. S.

    2018-01-01

    The paper is devoted to the assessment of accidental risks occurring at the works engaged in stone extracting and petroleum production. Two basic kinds of accidents common for stone extracting and petroleum production have been chosen to be discussed in the part under consideration. The most dangerous accidental situation characteristic for a stone milling line is an unsanctioned explosion, UE, of blasting agents used for the development of stone deposits. The analysis of a risk occurrence in certain accidental situations is to be carried out. With reference to petroleum extraction, a combustibles and lubricants (C & L) explosion is the most dangerous of characteristic accidental situations. To reveal the most probable causes of accidental situations to be realized, a graph of cause and effect relations has been constructed for each of the accidental situations most probable causes to real situation of an accident. Disasters of a natural origin are the most probable causes of unsanctioned explosions at the deposits of stone raw materials. Technology related natural disasters are the most probable causes of unsanctioned explosions to be realized at multiple well platforms engaged in petroleum production.

  5. Problems associated with the use of immediately dangerous to life and health (IDLH) values for estimating the hazard of accidental chemical releases.

    PubMed

    Alexeeff, G V; Lipsett, M J; Kizer, K W

    1989-11-01

    The possibility of accidental industrial chemical releases has generated considerable recent attention. One area requiring research for emergency planning is the development of safe exposure concentrations for the public in the event of an inadvertent release. The United States Environmental Protection Agency (EPA) has established a list of extremely hazardous substances and suggested that the toxicity ranking for 92 hazardous materials could be based on the "immediately dangerous to life or health" (IDLH) values developed by the National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA). Eighty-four compounds with IDLH values for which published toxicologic data were available were reviewed to assess the appropriateness of applying such values to accidental release situations. When compared with 30-min animal median lethal concentrations (LC50s), 18 of the IDLHs reviewed were in the same range as lethal levels for animals. For 45 compounds the IDLH values were comparable to concentrations producing severe toxic effects (specifically, unconsciousness, incapacitation, or intolerable irritation). Where available, emergency planning guidelines for the military were compared to IDLHs, and in all 31 cases, the IDLHs exceeded the military exposure guidelines. Twenty compounds also were found to pose a potential cancer risk according to common regulatory guidelines, even under the assumption of a single, 30-min exposure at the IDLH concentration. In addition, the high degree of variability (four orders of magnitude) in the relationship of IDLH values to outcomes of lethality or severe toxicity suggests that the use of IDLH values as emergency planning guidelines for accidental releases is questionable.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. The Ignition of Two Phase Detonation by a Branching Detonation Tube

    NASA Astrophysics Data System (ADS)

    Xiong, Cha; Qiu, Hua; Lu, Qinwei

    2017-11-01

    A branching tube is available to deliver sufficient energy to directly initiate a detonation wave. But sustaining the detonation wave through a branching tube is a challenge. In this study, a preliminary exploration about a branching pulsed detonation engine with a gas-liquid mixture was carried out to evaluate filling conditions on detonation initiation. Two detonation tubes were connected by three different schemes, such as Tail-Tail, Tail-Mid, and Tail-Head. Experimental results showed only end-head connected tubes can be ignited by the branching tube, which is quite different from the results using gas fuels or pre-evaporated liquid fuel. Liquid fuel distribution is crucial for successful detonation traveling through the branching tube.

  7. High temperature detonator

    DOEpatents

    Johnson, James O.; Dinegar, Robert H.

    1988-01-01

    A detonator assembly is provided which is usable at high temperatures about 300.degree. C. A detonator body is provided with an internal volume defining an anvil surface. A first acceptor explosive is disposed on the anvil surface. A donor assembly having an ignition element, an explosive material, and a flying plate, are placed in the body effective to accelerate the flying plate to impact the first acceptor explosive on the anvil for detonating the first acceptor explosive. A second acceptor explosive is eccentrically located in detonation relationship with the first acceptor explosive to thereafter effect detonation of a main charge.

  8. Detonation Propagation Through Ducts in a Pulsed Detonation Engine

    DTIC Science & Technology

    2011-03-01

    PDE head. This convention is used based on the fill and purge flow directions, not the detonation direction. Figure 21. Adapter used to rotate ...presented for the development of a continuously operating pulsed detonation engine ( PDE ). A PDE without a high energy ignition system or a... detonation wave. Propagation is left to right in the bottom tube. ..... 19  Figure 15. Research PDE head

  9. Miniature Precision Detonator

    DTIC Science & Technology

    1974-06-01

    Detonator Output Characterize the detonator output by the following 2-3.1 Dent Output Test. Test detonators Into steel witness plate to compare dent...Kovar with gold plating . The Insulating seal Is glass. The jead pin Is 0.012 ± 0.001 Inch In diameter by 0.25 Inch long. 3.2.2 Bridge. Detonators... plated for solderablllty. The bottom thickness Is 0.004 ± 0.001 Inch. It would be desirable to have 0.002 to 0.003-lnch-thlck bottom so that the mass

  10. Hydrazine vapor detonations

    NASA Technical Reports Server (NTRS)

    Pedley, M. D.; Bishop, C. V.; Benz, F. J.; Bennett, C. A.; Mcclenagan, R. D.

    1988-01-01

    The detonation velocity and cell widths for hydrazine decomposition were measured over a wide range of temperatures and pressures. The detonation velocity in pure hydrazine was within 5 percent of the calculated C-J velocity. The detonation cell width measurements were interpreted using the Zeldovich-Doering-von Neumann model with a detailed reaction mechanism for hydrazine decomposition. Excellent agreement with experimental data for pure hydrazine was obtained using the empirical relation that detonation cell width was equal to 29 times the kinetically calculated reaction zone length.

  11. Branch Detonation of a Pulse Detonation Engine With Flash Vaporized JP-8

    DTIC Science & Technology

    2006-12-01

    Mark F. Reeder (Member) date iii Abstract Pulse Detonation Engines ( PDE ) operating on liquid hydrocarbon fuels are... Detonation Transition FF – Fill Fraction FN – Flow Number NPT – National Pipe Thread OH – Hydroxyl PDE – Pulse Detonation Engine PF – Purge...Introduction Motivation Research on Pulsed Detonation Engines ( PDE ) has increased over the past ten years due to the potential for increased

  12. PREVENTION REFERENCE MANUAL: CHEMICAL SPECIFIC, VOLUME 14: CONTROL OF ACCIDENTAL RELEASES OF PHOSGENE

    EPA Science Inventory

    The report, discussing phosgene, is one of a series addressing the prevention of accidental releases of toxic chemicals. Phosgene, a highly reactive and corrosive liquid that boils at room temperature has an Immediately Dangerous to Life and Health (lDLH) conctntration of 2 ppm, ...

  13. Numerical study of nonequilibrium plasma assisted detonation initiation in detonation tube

    NASA Astrophysics Data System (ADS)

    Zhou, Siyin; Wang, Fang; Che, Xueke; Nie, Wansheng

    2016-12-01

    Nonequilibrium plasma has shown great merits in ignition and combustion nowadays, which should be especially useful for hypersonic propulsion. A coaxial electrodes configuration was established to investigate the effect of alternating current (AC) dielectric barrier discharge nonequilibrium plasma on the detonation initiation process in a hydrogen-oxygen mixture. A discharge simulation-combustion simulation loosely coupled method was used to simulate plasma assisted detonation initiation. First, the dielectric barrier discharge in the hydrogen-oxygen mixture driven by an AC voltage was simulated, which takes 17 kinds of particles (including positively charged particles, negatively charged particles, and neutral particles) and 47 reactions into account. The temporal and spatial characteristics of the discharge products were obtained. Then, the discharge products were incorporated into the combustion model of a detonation combustor as the initial conditions for the later detonation initiation simulation. Results showed that the number density distributions of plasma species are different in space and time, and develop highly nonuniformly from high voltage electrode to grounded electrode at certain times. All the active species reach their highest concentration at approximately 0.6T (T denotes a discharge cycle). Compared with the no plasma case, the differences of flowfield shape mainly appear in the early stage of the deflagration to detonation transition process. None of the sub-processes (including the very slow combustion, deflagration, over-driven detonation, detonation decay, and propagation of a self-sustained stable detonation wave) have been removed by the plasma. After the formation of a C-J detonation wave, the whole flowfield remains unchanged. With the help of plasma, the deflagration to detonation transition (DDT) time and distance are reduced by about 11.6% and 12.9%, respectively, which should be attributed to the active particles effect of

  14. Direct Initiation Through Detonation Branching in a Pulsed Detonation Engine

    DTIC Science & Technology

    2008-03-01

    important features noted ................................. 33  Figure 20. GM Quad 4 engine head used as the PDE research engine with the detonation tube...Deflagration to Detonation Transition EF – Engine Frequency FF – Fill Fraction NPT – National Pipe Thread MPT – Male National Pipe Thread PDE – Pulsed... Detonation Engines ( PDE ) has increased greatly in recent years due in part to the potential for increased thermal efficiency derived from constant

  15. Investigation of Sustained Detonation Devices: the Pulse Detonation Engine-Crossover System and the Rotating Detonation Engine System

    NASA Astrophysics Data System (ADS)

    Driscoll, Robert B.

    An experimental study is conducted on a Pulse Detonation Engine-Crossover System to investigate the feasibility of repeated, shock-initiated combustion and characterize the initiation performance. A PDE-crossover system can decrease deflagration-to-detonation transition length while employing a single spark source to initiate a multi-PDE system. Visualization of a transferred shock wave propagating through a clear channel reveals a complex shock train behind the leading shock. Shock wave Mach number and decay rate remains constant for varying crossover tube geometries and operational frequencies. A temperature gradient forms within the crossover tube due to forward flow of high temperature ionized gas into the crossover tube from the driver PDE and backward flow of ionized gas into the crossover tube from the driven PDE, which can cause intermittent auto-ignition of the driver PDE. Initiation performance in the driven PDE is strongly dependent on initial driven PDE skin temperature in the shock wave reflection region. An array of detonation tubes connected with crossover tubes is developed using optimized parameters and successful operation utilizing shock-initiated combustion through shock wave reflection is achieved and sustained. Finally, an air-breathing, PDE-Crossover System is developed to characterize the feasibility of shock-initiated combustion within an air-breathing pulse detonation engine. The initiation effectiveness of shock-initiated combustion is compared to spark discharge and detonation injection through a pre-detonator. In all cases, shock-initiated combustion produces improved initiation performance over spark discharge and comparable detonation transition run-up lengths relative to pre-detonator initiation. A computational study characterizes the mixing processes and injection flow field within a rotating detonation engine. Injection parameters including reactant flow rate, reactant injection area, placement of the fuel injection, and fuel

  16. Miniature plasma accelerating detonator and method of detonating insensitive materials

    DOEpatents

    Bickes, Jr., Robert W.; Kopczewski, Michael R.; Schwarz, Alfred C.

    1986-01-01

    The invention is a detonator for use with high explosives. The detonator comprises a pair of parallel rail electrodes connected to a power supply. By shorting the electrodes at one end, a plasma is generated and accelerated toward the other end to impact against explosives. A projectile can be arranged between the rails to be accelerated by the plasma. An alternative arrangement is to a coaxial electrode construction. The invention also relates to a method of detonating explosives.

  17. Detonation Propulsion - A Navy Perspective

    DTIC Science & Technology

    2013-07-01

    for Detonation of Stoichiometric C2H4/ 02 Pui•DIIIIIdll Elllllbell Pllllllll•a IIIII • Project/Program Components - Single tube multi-cycle PDE ... Detonation (mid stages) • Acoustic Wave Interaction - Rotating Detonation (mid stages) - Spinning Detonation (early stages) 62 1. 2. 3. 4. 5. 6...Session 2 Detonation Propulsion -A Navy Perspective Gabriel Roy Office of Naval Research Global 46 Report Documentation Page Form ApprovedOMB No

  18. Continuous spin detonation of poorly detonable fuel-air mixtures in annular combustors

    NASA Astrophysics Data System (ADS)

    Bykovskii, F. A.; Zhdan, S. A.

    2017-09-01

    This paper reports on the results of experimental investigations of continuous spin detonation of three fuel-air mixtures (syngas-air, CH4/H2-air, and kerosene/H2-air in a flow-type annular cylindrical combustor 503 mm in diameter. The limits of existence of continuous detonation in terms of the specific flow rates of the mixtures (minimum values) are determined. It is found that all gas mixtures, including the least detonable methane-air mixture, with addition of hydrogen can be burned in the continuous spin detonation regime.

  19. Miniature plasma accelerating detonator and method of detonating insensitive materials

    DOEpatents

    Bickes, R.W. Jr.; Kopczewski, M.R.; Schwarz, A.C.

    1985-01-04

    The invention is a detonator for use with high explosives. The detonator comprises a pair of parallel rail electrodes connected to a power supply. By shorting the electrodes at one end, a plasma is generated and accelerated toward the other end to impact against explosives. A projectile can be arranged between the rails to be accelerated by the plasma. An alternative arrangement is to a coaxial electrode construction. The invention also relates to a method of detonating explosives. 3 figs.

  20. PREVENTION REFERENCE MANUAL: CHEMICAL SPECIFIC, VOLUME 13: CONTROL OF ACCIDENTAL RELEASES OF METHYL ISOCYANATE

    EPA Science Inventory

    This is one of a series of manuals addressing accidental releases of toxic chemicals. Methyl isocyanite (MIC) has an Immediately Dangerous to Life and Health (IDLH) concentration of 20 ppm, making it a substantially acute toxic hazard. Reducing the risk associated with an acciden...

  1. High Explosive Detonation-Confiner Interactions

    NASA Astrophysics Data System (ADS)

    Short, Mark; Quirk, James J.

    2018-01-01

    The primary purpose of a detonation in a high explosive (HE) is to provide the energy to drive a surrounding confiner, typically for mining or munitions applications. The details of the interaction between an HE detonation and its confinement are essential to achieving the objectives of the explosive device. For the high pressures induced by detonation loading, both the solid HE and confiner materials will flow. The structure and speed of a propagating detonation, and ultimately the pressures generated in the reaction zone to drive the confiner, depend on the induced flow both within the confiner and along the HE-confiner material interface. The detonation-confiner interactions are heavily influenced by the material properties and, in some cases, the thickness of the confiner. This review discusses the use of oblique shock polar analysis as a means of characterizing the possible range of detonation-confiner interactions. Computations that reveal the fluid mechanics of HE detonation-confiner interactions for finite reaction-zone length detonations are discussed and compared with the polar analysis. This includes cases of supersonic confiner flow; subsonic, shock-driven confiner flow; subsonic, but shockless confiner flow; and sonic flow at the intersection of the detonation shock and confiner material interface. We also summarize recent developments, including the effects of geometry and porous material confinement, on detonation-confiner interactions.

  2. PREVENTION REFERENCE MANUAL: CHEMICAL SPECIFIC. VOL. 15: CONTROL OF ACCIDENTAL RELEASES OF SULFUR TRIOXIDE

    EPA Science Inventory

    The report, discussing sulfur trioxide (SO3), is one of a series addressing the prevention of accidental releases of toxic chemicals. SO3, a clear oily liquid or solid at typical ambient conditions, has an Immediately Dangerous to Life and Health (IDLH) concentration of 20 ppm, w...

  3. Measurements of observables during detonator function

    NASA Astrophysics Data System (ADS)

    Smilowitz, Laura; Henson, Bryan; Remelius, Dennis

    Thermal explosion and detonation are two phenomena which can both occur as the response of explosives to thermal or mechanical insults. Thermal explosion is typically considered in the safety envelope and detonation is considered in the performance regime of explosive behavior. However, the two regimes are tied together by a phenomenon called deflagration to detonation transition (DDT). In this talk, I will discuss experiments on commercial detonators aimed at understanding the mechanism for energy release during detonator function. Diagnostic development towards measuring temperature, pressure, and density during the extreme conditions and time scales of detonation will be discussed. Our current ability to perform table-top dynamic radiography on functioning detonators will be described. Dynamic measurements of temperature, pressure, and density will be shown and discussion of the function of a detonator will be given in terms of our current understanding of deflagration, detonation, and the transition between the two.

  4. Simulations of Heterogeneous Detonations and Post Detonation Turbulent Mixing and Afterburning

    NASA Astrophysics Data System (ADS)

    Menon, Suresh; Gottiparthi, Kalyana

    2011-06-01

    Most metal-loaded explosives and thermobaric explosives exploit the afterburning of metals to maintain pressure and temperature conditions.The use of such explosives in complex environment can result in post detonation flow containing many scales of vortical motion, flow jetting and shear, as well as plume-surface interactions due to flow impingement and wall flows. In general, all these interactions can lead to highly turbulent flow fields even if the initial ambient conditions were quiescent. Thus, turbulent mixing can dominate initial mixing and impact the final afterburn. We conduct three-dimensional numerical simulations of the propagation of detonation resulting from metal-loaded (inert or reacting) explosives and analyze the afterburn process as well as the generation of multiple scales of mixing in the post detonation flow field. Impact of the detonation and post-detonation flow field on solid surface is also considered for a variety of initial conditions. Comparison with available data is carried out to demonstrate validity of the simulation method. Supported by Defense Threat Reduction Agency

  5. Detonation command and control

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mace, Jonathan Lee; Seitz, Gerald J.; Echave, John A.

    The detonation of one or more explosive charges and propellant charges by a detonator in response to a fire control signal from a command and control system comprised of a command center and instrumentation center with a communications link therebetween. The fire control signal is selectively provided to the detonator from the instrumentation center if plural detonation control switches at the command center are in a fire authorization status, and instruments, and one or more interlocks, if included, are in a ready for firing status. The instrumentation and command centers are desirably mobile, such as being respective vehicles.

  6. Detonation command and control

    DOEpatents

    Mace, Jonathan L.; Seitz, Gerald J.; Echave, John A.; Le Bas, Pierre-Yves

    2015-11-10

    The detonation of one or more explosive charges and propellant charges by a detonator in response to a fire control signal from a command and control system comprised of a command center and instrumentation center with a communications link therebetween. The fire control signal is selectively provided to the detonator from the instrumentation center if plural detonation control switches at the command center are in a fire authorization status, and instruments, and one or more interlocks, if included, are in a ready for firing status. The instrumentation and command centers are desirably mobile, such as being respective vehicles.

  7. Detonation command and control

    DOEpatents

    Mace, Jonathan L.; Seitz, Gerald J.; Echave, John A.; Le Bas, Pierre-Yves

    2016-05-31

    The detonation of one or more explosive charges and propellant charges by a detonator in response to a fire control signal from a command and control system comprised of a command center and instrumentation center with a communications link there between. The fire control signal is selectively provided to the detonator from the instrumentation center if plural detonation control switches at the command center are in a fire authorization status, and instruments, and one or more interlocks, if included, are in a ready for firing status. The instrumentation and command centers are desirably mobile, such as being respective vehicles.

  8. The History of the Study of Detonation

    ERIC Educational Resources Information Center

    Bulat, Pavel V.; Volkov, Konstantin N.

    2016-01-01

    In this article we reviewed the main concepts of detonative combustion. Concepts of slow and fast combustion, of detonation adiabat are introduced. Landmark works on experimental and semi-empirical detonation study are presented. We reviewed Chapman-Jouguet stationary detonation and spin detonation. Various mathematical model of detonation wave…

  9. Initiation Mechanisms of Low-loss Swept-ramp Obstacles for Deflagration to Detonation Transition in Pulse Detonation Combustors

    DTIC Science & Technology

    2009-12-01

    minimal pressure losses. 15. NUMBER OF PAGES 113 14. SUBJECT TERMS Pulse Detonation Combustors, PDC, Pulse Detonation Engines, PDE , PDE ...Postgraduate School PDC Pulse Detonation Combustor PDE Pulse Detonation Engine RAM Random Access Memory RDT Research, Design and Test RPL...inhibiting the implementation of this advanced propulsion system. The primary advantage offered by pulse detonation engines ( PDEs ) is the high efficiency

  10. Bidirectional slapper detonator

    DOEpatents

    McCormick, Robert N.; Boyd, Melissa D.

    1984-01-01

    The disclosure is directed to a bidirectional slapper detonator. One embodiment utilizes a single bridge circuit to detonate a pair of opposing initiating pellets. A line generator embodiment uses a plurality of bridges in electrical series to generate opposing cylindrical wavefronts.

  11. Gaseous detonation initiation via wave implosion

    NASA Astrophysics Data System (ADS)

    Jackson, Scott Irving

    Efficient detonation initiation is a topic of intense interest to designers of pulse detonation engines. This experimental work is the first to detonate propane-air mixtures with an imploding detonation wave and to detonate a gas mixture with a non-reflected, imploding shock. In order to do this, a unique device has been developed that is capable of generating an imploding toroidal detonation wave inside of a tube from a single ignition point without any obstruction to the tube flow path. As part of this study, an initiator that creates a large-aspect-ratio planar detonation wave in gas-phase explosive from a single ignition point has also been developed. The effectiveness of our initiation devices has been evaluated. The minimum energy required by the imploding shock for initiation was determined to scale linearly with the induction zone length, indicating the presence of a planar initiation mode. The imploding toroidal detonation initiator was found to be more effective at detonation initiation than the imploding shock initiator, using a comparable energy input to that of current initiator tubes.

  12. Planar Reflection of Gaseous Detonations

    NASA Astrophysics Data System (ADS)

    Damazo, Jason Scott

    Pipes containing flammable gaseous mixtures may be subjected to internal detonation. When the detonation normally impinges on a closed end, a reflected shock wave is created to bring the flow back to rest. This study built on the work of Karnesky (2010) and examined deformation of thin-walled stainless steel tubes subjected to internal reflected gaseous detonations. A ripple pattern was observed in the tube wall for certain fill pressures, and a criterion was developed that predicted when the ripple pattern would form. A two-dimensional finite element analysis was performed using Johnson-Cook material properties; the pressure loading created by reflected gaseous detonations was accounted for with a previously developed pressure model. The residual plastic strain between experiments and computations was in good agreement. During the examination of detonation-driven deformation, discrepancies were discovered in our understanding of reflected gaseous detonation behavior. Previous models did not accurately describe the nature of the reflected shock wave, which motivated further experiments in a detonation tube with optical access. Pressure sensors and schlieren images were used to examine reflected shock behavior, and it was determined that the discrepancies were related to the reaction zone thickness extant behind the detonation front. During these experiments reflected shock bifurcation did not appear to occur, but the unfocused visualization system made certainty impossible. This prompted construction of a focused schlieren system that investigated possible shock wave-boundary layer interaction, and heat-flux gauges analyzed the boundary layer behind the detonation front. Using these data with an analytical boundary layer solution, it was determined that the strong thermal boundary layer present behind the detonation front inhibits the development of reflected shock wave bifurcation.

  13. The hydrodynamic theory of detonation

    NASA Technical Reports Server (NTRS)

    Langweiler, Heinz

    1939-01-01

    This report derives equations containing only directly measurable constants for the quantities involved in the hydrodynamic theory of detonation. The stable detonation speed, D, is revealed as having the lowest possible value in the case of positive material velocity, by finding the minimum of the Du curve (u denotes the speed of the gases of combustion). A study of the conditions of energy and impulse in freely suspended detonating systems leads to the disclosure of a rarefaction front traveling at a lower speed behind the detonation front; its velocity is computed. The latent energy of the explosive passes into the steadily growing detonation zone - the region between the detonation front and the rarefaction front. The conclusions lead to a new definition of the concept of shattering power. The calculations are based on the behavior of trinitrotoluene.

  14. Social, psychological, and behavioral responses to a nuclear detonation in a US city: implications for health care planning and delivery.

    PubMed

    Dodgen, Daniel; Norwood, Ann E; Becker, Steven M; Perez, Jon T; Hansen, Cynthia K

    2011-03-01

    A nuclear detonation in a US city would have profound psychological, social, and behavioral effects. This article reviews the scientific literature on human responses to radiation incidents and disasters in general, and examines potential behavioral health care provider (BHCP) contributions in the hours and days after a nuclear detonation. In the area directly affected by the blast, the immediate overarching goal of BHCP interventions is the support of lifesaving activities and the prevention of additional casualties from fallout. These interventions include 6 broad categories: promoting appropriate protective actions, discouraging dangerous behaviors, managing patient/survivor flow to facilitate the best use of scarce resources, supporting first responders, assisting with triage, and delivering palliative care when appropriate. At more distant sites, BHCP should work with medical providers to support hospitalized survivors of the detonation. Recommendations are also made on BHCP interventions later in the response phase and during recovery.

  15. Diminishing detonator effectiveness through electromagnetic effects

    DOEpatents

    Schill, Jr, Robert A.

    2016-09-20

    An inductively coupled transmission line with distributed electromotive force source and an alternative coupling model based on empirical data and theory were developed to initiate bridge wire melt for a detonator with an open and a short circuit detonator load. In the latter technique, the model was developed to exploit incomplete knowledge of the open circuited detonator using tendencies common to all of the open circuit loads examined. Military, commercial, and improvised detonators were examined and modeled. Nichrome, copper, platinum, and tungsten are the detonator specific bridge wire materials studied. The improvised detonators were made typically made with tungsten wire and copper (.about.40 AWG wire strands) wire.

  16. Detonation Jet Engine. Part 2--Construction Features

    ERIC Educational Resources Information Center

    Bulat, Pavel V.; Volkov, Konstantin N.

    2016-01-01

    We present the most relevant works on jet engine design that utilize thermodynamic cycle of detonative combustion. Detonation engines of various concepts, pulse detonation, rotational and engine with stationary detonation wave, are reviewed. Main trends in detonation engine development are discussed. The most important works that carried out…

  17. Reduced detonation kinetics and detonation structure in one- and multi-fuel gaseous mixtures

    NASA Astrophysics Data System (ADS)

    Fomin, P. A.; Trotsyuk, A. V.; Vasil'ev, A. A.

    2017-10-01

    Two-step approximate models of chemical kinetics of detonation combustion of (i) one-fuel (CH4/air) and (ii) multi-fuel gaseous mixtures (CH4/H2/air and CH4/CO/air) are developed for the first time. The models for multi-fuel mixtures are proposed for the first time. Owing to the simplicity and high accuracy, the models can be used in multi-dimensional numerical calculations of detonation waves in corresponding gaseous mixtures. The models are in consistent with the second law of thermodynamics and Le Chatelier’s principle. Constants of the models have a clear physical meaning. Advantages of the kinetic model for detonation combustion of methane has been demonstrated via numerical calculations of a two-dimensional structure of the detonation wave in a stoichiometric and fuel-rich methane-air mixtures and stoichiometric methane-oxygen mixture. The dominant size of the detonation cell, determines in calculations, is in good agreement with all known experimental data.

  18. Pulse detonation engines and components thereof

    NASA Technical Reports Server (NTRS)

    Tangirala, Venkat Eswarlu (Inventor); Rasheed, Adam (Inventor); Vandervort, Christian Lee (Inventor); Dean, Anthony John (Inventor)

    2009-01-01

    A pulse detonation engine comprises a primary air inlet; a primary air plenum located in fluid communication with the primary air inlet; a secondary air inlet; a secondary air plenum located in fluid communication with the secondary air inlet, wherein the secondary air plenum is substantially isolated from the primary air plenum; a pulse detonation combustor comprising a pulse detonation chamber, wherein the pulse detonation chamber is located downstream of and in fluid communication with the primary air plenum; a coaxial liner surrounding the pulse detonation combustor defining a cooling plenum, wherein the cooling plenum is in fluid communication with the secondary air plenum; an axial turbine assembly located downstream of and in fluid communication with the pulse detonation combustor and the cooling plenum; and a housing encasing the primary air plenum, the secondary air plenum, the pulse detonation combustor, the coaxial liner, and the axial turbine assembly.

  19. Detonation waves in pentaerythritol tetranitrate

    NASA Astrophysics Data System (ADS)

    Tarver, Craig M.; Breithaupt, R. Don; Kury, John W.

    1997-06-01

    Fabry-Perot laser interferometry was used to obtain nanosecond time resolved particle velocity histories of the free surfaces of tantalum discs accelerated by detonating pentaerythritol tetranitrate (PETN) charges and of the interfaces between PETN detonation products and lithium fluoride crystals. The experimental records were compared to particle velocity histories calculated using very finely zoned meshes of the exact dimensions with the DYNA2D hydrodynamic code. The duration of the PETN detonation reaction zone was demonstrated to be less than the 5 ns initial resolution of the Fabry-Perot technique, because the experimental records were accurately calculated using an instantaneous chemical reaction, the Chapman-Jouguet (C-J) model of detonation, and the reaction product Jones-Wilkins-Lee (JWL) equation of state for PETN detonation products previously determined by supracompression (overdriven detonation) studies. Some of the PETN charges were pressed to densities approaching the crystal density and exhibited the phenomenon of superdetonation. An ignition and growth Zeldovich-von Neumann-Doring (ZND) reactive flow model was developed to explain these experimental records and the results of previous PETN shock initiation experiments on single crystals of PETN. Good agreement was obtained for the induction time delays preceding chemical reaction, the run distances at which the initial shock waves were overtaken by the detonation waves in the compressed PETN, and the measured particle velocity histories produced by the overdriven detonation waves before they could relax to steady state C-J velocity and pressure.

  20. Numerical modeling of divergent detonation wave

    NASA Astrophysics Data System (ADS)

    Li, Zhiwei; Liu, Bangdi

    1987-11-01

    The indefinite nature of divergent detonations under the assumption of instantaneous stable detonation is described. In the numerical modeling method for divergent detonation, the artificial cohesiveness was improved and the Cochran reaction rate and the JWL equations of state were used to describe the ignition process of the explosion. Several typical divergent detonation problems were computed obtaining rather satisfying results.

  1. Detonation waves in pentaerythritol tetranitrate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tarver, C.M.; Breithaupt, R.D.; Kury, J.W.

    1997-06-01

    Fabry{endash}Perot laser interferometry was used to obtain nanosecond time resolved particle velocity histories of the free surfaces of tantalum discs accelerated by detonating pentaerythritol tetranitrate (PETN) charges and of the interfaces between PETN detonation products and lithium fluoride crystals. The experimental records were compared to particle velocity histories calculated using very finely zoned meshes of the exact dimensions with the DYNA2D hydrodynamic code. The duration of the PETN detonation reaction zone was demonstrated to be less than the 5 ns initial resolution of the Fabry{endash}Perot technique, because the experimental records were accurately calculated using an instantaneous chemical reaction, the Chapman{endash}Jouguetmore » (C-J) model of detonation, and the reaction product Jones{endash}Wilkins{endash}Lee (JWL) equation of state for PETN detonation products previously determined by supracompression (overdriven detonation) studies. Some of the PETN charges were pressed to densities approaching the crystal density and exhibited the phenomenon of superdetonation. An ignition and growth Zeldovich{endash}von Neumann{endash}Doring (ZND) reactive flow model was developed to explain these experimental records and the results of previous PETN shock initiation experiments on single crystals of PETN. Good agreement was obtained for the induction time delays preceding chemical reaction, the run distances at which the initial shock waves were overtaken by the detonation waves in the compressed PETN, and the measured particle velocity histories produced by the overdriven detonation waves before they could relax to steady state C-J velocity and pressure. {copyright} {ital 1997 American Institute of Physics.}« less

  2. Low voltage nonprimary explosive detonator

    DOEpatents

    Dinegar, Robert H.; Kirkham, John

    1982-01-01

    A low voltage, electrically actuated, nonprimary explosive detonator is disclosed wherein said detonation is achieved by means of an explosive train in which a deflagration-to-detonation transition is made to occur. The explosive train is confined within a cylindrical body and positioned adjacent to low voltage ignition means have electrical leads extending outwardly from the cylindrical confining body. Application of a low voltage current to the electrical leads ignites a self-sustained deflagration in a donor portion of the explosive train which then is made to undergo a transition to detonation further down the train.

  3. Detonation wave compression in gas turbines

    NASA Technical Reports Server (NTRS)

    Wortman, A.

    1986-01-01

    A study was made of the concept of augmenting the performance of low pressure ratio gas turbines by detonation wave compression of part of the flow. The concept exploits the constant volume heat release of detonation waves to increase the efficiency of the Brayton cycle. In the models studied, a fraction of the compressor output was channeled into detonation ducts where it was processed by transient transverse detonation waves. Gas dynamic studies determined the maximum cycling frequency of detonation ducts, proved that upstream propagation of pressure pulses represented no problems and determined the variations of detonation duct output with time. Mixing and wave compression were used to recombine the combustor and detonation duct flows and a concept for a spiral collector to further smooth the pressure and temperature pulses was presented as an optional component. The best performance was obtained with a single firing of the ducts so that the flow could be re-established before the next detonation was initiated. At the optimum conditions of maximum frequency of the detonation ducts, the gas turbine efficiency was found to be 45 percent while that of a corresponding pressure ratio 5 conventional gas turbine was only 26%. Comparable improvements in specific fuel consumption data were found for gas turbines operating as jet engines, turbofans, and shaft output machines. Direct use of the detonation duct output for jet propulsion proved unsatisfactory. Careful analysis of the models of the fluid flow phenomena led to the conclusion that even more elaborate calculations would not diminish the uncertainties in the analysis of the system. Feasibility of the concept to work as an engine now requires validation in an engineering laboratory experiment.

  4. Impulse generation by detonation tubes

    NASA Astrophysics Data System (ADS)

    Cooper, Marcia Ann

    Impulse generation with gaseous detonation requires conversion of chemical energy into mechanical energy. This conversion process is well understood in rocket engines where the high pressure combustion products expand through a nozzle generating high velocity exhaust gases. The propulsion community is now focusing on advanced concepts that utilize non-traditional forms of combustion like detonation. Such a device is called a pulse detonation engine in which laboratory tests have proven that thrust can be achieved through continuous cyclic operation. Because of poor performance of straight detonation tubes compared to conventional propulsion systems and the success of using nozzles on rocket engines, the effect of nozzles on detonation tubes is being investigated. Although previous studies of detonation tube nozzles have suggested substantial benefits, up to now there has been no systematic investigations over a range of operating conditions and nozzle configurations. As a result, no models predicting the impulse when nozzles are used exist. This lack of data has severely limited the development and evaluation of models and simulations of nozzles on pulse detonation engines. The first experimental investigation measuring impulse by gaseous detonation in plain tubes and tubes with nozzles operating in varying environment pressures is presented. Converging, diverging, and converging-diverging nozzles were tested to determine the effect of divergence angle, nozzle length, and volumetric fill fraction on impulse. The largest increases in specific impulse, 72% at an environment pressure of 100 kPa and 43% at an environment pressure of 1.4 kPa, were measured with the largest diverging nozzle tested that had a 12° half angle and was 0.6 m long. Two regimes of nozzle operation that depend on the environment pressure are responsible for these increases and were first observed from these data. To augment this experimental investigation, all data in the literature regarding

  5. Using Schlieren Visualization to Track Detonator Performance

    NASA Astrophysics Data System (ADS)

    Clarke, S. A.; Bolme, C. A.; Murphy, M. J.; Landon, C. D.; Mason, T. A.; Adrian, R. J.; Akinci, A. A.; Martinez, M. E.; Thomas, K. A.

    2007-12-01

    Several experiments will be presented that are part of a phased plan to understand the evolution of detonation in a detonator from initiation shock through run to detonation, to full detonation, to transition, to booster and booster detonation. High-speed multiframe schlieren imagery has been used to study several explosive initiation events, such as exploding bridgewires (EBWs), exploding foil initiators (EFIs or "slappers"), direct optical initiation (DOI), and electrostatic discharge. Additionally, a series of tests has been performed on "cut-back" detonators with varying initial pressing heights. We have also used this diagnostic to visualize a range of EBW, EFI, and DOI full-up detonators. Future applications to other explosive events, such as boosters and insensitive high explosives booster evaluation, will be discussed. The EPIC finite element code has been used to analyze the shock fronts from the schlieren images to solve iteratively for consistent boundary or initial conditions to determine the temporal-spatial pressure profile across the output face of the detonator.

  6. Using Schlieren Visualization to Track Detonator Performance

    NASA Astrophysics Data System (ADS)

    Clarke, Steven; Thomas, Keith; Martinez, Michael; Akinci, Adrian; Murphy, Michael; Adrian, Ronald

    2007-06-01

    Several experiments that are part of a phased plan to understand the evolution of detonation in a detonator from initiation shock through run to detonation to full detonation to transition to booster and booster detonation will be presented. High Speed Laser Schlieren Movies have been used to study several explosive initiation events, such as exploding bridgewires (EBW), Exploding Foil Initiators (EFI) (or slappers), Direct Optical Initiation (DOI), and ElectroStatic Discharge (ESD). Additionally, a series of tests have been performed on ``cut-back'' detonators with varying initial pressing (IP) heights. We have also used this diagnostic to visualize a range of EBW, EFI, and DOI full-up detonators. Future applications to other explosive events such as boosters and IHE booster evaluation will be discussed. EPIC Hydrodynamic code has been used to analyze the shock fronts from the Schlieren images to reverse calculate likely boundary or initial conditions to determine the temporal-spatial pressure profile across the output face of the detonator. LA-UR-07-1229

  7. Detonation properties of nitromethane/diethylenetriamine solution

    NASA Astrophysics Data System (ADS)

    Mochalova, V.; Utkin, A.; Lapin, S.

    2017-01-01

    The results of the experimental determination of the detonation parameters of nitromethane (NM) with diethylenetriamine (DETA) solution are presented in this work. With the using of a laser interferometer VISAR the stability of detonation waves, the detonation velocity and the reaction time at the concentration of DETA from 0 to 60 weight percentage were investigated. It is shown that the stability of detonation waves is retained up to 25% DETA, at that the characteristic reaction time is reduced by about half at the addition of several percentage of the sensitizer to NM and then remains almost constant. The increase of the detonation velocity in the vicinity of the small, about 0.1%, concentrations of sensitizer is recorded.

  8. Preventing Accidental Ignition of Upper-Stage Rocket Motors

    NASA Technical Reports Server (NTRS)

    Hickman, John; Morgan, Herbert; Cooper, Michael; Murbach, Marcus

    2005-01-01

    A report presents a proposal to reduce the risk of accidental ignition of certain upper-stage rocket motors or other high energy hazardous systems. At present, mechanically in-line initiators are used for initiation of many rocket motors and/or other high-energy hazardous systems. Electrical shorts and/or mechanical barriers, which are the basic safety devices in such systems, are typically removed as part of final arming or pad preparations while personnel are present. At this time, static discharge, test equipment malfunction, or incorrect arming techniques can cause premature firing. The proposal calls for a modular out-of-line ignition system incorporating detonating-cord elements, identified as the donor and the acceptor, separated by an air gap. In the safe configuration, the gap would be sealed with two shields, which would prevent an accidental firing of the donor from igniting the system. The shields would be removed to enable normal firing, in which shrapnel generated by the donor would reliably ignite the acceptor to continue the ordnance train. The acceptor would then ignite a through bulkhead initiator (or other similar device), which would ignite the motor or high-energy system. One shield would be remotely operated and would be moved to the armed position when a launch was imminent or conversely returned to the safe position if the launch were postponed. In the event of failure of the remotely operated shield, the other shield could be inserted manually to safe the system.

  9. Planar Reflection of Detonations Waves

    NASA Astrophysics Data System (ADS)

    Damazo, Jason; Shepherd, Joseph

    2012-11-01

    An experimental study examining normally reflected gaseous detonation waves is undertaken so that the physics of reflected detonations may be understood. Focused schlieren visualization is used to describe the boundary layer development behind the incident detonation wave and the nature of the reflected shock wave. Reflected shock wave bifurcation-which has received extensive study as it pertains to shock tube performance-is predicted by classical bifurcation theory, but is not observed in the present study for undiluted hydrogen-oxygen and ethylene-oxygen detonation waves. Pressure and thermocouple gauges are installed in the floor of the detonation tube so as to examine both the wall pressure and heat flux. From the pressure results, we observe an inconsistency between the measured reflected shock speed and the measured reflected shock strength with one dimensional flow predictions confirming earlier experiments performed in our laboratory. This research is sponsored by the DHS through the University of Rhode Island, Center of Excellence for Explosives Detection.

  10. Rotating Detonation Engine Operation (Preprint)

    DTIC Science & Technology

    2012-01-01

    MdotH2 = mass flow of hydrogen MdotAir = mass flow of air PCB = Piezoelectric Pressure Sensor PDE = Pulsed Detonation Engine RDE = Rotating ...and unsteady thrust output of PDEs . One of the new designs was the Rotating Detonation Engine (RDE). An RDE operates by exhausting an initial...AFRL-RZ-WP-TP-2012-0003 ROTATING DETONATION ENGINE OPERATION (PREPRINT) James A. Suchocki and Sheng-Tao John Yu The Ohio State

  11. Effect of Aluminium Confinement on ANFO Detonation

    NASA Astrophysics Data System (ADS)

    Short, Mark; Jackson, Scott; Kiyanda, Charles; Shinas, Mike; Hare, Steve; Briggs, Matt

    2013-06-01

    Detonations in confined non-ideal high explosives often have velocities below the confiner sound speed. The effect on detonation propagation of the resulting subsonic flow in the confiner (such as confiner stress waves traveling ahead of the main detonation front or upstream wall deflection into the HE) has yet to be fully understood. Previous work by Sharpe and Bdzil (J. Eng. Math, 2006) has shown that for subsonic confiner flow, there is no limiting thickness for which the detonation dynamics are uninfluenced by further increases in wall thickness. The critical parameters influencing detonation behavior are the wall thickness relative to the HE reaction zone size, and the difference in the detonation velocity and confiner sound speed. Additional possible outcomes of subsonic flow are that for increasing thickness, the confiner is increasingly deflected into the HE upstream of the detonation, and that for sufficiently thick confiners, the detonation speed could be driven up to the sound speed in the confiner. We report here on a further series of experiments in which a mixture of ammonium nitrate and fuel oil (ANFO) is detonated in aluminum confiners with varying HE charge diameter and confiner thickness, and compare the results with the outcomes suggested by Sharpe and Bdzil.

  12. Detonator-activated ball shutter

    DOEpatents

    McWilliams, Roy A.; von Holle, William G.

    1983-01-01

    A detonator-activated ball shutter for closing an aperture in about 300.mu. seconds. The ball shutter containing an aperture through which light, etc., passes, is closed by firing a detonator which propels a projectile for rotating the ball shutter, thereby blocking passage through the aperture.

  13. Accidental poisoning in childhood: five year urban population study with 15 year analysis of fatality.

    PubMed Central

    Pearn, J; Nixon, J; Ansford, A; Corcoran, A

    1984-01-01

    Patterns of accidental poisoning in children are changing dramatically. A five year population study (1977-81) was undertaken in urban children from Brisbane (population 1 000 000). A total of 2098 children were poisoned during this period with only one fatality, which represents a dramatic reduction in mortality. Over the past 15 years (1968-82) 13 children have died from accidental poisoning from this population, and two were murdered with drugs. A study of secular trends has indicated that peak incidence occurred in 1979, and the rate has been falling progressively since. The current age corrected rate of poisoning is 393 per 100 000 children per year (0-5 year olds). The rank order of poisons, drugs, and chemicals causing hospital admission and death is: petroleum distillates 13%; antihistamines 9%; benzodiazepines 9%; bleach and detergents 7%; and aspirin 6%. The ratio of fatalities to ingestions requiring hospital admission was calculated to give an index of a practical danger of noxious agents to which children are currently exposed and the rank order is: cardiotoxic drugs, one fatality to 25 ingestions; tricyclic antidepressants, one to 44; sympathomimetic drugs, one to 54; caustic soda, one to 68; aspirin, one fatality to 350 ingestions. Accidental poisoning of children leading to death has been reduced because patterns of drug prescriptions have changed, packaging of dangerous drugs has been made safer, and substances such as kerosene have been coloured blue. PMID:6140065

  14. The dangers of long-term catheter drainage.

    PubMed

    Lowthian, P

    There are many dangers associated with long-term urinary bladder drainage by catheter. For various reasons, the choice of catheter is important, and its initial insertion can be particularly hazardous. All catheterizations should, however, be safer when there is some urine (or other fluid) in the bladder. The appropriate choice of drainage system attached to the catheter can delay bacterial invasion of the bladder. Great care is needed to prevent blockage of the system, particularly when bacteriuria is present. Recent evidence indicates that some bacteria encourage the development of encrustations, so that, in some circumstances, catheters may become blocked within 24 hours. This, together with other considerations, strongly suggests that indwelling catheters should be changed at intervals of not more than 5 days. The practical implications of this are considered, as are the benefits that may accrue. Accidental catheter traction is another danger, and some possible methods of avoiding this are discussed. Finally, the need for a new kind of drainage-bag support is highlighted.

  15. Detonation velocity in poorly mixed gas mixtures

    NASA Astrophysics Data System (ADS)

    Prokhorov, E. S.

    2017-10-01

    The technique for computation of the average velocity of plane detonation wave front in poorly mixed mixture of gaseous hydrocarbon fuel and oxygen is proposed. Here it is assumed that along the direction of detonation propagation the chemical composition of the mixture has periodic fluctuations caused, for example, by layered stratification of gas charge. The technique is based on the analysis of functional dependence of ideal (Chapman-Jouget) detonation velocity on mole fraction (with respect to molar concentration) of the fuel. It is shown that the average velocity of detonation can be significantly (by more than 10%) less than the velocity of ideal detonation. The dependence that permits to estimate the degree of mixing of gas mixture basing on the measurements of average detonation velocity is established.

  16. Premature detonation of an NH₄NO₃ emulsion in reactive ground.

    PubMed

    Priyananda, Pramith; Djerdjev, Alex M; Gore, Jeff; Neto, Chiara; Beattie, James K; Hawkett, Brian S

    2015-01-01

    When NH4NO3 emulsions are used in blast holes containing pyrite, they can exothermally react with pyrite, causing the emulsion to intensively heat and detonate prematurely. Such premature detonations can inflict fatal and very costly damages. The mechanism of heating of the emulsions is not well understood though such an understanding is essential for designing safe blasting. In this study the heating of an emulsion in model blast holes was simulated by solving the heat equation. The physical factors contributing to the heating phenomenon were studied using microscopic and calorimetric methods. Microscopic studies revealed the continuous formation of a large number of gas bubbles as the reaction progressed at the emulsion-pyrite interface, which made the reacting emulsion porous. Calculations show that the increase in porosity causes the thermal conductivity of a reacting region of an emulsion column in a blast hole to decrease exponentially. This large reduction in the thermal conductivity retards heat dissipation from the reacting region causing its temperature to rise. The rise in temperature accelerates the exothermic reaction producing more heat. Simulations predict a migration of the hottest spot of the emulsion column, which could dangerously heat the primers and boosters located in the blast hole. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Detonator-activated ball shutter

    DOEpatents

    McWilliams, R.A.; Holle, W.G. von.

    1983-08-16

    A detonator-activated ball shutter for closing an aperture in about 300[mu] seconds. The ball shutter containing an aperture through which light, etc., passes, is closed by firing a detonator which propels a projectile for rotating the ball shutter, thereby blocking passage through the aperture. 3 figs.

  18. Recent work on gaseous detonations

    NASA Astrophysics Data System (ADS)

    Nettleton, M. A.

    The paper reviews recent progress in the field of gaseous detonations, with sections on shock diffraction and reflection, the transition to detonation, hybrid, spherically-imploding, and galloping and stuttering fronts, their structure, their transmission and quenching by additives, the critical energy for initiation and detonation of more unusual fuels. The final section points out areas where our understanding is still far from being complete and contains some suggestions of ways in which progress might be made.

  19. Detonating apparatus

    DOEpatents

    Johnston, Lawrence H.

    1976-01-01

    1. Apparatus for detonation of high explosive in uniform timing comprising in combination, an outer case, spark gap electrodes insulatedly supported in spaced relationship within said case to form a spark gap, high explosive of the class consisting of pentaerythritol tetranitrate and trimethylene trinitramine substantially free from material sensitive to detonation by impact compressed in surrounding relation to said electrodes including said spark gap under a pressure from about 100 psi to about 500 psi, said spark gap with said compressed explosive therein requiring at least 1000 volts for sparking, and means for impressing at least 1000 volts on said spark gap.

  20. Detonation properties of the nitromethane/ diethylenetriamine solution

    NASA Astrophysics Data System (ADS)

    Mochalova, Valentina; Utkin, Alexander; Lapin, Sergey

    2015-06-01

    The results of the experimental determination of detonation parameters for the mixture of nitromethane (NM) with diethylenetriamine (DETA) are presented in this work. By the using of a laser interferometer VISAR the stability of detonation waves, detonation velocity and the reaction time with the change of the DETA concentration from 0 to 60 weight percentages were investigated. It is shown that detonation waves are stable up to 25% DETA, and the character reaction time is reduced from 50 ns up to 30 ns with the addition of a few percentages of the sensitizer and then remains almost the constant. With further increase of the DETA concentration the detonation front becomes unstable, and it results in an arising of pulsations with amplitude of 10 microns. The limit concentration of DETA, above which the detonation of the mixture was impossible, was determined. This concentration was equal to 60%. It is shown that the dependence of the detonation velocity on the DETA concentration is non-monotonic. In particular, the increase of detonation velocity in the vicinity of small concentrations of the sensitizer, about 0.1%, was recorded. The work was supported by Russian Foundation for Basic Research (Project 15-03-07830).

  1. Optically detonated explosive device

    NASA Technical Reports Server (NTRS)

    Yang, L. C.; Menichelli, V. J. (Inventor)

    1974-01-01

    A technique and apparatus for optically detonating insensitive high explosives, is disclosed. An explosive device is formed by containing high explosive material in a house having a transparent window. A thin metallic film is provided on the interior surface of the window and maintained in contact with the high explosive. A laser pulse provided by a Q-switched laser is focussed on the window to vaporize the metallic film and thereby create a shock wave which detonates the high explosive. Explosive devices may be concurrently or sequentially detonated by employing a fiber optic bundle to transmit the laser pulse to each of the several individual explosive devices.

  2. Stability of cosmological detonation fronts

    NASA Astrophysics Data System (ADS)

    Mégevand, Ariel; Membiela, Federico Agustín

    2014-05-01

    The steady-state propagation of a phase-transition front is classified, according to hydrodynamics, as a deflagration or a detonation, depending on its velocity with respect to the fluid. These propagation modes are further divided into three types, namely, weak, Jouguet, and strong solutions, according to their disturbance of the fluid. However, some of these hydrodynamic modes will not be realized in a phase transition. One particular cause is the presence of instabilities. In this work we study the linear stability of weak detonations, which are generally believed to be stable. After discussing in detail the weak detonation solution, we consider small perturbations of the interface and the fluid configuration. When the balance between the driving and friction forces is taken into account, it turns out that there are actually two different kinds of weak detonations, which behave very differently as functions of the parameters. We show that the branch of stronger weak detonations are unstable, except very close to the Jouguet point, where our approach breaks down.

  3. Detonability of hydrocarbon fuels in air

    NASA Technical Reports Server (NTRS)

    Beeson, H. D.; Mcclenagan, R. D.; Bishop, C. V.; Benz, F. J.; Pitz, W. J.; Westbrook, C. K.; Lee, J. H. S.

    1991-01-01

    Studies were conducted of the detonation of gas-phase mixtures of n-hexane and JP-4, with oxidizers as varied as air and pure oxygen, measuring detonation velocities and cell sizes as a function of stoichiometry and diluent concentration. The induction length of a one-dimensional Zeldovich-von Neumann-Doering detonation was calculated on the basis of a theoretical model that employed the reaction kinetics of the hydrocarbon fuels used. Critical energy and critical tube diameter are compared for a relative measure of the heavy hydrocarbon fuels studied; detonation sensitivity appears to increase slightly with increasing carbon number.

  4. Detonability of H/sub 2/-air-diluent mixtures

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tieszen, S.R.; Sherman, M.P.; Benedick, W.B.

    1987-06-01

    This report describes the Heated Detonation Tube (HDT). Detonation cell width and velocity results are presented for H/sub 2/-air mixtures, undiluted and diluted with CO/sub 2/ and H/sub 2/O for a range of H/sub 2/ concentration, initial temperature and pressure. The results show that the addition of either CO/sub 2/ or H/sub 2/O significantly increases the detonation cell width and hence reduces the detonability of the mixture. The results also show that the detonation cell width is reduced (detonability is increased) for increased initial temperature and/or pressure.

  5. Effects of Fuel Distribution on Detonation Tube Performance

    NASA Technical Reports Server (NTRS)

    Perkins, H. Douglas; Sung, Chih-Jen

    2003-01-01

    A pulse detonation engine uses a series of high frequency intermittent detonation tubes to generate thrust. The process of filling the detonation tube with fuel and air for each cycle may yield non-uniform mixtures. Uniform mixing is commonly assumed when calculating detonation tube thrust performance. In this study, detonation cycles featuring idealized non-uniform Hz/air mixtures were analyzed using a two-dimensional Navier-Stokes computational fluid dynamics code with detailed chemistry. Mixture non-uniformities examined included axial equivalence ratio gradients, transverse equivalence ratio gradients, and partially fueled tubes. Three different average test section equivalence ratios were studied; one stoichiometric, one fuel lean, and one fuel rich. All mixtures were detonable throughout the detonation tube. Various mixtures representing the same average test section equivalence ratio were shown to have specific impulses within 1% of each other, indicating that good fuel/air mixing is not a prerequisite for optimal detonation tube performance under conditions investigated.

  6. Reverse slapper detonator

    DOEpatents

    Weingart, Richard C.

    1990-01-01

    A reverse slapper detonator (70), and methodology related thereto, are provided. The detonator (70) is adapted to be driven by a pulse of electric power from an external source (80). A conductor (20) is disposed along the top (14), side (18), and bottom (16) surfaces of a sheetlike insulator (12). Part of the conductor (20) comprises a bridge (28), and an aperture (30) is positioned within the conductor (20), with the bridge (28) and the aperture (30) located on opposite sides of the insulator (12). A barrel (40) and related explosive charge (50) are positioned adjacent to and in alignment with the aperture (30), and the bridge (28) is buttressed with a backing layer (60). When the electric power pulse vaporizes the bridge (28), a portion of the insulator (12) is propelled through the aperture (30) and barrel (40), and against the explosive charge (50), thereby detonating it.

  7. Novel uses of detonator diagnostics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gibson, John R.; Wilde, Zakary Robert; Tasker, Douglas George

    A novel combination of diagnostics is being used to research the physics of detonator initiation. The explosive PETN (Pentaerythritol tetranitrate) commonly used in detonators, is also a piezo-electric material that, when sufficiently shocked, emits an electromagnetic field in the radio frequency (RF) range, along crystal fracture planes. In an effort to capture this RF signal, a new diagnostic was created. A copper foil, used as an RF antenna, was wrapped around a foam fixture encompassing a PETN pellet. Rogowski coils were used to obtain the change in current with respect to time (di/dt) the detonator circuit, in and polyvinylidene difluoridemore » (PVDF) stress sensors were used to capture shockwave arrival time. The goal of these experiments is to use these diagnostics to study the reaction response of a PETN pellet of known particle size to shock loading with various diagnostics including an antenna to capture RF emissions. Our hypothesis is that RF feedback may signify the rate of deflagration to detonation transition (DDT) or lack thereof. The new diagnostics and methods will be used to determine the timing of start of current, bridge burst, detonator breakout timing and RF generated from detonation. These data will be compared to those of currently used diagnostics in order to validate the accuracy of these new methods. Future experiments will incorporate other methods of validation including dynamic radiography, optical initiation and use of magnetic field sensors.« less

  8. Measuring In-Situ Mdf Velocity Of Detonation

    DOEpatents

    Horine, Frank M.; James, Jr., Forrest B.

    2005-10-25

    A system for determining the velocity of detonation of a mild detonation fuse mounted on the surface of a device includes placing the device in a predetermined position with respect to an apparatus that carries a couple of sensors that sense the passage of a detonation wave at first and second spaced locations along the fuse. The sensors operate a timer and the time and distance between the locations is used to determine the velocity of detonation. The sensors are preferably electrical contacts that are held spaced from but close to the fuse such that expansion of the fuse caused by detonation causes the fuse to touch the contact, causing an electrical signal to actuate the timer.

  9. Effects of Fuel Distribution on Detonation Tube Performance

    NASA Technical Reports Server (NTRS)

    Perkins, Hugh Douglas

    2002-01-01

    A pulse detonation engine (PDE) uses a series of high frequency intermittent detonation tubes to generate thrust. The process of filling the detonation tube with fuel and air for each cycle may yield non-uniform mixtures. Lack of mixture uniformity is commonly ignored when calculating detonation tube thrust performance. In this study, detonation cycles featuring idealized non-uniform H2/air mixtures were analyzed using the SPARK two-dimensional Navier-Stokes CFD code with 7-step H2/air reaction mechanism. Mixture non-uniformities examined included axial equivalence ratio gradients, transverse equivalence ratio gradients, and partially fueled tubes. Three different average test section equivalence ratios (phi), stoichiometric (phi = 1.00), fuel lean (phi = 0.90), and fuel rich (phi = 1.10), were studied. All mixtures were detonable throughout the detonation tube. It was found that various mixtures representing the same test section equivalence ratio had specific impulses within 1 percent of each other, indicating that good fuel/air mixing is not a prerequisite for optimal detonation tube performance.

  10. Initiation of Gaseous Detonation by Conical Projectiles

    NASA Astrophysics Data System (ADS)

    Verreault, Jimmy

    Initiation and stabilization of detonation by hypersonic conical projectiles launched into combustible gas mixtures is investigated. This phenomenon must be understood for the design and optimization of specific hypersonic propulsion devices, such as the oblique detonation wave engine and the ram accelerator. The criteria for detonation initiation by a projectile is also related to fundamental aspects of detonation research, such as the requirement for direct initiation of a detonation by a blast wave. Experimental results of this problem also offer useful references for validation of numerical and theoretical modeling. Projectiles with cone half angles varying from 15° to 60° were launched into stoichiometric mixtures of hydrogen/oxygen with 70% argon dilution at initial pressures between 10 and 200 kPa. The projectiles were launched from a combustion-driven gas gun at velocities up to 2.2 km/s (corresponding to 133% of the Chapman Jouguet velocity). Pictures of the flowfields generated by the projectiles were taken via Schlieren photography. Five combustion regimes were observed about the projectile ranging from prompt and delayed oblique detonation wave formation, combustion instabilities, a wave splitting, and an inert shock wave. Two types of transition from the prompt oblique detonation wave regime to the inert shock regime were observed. The first (the delayed oblique detonation wave regime) showed an inert shock attached to the tip of the projectile followed by a sharp kink at the onset of an oblique detonation wave; this regime occurred by decreasing the cone angle at high mixture pressures. The second (the combustion instabilities regime) exhibited large density gradients due to combustion ignition and quenching phenomena; this regime occurred by decreasing the mixture pressure at large cone angles. A number of theoretical models were considered to predict critical conditions for the initiation of oblique detonations. The Lee-Vasiljev model agreed

  11. Theory and Modeling of Liquid Explosive Detonation

    NASA Astrophysics Data System (ADS)

    Tarver, Craig M.; Urtiew, Paul A.

    2010-10-01

    The current understanding of the detonation reaction zones of liquid explosives is discussed in this article. The physical and chemical processes that precede and follow exothermic chemical reaction within the detonation reaction zone are discussed within the framework of the nonequilibrium Zeldovich-von Neumann-Doring (NEZND) theory of self-sustaining detonation. Nonequilibrium chemical and physical processes cause finite time duration induction zones before exothermic chemical energy release occurs. This separation between the leading shock wave front and the chemical energy release needed to sustain it results in shock wave amplification and the subsequent formation of complex three-dimensional cellular structures in all liquid detonation waves. To develop a practical Zeldovich-von Neumann-Doring (ZND) reactive flow model for liquid detonation, experimental data on reaction zone structure, confined failure diameter, unconfined failure diameter, and failure wave velocity in the Dremin-Trofimov test for detonating nitromethane are calculated using the ignition and growth reactive flow model.

  12. Competency Development Detonator Development and Design

    DTIC Science & Technology

    2007-09-01

    required. Exploding foil initiators ( EFI or Slapper) - The benefits of using an EFI is that the metal bridge is separated from the explosive, the explosive...to the materials ignition temperature to begin a burning reaction that propagates to the next material in the initiator . Exploding bridgewire (EBW...principles "* Initiation capabilities of the MEMS scale detonator DETONATOR BACKGROUND In a typical detonator, an explosive train is used. The explosive train

  13. Optically triggered fire set/detonator system

    DOEpatents

    Chase, Jay B.; Pincosy, Philip A.; Chato, Donna M.; Kirbie, Hugh; James, Glen F.

    2007-03-20

    The present invention is directed to a system having a plurality of capacitor discharge units (CDUs) that includes electrical bridge type detonators operatively coupled to respective explosives. A pulse charging circuit is adapted to provide a voltage for each respective capacitor in each CDU. Such capacitors are discharged through the electrical bridge type detonators upon receiving an optical signal to detonate respective operatively coupled explosives at substantially the same time.

  14. One Year Term Review as a Participating Guest in the Detonator and Detonation Physics Group

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lefrancois, A; Roeske, F; Tran, T

    2006-02-06

    The one year stay was possible after a long administrative process, because of the fact that this was the first participating guest of B division as a foreign national in HEAF (High Explosives Application Facility) with the Detonator/Detonation Physics Group.

  15. Propagation of detonations in hydrazine vapor

    NASA Technical Reports Server (NTRS)

    Heinrich, H. J.

    1985-01-01

    In the range of greater hydrazine vapor pressure, detonation speed depends exclusively on the extent of the ammonia decomposition in the second reaction stage. As vapor pressure decreases, the ammonia disintegration speed becomes increasingly slower and the reaction reached in the reaction zone increasingly decreases until finally, in the vapor pressure range between 53 and 16 Torr, the contribution of the second stage to detonation propagation disappears, and only the first stage remains active. Since the disintegration speed of the hydrazine in this pressure range has decreased markedly as well, no level, but rather only spinning, detonations occur. Temporary separations of the impact front and the reaction zone in the process lead to fluctuations of the detonation speed.

  16. Underwater sympathetic detonation of pellet explosive

    NASA Astrophysics Data System (ADS)

    Kubota, Shiro; Saburi, Tei; Nagayama, Kunihito

    2017-06-01

    The underwater sympathetic detonation of pellet explosives was taken by high-speed photography. The diameter and the thickness of the pellet were 20 and 10 mm, respectively. The experimental system consists of the precise electric detonator, two grams of composition C4 booster and three pellets, and these were set in water tank. High-speed video camera, HPV-X made by Shimadzu was used with 10 Mfs. The underwater explosions of the precise electric detonator, the C4 booster and a pellet were also taken by high-speed photography to estimate the propagation processes of the underwater shock waves. Numerical simulation of the underwater sympathetic detonation of the pellet explosives was also carried out and compared with experiment.

  17. Detonation Jet Engine. Part 1--Thermodynamic Cycle

    ERIC Educational Resources Information Center

    Bulat, Pavel V.; Volkov, Konstantin N.

    2016-01-01

    We present the most relevant works on jet engine design that utilize thermodynamic cycle of detonative combustion. The efficiency advantages of thermodynamic detonative combustion cycle over Humphrey combustion cycle at constant volume and Brayton combustion cycle at constant pressure were demonstrated. An ideal Ficket-Jacobs detonation cycle, and…

  18. Precursor detonation wave development in ANFO due to aluminum confinement

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jackson, Scott I; Klyanda, Charles B; Short, Mark

    2010-01-01

    Detonations in explosive mixtures of ammonium-nitrate-fuel-oil (ANFO) confined by aluminum allow for transport of detonation energy ahead of the detonation front due to the aluminum sound speed exceeding the detonation velocity. The net effect of this energy transport on the detonation is unclear. It could enhance the detonation by precompressing the explosive near the wall. Alternatively, it could decrease the explosive performance by crushing porosity required for initiation by shock compression or destroying confinement ahead of the detonation. At present, these phenomena are not well understood. But with slowly detonating, non-ideal high explosive (NIHE) systems becoming increasing prevalent, proper understandingmore » and prediction of the performance of these metal-confined NIHE systems is desirable. Experiments are discussed that measured the effect of this ANFO detonation energy transported upstream of the front by a 76-mm-inner-diameter aluminum confining tube. Detonation velocity, detonation-front shape, and aluminum response are recorded as a function of confiner wall thickness and length. Detonation shape profiles display little curvature near the confining surface, which is attributed to energy transported upstream modifying the flow. Average detonation velocities were seen to increase with increasing confiner thickness, while wavefront curvature decreased due to the stiffer, subsonic confinement. Significant radial sidewall tube motion was observed immediately ahead of the detonation. Axial motion was also detected, which interfered with the front shape measurements in some cases. It was concluded that the confiner was able to transport energy ahead of the detonation and that this transport has a definite effect on the detonation by modifying its characteristic shape.« less

  19. Sub-Chandrasekhar-mass White Dwarf Detonations Revisited

    NASA Astrophysics Data System (ADS)

    Shen, Ken J.; Kasen, Daniel; Miles, Broxton J.; Townsley, Dean M.

    2018-02-01

    The detonation of a sub-Chandrasekhar-mass white dwarf (WD) has emerged as one of the most promising Type Ia supernova (SN Ia) progenitor scenarios. Recent studies have suggested that the rapid transfer of a very small amount of helium from one WD to another is sufficient to ignite a helium shell detonation that subsequently triggers a carbon core detonation, yielding a “dynamically driven double-degenerate double-detonation” SN Ia. Because the helium shell that surrounds the core explosion is so minimal, this scenario approaches the limiting case of a bare C/O WD detonation. Motivated by discrepancies in previous literature and by a recent need for detailed nucleosynthetic data, we revisit simulations of naked C/O WD detonations in this paper. We disagree to some extent with the nucleosynthetic results of previous work on sub-Chandrasekhar-mass bare C/O WD detonations; for example, we find that a median-brightness SN Ia is produced by the detonation of a 1.0 {M}ȯ WD instead of a more massive and rarer 1.1 {M}ȯ WD. The neutron-rich nucleosynthesis in our simulations agrees broadly with some observational constraints, although tensions remain with others. There are also discrepancies related to the velocities of the outer ejecta and light curve shapes, but overall our synthetic light curves and spectra are roughly consistent with observations. We are hopeful that future multidimensional simulations will resolve these issues and further bolster the dynamically driven double-degenerate double-detonation scenario’s potential to explain most SNe Ia.

  20. Detonator Performance Characterization Using Multi-Frame Laser Schlieren Imaging

    NASA Astrophysics Data System (ADS)

    Clarke, S. A.; Landon, C. D.; Murphy, M. J.; Martinez, M. E.; Mason, T. A.; Thomas, K. A.

    2009-12-01

    Several experiments that are part of a phased plan to understand the evolution of detonation in a detonator from initiation shock through run to detonation to full detonation to transition to booster and booster detonation will be presented. High speed laser schlieren movies have been used to study several explosive initiation events, such as exploding bridgewires (EBW), exploding foil initiators (EFI) (or slappers), direct optical initiation (DOI), and electrostatic discharge (ESD). Additionally, a series of tests have been performed on "cut-back" detonators with varying initial pressing (IP) heights. We have also used this diagnostic to visualize a range of EBW, EFI, and DOI full-up detonators. Future applications to other explosive events such as boosters and IHE booster evaluation will be discussed. The EPIC hydrodynamic code has been used to analyze the shock fronts from the schlieren images to reverse calculate likely boundary or initial conditions to determine the temporal-spatial pressure profile across the output face of the detonator. LA-UR-05099

  1. Observations on the normal reflection of gaseous detonations

    NASA Astrophysics Data System (ADS)

    Damazo, J.; Shepherd, J. E.

    2017-09-01

    Experimental results are presented examining the behavior of the shock wave created when a gaseous detonation wave normally impinges upon a planar wall. Gaseous detonations are created in a 7.67-m-long, 280-mm-internal-diameter detonation tube instrumented with a test section of rectangular cross section enabling visualization of the region at the tube-end farthest from the point of detonation initiation. Dynamic pressure measurements and high-speed schlieren photography in the region of detonation reflection are used to examine the characteristics of the inbound detonation wave and outbound reflected shock wave. Data from a range of detonable fuel/oxidizer/diluent/initial pressure combinations are presented to examine the effect of cell-size and detonation regularity on detonation reflection. The reflected shock does not bifurcate in any case examined and instead remains nominally planar when interacting with the boundary layer that is created behind the incident wave. The trajectory of the reflected shock wave is examined in detail, and the wave speed is found to rapidly change close to the end-wall, an effect we attribute to the interaction of the reflected shock with the reaction zone behind the incident detonation wave. Far from the end-wall, the reflected shock wave speed is in reasonable agreement with the ideal model of reflection which neglects the presence of a finite-length reaction zone. The net far-field effect of the reaction zone is to displace the reflected shock trajectory from the predictions of the ideal model, explaining the apparent disagreement of the ideal reflection model with experimental reflected shock observations of previous studies.

  2. The delayed-detonation model of Type Ia supernovae. 2: The detonation phase

    NASA Technical Reports Server (NTRS)

    Arnett, David; Livne, Eli

    1994-01-01

    The investigation, by use of two-dimensional numerical hydrodynamics simulations, of the 'delayed detonation' mechanism of Khokhlov for the explosion of Type Ia supernovae is continued. Previously we found that the deflagration is insufficient to unbind the star. Expansion shuts off the flame; much of this small production of iron group nuclei occurs at lower densities, which reduces the electron-capture problem. Because the degenerate star has an adiabatic exponent only slightly above 4/3, the energy released by deflagration drives a pulsation of large amplitude. During the first expansion phase, adiabatic cooling shuts off the burning, and a Rayleigh-Taylor instability then gives mixing of high-entropy ashes with low-entropy fuel. During the first contraction phase, compressional heating reignites the material. The burning was allowed to develop into a detonation in these nonspherical models. The detonation grows toward spherical symmetry at late times. At these densities (rho approx. 10(exp 7) to 10(exp 8) g cm(exp -3)), either Ni-56 or nuclei of the Si-Ca group are the dominant products of the burning. The bulk yields are sensitive to the density of the star when the transition to detonation occurs. The relevance of the abundances, velocities, mixing, and total energy release to the theory and interpretation of Type Ia supernovae is discussed.

  3. Detonation engine fed by acetylene-oxygen mixture

    NASA Astrophysics Data System (ADS)

    Smirnov, N. N.; Betelin, V. B.; Nikitin, V. F.; Phylippov, Yu. G.; Koo, Jaye

    2014-11-01

    The advantages of a constant volume combustion cycle as compared to constant pressure combustion in terms of thermodynamic efficiency has focused the search for advanced propulsion on detonation engines. Detonation of acetylene mixed with oxygen in various proportions is studied using mathematical modeling. Simplified kinetics of acetylene burning includes 11 reactions with 9 components. Deflagration to detonation transition (DDT) is obtained in a cylindrical tube with a section of obstacles modeling a Shchelkin spiral; the DDT takes place in this section for a wide range of initial mixture compositions. A modified ka-omega turbulence model is used to simulate flame acceleration in the Shchelkin spiral section of the system. The results of numerical simulations were compared with experiments, which had been performed in the same size detonation chamber and turbulent spiral ring section, and with theoretical data on the Chapman-Jouguet detonation parameters.

  4. A Computational Examination of Detonation Physics and Blast Chemistry

    DTIC Science & Technology

    2011-08-01

    State 5 3 Detonation and Shock Hugoniots for TNT using the JWL Equation of State 6 4 Detonation and Shock Hugoniots for HMX using the JWL ...Equation of State 6 5 Detonation and Shock Hugoniots for Composition C-4 using the JWL Equation of State 7 6 Detonation and Shock...Hugoniots for PBX-9502 using the JWL Equation of State 7 7 Detonation and Shock Hugoniots for PETN using the JWL Equation of State 8 8

  5. A Computational Examination of Detonation Physics and Blast Chemistry

    DTIC Science & Technology

    2011-08-01

    Equation of State 5 3 Detonation and Shock Hugoniots for TNT using the JWL Equation of State 6 4 Detonation and Shock Hugoniots for HMX using the... JWL Equation of State 6 5 Detonation and Shock Hugoniots for Composition C-4 using the JWL Equation of State 7 6 Detonation and...Shock Hugoniots for PBX-9502 using the JWL Equation of State 7 7 Detonation and Shock Hugoniots for PETN using the JWL Equation of State 8

  6. Detonation wave augmentation of gas turbines

    NASA Technical Reports Server (NTRS)

    Wortman, A.

    1984-01-01

    The results of a feasibility study that examined the effects of using detonation waves to augment the performance of gas turbines are reported. The central ideas were to reduce compressor requirements and to maintain high performance in jet engines. Gasdynamic equations were used to model the flows associated with shock waves generated by the detonation of fuel in detonator tubes. Shock wave attenuation to the level of Mach waves was found possible, thus eliminating interference with the compressor and the necessity of valves and seals. A preliminary parametric study of the performance of a compressor working at a 4:1 ratio in a conceptual design of a detonation wave augmented jet engine in subsonic flight indicated a clear superiority over conventional designs in terms of fuel efficiency and thrust.

  7. Effect of fuel stratification on detonation wave propagation

    NASA Astrophysics Data System (ADS)

    Masselot, Damien; Fievet, Romain; Raman, Venkat

    2016-11-01

    Rotating detonation engines (RDEs) form a class of pressure-gain combustion systems of higher efficiency compared to conventional gas turbine engines. One of the key features of the design is the injection system, as reactants need to be continuously provided to the detonation wave to sustain its propagation speed. As inhomogeneities in the reactant mixture can perturb the detonation wave front, premixed fuel jet injectors might seem like the most stable solution. However, this introduces the risk of the detonation wave propagating through the injector, causing catastrophic failure. On the other hand, non-premixed fuel injection will tend to quench the detonation wave near the injectors, reducing the likelihood of such failure. Still, the effects of such non-premixing and flow inhomogeneities ahead of a detonation wave have yet to be fully understood and are the object of this study. A 3D channel filled with O2 diluted in an inert gas with circular H2 injectors is simulated as a detonation wave propagates through the system. The impact of key parameters such as injector spacing, injector size, mixture composition and time variations will be discussed. PhD Candidate.

  8. Operational Characteristics of a Rotating Detonation Engine Using Hydrogen and Air

    DTIC Science & Technology

    2011-06-01

    Naval Research Laboratory PDE Pulsed detonation engine RDE Rotating detonation engine TDW Transverse detonation wave Symbols [SI units...primarily been on pulsed detonation engines ( PDEs ). Recently, however, detonation research has begun to also focus on rotating , or continuous... rotating detonation engines have been studied, however, more progress was initially made regarding PDEs . Recently, though, there has been a renewed

  9. 30 CFR 57.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Electric Blasting-Surface and Underground § 57.6402 Deenergized circuits near detonators. Electrical distribution circuits within 50 feet of electric detonators at the blast site shall be deenergized. Such circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current tests...

  10. 30 CFR 56.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Electric Blasting § 56.6402 Deenergized circuits near detonators. Electrical distribution circuits within 50 feet of electric detonators at the blast site shall be deenergized. Such circuits need not be... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Deenergized circuits near detonators. 56.6402...

  11. High speed spectral measurements of IED detonation fireballs

    NASA Astrophysics Data System (ADS)

    Gordon, J. Motos; Spidell, Matthew T.; Pitz, Jeremey; Gross, Kevin C.; Perram, Glen P.

    2010-04-01

    Several homemade explosives (HMEs) were manufactured and detonated at a desert test facility. Visible and infrared signatures were collected using two Fourier transformspectrometers, two thermal imaging cameras, a radiometer, and a commercial digital video camera. Spectral emissions from the post-detonation combustion fireball were dominated by continuum radiation. The events were short-lived, decaying in total intensity by an order of magnitude within approximately 300ms after detonation. The HME detonation produced a dust cloud in the immediate area that surrounded and attenuated the emitted radiation from the fireball. Visible imagery revealed a dark particulate (soot) cloud within the larger surrounding dust cloud. The ejected dust clouds attenuated much of the radiation from the post-detonation combustion fireballs, thereby reducing the signal-to-noise ratio. The poor SNR at later times made it difficult to detect selective radiation from by-product gases on the time scale (~500ms) in which they have been observed in other HME detonations.

  12. Laser detonator development for test-firing applications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Munger, A. C.; Thomas, K. A.; Kennedy, J. E.

    2004-01-01

    Los Alamos National Laboratory has historically fielded two types of electro-explosive detonators. The exploding-bridgewire detonator (EBW) has an exploding wire as the initiating element, a low-density transfer charge and a high-density output pellet. The slapper detonator, or exploding-foil initiator (EFI), utilizes an exploding foil to drive a flying plate element into a high-density output pellet. The last twenty years has seen various research and development activities from many laboratories and manufacturing facilities around the world to develop laser-driven analogs of these devices, but to our knowledge none of those is in general use. Los Alamos is currently committed to designmore » and manufacture a laser analog to the long-standing, generic, general-purpose SE-1 EBW detonator, which is intended to provide increased safety in large-scale test-firing operations. This paper will discuss the major design parameters of this laser detonator and present some preliminary testing results.« less

  13. Detonation properties of 1,1-diamino-2,2-dinitroethene (DADNE).

    PubMed

    Trzciński, Waldemar A; Cudziło, Stanisław; Chyłek, Zbigniew; Szymańczyk, Leszek

    2008-09-15

    1,1-Diamino-2,2-dinitroethene (DADNE, FOX-7) is an explosive of current interest. In our work, an advanced study of detonation characteristics of this explosive was performed. DADNE was prepared and recrystallized on a laboratory scale. Some sensitivity and detonation properties of DADNE were determined. The detonation performance was established by measurements of the detonation wave velocity, detonation pressure and calorimetric heat of explosion as well as the accelerating ability. The JWL (Jones-Wilkins-Lee) isentrope and the constant-gamma isentrope for the detonation products of DADNE were also found.

  14. 30 CFR 56.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compatibility of electric detonators. 56.6400... Electric Blasting § 56.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical firing characteristics. ...

  15. 30 CFR 57.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Compatibility of electric detonators. 57.6400... Electric Blasting-Surface and Underground § 57.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical...

  16. 30 CFR 56.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compatibility of electric detonators. 56.6400... Electric Blasting § 56.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical firing characteristics. ...

  17. 30 CFR 56.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compatibility of electric detonators. 56.6400... Electric Blasting § 56.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical firing characteristics. ...

  18. 30 CFR 56.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Compatibility of electric detonators. 56.6400... Electric Blasting § 56.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical firing characteristics. ...

  19. 30 CFR 57.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compatibility of electric detonators. 57.6400... Electric Blasting-Surface and Underground § 57.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical...

  20. 30 CFR 57.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compatibility of electric detonators. 57.6400... Electric Blasting-Surface and Underground § 57.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical...

  1. 30 CFR 56.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compatibility of electric detonators. 56.6400... Electric Blasting § 56.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical firing characteristics. ...

  2. 30 CFR 57.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compatibility of electric detonators. 57.6400... Electric Blasting-Surface and Underground § 57.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical...

  3. 30 CFR 57.6400 - Compatibility of electric detonators.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compatibility of electric detonators. 57.6400... Electric Blasting-Surface and Underground § 57.6400 Compatibility of electric detonators. All electric detonators to be fired in a round shall be from the same manufacturer and shall have similar electrical...

  4. Laser diode initiated detonators for space applications

    NASA Technical Reports Server (NTRS)

    Ewick, David W.; Graham, J. A.; Hawley, J. D.

    1993-01-01

    Ensign Bickford Aerospace Company (EBAC) has over ten years of experience in the design and development of laser ordnance systems. Recent efforts have focused on the development of laser diode ordnance systems for space applications. Because the laser initiated detonators contain only insensitive secondary explosives, a high degree of system safety is achieved. Typical performance characteristics of a laser diode initiated detonator are described in this paper, including all-fire level, function time, and output. A finite difference model used at EBAC to predict detonator performance, is described and calculated results are compared to experimental data. Finally, the use of statistically designed experiments to evaluate performance of laser initiated detonators is discussed.

  5. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Transporting explosives and detonators. 75.1311... Transporting explosives and detonators. (a) When explosives and detonators are to be transported underground... transported by any cars or vehicles— (1) The cars or vehicles shall be marked with warnings to identify the...

  6. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Transporting explosives and detonators. 75.1311... Transporting explosives and detonators. (a) When explosives and detonators are to be transported underground... transported by any cars or vehicles— (1) The cars or vehicles shall be marked with warnings to identify the...

  7. Transmission of a detonation across a density interface

    NASA Astrophysics Data System (ADS)

    Tang Yuk, K. C.; Mi, X. C.; Lee, J. H. S.; Ng, H. D.

    2018-05-01

    The present study investigates the transmission of a detonation wave across a density interface. The problem is first studied theoretically considering an incident Chapman-Jouguet (CJ) detonation wave, neglecting its detailed reaction-zone structure. It is found that, if there is a density decrease at the interface, a transmitted strong detonation wave and a reflected expansion wave would be formed; if there is a density increase, one would obtain a transmitted CJ detonation wave followed by an expansion wave and a reflected shock wave. Numerical simulations are then performed considering that the incident detonation has the Zel'dovich-von Neumann-Döring reaction-zone structure. The transient process that occurs subsequently to the detonation-interface interaction has been captured by the simulations. The effects of the magnitude of density change across the interface and different reaction kinetics (i.e., single-step Arrhenius kinetics vs. two-step induction-reaction kinetics) on the dynamics of the transmission process are explored. After the transient relaxation process, the transmitted wave reaches the final state in the new medium. For the cases with two-step induction-reaction kinetics, the transmitted wave fails to evolve to a steady detonation wave if the magnitude of density increase is greater than a critical value. For the cases wherein the transmitted wave can evolve to a steady detonation, the numerical results for both reaction models give final propagation states that agree with the theoretical solutions.

  8. Transient Heat Transfer Properties in a Pulse Detonation Combustor

    DTIC Science & Technology

    2011-03-01

    strategies for future systems. 15. NUMBER OF PAGES 89 14. SUBJECT TERMS Pulse Detonation Engines, PDE , Heat Transfer 16. PRICE CODE 17. SECURITY...GUI Graphical User Interface NPS Naval Postgraduate School PDC Pulse Detonation Combustion PDE Pulse Detonation Engine RPL Rocket...a tactical missile with a Pulse Detonation Engine ( PDE ) and provide greater range for the same amount of fuel as compared to other current

  9. On the deflagration-to-detonation transition (DDT) process with added energetic solid particles for pulse detonation engines (PDE)

    NASA Astrophysics Data System (ADS)

    Nguyen, V. B.; Li, J.; Chang, P.-H.; Phan, Q. T.; Teo, C. J.; Khoo, B. C.

    2018-01-01

    In this paper, numerical simulations are performed to study the dynamics of the deflagration-to-detonation transition (DDT) in pulse detonation engines (PDE) using energetic aluminum particles. The DDT process and detonation wave propagation toward the unburnt hydrogen/air mixture containing solid aluminum particles is numerically studied using the Eulerian-Lagrangian approach. A hybrid numerical methodology combined with appropriate sub-models is used to capture the gas dynamic characteristics, particle behavior, combustion characteristics, and two-way solid-particle-gas flow interactions. In our approach, the gas mixture is expressed in the Eulerian frame of reference, while the solid aluminum particles are tracked in the Lagrangian frame of reference. The implemented computer code is validated using published benchmark problems. The obtained results show that the aluminum particles not only shorten the DDT length but also reduce the DDT time. The improvement of DDT is primarily attributed to the heat released from surface chemical reactions on the aluminum particles. The temperatures associated with the DDT process are greater than the case of non-reacting particles added, with an accompanying rise in the pressure. For an appropriate range of particle volume fraction, particularly in this study, the higher volume fraction of the micro-aluminum particles added in the detonation chamber can lead to more heat energy released and more local instabilities in the combustion process (caused by the local high temperature), thereby resulting in a faster DDT process. In essence, the aluminum particles contribute to the DDT process of successfully transitioning to detonation waves for (failure) cases in which the fuel gas mixture can be either too lean or too rich. With a better understanding of the influence of added aluminum particles on the dynamics of the DDT and detonation process, we can apply it to modify the geometry of the detonation chamber (e.g., the length of

  10. Effect of Detonation through a Turbine Stage

    NASA Technical Reports Server (NTRS)

    Ellis, Matthew T.

    2004-01-01

    Pulse detonation engines (PDE) have been investigated as a more efficient means of propulsion due to its constant volume combustion rather than the more often used constant pressure combustion of other propulsion systems. It has been proposed that a hybrid PDE-gas turbine engine would be a feasible means of improving the efficiency of the typical constant pressure combustion gas turbine cycle. In this proposed system, multiple pulse detonation tubes would replace the conventional combustor. Also, some of the compressor stages may be removed due to the pressure rise gained across the detonation wave. The benefits of higher thermal efficiency and reduced compressor size may come at a cost. The first question that arises is the unsteadiness in the flow created by the pulse detonation tubes. A constant pressure combustor has the advantage of supplying a steady and large mass flow rate. The use of the pulse detonation tubes will create an unsteady mass flow which will have currently unknown effects on the turbine located downstream of the combustor. Using multiple pulse detonation tubes will hopefully improve the unsteadiness. The interaction between the turbine and the shock waves exiting the tubes will also have an unknown effect. Noise levels are also a concern with this hybrid system. These unknown effects are being investigated using TURBO, an unsteady turbomachinery flow simulation code developed at Mississippi State University. A baseline case corresponding to a system using a constant pressure combustor with the same mass flow rate achieved with the pulse detonation hybrid system will be investigated first.

  11. Insensitive detonator apparatus for initiating large failure diameter explosives

    DOEpatents

    Perry, III, William Leroy

    2015-07-28

    A munition according to a preferred embodiment can include a detonator system having a detonator that is selectively coupled to a microwave source that functions to selectively prime, activate, initiate, and/or sensitize an insensitive explosive material for detonation. The preferred detonator can include an explosive cavity having a barrier within which an insensitive explosive material is disposed and a waveguide coupled to the explosive cavity. The preferred system can further include a microwave source coupled to the waveguide such that microwaves enter the explosive cavity and impinge on the insensitive explosive material to sensitize the explosive material for detonation. In use the preferred embodiments permit the deployment and use of munitions that are maintained in an insensitive state until the actual time of use, thereby substantially preventing unauthorized or unintended detonation thereof.

  12. 14 CFR 33.47 - Detonation test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Detonation test. 33.47 Section 33.47 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.47 Detonation test. Each engine...

  13. 14 CFR 33.47 - Detonation test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Detonation test. 33.47 Section 33.47 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.47 Detonation test. Each engine...

  14. 14 CFR 33.47 - Detonation test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Detonation test. 33.47 Section 33.47 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.47 Detonation test. Each engine...

  15. 14 CFR 33.47 - Detonation test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Detonation test. 33.47 Section 33.47 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.47 Detonation test. Each engine...

  16. Environmentally Benign Stab Detonators

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gash, A

    2005-12-21

    Many energetic systems can be activated via mechanical means. Percussion primers in small caliber ammunition and stab detonators used in medium caliber ammunition are just two examples. Current medium caliber (20-60mm) munitions are detonated through the use of impact sensitive stab detonators. Stab detonators are very sensitive and must be small, as to meet weight and size limitations. A mix of energetic powders, sensitive to mechanical stimulus, is typically used to ignite such devices. Stab detonators are mechanically activated by forcing a firing pin through the closure disc of the device and into the stab initiating mix. Rapid heating causedmore » by mechanically driven compression and friction of the mixture results in its ignition. The rapid decomposition of these materials generates a pressure/temperature pulse that is sufficient to initiate a transfer charge, which has enough output energy to detonate the main charge. This general type of ignition mix is used in a large variety of primers, igniters, and detonators.[1] Common primer mixes, such as NOL-130, are made up of lead styphnate (basic) 40%, lead azide (dextrinated) 20%, barium nitrate 20%, antimony sulfide 15%, and tetrazene 5%.[1] These materials pose acute and chronic toxicity hazards during mixing of the composition and later in the item life cycle after the item has been field functioned. There is an established need to replace these mixes on toxicity, health, and environmental hazard grounds. This effort attempts to demonstrate that environmentally acceptable energetic solgel coated flash metal multilayer nanocomposites can be used to replace current impact initiated devices (IIDs), which have hazardous and toxic components. Successful completion of this project will result in IIDs that include innocuous compounds, have sufficient output energy for initiation, meet current military specifications, are small, cost competitive, and perform as well as or better than current devices. We expect

  17. Formation Pathways of Carbon Allotropes in Detonation Condensates

    NASA Astrophysics Data System (ADS)

    Nielsen, Michael; Bagge-Hansen, Michael; Hammons, Josh; Lauderbach, Lisa; Hodgin, Ralph; Bastea, Sorin; Fried, Larry; Lee, Jonathan; van Buuren, Tony; Pagoria, Phil; May, Chadd; Aloni, Shaul; Willey, Trevor

    2017-06-01

    Time-resolved small-angle scattering (TR-SAXS) data reveal evolution in the size and morphology of nano-carbon particles that form during the first microsecond during the detonation of high explosive (HE) materials, but do not provide chemical or phase information. Herein, we present analysis of complementary post-detonation soots collected with minimal environmental carbon or other contamination: HE samples are detonated whithin clean ice capture layers to yield aqueous dispersions of the carbonaceous soot. We report substantial variation in soots formed through the detonation of HE materials that attain a variety of temperatures and pressures during detonation. Transmission electron microscopy analysis of these recovered soots provides physical and chemical information that we compare directly to TR-SAXS data and SAXS measurements from recovered soots. We observe various structures including graphitic and amorphous carbon, nanodiamond, and spherical carbon onions. These experimental data correlate to models of how products from HE materials traverse the carbon phase diagram during detonation. Prepared by LLNL under Contract DE-AC52-07NA27344.

  18. Deflagration-to-detonation characteristics of a laser exploding bridge detonator

    NASA Astrophysics Data System (ADS)

    Welle, E. J.; Fleming, K. J.; Marley, S. K.

    2006-08-01

    Evaluation of laser initiated explosive trains has been an area of extreme interest due to the safety benefits of these systems relative to traditional electro-explosive devices. A particularly important difference is these devices are inherently less electro-static discharge (ESD) sensitive relative to traditional explosive devices due to the isolation of electrical power and associated materials from the explosive interface. This paper will report work conducted at Sandia National Laboratories' Explosive Components Facility, which evaluated the initiation and deflagration-to-detonation characteristics of a Laser Driven Exploding Bridgewire detonator. This paper will report and discuss characteristics of Laser Exploding Bridgewire devices loaded with hexanitrohexaazaisowurtzitane (CL-20) and tetraammine-cis-bis-(5-nitro-2H-tetrazolato-N2) cobalt (III) perchlorate (BNCP).

  19. Accidental strangulation of a mentally retarded patient by a clothing collar: a case report.

    PubMed

    Hitosugi, Masahito; Yokoyama, Tomoko; Kido, Masahito; Kawato, Hitoshi; Matsushima, Kazumi; Nagai, Toshiaki; Tokudome, Shogo

    2006-07-01

    A 40-year-old mentally retarded woman died of accidental strangulation in a nursing home. She was found in a kneeling position with her hands on her knees and the collar of her clothing compressing the front and sides of the neck. Before the accident, a nurse had dressed the patient in one-piece overall-style pyjamas put on back to front so that she could not remove the garment herself. The post-mortem findings and reconstruction of the scene of death suggested that the patient had been strangled by the collar of her backward-facing clothing while in a kneeling position. Because patients with psychiatric illnesses may have a limited ability to recognize or communicate symptoms of physical danger, they must be closely monitored by knowledgeable medical and nursing staff. This case highlights the importance of preventing the accidental deaths of mentally retarded patients in nursing homes.

  20. Accidental ingestion of BiTine ring and a note on inefficient ring separation forceps.

    PubMed

    Baghele, Om Nemichand; Baghele, Mangala Om

    2011-01-01

    Accidental ingestion of medium-to-large instruments is relatively uncommon during dental treatment but can be potentially dangerous. A case of BiTine ring ingestion is presented with a note on inefficient ring separation forceps. A 28-year-old male patient accidentally ingested the BiTine ring (2 cm diameter, 0.5 cm outward projections) while it was being applied to a distoproximal cavity in tooth # 19. The ring placement forceps were excessively flexible; bending of the beaks towards the ring combined with a poor no-slippage mechanism led to sudden disengagement of the ring and accelerated movement towards the pharynx. We followed the patient with bulk forming agents and radiographs. Fortunately the ring passed out without any complications. Checking equipment and methods is as important as taking precautions against any preventable medical emergency. It is the responsibility of the clinician to check, verify and then use any instrument/equipment.

  1. New detonation concepts for propulsion and power generation

    NASA Astrophysics Data System (ADS)

    Braun, Eric M.

    A series of related analytical and experimental studies are focused on utilizing detonations for emerging propulsion and power generation devices. An understanding of the physical and thermodynamic processes for this unsteady thermodynamic cycle has taken over 100 years to develop. An overview of the thermodynamic processes and development history is provided. Thermodynamic cycle analysis of detonation-based systems has often been studied using surrogate models. A real gas model is used for a thermal efficiency prediction of a detonation wave based on the work and heat specified by process path diagrams and a control volume analysis. A combined first and second law analysis aids in understanding performance trends for different initial conditions. A cycle analysis model for an airbreathing, rotating detonation wave engine (RDE) is presented. The engine consists of a steady inlet system with an isolator which delivers air into an annular combustor. A detonation wave continuously rotates around the combustor with side relief as the flow expands towards the nozzle. Air and fuel enter the combustor when the rarefaction wave pressure behind the detonation front drops to the inlet supply pressure. To create a stable RDE, the inlet pressure is matched in a convergence process with the average combustor pressure by increasing the annulus channel width with respect to the isolator channel. Performance of this engine is considered using several parametric studies. RDEs require a fuel injection system that can cycle beyond the limits of mechanical valves. Fuel injectors composed of an orifice connected to a small plenum cavity were mounted on a detonation tube. These fuel injectors, termed fluidic valves, utilize their geometry and a supply pressure to deliver fuel and contain no moving parts. Their behavior is characterized in order to determine their feasibility for integration with high-frequency RDEs. Parametric studies have been conducted with the type of fuel injected

  2. Predicting propagation limits of laser-supported detonation by Hugoniot analysis

    NASA Astrophysics Data System (ADS)

    Shimamura, Kohei; Ofosu, Joseph A.; Komurasaki, Kimiya; Koizumi, Hiroyuki

    2015-01-01

    Termination conditions of a laser-supported detonation (LSD) wave were investigated using control volume analysis with a Shimada-Hugoniot curve and a Rayleigh line. Because the geometric configurations strongly affect the termination condition, a rectangular tube was used to create the quasi-one-dimensional configuration. The LSD wave propagation velocity and the pressure behind LSD were measured. Results reveal that the detonation states during detonation and at the propagation limit are overdriven detonation and Chapman-Jouguet detonation, respectively. The termination condition is the minimum velocity criterion for the possible detonation solution. Results were verified using pressure measurements of the stagnation pressure behind the LSD wave.

  3. High Resolution WENO Simulation of 3D Detonation Waves

    DTIC Science & Technology

    2012-02-27

    pocket behind the detonation front was not observed in their results because the rotating transverse detonation completely consumed the unburned gas. Dou...three-dimensional detonations We add source terms (functions of x, y, z and t) to the PDE system so that the following functions are exact solutions to... detonation rotates counter-clockwise, opposite to that in [48]. It can be seen that, the triple lines and transverse waves collide with the walls, and strong

  4. Pulse Detonation Engine Test Bed Developed

    NASA Technical Reports Server (NTRS)

    Breisacher, Kevin J.

    2002-01-01

    A detonation is a supersonic combustion wave. A Pulse Detonation Engine (PDE) repetitively creates a series of detonation waves to take advantage of rapid burning and high peak pressures to efficiently produce thrust. NASA Glenn Research Center's Combustion Branch has developed a PDE test bed that can reproduce the operating conditions that might be encountered in an actual engine. It allows the rapid and cost-efficient evaluation of the technical issues and technologies associated with these engines. The test bed is modular in design. It consists of various length sections of both 2- and 2.6- in. internal-diameter combustor tubes. These tubes can be bolted together to create a variety of combustor configurations. A series of bosses allow instrumentation to be inserted on the tubes. Dynamic pressure sensors and heat flux gauges have been used to characterize the performance of the test bed. The PDE test bed is designed to utilize an existing calorimeter (for heat load measurement) and windowed (for optical access) combustor sections. It uses hydrogen as the fuel, and oxygen and nitrogen are mixed to simulate air. An electronic controller is used to open the hydrogen and air valves (or a continuous flow of air is used) and to fire the spark at the appropriate times. Scheduled tests on the test bed include an evaluation of the pumping ability of the train of detonation waves for use in an ejector and an evaluation of the pollutants formed in a PDE combustor. Glenn's Combustion Branch uses the National Combustor Code (NCC) to perform numerical analyses of PDE's as well as to evaluate alternative detonative combustion devices. Pulse Detonation Engine testbed.

  5. Deflagration-to-detonation transition in gases in tubes with cavities

    NASA Astrophysics Data System (ADS)

    Smirnov, N. N.; Nikitin, V. F.; Phylippov, Yu. G.

    2010-12-01

    The existence of a supersonic second combustion mode — detonation — discovered by Mallard and Le Chatelier and by Berthélot and Vieille in 1881 posed the question of mechanisms for transition from one mode to the other. In the period 1959-1969, experiments by Salamandra, Soloukhin, Oppenheim, and their coworkers provided insights into this complex phenomenon. Since then, among all the phenomena related to combustion processes, deflagration-to-detonation transition is, undoubtedly, the most intriguing one. Deflagration-to-detonation transition (DDT) in gases is connected with gas and vapor explosion safety issues. Knowing mechanisms of detonation onset control is of major importance for creating effective mitigation measures addressing two major goals: to prevent DDT in the case of mixture ignition, or to arrest the detonation wave in the case where it has been initiated. A new impetus to the increase in interest in deflagration-to-detonation transition processes was given by the recent development of pulse detonation devices. The probable application of these principles to creation of a new generation of engines put the problem of effectiveness of pulse detonating devices at the top of current research needs. The effectiveness of the pulse detonation cycle turned out to be the key factor characterizing the Pulse Detonation Engine (PDE), whose operation modes were shown to be closely related to periodical onset and degeneration of a detonation wave. Those unsteady-state regimes should be self-sustained to guarantee a reliable operation of devices using the detonation mode of burning fuels as a constitutive part of their working cycle. Thus deflagration-to-detonation transition processes are of major importance for the issue. Minimizing the predetonation length and ensuring stability of the onset of detonation enable one to increase the effectiveness of a PDE. The DDT turned out to be the key factor characterizing the PDE operating cycle. Thus, the problem of

  6. MC3196 Detonator Shipping Package Hazard Classification Assessment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jones; Robert B.

    1979-05-31

    An investigation was made to determine whether the MC3196 detonator should be assigned a DOT hazard classification of Detonating Fuze, Class C Explosives per 49 CFR 173.113. This study covers the Propagation Test and the External Heat Test as approved by DOE Albuquerque Operations Office. Test data led to the recommeded hazard classification of detonating fuze, Class C explosives.

  7. Effects of high sound speed confiners on ANFO detonations

    NASA Astrophysics Data System (ADS)

    Kiyanda, Charles; Jackson, Scott; Short, Mark

    2011-06-01

    The interaction between high explosive (HE) detonations and high sound speed confiners, where the confiner sound speed exceeds the HE's detonation speed, has not been thoroughly studied. The subsonic nature of the flow in the confiner allows stress waves to travel ahead of the main detonation front and influence the upstream HE state. The interaction between the detonation wave and the confiner is also no longer a local interaction, so that the confiner thickness now plays a significant role in the detonation dynamics. We report here on larger scale experiments in which a mixture of ammonium nitrate and fuel oil (ANFO) is detonated in aluminium confiners with varying charge diameter and confiner thickness. The results of these large-scale experiments are compared with previous large-scale ANFO experiments in cardboard, as well as smaller-scale aluminium confined ANFO experiments, to characterize the effects of confiner thickness.

  8. Near-limit propagation of gaseous detonations in narrow annular channels

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Ng, H. D.; Lee, J. H. S.

    2017-03-01

    New results on the near-limit behaviors of gaseous detonations in narrow annular channels are reported in this paper. Annular channels of widths 3.2 and 5.9 mm were made using circular inserts in a 50.8 mm-diameter external tube. The length of each annular channel was 1.8 m. Detonations were initiated in a steel driver tube where a small volume of a sensitive C2H2+ 2.5O2 mixture was injected to facilitate detonation initiation. A 2 m length of circular tube with a 50.8 mm diameter preceded the annular channel so that a steady Chapman-Jouguet (CJ) detonation was established prior to entering the annular channel. Four detonable mixtures of C2H2 {+} 2.5O2 {+} 85 % Ar, C2H2 {+} 2.5O2 {+} 70 % Ar, C3H8 {+} 5O2, and CH4 {+} 2O2 were used in the present study. Photodiodes spaced 10 cm throughout the length of both the annular channel and circular tube were used to measure the detonation velocity. In addition, smoked foils were inserted into the annular channel to monitor the cellular structure of the detonation wave. The results show that, well within the detonability limits, the detonation wave propagates along the channel with a small local velocity fluctuation and an average global velocity can be deduced. The average detonation velocity has a small deficit of 5-15 % far from the limits and the velocity rapidly decreases to 0.7V_{CJ}-0.8V_{CJ} when the detonation propagates near the limit. Subsequently, the fluctuation of local velocity also increases as the decreasing initial pressure approaches the limit. In the two annular channels used in this work, no galloping detonations were observed for both the stable and unstable mixtures tested. The present study also confirms that single-headed spinning detonation occurs at the limit, as in a circular tube, rather than the up and down "zig zag" mode in a two-dimensional, rectangular channel.

  9. Performance Characterization of Swept Ramp Obstacle Fields in Pulse Detonation Applications

    DTIC Science & Technology

    2010-03-01

    field of practical obstacle geometries. 15. NUMBER OF PAGES 97 14. SUBJECT TERMS Pulse Detonation , PDE , Transient Plasma Ignition, TPI, Swept... Detonation Transition NI - National Instruments NPS - Naval Postgraduate School PDC - Pulse Detonation Combustor PDE - Pulse Detonation Engine...with incredible grace. xvi THIS PAGE INTENTIONALLY LEFT BLANK 1 I. INTRODUCTION Pulse detonation engines ( PDE ) continue to be explored due to

  10. Mid-infrared Laser Absorption Diagnostics for Detonation Studies

    NASA Astrophysics Data System (ADS)

    Spearrin, R. M.; Goldenstein, C. S.; Jeffries, J. B.; Hanson, R. K.

    Detonation-based engines represent a challenging application for diagnostics due to the wide range of thermodynamic conditions involved (T~500-3000 K, P~2-60 atm) and the short time scales of change (~10- 6 to 10- 4 sec) associated with such systems. Non-intrusive laser absorption diagnostics can provide high time-resolution and have been employed extensively in shock tube kinetics experiments (P~1-20 atm), offering high potential for application in detonation environments with modest utilization to date [1-4]. Limiting factors in designing effective tunable laser absorption sensors for detonation engines can be divided into two sets of challenges: high-pressure, high-temperature absorption spectroscopy and harsh thermo-mechanical environments. The present work, conducted in a high-pressure shock tube and operating detonation combustor, addresses both sets of difficulties, with the objective of developing time-resolved, in-situ temperature and concentration sensors for detonation studies.

  11. Sensitized Liquid Hydrazine Detonation Studies

    NASA Technical Reports Server (NTRS)

    Rathgeber, K. A.; Keddy, C. P.; Bunker, R. L.

    1999-01-01

    Vapor-phase hydrazine (N2H4) is known to be very sensitive to detonation while liquid hydrazine is very insensitive to detonation, theoretically requiring extremely high pressures to induce initiation. A review of literature on solid and liquid explosives shows that when pure explosive substances are infiltrated with gas cavities, voids, and/or different phase contaminants, the energy or shock pressure necessary to induce detonation can decrease by an order of magnitude. Tests were conducted with liquid hydrazine in a modified card-gap configuration. Sensitization was attempted by bubbling helium gas through and/or suspending ceramic microspheres in the liquid. The hydrazine was subjected to the shock pressure from a 2 lb (0.9 kg) Composition C-4 explosive charge. The hydrazine was contained in a 4 in. (10.2 cm) diameter stainless steel cylinder with a 122 in(sup 3) (2 L) volume and sealed with a polyethylene cap. Blast pressures from the events were recorded by 63 high speed pressure transducers located on three radial legs extending from 4 to 115 ft (1.2 to 35.1 in) from ground zero. Comparison of the neat hydrazine and water baseline tests with the "sensitized" hydrazine tests indicates the liquid hydrazine did not detonate under these conditions.

  12. Hydroxyapatite Reinforced Coatings with Incorporated Detonationally Generated Nanodiamonds

    NASA Astrophysics Data System (ADS)

    Pramatarova, L.; Pecheva, E.; Dimitrova, R.; Spassov, T.; Krasteva, N.; Hikov, T.; Fingarova, D.; Mitev, D.

    2010-01-01

    We studied the effect of the substrate chemistry on the morphology of hydroxyapatite-detonational nanodiamond composite coatings grown by a biomimetic approach (immersion in a supersaturated simulated body fluid). When detonational nanodiamond particles were added to the solution, the morphology of the grown for 2 h composite particles was porous but more compact then that of pure hydroxyapatite particles. The nanodiamond particles stimulated the hydroxyapatite growth with different morphology on the various substrates (Ti, Ti alloys, glasses, Si, opal). Biocompatibility assay with MG63 osteoblast cells revealed that the detonational nanodiamond water suspension with low and average concentration of the detonational nanodiamond powder is not toxic to living cells.

  13. Optimum performance of explosives in a quasistatic detonation cycle

    NASA Astrophysics Data System (ADS)

    Baker, Ernest L.; Stiel, Leonard I.

    2017-01-01

    Analyses were conducted on the behavior of explosives in a quasistatic detonation cycle. This type of cycle has been proposed for the determination of the maximum work that can be performed by the explosive. The Jaguar thermochemical equilibrium program enabled the direct analyses of explosive performance at the various steps in the detonation cycle. In all cases the explosive is initially detonated to a point on the Hugoniot curve for the reaction products. The maximum useful work that can be obtained from the explosive is equal to the P-V work on the isentrope for expansion after detonation to atmospheric pressure, minus one-half the square of the particle velocity at the detonation point. This quantity is calculated form the internal energy of the explosive at the initial and final atmospheric temperatures. Cycle efficiencies (net work/ heat added) are also calculated with these procedures. For several explosives including TNT, RDX, and aluminized compositions, maximum work effects were established through the Jaguar calculations for Hugoniot points corresponding to C-J, overdriven, underdriven and constant volume detonations. Detonation to the C-J point is found to result in the maximum net work in all cases.

  14. Detonation Shock Dynamics Calibration for Non-Ideal HE: ANFO

    NASA Astrophysics Data System (ADS)

    Short, Mark; Salyer, Terry

    2009-06-01

    The detonation of ammonium nitrate (AN) and fuel-oil (FO) mixtures (ANFO) is significantly influenced by the properties of the AN (porosity, particle size, coating) and fuel-oil stoichiometry. We report on a new series of rate-stick experiments in cardboard confinement that highlight detonation front speed and curvature dependence on AN/FO stoichiometry and AN particle properties. Standard detonation velocity-curvature calibrations to the experimental data will be presented, as well as higher-order time-dependent detonation shock dynamics calibrations.

  15. High-Speed Photography of Detonation Propagation in Dynamically Precompressed Liquid Explosives

    NASA Astrophysics Data System (ADS)

    Petel, O. E.; Higgins, A. J.; Yoshinaka, A. C.; Zhang, F.

    2007-12-01

    The propagation of detonation in shock-compressed nitromethane was observed with a high-speed framing camera. The test explosive, nitromethane, was compressed by a reverberating shock wave to pressures as high as 10 GPa prior to being detonated by a secondary detonation event. The pressure and density in the test explosive prior to detonation were determined using two methods: manganin stress gauge measurements and LS-DYNA simulations. The velocity of the detonation front was determined from consecutive frames and correlated to the density of the reverberating shock-compressed explosive prior to detonation. Observing detonation propagation under these non-ambient conditions provides data which can be useful in the validation of equation of state models.

  16. High-Speed Photography of Detonation Propagation in Dynamically Precompressed Liquid Explosives

    NASA Astrophysics Data System (ADS)

    Petel, Oren; Higgins, Andrew; Yoshinaka, Akio; Zhang, Fan

    2007-06-01

    The propagation of detonation in shock compressed nitromethane was observed with a high speed framing camera. The test explosive, nitromethane, was compressed by a reverberating shock wave to pressures on the order of 10 GPa prior to being detonated by a secondary detonation event. The pressure and density in the test explosive prior to detonation was determined using two methods: manganin strain gauge measurements and LS-DYNA simulations. The velocity of the detonation front was determined from consecutive frames and correlated to the density of the explosive post-reverberating shock wave and prior to being detonated. Observing detonation propagation under these non-ambient conditions provides data which can be useful in the validation of equation of state models.

  17. CONDITIONS FOR SUCCESSFUL HELIUM DETONATIONS IN ASTROPHYSICAL ENVIRONMENTS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Holcomb, Cole; Guillochon, James; De Colle, Fabio

    2013-07-01

    Several models for Type Ia-like supernova events rely on the production of a self-sustained detonation powered by nuclear reactions. In the absence of hydrogen, the fuel that powers these detonations typically consists of either pure helium (He) or a mixture of carbon and oxygen (C/O). Studies that systematically determine the conditions required to initiate detonations in C/O material exist, but until now no analogous investigation of He matter has been conducted. We perform one-dimensional reactive hydrodynamical simulations at a variety of initial density and temperature combinations and find critical length scales for the initiation of He detonations that range betweenmore » 1 and 10{sup 10} cm. A simple estimate of the length scales over which the total consumption of fuel will occur for steady-state detonations is provided by the Chapman-Jouguet (CJ) formalism. Our initiation lengths are consistently smaller than the corresponding CJ length scales by a factor of {approx}100, providing opportunities for thermonuclear explosions in a wider range of low-mass white dwarfs (WDs) than previously thought possible. We find that virialized WDs with as little mass as 0.24 M{sub Sun} can be detonated, and that even less massive WDs can be detonated if a sizable fraction of their mass is raised to a higher adiabat. That the initiation length is exceeded by the CJ length implies that certain systems may not reach nuclear statistical equilibrium within the time it takes a detonation to traverse the object. In support of this hypothesis, we demonstrate that incomplete burning will occur in the majority of He WD detonations and that {sup 40}Ca, {sup 44}Ti, or {sup 48}Cr, rather than {sup 56}Ni, is the predominant burning product for many of these events. We anticipate that a measure of the quantity of the intermediate-mass elements and {sup 56}Ni produced in a helium-rich thermonuclear explosion can potentially be used to constrain the nature of the progenitor system.« less

  18. Effects of Injection Scheme on Rotating Detonation Engine Operation

    NASA Astrophysics Data System (ADS)

    Chacon, Fabian; Duvall, James; Gamba, Mirko

    2017-11-01

    In this work, we experimentally investigate the operation and performance characteristics of a rotating detonation engine (RDE) operated with different fuel injection schemes and operating conditions. In particular, we investigate the detonation and operation characteristics produced with an axial flow injector configuration and semi-impinging injector configurations. These are compared to the characteristics produced with a canonical radial injection system (AFRL injector). Each type produces a different flowfield and mixture distribution, leading to a different detonation initiation, injector dynamic response, and combustor pressure rise. By using a combination of diagnostics, we quantify the pressure loses and gains in the system, the ability to maintain detonation over a range of operating points, and the coupling between the detonation and the air/fuel feed lines. We particularly focus on how this coupling affects both the stability and the performance of the detonation wave. This work is supported by the DOE/UTSR program under project DE-FE0025315.

  19. Development and testing of pulsed and rotating detonation combustors

    NASA Astrophysics Data System (ADS)

    St. George, Andrew C.

    Detonation is a self-sustaining, supersonic, shock-driven, exothermic reaction. Detonation combustion can theoretically provide significant improvements in thermodynamic efficiency over constant pressure combustion when incorporated into existing cycles. To harness this potential performance benefit, countless studies have worked to develop detonation combustors and integrate these devices into existing systems. This dissertation consists of a series of investigations on two types of detonation combustors: the pulse detonation combustor (PDC) and the rotating detonation combustor (RDC). In the first two investigations, an array of air-breathing PDCs is integrated with an axial power turbine. The system is initially operated with steady and pulsed cold air flow to determine the effect of pulsed flow on turbine performance. Various averaging approaches are employed to calculate turbine efficiency, but only flow-weighted (e.g., mass or work averaging) definitions have physical significance. Pulsed flow turbine efficiency is comparable to steady flow efficiency at high corrected flow rates and low rotor speeds. At these conditions, the pulse duty cycle expands and the variation of the rotor incidence angle is constrained to a favorable range. The system is operated with pulsed detonating flow to determine the effect of frequency, fill fraction, and rotor speed on turbine performance. For some conditions, output power exceeds the maximum attainable value from steady constant pressure combustion due to a significant increase in available power from the detonation products. However, the turbine component efficiency estimated from classical thermodynamic analysis is four times lower than the steady design point efficiency. Analysis of blade angles shows a significant penalty due to the detonation, fill, and purge processes simultaneously imposed on the rotor. The latter six investigations focus on fundamental research of the RDC concept. A specially-tailored RDC data

  20. Ignition of detonation in accreted helium envelopes

    NASA Astrophysics Data System (ADS)

    Glasner, S. Ami; Livne, E.; Steinberg, E.; Yalinewich, A.; Truran, James W.

    2018-05-01

    Sub-Chandrasekhar CO white dwarfs accreting helium have been considered as candidates for Type Ia supernova (SNIa) progenitors since the early 1980s (helium shell mass >0.1 M⊙). These models, once detonated, did not fit the observed spectra and light curve of typical SNIa observations. New theoretical work examined detonations on much less massive (<0.05 M⊙) envelopes. They find stable detonations that lead to light curves, spectra, and abundances that compare relatively well with the observational data. The exact mechanism leading to the ignition of helium detonation is a key issue, since it is a mandatory first step for the whole scenario. As the flow of the accreted envelope is unstable to convection long before any hydrodynamic phenomena develops, a multidimensional approach is needed in order to study the ignition process. The complex convective reactive flow is challenging to any hydrodynamical solver. To the best of our knowledge, all previous 2D studies ignited the detonation artificially. We present here, for the first time, fully consistent results from two hydrodynamical 2D solvers that adopt two independent accurate schemes. For both solvers, an effort was made to overcome the problematics raised by the finite resolution and numerical diffusion by the advective terms. Our best models lead to the ignition of a detonation in a convective cell. Our results are robust and the agreement between the two different numerical approaches is very good.

  1. The dependence of Ammonium-Nitrate Fuel-Oil (ANFO) detonation on confinement

    DOE PAGES

    Jackson, Scott I.

    2016-11-17

    As detonation is a coupled fluid-chemical process, flow divergence inside the detonation reaction zone can strongly influence detonation velocity and energy release. Such divergence is responsible for the diameter-effect and failure-diameter phenomena in condensed-phase explosives and particularly dominant in detonation of nonideal explosives such as Ammonium Nitrate and Fuel Oil (ANFO). In this study, the effect of reaction zone flow divergence on ANFO detonation was explored through variation of the inert confinement and explosive diameter in the rate-stick geometry with cylinder expansion experiments. New tests are discussed and compared to prior experiments. Presented results include the detonation velocity as amore » function of diameter and confinement, reaction zone times, detonation product isentropes and energies, as well as sonic surface pressures and velocities. Product energy densities and isentropes were found to increase with detonation velocity, indicating more complete chemical reaction with increased detonation velocity. In addition, detonation reaction zone times were found to scale with the acoustic transit time of the confiner wall and used to show that the ANFO diameter effect scaled with the reaction zone time for a particle along the flow centerline, regardless of the confinement. Such a result indicates that the ANFO reaction mechanisms are sufficiently slow that the centerline fluid expansion timescale is a limiting factor controlling detonation velocity and energy release.« less

  2. Equation of state for detonation product gases

    NASA Astrophysics Data System (ADS)

    Nagayama, Kunihito; Kubota, Shiro

    2003-03-01

    A thermodynamic analysis procedure of the detonation product equation of state (EOS) together with the experimental data set of the detonation velocity as a function of initial density has been formulated. The Chapman-Jouguet (CJ) state [W. Ficket and W. C. Davis, Detonation: Theory and Experiment (University of California Press, Berkeley 1979)] on the p-ν plane is found to be well approximated by the envelope function formed by the collection of Rayleigh lines with many different initial density states. The Jones-Stanyukovich-Manson relation [W. Ficket and W. C. Davis, Detonation: Theory and Experiment (University of California Press, Berkeley, 1979)] is used to estimate the error included in this approximation. Based on this analysis, a simplified integration method to calculate the Grüneisen parameter along the CJ state curve with different initial densities utilizing the cylinder expansion data has been presented. The procedure gives a simple way of obtaining the EOS function, compatible with the detonation velocity data. Theoretical analysis has been performed for the precision of the estimated EOS function. EOS of the pentaerithrytoltetranitrate explosive is calculated and compared with some of the experimental data such as CJ pressure data and cylinder expansion data.

  3. Detonation Synthesis of Alpha-Variant Silicon Carbide

    NASA Astrophysics Data System (ADS)

    Langenderfer, Martin; Johnson, Catherine; Fahrenholtz, William; Mochalin, Vadym

    2017-06-01

    A recent research study has been undertaken to develop facilities for conducting detonation synthesis of nanomaterials. This process involves a familiar technique that has been utilized for the industrial synthesis of nanodiamonds. Developments through this study have allowed for experimentation with the concept of modifying explosive compositions to induce synthesis of new nanomaterials. Initial experimentation has been conducted with the end goal being synthesis of alpha variant silicon carbide (α-SiC) in the nano-scale. The α-SiC that can be produced through detonation synthesis methods is critical to the ceramics industry because of a number of unique properties of the material. Conventional synthesis of α-SiC results in formation of crystals greater than 100 nm in diameter, outside nano-scale. It has been theorized that the high temperature and pressure of an explosive detonation can be used for the formation of α-SiC in the sub 100 nm range. This paper will discuss in detail the process development for detonation nanomaterial synthesis facilities, optimization of explosive charge parameters to maximize nanomaterial yield, and introduction of silicon to the detonation reaction environment to achieve first synthesis of nano-sized alpha variant silicon carbide.

  4. Unsteady self-sustained detonation in flake aluminum dust/air mixtures

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Li, S.; Huang, J.; Zhang, Y.

    2017-07-01

    Self-sustained detonation waves in flake aluminum dust/air mixtures have been studied in a tube of diameter 199 mm and length 32.4 m. A pressure sensor array of 32 sensors mounted around certain circumferences of the tube was used to measure the shape of the detonation front in the circumferential direction and pressure histories of the detonation wave. A two-head spin detonation wave front was observed for the aluminum dust/air mixtures, and the cellular structure resulting from the spinning movement of the triple point was analyzed. The variations in velocity and overpressure of the detonation wave with propagation distance in a cell were studied. The interactions of waves in triple-point configurations were analyzed and the flow-field parameters were calculated. Three types of triple-point configuration have been found in the wave front of the detonation wave of an aluminum dust/air mixture. Both strong and weak transverse waves exist in the unstable self-sustained detonation wave.

  5. Detonator Performance Characterization using Multi-Frame Laser Schlieren Imaging

    NASA Astrophysics Data System (ADS)

    Clarke, Steven; Landon, Colin; Murphy, Michael; Martinez, Michael; Mason, Thomas; Thomas, Keith

    2009-06-01

    Multi-frame Laser Schlieren Imaging of shock waves produced by detonators in transparent witness materials can be used to evaluate detonator performance. We use inverse calculations of the 2D propagation of shock waves in the EPIC finite element model computer code to calculate a temporal-spatial-pressure profile on the surface of the detonator that is consistent with the experimental shock waves from the schlieren imaging. Examples of calculated 2D temporal-spatial-pressure profiles from a range of detonator types (EFI --exploding foil initiators, DOI -- direct optical initiation, EBW -- exploding bridge wire, hotwire), detonator HE materials (PETN, HMX, etc), and HE densities. Also pressure interaction profiles from the interaction of multiple shock waves will be shown. LA-UR-09-00909.

  6. Eigenvalue Detonation of Combined Effects Aluminized Explosives

    NASA Astrophysics Data System (ADS)

    Capellos, C.; Baker, E. L.; Nicolich, S.; Balas, W.; Pincay, J.; Stiel, L. I.

    2007-12-01

    Theory and performance for recently developed combined—effects aluminized explosives are presented. Our recently developed combined-effects aluminized explosives (PAX-29C, PAX-30, PAX-42) are capable of achieving excellent metal pushing, as well as high blast energies. Metal pushing capability refers to the early volume expansion work produced during the first few volume expansions associated with cylinder and wall velocities and Gurney energies. Eigenvalue detonation explains the observed detonation states achieved by these combined effects explosives. Cylinder expansion data and thermochemical calculations (JAGUAR and CHEETAH) verify the eigenvalue detonation behavior.

  7. A transient semimetallic layer in detonating nitromethane

    NASA Astrophysics Data System (ADS)

    Reed, Evan J.; Riad Manaa, M.; Fried, Laurence E.; Glaesemann, Kurt R.; Joannopoulos, J. D.

    2008-01-01

    Despite decades of research, the microscopic details and extreme states of matter found within a detonating high explosive have yet to be elucidated. Here we present the first quantum molecular-dynamics simulation of a shocked explosive near detonation conditions. We discover that the wide-bandgap insulator nitromethane (CH3NO2) undergoes chemical decomposition and a transformation into a semimetallic state for a limited distance behind the detonation front. We find that this transformation is associated with the production of charged decomposition species and provides a mechanism to explain recent experimental observations.

  8. Pulse Detonation Physiochemical and Exhaust Relaxation Processes

    DTIC Science & Technology

    2006-05-01

    based on total time to detonation and detonation percentage. Nomenclature A = Arrehenius Constant Ea = Activation Energy Ecrit = Critical...the precision uncertainties vary for each data point. Therefore, the total experimental uncertainty will vary by data point. A comprehensive bias

  9. Determination of detonation parameters for liquid High Explosives

    NASA Astrophysics Data System (ADS)

    Mochalova, Valentina; Utkin, Alexander

    2011-06-01

    The experimental investigation of detonation parameters and reaction zone structure in liquid HE (bis-(2-fluoro-2,2-dinitroethyl)formal (FEFO), tetranitromethane (TNM), nitromethane (NM)) was conducted. Detonation front in TNM and NM was stable while the instability of detonation in FEFO was observed. Von Neumann spike was recorded for these HE and its parameters were determined. The different methods for C-J point determination were used for each HE. For FEFO reaction time τ was found from experiments with different charge diameters (τ is approximately equal to 300 ns); for TNM - at fixed diameter and different lengths of charges (τ ~ 200 ns); for NM - at fixed diameter and length of charges, but detonation initiation was carried out by different explosive charges (τ ~ 50 ns). It was found that in TNM the detonation velocity depends on charge diameter. Maximum value of reaction rate in investigated liquid HE was observed after shock jump and induction time was not recorded.

  10. Determination of detonation parameters for liquid high explosives

    NASA Astrophysics Data System (ADS)

    Mochalova, Valentina; Utkin, Alexander

    2012-03-01

    The experimental investigation of detonation parameters and reaction zone structure in liquid HE (bis-(2-fluoro-2,2-dinitroethyl)formal (FEFO), tetranitromethane (TNM), nitromethane (NM)) was conducted by means of laser interferometer VISAR. Detonation front in TNM and NM was stable while the instability of detonation in FEFO was observed. The parameters of Von Neumann spike were determined for these HE. The different methods for C-J point determination were used for each HE. For FEFO reaction time t was found from experiments with different charge diameters (τ is approximately equal to 300 ns); for TNM - at fixed diameter and different lengths of charges (τ ≈ 200 ns); for NM - at fixed diameter and length of charges, but detonation initiation was carried out by different explosive charges (τ ≈ 50 ns). It was found that in TNM the detonation velocity depends on charge diameter. Maximum value of reaction rate in investigated liquid HE was observed after shock jump.

  11. Detonation energies of explosives by optimized JCZ3 procedures

    NASA Astrophysics Data System (ADS)

    Stiel, Leonard I.; Baker, Ernest L.

    1998-07-01

    Procedures for the detonation properties of explosives have been extended for the calculation of detonation energies at adiabatic expansion conditions. The use of the JCZ3 equation of state with optimized Exp-6 potential parameters leads to lower errors in comparison to JWL detonation energies than for other methods tested.

  12. Numerical Simulation of the Detonation of Condensed Explosives

    NASA Astrophysics Data System (ADS)

    Wang, Cheng; Ye, Ting; Ning, Jianguo

    Detonation process of a condensed explosive was simulated using a finite difference method. Euler equations were applied to describe the detonation flow field, an ignition and growth model for the chemical reaction and Jones-Wilkins-Lee (JWL) equations of state for the state of explosives and detonation products. Based on the simple mixture rule that assumes the reacting explosives to be a mixture of the reactant and product components, 1D and 2D codes were developed to simulate the detonation process of high explosive PBX9404. The numerical results are in good agreement with the experimental results, which demonstrates that the finite difference method, mixture rule and chemical reaction proposed in this paper are adequate and feasible.

  13. A small-scale experiment using microwave interferometry to investigate detonation and shock-to-detonation transition in pressed TATB

    NASA Astrophysics Data System (ADS)

    Renslow, Peter John

    A small-scale characterization test utilizing microwave interferometry was developed to dynamically measure detonation and run to detonation distance in explosives. The technique was demonstrated by conducting two experimental series on the well-characterized explosive triaminotrinitrobenzene (TATB). In the first experiment series, the detonation velocity was observed at varying porosity. The velocity during TATB detonation matched well with predictions made using CHEETAH and an empirical relation from the Los Alamos National Laboratory (LANL). The microwave interferometer also captured unsteady propagation of the reaction when a low density charge was near the failure diameter. In the second experiment series, Pop-plots were produced using data obtained from shock initiation of the TATB through a polymethyl methacrylate (PMMA) attenuator. The results compared well to wedge test data from LANL despite the microwave interferometer test being of substantially smaller scale. The results showed the test method is attractive for rapid characterization of new and improvised explosive materials.

  14. Simulations of heterogeneous detonations and post-detonation turbulent mixing and afterburning

    NASA Astrophysics Data System (ADS)

    Gottiparthi, Kalyana Chakravarthi; Menon, Suresh

    2012-03-01

    We conduct three-dimensional numerical simulations of the propagation of blast waves resulting from detonation of a nitromethane charge of radius 5.9 cm loaded with aluminum particles and analyze the afterburn process as well as the generation of multiple scales ofmixing in the post detonation flow field. In the current study, the particle combustion is observed to be dependent on particle dispersal and mixing of gases in the flow where particle dispersal spreads aluminum within the flow and mixing provides the necessary oxidizer. Thus, 5 μm aluminum particles are burnt more effectively in comparison to 10 μm particles for a fixed initial mass of particles. Also, for a fixed initial particle size, increase in the initial mass of aluminum particles resulted in greater mixing.

  15. Safety and performance enhancement circuit for primary explosive detonators

    DOEpatents

    Davis, Ronald W [Tracy, CA

    2006-04-04

    A safety and performance enhancement arrangement for primary explosive detonators. This arrangement involves a circuit containing an energy storage capacitor and preset self-trigger to protect the primary explosive detonator from electrostatic discharge (ESD). The circuit does not discharge into the detonator until a sufficient level of charge is acquired on the capacitor. The circuit parameters are designed so that normal ESD environments cannot charge the protection circuit to a level to achieve discharge. When functioned, the performance of the detonator is also improved because of the close coupling of the stored energy.

  16. Evaluation of the oblique detonation wave ramjet

    NASA Technical Reports Server (NTRS)

    Morrison, R. B.

    1978-01-01

    The potential performance of oblique detonation wave ramjets is analyzed in terms of multishock diffusion, oblique detonation waves, and heat release. Results are presented in terms of thrust coefficients and specific impulses for a range of flight Mach numbers of 6 to 16.

  17. Design and Evaluation of a Single-Inlet Pulse Detonation Combustor

    DTIC Science & Technology

    2011-06-01

    Kilogram/second m/s Meters/ second N Nitrogen NPS Naval Postgraduate School O Oxygen PDC Pulse Detonation Combustion PDE Pulse Detonation Engine...EVALUATION OF A SINGLE-INLET PULSE DETONATION COMBUSTOR by Danny Soria June 2011 Thesis Advisor: Christopher M. Brophy Second Reader: Garth V...COVERED Master’s Thesis 4. TITLE AND SUBTITLE Design and Evaluation of a Single-Inlet Pulse Detonation Combustor 6. AUTHOR(S) Danny Soria 5

  18. On the Initiation Mechanism in Exploding Bridgewire and Laser Detonators

    NASA Astrophysics Data System (ADS)

    Stewart, D. Scott; Thomas, K.; Saenz, J.

    2005-07-01

    Since its invention by Los Alamos during the Manhattan Project era the exploding bridgewire detonator (EBW) has seen tremendous use and study. Recent development of a laser-powered device with detonation properties similar to an EBW is reviving interest in the basic physics of the Deflagration-to-Detonation (DDT) process in both of these devices,[1]. Cutback experiments using both laser interferometry and streak camera observations are providing new insight into the initiation mechanism in EBWs. These measurements are being correlated to a DDT model of compaction to detonation and shock to detonation developed previously by Xu and Stewart, [2]. The DDT model is incorporated into a high-resolution, multi-material model code for simulating the complete process. Model formulation and predictions against the test data will be discussed. REFS. [1] A. Munger, J. Kennedy, A. Akinci, and K. Thomas, "Dev. of a Laser Detonator" 30th Int. Pyrotechnics Seminar, Fort Collins, CO, (2004). [2] Xu, S. and Stewart, D. S. Deflagration to detonation transition in porous energetic materials: A model study. J. Eng. Math., 31, 143-172 (1997)

  19. A morphological investigation of soot produced by the detonation of munitions.

    PubMed

    Pantea, Dana; Brochu, Sylvie; Thiboutot, Sonia; Ampleman, Guy; Scholz, Günter

    2006-10-01

    The morphology of three different detonation soot samples along with other common soot materials such as carbon black, diesel soot and chimney soot was studied by elemental and proximate analysis, X-ray diffraction and electron microscopy. The goal of this study was to better define the morphology of the detonation soot in order to better assess the interactions of this type of soot with explosive residues. The detonation soot samples were obtained by the detonation of artillery 155mm projectiles filled with either pure TNT (2,4,6-trinitrotoluene) or composition B, a military explosive based on a mixture of TNT and RDX (trimethylentrinitramine). The carbon content of the soot samples varied considerably depending on the feedstock composition. Detonation soot contains less carbon and more nitrogen than the other carbonaceous samples studied, due to the molecular structure of the energetic materials detonated such as TNT and RDX. The ash concentration was higher for detonation soot samples due to the high metal content coming from the projectiles shell and to the soil contamination which occurred during the detonation. By X-ray diffraction, diamond and graphite were found to be the major crystalline carbon forms in the detonation soot. Two electron microscopy techniques were used in this study to visualise the primary particles and to try to explain the formation mechanism of detonation soot samples.

  20. Numerical simulations of detonation propagation in gaseous fuel-air mixtures

    NASA Astrophysics Data System (ADS)

    Honhar, Praveen; Kaplan, Carolyn; Houim, Ryan; Oran, Elaine

    2017-11-01

    Unsteady multidimensional numerical simulations of detonation propagation and survival in mixtures of fuel (hydrogen or methane) diluted with air were carried out with a fully compressible Navier-Stokes solver using a simplified chemical-diffusive model (CDM). The CDM was derived using a genetic algorithm combined with the Nelder-Mead optimization algorithm and reproduces physically correct laminar flame and detonation properties. Cases studied are overdriven detonations propagating through confined mediums, with or without gradients in composition. Results from simulations confirm that the survival of the detonation depends on the channel heights. In addition, the simulations show that the propagation of the detonation waves depends on the steepness in composition gradients.

  1. Social evaluation of intentional, truly accidental, and negligently accidental helpers and harmers by 10-month-old infants.

    PubMed

    Woo, Brandon M; Steckler, Conor M; Le, Doan T; Hamlin, J Kiley

    2017-11-01

    Whereas adults largely base their evaluations of others' actions on others' intentions, a host of research in developmental psychology suggests that younger children privilege outcome over intention, leading them to condemn accidental harm. To date, this question has been examined only with children capable of language production. In the current studies, we utilized a non-linguistic puppet show paradigm to examine the evaluation of intentional and accidental acts of helping or harming in 10-month-old infants. In Experiment 1 (n=64), infants preferred intentional over accidental helpers but accidental over intentional harmers, suggestive that by this age infants incorporate information about others' intentions into their social evaluations. In Experiment 2 (n=64), infants did not distinguish "negligently" accidental from intentional helpers or harmers, suggestive that infants may find negligent accidents somewhat intentional. In Experiment 3 (n=64), we found that infants preferred truly accidental over negligently accidental harmers, but did not reliably distinguish negligently accidental from truly accidental helpers, consistent with past work with adults and children suggestive that humans are particularly sensitive to negligently accidental harm. Together, these results imply that infants engage in intention-based social evaluation of those who help and harm accidentally, so long as those accidents do not stem from negligence. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Detonation propagation in a high loss configuration

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jackson, Scott I; Shepherd, Joseph E

    2009-01-01

    This work presents an experimental study of detonation wave propagation in tubes with inner diameters (ID) comparable to the mixture cell size. Propane-oxygen mixtures were used in two test section tubes with inner diameters of 1.27 mm and 6.35 mm. For both test sections, the initial pressure of stoichiometric mixtures was varied to determine the effect on detonation propagation. For the 6.35 mm tube, the equivalence ratio {phi} (where the mixture was {phi} C{sub 3}H{sub 8} + 50{sub 2}) was also varied. Detonations were found to propagate in mixtures with cell sizes as large as five times the diameter ofmore » the tube. However, under these conditions, significant losses were observed, resulting in wave propagation velocities as slow as 40% of the CJ velocity U{sub CJ}. A review of relevant literature is presented, followed by experimental details and data. Observed velocity deficits are predicted using models that account for boundary layer growth inside detonation waves.« less

  3. Determination of Effective Crossover Location and Dimensions for Branched Detonation in a Pulsed Detonation Engine

    DTIC Science & Technology

    2012-03-22

    location is varied from the aft end of the detonation tube to the middle of the detonation tube while the crossover width is varied from 2.5 in to 0.5...the other end where the tube is connected to a source of fuel, oxidizer, and ignition .7 The engine cycle is divided into three equal phases: fill...location and width of the crossover duct for hydrogen, ethylene and an n-alkane. The crossover location is varied from the aft end of the

  4. The ignition of carbon detonations via converging shock waves in white dwarfs

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shen, Ken J.; Bildsten, Lars, E-mail: kenshen@astro.berkeley.edu, E-mail: bildsten@kitp.ucsb.edu

    2014-04-10

    The progenitor channel responsible for the majority of Type Ia supernovae is still uncertain. One emergent scenario involves the detonation of a He-rich layer surrounding a C/O white dwarf, which sends a shock wave into the core. The quasi-spherical shock wave converges and strengthens at an off-center location, forming a second, C-burning, detonation that disrupts the whole star. In this paper, we examine this second detonation of the double detonation scenario using a combination of analytic and numeric techniques. We perform a spatially resolved study of the imploding shock wave and outgoing detonation and calculate the critical imploding shock strengthsmore » needed to achieve a core C detonation. We find that He detonations in recent two-dimensional simulations yield converging shock waves that are strong enough to ignite C detonations in high-mass C/O cores, with the caveat that a truly robust answer requires multi-dimensional detonation initiation calculations. We also find that convergence-driven detonations in low-mass C/O cores and in O/Ne cores are harder to achieve and are perhaps unrealized in standard binary evolution.« less

  5. Flying-plate detonator using a high-density high explosive

    DOEpatents

    Stroud, John R.; Ornellas, Donald L.

    1988-01-01

    A flying-plate detonator containing a high-density high explosive such as benzotrifuroxan (BTF). The detonator involves the electrical explosion of a thin metal foil which punches out a flyer from a layer overlying the foil, and the flyer striking a high-density explosive pellet of BTF, which is more thermally stable than the conventional detonator using pentaerythritol tetranitrate (PETN).

  6. Flowfield characterization and model development in detonation tubes

    NASA Astrophysics Data System (ADS)

    Owens, Zachary Clark

    A series of experiments and numerical simulations are performed to advance the understanding of flowfield phenomena and impulse generation in detonation tubes. Experiments employing laser-based velocimetry, high-speed schlieren imaging and pressure measurements are used to construct a dataset against which numerical models can be validated. The numerical modeling culminates in the development of a two-dimensional, multi-species, finite-rate-chemistry, parallel, Navier-Stokes solver. The resulting model is specifically designed to assess unsteady, compressible, reacting flowfields, and its utility for studying multidimensional detonation structure is demonstrated. A reduced, quasi-one-dimensional model with source terms accounting for wall losses is also developed for rapid parametric assessment. Using these experimental and numerical tools, two primary objectives are pursued. The first objective is to gain an understanding of how nozzles affect unsteady, detonation flowfields and how they can be designed to maximize impulse in a detonation based propulsion system called a pulse detonation engine. It is shown that unlike conventional, steady-flow propulsion systems where converging-diverging nozzles generate optimal performance, unsteady detonation tube performance during a single-cycle is maximized using purely diverging nozzles. The second objective is to identify the primary underlying mechanisms that cause velocity and pressure measurements to deviate from idealized theory. An investigation of the influence of non-ideal losses including wall heat transfer, friction and condensation leads to the development of improved models that reconcile long-standing discrepancies between predicted and measured detonation tube performance. It is demonstrated for the first time that wall condensation of water vapor in the combustion products can cause significant deviations from ideal theory.

  7. Heat Exchanger Design and Testing for a 6-Inch Rotating Detonation Engine

    DTIC Science & Technology

    2013-03-01

    Engine Research Facility HHV Higher heating value LHV Lower heating value PDE Pulsed detonation engine RDE Rotating detonation engine RTD...the combustion community are pulse detonation engines ( PDEs ) and rotating detonation engines (RDEs). 1.1 Differences between Pulsed and Rotating ...steadier than that of a PDE (2, 3). (2) (3) Figure 1. Unrolled rotating detonation wave from high-speed video (4) Another difference that

  8. Deflagration-to-detonation transition in spiral channels

    NASA Astrophysics Data System (ADS)

    Golovastov, S. V.; Mikushkin, A. Yu.; Golub, V. V.

    2017-10-01

    The deflagration-to-detonation transition in hydrogen-air mixtures that fill spiral channels has been studied. A spiral channel has been produced in a cylindrical detonation tube with a twisted ribbon inside. The gas mixture has been ignited by means of a spark gap switch. The predetonation distance versus the twisted ribbon configuration and molar ratio between the gas mixture components has been determined. A pulling force exerted by the detonation tube after a single event of hydrogen-air mixture burnout has been found for four configurations of the twisted ribbon. Conditions under which the use of a spiral tube can be more effective (increase the pulling force) have been formulated.

  9. 29 CFR 1926.908 - Use of detonating cord.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... be handled and used with the same respect and care given other explosives. (c) The line of detonating... explosive core is dry. (f) All detonating cord trunklines and branchlines shall be free of loops, sharp...

  10. Particle Size Effects on CL-20 Initiation and Detonation

    NASA Astrophysics Data System (ADS)

    Valancius, Cole; Bainbridge, Joe; Love, Cody; Richardson, Duane

    2017-06-01

    Particle size or specific surface area effects on explosives has been of interest to the explosives community for both application and modeling of initiation and detonation. Different particles sizes of CL-20 were used in detonator experiments to determine the effects of particle size on initiation, run-up to steady state detonation, and steady state detonation. Historical tests have demonstrated a direct relationship between particle size and initiation. However, historical tests inadvertently employed density gradients, making it difficult to discern the effects of particle size from the effects of density. Density gradients were removed from these tests using a larger diameter, shorter charge column, allowing for similar loading across different particle sizes. Without the density gradient, the effects of particle size on initiation and detonation are easier to determine. The results of which contrast with historical results, showing particle size does not directly affect initiation threshold.

  11. Ignition and growth reactive flow modeling of recent HMX/TATB detonation experiments

    NASA Astrophysics Data System (ADS)

    Tarver, Craig M.

    2017-01-01

    Two experimental studies in which faster HMX detonation waves produced oblique detonation waves in adjoining slower detonating TATB charges were modeled using the Ignition and Growth (I&G) reactive flow detonation model parameters for PBX 9501 (95% HMX / 2.5% Estane / 2.5% BDNPA/F) and PBX 9502 (95% TATB / 5% Kel-F binder). Matignon et al. used X1 explosive (96% HMX / 4% binder) to drive an oblique detonation wave into an attached charge of T2 explosive (97% TATB / 3% binder). The flow angles were measured in the T2 shock initiation region and in steady T2 detonation. Anderson et al. used detonating PBX 9501 slabs of various thicknesses ranging from 0.56 mm to 2.5 mm to create oblique detonation waves in 8 mm thick slabs of PBX 9502. Several diagnostics were employed to: photograph the waves; measure detonation velocities and flow angles; and determine the output of the PBX 9501 slabs, the PBX 9502 slabs, and the "initiation regions" using LiF windows and PDV probes.

  12. Heat Transfer Experiments on a Pulse Detonation Driven Combustor

    DTIC Science & Technology

    2011-03-01

    steps that need to take place before such a hybrid is successfully developed. PDEs obtain their increased efficiency by means of detonation , a pressure...combustion in the Brayton cycle. A PDE utilizes detonations , which offer much higher pressures at the site of fuel ignition, generating less...HEAT TRANSFER EXPERIMENTS ON A PULSE DETONATION DRIVEN COMBUSTOR THESIS Nicholas C. Longo, Captain, USAF AFIT/GAE/ENY/11-M18

  13. Deflagration-to-Detonation Transition Control by Nanosecond Gas Discharges

    DTIC Science & Technology

    2008-04-07

    Report 3. DATES COVERED (From – To) 1 April 2007 - 18 August 09 4. TITLE AND SUBTITLE Deflagration-To- Detonation Transition Control By Nanosecond...SUPPLEMENTARY NOTES 14. ABSTRACT During the current project, an extensive experimental study of detonation initiation by high{voltage...nanosecond gas discharges has been performed in a smooth detonation tube with different discharge chambers and various discharge cell numbers. The chambers

  14. Rapid detonation initiation by sparks in a short duct: a numerical study

    NASA Astrophysics Data System (ADS)

    Hu, Z. M.; Dou, H. S.; Khoo, B. C.

    2010-06-01

    Rapid onset of detonation can efficiently increase the working frequency of a pulse detonation engine (PDE). In the present study, computations of detonation initiation in a duct are conducted to investigate the mechanisms of detonation initiation. The governing equations are the Euler equations and the chemical kinetic model consists of 19 elementary reactions and nine species. Different techniques of initiation have been studied for the purpose of accelerating detonation onset with a relatively weak ignition energy. It is found that detonation ignition induced by means of multiple sparks is applicable to auto-ignition for a PDE. The interaction among shock waves, flame fronts and the strip of pre-compressed fresh (unburned) mixture plays an important role in rapid onset of detonation.

  15. Mechanisms of detonation formation due to a temperature gradient

    NASA Astrophysics Data System (ADS)

    Kapila, A. K.; Schwendeman, D. W.; Quirk, J. J.; Hawa, T.

    2002-12-01

    Emergence of a detonation in a homogeneous, exothermically reacting medium can be deemed to occur in two phases. The first phase processes the medium so as to create conditions ripe for the onset of detonation. The actual events leading up to preconditioning may vary from one experiment to the next, but typically, at the end of this stage the medium is hot and in a state of nonuniformity. The second phase consists of the actual formation of the detonation wave via chemico-gasdynamic interactions. This paper considers an idealized medium with simple, rate-sensitive kinetics for which the preconditioned state is modelled as one with an initially prescribed linear gradient of temperature. Accurate and well-resolved numerical computations are carrried out to determine the mode of detonation formation as a function of the size of the initial gradient. For shallow gradients, the result is a decelerating supersonic reaction wave, a weak detonation, whose trajectory is dictated by the initial temperature profile, with only weak intervention from hydrodynamics. If the domain is long enough, or the gradient less shallow, the wave slows down to the Chapman-Jouguet speed and undergoes a swift transition to the ZND structure. For sharp gradients, gasdynamic nonlinearity plays a much stronger role. Now the path to detonation is through an accelerating pulse that runs ahead of the reaction wave and rearranges the induction-time distribution there to one that bears little resemblance to that corresponding to the initial temperature gradient. The pulse amplifies and steepens, transforming itself into a complex consisting of a lead shock, an induction zone, and a following fast deflagration. As the pulse advances, its three constituent entities attain progressively higher levels of mutual coherence, to emerge as a ZND detonation. For initial gradients that are intermediate in size, aspects of both the extreme scenarios appear in the path to detonation. The novel aspect of this study

  16. Mechanism of Gaseous Detonation Propagation Through Reactant Layers Bounded by Inert Gas

    NASA Astrophysics Data System (ADS)

    Houim, Ryan

    2017-11-01

    Vapor cloud explosions and rotating detonation engines involve the propagation of gaseous detonations through a layer of reactants that is bounded by inert gas. Mechanistic understanding of how detonations propagate stably or fail in these scenarios is incomplete. Numerical simulations were used to investigate mechanisms of gaseous detonation propagation through reactant layers bounded by inert gas. The reactant layer was a stoichiometric mixture of C2H4/O2 at 1 atm and 300K and is 4 detonation cells in height. Cases where the inert gas temperature was 300, 1500, and 3500 K will be discussed. The detonation failed for the 300 K case and propagated marginally for the 1500 K case. Surprisingly, the detonation propagated stably for the 3500 K case. A shock structure forms that involves a detached shock in the inert gas and a series of oblique shocks in the reactants. A small local explosion is triggered when the Mach stem of a detonation cell interacts with the compressed reactants behind one of these oblique shocks. The resulting pressure wave produces a new Mach stem and a new triple point that leads to a stable detonation. Preliminary results on the influence of a deflagration at the inert/reactant interface on the stability of a layered detonation will be discussed.

  17. Detonation charge size versus coda magnitude relations in California and Nevada

    USGS Publications Warehouse

    Brocher, T.M.

    2003-01-01

    Magnitude-charge size relations have important uses in forensic seismology and are used in Comprehensive Nuclear-Test-Ban Treaty monitoring. I derive empirical magnitude versus detonation-charge-size relationships for 322 detonations located by permanent seismic networks in California and Nevada. These detonations, used in 41 different seismic refraction or network calibration experiments, ranged in yield (charge size) between 25 and 106 kg; coda magnitudes reported for them ranged from 0.5 to 3.9. Almost all represent simultaneous (single-fired) detonations of one or more boreholes. Repeated detonations at the same shotpoint suggest that the reported coda magnitudes are repeatable, on average, to within 0.1 magnitude unit. An empirical linear regression for these 322 detonations yields M = 0.31 + 0.50 log10(weight [kg]). The detonations compiled here demonstrate that the Khalturin et al. (1998) relationship, developed mainly for data from large chemical explosions but which fits data from nuclear blasts, can be used to estimate the minimum charge size for coda magnitudes between 0.5 and 3.9. Drilling, loading, and shooting logs indicate that the explosive specification, loading method, and effectiveness of tamp are the primary factors determining the efficiency of a detonation. These records indicate that locating a detonation within the water table is neither a necessary nor sufficient condition for an efficient shot.

  18. Hazard classification assessment for the MC3423 detonator shipping package

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jones, R.B.

    1981-11-05

    An investigation was made to determine whether the MC3423 detonator should be assigned a DOT hazard classification of Detonating Fuze, Class C Explosive, per Federal Register 49 CFR 173.113, when packaged as specified. This study covers two propagation tests which evaluated the effects of two orientations of the MC3423 in its shipping tray. The method of testing was approved by DOE, Albuquerque Operations Office. Test data led to the recommended hazard classification of Detonating Fuze, Class C Explosive for both orientations of the detonator.

  19. Synchro-ballistic recording of detonation phenomena

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Critchfield, R.R.; Asay, B.W.; Bdzil, J.B.

    1997-09-01

    Synchro-ballistic use of rotating-mirror streak cameras allows for detailed recording of high-speed events of known velocity and direction. After an introduction to the synchro-ballistic technique, this paper details two diverse applications of the technique as applied in the field of high-explosives research. In the first series of experiments detonation-front shape is recorded as the arriving detonation shock wave tilts an obliquely mounted mirror, causing reflected light to be deflected from the imaging lens. These tests were conducted for the purpose of calibrating and confirming the asymptotic Detonation Shock Dynamics (DSD) theory of Bdzil and Stewart. The phase velocities of themore » events range from ten to thirty millimeters per microsecond. Optical magnification is set for optimal use of the film`s spatial dimension and the phase velocity is adjusted to provide synchronization at the camera`s maximum writing speed. Initial calibration of the technique is undertaken using a cylindrical HE geometry over a range of charge diameters and of sufficient length-to-diameter ratio to insure a stable detonation wave. The final experiment utilizes an arc-shaped explosive charge, resulting in an asymmetric detonation-front record. The second series of experiments consists of photographing a shaped-charge jet having a velocity range of two to nine millimeters per microsecond. To accommodate the range of velocities it is necessary to fire several tests, each synchronized to a different section of the jet. The experimental apparatus consists of a vacuum chamber to preclude atmospheric ablation of the jet tip with shocked-argon back lighting to produce a shadow-graph image.« less

  20. Analysis of Porous Media as Inlet Concept for Rotating Detonation Engines

    NASA Astrophysics Data System (ADS)

    Grogan, Kevin; Ihme, Matthias; Department of Mechanical Engineering Team

    2016-11-01

    Rotating detonation engines combust reactive gas mixtures with a high-speed, annularly-propagating detonation wave, which provides many advantages including a stagnation pressure gain and a compact, lightweight design. However, the optimal design of the inlet to the combustion chamber inlet is a moot topic since improper design can significantly reduce detonability and increase pressure losses. The highly diffusive properties of porous media could make it an ideal material to prevent the flashback of the detonation wave and therefore, allow the inlet gas to be premixed. Motivated by this potential, this work employs simulation to evaluate the application of porous media to the inlet of a rotating detonation engine as a novel means to stabilize a detonation wave while reducing the pressure losses incurred by non-ideal mixing strategies. Department of the Air Force.

  1. Structure and characteristics of heterogeneous detonation

    NASA Astrophysics Data System (ADS)

    Nicholls, J. A.; Sichel, M.; Kauffman, C. W.

    1983-09-01

    The emphasis of this research program centered around the structure of heterogeneous detonation waves, inasmuch as this had been found to be very important to the detonation characteristics of heterogeneous mixtures. On the experimental side, a vertical detonation tube was used wherein liquid fuel drops, all of one size, were generated at the top of the tube and allowed to fall vertically into the desired gaseous mixture. A strong blast wave was transmitted into the mixture through use of an auxiliary shock tube. The propagation of the resultant wave was monitored by pressure switches, pressure transducers, and photography. The low vapor pressure liquid fuel, decane (400 micrometer drop size) was used for most of the experiments. Attention was given to wave structure, wave velocity, and initiation energy. Three atmospheres (100% O2; 40% O2/60% N2; and air) and a number of equivalence ratios were investigated. Holographic pictures and streak photography were employed to study the drop shattering process and the structure of the front. Other experiments investigated the addition of the sensitizer, normal propyl nitrate (NPN), to the decane. The important aspect of vapor pressure was studied by heating the entire tube to various elevated temperatures and then noting the effect on detonability.

  2. Detonation duct gas generator demonstration program

    NASA Technical Reports Server (NTRS)

    Wortman, Andrew; Brinlee, Gayl A.; Othmer, Peter; Whelan, Michael A.

    1991-01-01

    The feasibility of the generation of detonation waves moving periodically across high speed channel flow is experimentally demonstrated. Such waves are essential to the concept of compressing requirements and increasing the engine pressure compressor with the objective of reducing conventional compressor requirements and increasing the engine thermodynamic efficiency through isochoric energy addition. By generating transient transverse waves, rather than standing waves, shock wave losses are reduced by an order of magnitude. The ultimate objective is to use such detonation ducts downstream of a low pressure gas turbine compressor to produce a high overall pressure ratio thermodynamic cycle. A 4 foot long, 1 inch x 12 inch cross-section, detonation duct was operated in a blow-down mode using compressed air reservoirs. Liquid or vapor propane was injected through injectors or solenoid valves located in the plenum or the duct itself. Detonation waves were generated when the mixture was ignited by a row of spark plugs in the duct wall. Problems with fuel injection and mixing limited the air speeds to about Mach 0.5, frequencies to below 10 Hz, and measured pressure ratios of about 5 to 6. The feasibility of the gas dynamic compression was demonstrated and the critical problem areas were identified.

  3. Attenuation of a hydrogen-air detonation by acoustic absorbing covering

    NASA Astrophysics Data System (ADS)

    Bivol, G. Yu; Golovastov, S. V.; Golub, V. V.; Ivanov, K. V.; Korobov, A. E.

    2015-11-01

    Using of sound-absorbing surfaces to weaken and decay of a detonation wave in hydrogen-air mixtures was investigated experimentally. Experiments were carried out in a cylindrical detonation tube open at one end. Initiation of the explosive mixture was carried out by a spark discharge, which is located at the closed end of the detonation tube. Acoustical sound absorbing foam element of a specific weight of 0.035 g/cm3 with open pores of 0.5 mm was used. The degree of attenuation of the intensity of the detonation wave front was determined.

  4. Deflagration-to-detonation transition in granular HMX

    NASA Technical Reports Server (NTRS)

    Campbell, A. W.

    1980-01-01

    Granular HMX of three degrees of fineness was packed into heavy-walled steel tubes closed at both ends. Ignition was obtained at one end using an intimate mixture of finely divided titanium and boron as an igniter that produced heat with little gas. The distance to detonation was determined by examination of the resulting tube fragments. By inserting tightly-fitted neoprene diaphragms periodically into the HMX column, it was shown that the role of convective combustion was limited to the initial stage of the deflagration to detonation (DDT) process. Experiments in which various combinations of two of the three types of HMX were loaded into the same tube showed that heating by adiabatic shear of explosive grains was an essential factor in the final buildup to detonation. A description of the DDT process is developed in which conductive burning is followed in turn by convective burning, bed collapse with plug formation, onset of accelerated burning at the front of the plug through heating by intercrystalline friction and adiabatic shear, and intense shock formation resulting in high-order detonation.

  5. On the neutralization of bacterial spores in post-detonation flows

    NASA Astrophysics Data System (ADS)

    Gottiparthi, K. C.; Schulz, J. C.; Menon, S.

    2014-09-01

    In multiple operational scenarios, explosive charges are used to neutralize confined or unconfined stores of bacterial spores. The spore destruction is achieved by post-detonation combustion and mixing of hot detonation product gases with the ambient flow and spore clouds. In this work, blast wave interaction with bacterial spore clouds and the effect of post-detonation combustion on spore neutralization are investigated using numerical simulations. Spherical explosive charges (radius, = 5.9 cm) comprising of nitromethane are modeled in the vicinity of a spore cloud, and the spore kill in the post-detonation flow is quantified. The effect of the mass of the spores and the initial distance, , of the spore cloud from the explosive charge on the percentage of spores neutralized is investigated. When the spores are initially placed within a distance of 3.0, within 0.1 ms after detonation of the charge, all the spores are neutralized by the blast wave and the hot detonation product gases. In contrast, almost all the spores survived the explosion when is greater than 8.0. The percentage of intact spores varied from 0 to 100 for 3.0 8.0 with spore neutralization dependent on time spent by the spores in the post-detonation mixing/combustion zone.

  6. Improved detonation modeling with CHEETAH

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Heller, A.

    1997-11-01

    A Livermore software program called CHEETAH, an important, even indispensable tool for energetic materials researchers worldwide, was made more powerful in the summer of 1997 with the release of CHEETAH 2.0, an advanced version that simulates a wider variety of detonations. Derived from more than 40 years of experiments on high explosives at Lawrence Livermore and Los Alamos national laboratories, CHEETAH predicts the results from detonating a mixture of specified reactants. It operates by solving thermodynamic equations to predict detonation products and such properties as temperature, pressure, volume, and total energy released. The code is prized by synthesis chemists andmore » other researchers because it allows them to vary the starting molecules and conditions to optimize the desired performance properties. One of the Laboratory`s most popular computer codes, CHEETAH is used at more than 200 sites worldwide, including ones in England, Canada, Sweden, Switzerland, and France. Most sites are defense-related, although a few users, such as Japanese fireworks researchers, are in the civilian sector.« less

  7. Detonation of Meta-stable Clusters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kuhl, Allen; Kuhl, Allen L.; Fried, Laurence E.

    2008-05-31

    We consider the energy accumulation in meta-stable clusters. This energy can be much larger than the typical chemical bond energy (~;;1 ev/atom). For example, polymeric nitrogen can accumulate 4 ev/atom in the N8 (fcc) structure, while helium can accumulate 9 ev/atom in the excited triplet state He2* . They release their energy by cluster fission: N8 -> 4N2 and He2* -> 2He. We study the locus of states in thermodynamic state space for the detonation of such meta-stable clusters. In particular, the equilibrium isentrope, starting at the Chapman-Jouguet state, and expanding down to 1 atmosphere was calculated with the Cheetahmore » code. Large detonation pressures (3 and 16 Mbar), temperatures (12 and 34 kilo-K) and velocities (20 and 43 km/s) are a consequence of the large heats of detonation (6.6 and 50 kilo-cal/g) for nitrogen and helium clusters respectively. If such meta-stable clusters could be synthesized, they offer the potential for large increases in the energy density of materials.« less

  8. On the Initiation Mechanism in Exploding Bridgewire and Laser Detonators

    NASA Astrophysics Data System (ADS)

    Stewart, D. Scott; Thomas, Keith A.; Clarke, S.; Mallett, H.; Martin, E.; Martinez, M.; Munger, A.; Saenz, Juan

    2006-07-01

    Since its invention by Los Alamos during the Manhattan Project era the exploding bridgewire detonator (EBW) has seen tremendous use and study. Recent development of a laser-powered device with detonation properties similar to an EBW is reviving interest in the basic physics of the deflagration-to-detonation (DDT) process in both of these devices. Cutback experiments using both laser interferometry and streak camera observations are providing new insight into the initiation mechanism in EBWs. These measurements are being correlated to a DDT model of compaction to detonation and shock to detonation developed previously by Xu and Stewart. The DDT model is incorporated into a high-resolution, multi-material model code for simulating the complete process. Model formulation and the modeling issues required to describe the test data will be discussed.

  9. Equation of state of detonation products based on statistical mechanical theory

    NASA Astrophysics Data System (ADS)

    Zhao, Yanhong; Liu, Haifeng; Zhang, Gongmu; Song, Haifeng

    2015-06-01

    The equation of state (EOS) of gaseous detonation products is calculated using Ross's modification of hard-sphere variation theory and the improved one-fluid van der Waals mixture model. The condensed phase of carbon is a mixture of graphite, diamond, graphite-like liquid and diamond-like liquid. For a mixed system of detonation products, the free energy minimization principle is used to calculate the equilibrium compositions of detonation products by solving chemical equilibrium equations. Meanwhile, a chemical equilibrium code is developed base on the theory proposed in this article, and then it is used in the three typical calculations as follow: (i) Calculation for detonation parameters of explosive, the calculated values of detonation velocity, the detonation pressure and the detonation temperature are in good agreement with experimental ones. (ii) Calculation for isentropic unloading line of RDX explosive, whose starting points is the CJ point. Comparison with the results of JWL EOS it is found that the calculated value of gamma is monotonically decreasing using the presented theory in this paper, while double peaks phenomenon appears using JWL EOS.

  10. Equation of state of detonation products based on statistical mechanical theory

    NASA Astrophysics Data System (ADS)

    Zhao, Yanhong; Liu, Haifeng; Zhang, Gongmu; Song, Haifeng; Iapcm Team

    2013-06-01

    The equation of state (EOS) of gaseous detonation products is calculated using Ross's modification of hard-sphere variation theory and the improved one-fluid van der Waals mixture model. The condensed phase of carbon is a mixture of graphite, diamond, graphite-like liquid and diamond-like liquid. For a mixed system of detonation products, the free energy minimization principle is used to calculate the equilibrium compositions of detonation products by solving chemical equilibrium equations. Meanwhile, a chemical equilibrium code is developed base on the theory proposed in this article, and then it is used in the three typical calculations as follow: (i) Calculation for detonation parameters of explosive, the calculated values of detonation velocity, the detonation pressure and the detonation temperature are in good agreement with experimental ones. (ii) Calculation for isentropic unloading line of RDX explosive, whose starting points is the CJ point. Comparison with the results of JWL EOS it is found that the calculated value of gamma is monotonically decreasing using the presented theory in this paper, while double peaks phenomenon appears using JWL EOS.

  11. Non-Ideal Detonation Properties of Ammonium Nitrate and Activated Carbon Mixtures

    NASA Astrophysics Data System (ADS)

    Miyake, Atsumi; Echigoya, Hiroshi; Kobayashi, Hidefumi; Ogawa, Terushige; Katoh, Katsumi; Kubota, Shiro; Wada, Yuji; Ogata, Yuji

    To obtain a better understanding of detonation properties of ammonium nitrate (AN) and activated carbon (AC) mixtures, steel tube tests with several diameters were carried out for various compositions of powdered AN and AC mixtures and the influence of the charge diameter on the detonation velocity was investigated. The results showed that the detonation velocity increased with the increase of the charge diameter. The experimentally observed values were far below the theoretically predicted values made by the thermodynamic CHEETAH code and they showed so-called non-ideal detonation. The extrapolated detonation velocity of stoichiometric composition to the infinite diameter showed a good agreement with the theoretical value.

  12. Modeling Hemispheric Detonation Experiments in 2-Dimensions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Howard, W M; Fried, L E; Vitello, P A

    2006-06-22

    Experiments have been performed with LX-17 (92.5% TATB and 7.5% Kel-F 800 binder) to study scaling of detonation waves using a dimensional scaling in a hemispherical divergent geometry. We model these experiments using an arbitrary Lagrange-Eulerian (ALE3D) hydrodynamics code, with reactive flow models based on the thermo-chemical code, Cheetah. The thermo-chemical code Cheetah provides a pressure-dependent kinetic rate law, along with an equation of state based on exponential-6 fluid potentials for individual detonation product species, calibrated to high pressures ({approx} few Mbars) and high temperatures (20000K). The parameters for these potentials are fit to a wide variety of experimental data,more » including shock, compression and sound speed data. For the un-reacted high explosive equation of state we use a modified Murnaghan form. We model the detonator (including the flyer plate) and initiation system in detail. The detonator is composed of LX-16, for which we use a program burn model. Steinberg-Guinan models5 are used for the metal components of the detonator. The booster and high explosive are LX-10 and LX-17, respectively. For both the LX-10 and LX-17, we use a pressure dependent rate law, coupled with a chemical equilibrium equation of state based on Cheetah. For LX-17, the kinetic model includes carbon clustering on the nanometer size scale.« less

  13. Assessment of the MC3608 detonator shipping package hazard classification

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jones, R.B.

    1981-08-07

    An investigation was made to determine whether the MC 3608 Detonator should be assigned a DOT hazard classification of Detonating Fuze, Class C Explosive, per 49 CFR 173.113. This study covers the propagation test as approved by DOE-Albuquerque Operations Office. Analysis of the test data led to the recommended hazard classification of Detonating Fuze, Class C Explosive.

  14. Near-failure detonation behavior of vapor-deposited hexanitrostilbene (HNS) films

    NASA Astrophysics Data System (ADS)

    Knepper, Robert; Wixom, Ryan R.; Marquez, Michael P.; Tappan, Alexander S.

    2017-01-01

    Hexanitrostilbene (HNS) films were deposited onto polycarbonate substrates using vacuum thermal sublimation. The deposition conditions were varied in order to alter porosity in the films, and the resulting microstructures were quantified by analyzing ion-polished cross-sections using scanning electron microscopy. The effects of these changes in microstructure on detonation velocity and the critical thickness needed to sustain detonation were determined. The polycarbonate substrates also acted as recording plates for detonation experiments, and films near the critical thickness displayed distinct patterns in the dent tracks that indicate instabilities in the detonation front when approaching failure conditions.

  15. Detonation Performance Testing of LX-19

    NASA Astrophysics Data System (ADS)

    Vincent, Samuel; Aslam, Tariq; Jackson, Scott

    2015-06-01

    CL-20 was developed at the Naval Surface Weapons Center at China Lake, CA in the mid 80's. Being less sensitive than PETN, but considerably more powerful than HMX, it is the highest energy and density compound known among organic chemicals. LX-19 was developed at LLNL in the early 90's. It is a high-energy plastic bonded explosive, composed of 95.8 wt% CL-20 and 4.2 wt% Estane binder, and is similar to LX-14 (composed of HMX and Estane), but with greater sensitivity characteristics with use of the more energetic CL-20 explosive. We report detonation performance results for unconfined cylindrical rate sticks of LX-19. The experimental diameter effects are shown, along with detonation front shapes, and reaction zone profiles for different test diameters. This data is critical for calibration to Detonation Shock Dynamics (DSD). LA-UR-15-20672.

  16. Combustion and Magnetohydrodynamic Processes in Advanced Pulse Detonation Rocket Engines

    NASA Astrophysics Data System (ADS)

    Cole, Lord Kahil

    A number of promising alternative rocket propulsion concepts have been developed over the past two decades that take advantage of unsteady combustion waves in order to produce thrust. These concepts include the Pulse Detonation Rocket Engine (PDRE), in which repetitive ignition, propagation, and reflection of detonations and shocks can create a high pressure chamber from which gases may be exhausted in a controlled manner. The Pulse Detonation Rocket Induced Magnetohydrodynamic Ejector (PDRIME) is a modification of the basic PDRE concept, developed by Cambier (1998), which has the potential for performance improvements based on magnetohydrodynamic (MHD) thrust augmentation. The PDRIME has the advantage of both low combustion chamber seeding pressure, per the PDRE concept, and efficient energy distribution in the system, per the rocket-induced MHD ejector (RIME) concept of Cole, et al. (1995). In the initial part of this thesis, we explore flow and performance characteristics of different configurations of the PDRIME, assuming quasi-one-dimensional transient flow and global representations of the effects of MHD phenomena on the gas dynamics. By utilizing high-order accurate solvers, we thus are able to investigate the fundamental physical processes associated with the PDRIME and PDRE concepts and identify potentially promising operating regimes. In the second part of this investigation, the detailed coupling of detonations and electric and magnetic fields are explored. First, a one-dimensional spark-ignited detonation with complex reaction kinetics is fully evaluated and the mechanisms for the different instabilities are analyzed. It is found that complex kinetics in addition to sufficient spatial resolution are required to be able to quantify high frequency as well as low frequency detonation instability modes. Armed with this quantitative understanding, we then examine the interaction of a propagating detonation and the applied MHD, both in one-dimensional and two

  17. Design and optimization of a deflagration to detonation transition (ddt) section

    NASA Astrophysics Data System (ADS)

    Romo, Francisco X.

    Throughout the previous century, hydrocarbon-fueled engines have used and optimized the `traditional' combustion process called deflagration (subsonic combustion). An alternative form of combustion, detonation (supersonic combustion), can increase the thermal efficiency of the process by anywhere from 20 - 50%. Even though several authors have studied detonation waves since the 1890's and a plethora of papers and books have been published, it was not until 2008 that the first detonation-powered flight took place. It lasted for 10 seconds at 100 ft. altitude. Achieving detonation presents its own challenges: some fuels are not prone to detonate, severe vibrations caused by the cyclic nature of the engine and its intense noise are some of the key areas that need further research. Also, to directly achieve detonation either a high-energy, bulky, ignition system is required, or the combustion chamber must be fairly long (5 ft. or more in some cases). In the latter method, a subsonic flame front accelerates within the combustion chamber until it reaches supersonic speeds, thus detonation is attained. This is called deflagration-todetonation transition (DDT). Previous papers and experiments have shown that obstacles, such as discs with an orifice, located inside the combustion chamber can shorten the distance required to achieve detonation. This paper describes a hands-on implementation of a DDT device. Different disc geometries inside the chamber alter the wave characteristics at the exit of the tube. Although detonation was reached only when using pure oxygen, testing identified an obstacle configuration for LPG and air mixtures that increased pressure and wave speed significantly when compared to baseline or other obstacle configurations. Mixtures of LPG and air were accelerated to Mach 0.96 in the downstream frame of reference, which would indicate a transition to detonation was close. Reasons for not achieving detonation may include poor fuel and oxidizer mixing

  18. Detonation Diffraction in a Multi-Step Channel

    DTIC Science & Technology

    2010-12-01

    openings. This allowed the detonation wave diffraction transmission limits to be determined for hydrogen/air mixtures and to better understand...imaging systems to provide shock wave detail and velocity information. The images were observed through a newly designed explosive proof optical section...stepped openings. This allowed the detonation wave diffraction transmission limits to be determined for hydrogen/air mixtures and to better

  19. The development and testing of pulsed detonation engine ground demonstrators

    NASA Astrophysics Data System (ADS)

    Panicker, Philip Koshy

    2008-10-01

    The successful implementation of a PDE running on fuel and air mixtures will require fast-acting fuel-air injection and mixing techniques, detonation initiation techniques such as DDT enhancing devices or a pre-detonator, an effective ignition system that can sustain repeated firing at high rates and a fast and capable, closed-loop control system. The control system requires high-speed transducers for real-time monitoring of the PDE and the detection of the detonation wave speed. It is widely accepted that the detonation properties predicted by C-J detonation relations are fairly accurate in comparison to experimental values. The post-detonation flow properties can also be expressed as a function of wave speed or Mach number. Therefore, the PDE control system can use C-J relations to predict the post-detonation flow properties based on measured initial conditions and compare the values with those obtained from using the wave speed. The controller can then vary the initial conditions within the combustor for the subsequent cycle, by modulating the frequency and duty cycle of the valves, to obtain optimum air and fuel flow rates, as well as modulate the energy and timing of the ignition to achieve the required detonation properties. Five different PDE ground demonstrators were designed, built and tested to study a number of the required sub-systems. This work presents a review of all the systems that were tested, along with suggestions for their improvement. The PDE setups, ranged from a compact PDE with a 19 mm (3/4 in.) i.d., to two 25 mm (1 in.) i.d. setups, to a 101 mm (4 in.) i.d. dual-stage PDE setup with a pre-detonator. Propane-oxygen mixtures were used in the smaller PDEs. In the dual-stage PDE, propane-oxygen was used in the pre-detonator, while propane-air mixtures were used in the main combustor. Both rotary valves and solenoid valve injectors were studied. The rotary valves setups were tested at 10 Hz, while the solenoid valves were tested at up to 30 Hz

  20. Modeling the Effects of Turbulence in Rotating Detonation Engines

    NASA Astrophysics Data System (ADS)

    Towery, Colin; Smith, Katherine; Hamlington, Peter; van Schoor, Marthinus; TESLa Team; Midé Team

    2014-03-01

    Propulsion systems based on detonation waves, such as rotating and pulsed detonation engines, have the potential to substantially improve the efficiency and power density of gas turbine engines. Numerous technical challenges remain to be solved in such systems, however, including obtaining more efficient injection and mixing of air and fuels, more reliable detonation initiation, and better understanding of the flow in the ejection nozzle. These challenges can be addressed using numerical simulations. Such simulations are enormously challenging, however, since accurate descriptions of highly unsteady turbulent flow fields are required in the presence of combustion, shock waves, fluid-structure interactions, and other complex physical processes. In this study, we performed high-fidelity three dimensional simulations of a rotating detonation engine and examined turbulent flow effects on the operation, performance, and efficiency of the engine. Along with experimental data, these simulations were used to test the accuracy of commonly-used Reynolds averaged and subgrid-scale turbulence models when applied to detonation engines. The authors gratefully acknowledge the support of the Defense Advanced Research Projects Agency (DARPA).

  1. JAGUAR Procedures for Detonation Behavior of Explosives Containing Boron

    NASA Astrophysics Data System (ADS)

    Stiel, Leonard; Baker, Ernest; Capellos, Christos

    2009-06-01

    The JAGUAR product library was expanded to include boron and boron containing products. Relationships of the Murnaghan form for molar volumes and derived properties were implemented in JAGUAR. Available Hugoniot and static volumertic data were analyzed to obtain constants of the Murnaghan relationship for solid boron, boron oxide, boron nitride, boron carbide, and boric acid. Experimental melting points were also utilized with optimization procedures to obtain the constants of the volumetric relationships for liquid boron and boron oxide. Detonation velocities for HMX - boron mixtures calculated with these relationships using JAGUAR are in closer agreement with literature values at high initial densities for inert (unreacted) boron than with the completely reacted metal. These results indicate that boron mixtures may exhibit eigenvalue detonation behavior, as observed by aluminized combined effects explosives, with higher detonation velocities than would be achieved by a classical Chapman-Jouguet detonation. Analyses of calorimetric measurements for RDX - boron mixtures indicate that at high boron contents the formation of side products, including boron nitride and boron carbide, inhibits the energy output obtained from the detonation of the formulation.

  2. Ignition Study on a Rotary-valved Air-breathing Pulse Detonation Engine

    NASA Astrophysics Data System (ADS)

    Wu, Yuwen; Han, Qixiang; Shen, Yujia; Zhao, Wei

    2017-05-01

    In the present study, the ignition effect on detonation initiation was investigated in the air-breathing pulse detonation engine. Two kinds of fuel injection and ignition methods were applied. For one method, fuel and air was pre-mixed outside the PDE and then injected into the detonation tube. The droplet sizes of mixtures were measured. An annular cavity was used as the ignition section. For the other method, fuel-air mixtures were mixed inside the PDE, and a pre-combustor was utilized as the ignition source. At firing frequency of 20 Hz, transition to detonation was obtained. Experimental results indicated that the ignition position and initial flame acceleration had important effects on the deflagration-to-detonation transition.

  3. Subnanosecond measurements of detonation fronts in solid high explosives

    NASA Astrophysics Data System (ADS)

    Sheffield, S. A.; Bloomquist, D. D.; Tarver, C. M.

    1984-04-01

    Detonation fronts in solid high explosives have been examined through measurements of particle velocity histories resulting from the interaction of a detonation wave with a thin metal foil backed by a water window. Using a high time resolution velocity-interferometer system, experiments were conducted on three explosives—a TATB (1,3,5-triamino-trinitrobenzene)-based explosive called PBX-9502, TNT (2,4,6-Trinitrotoluene), and CP (2-{5-cyanotetrazolato} pentaamminecobalt {III} perchlorate). In all cases, detonation-front rise times were found to be less than the 300 ps resolution of the interferometer system. The thermodynamic state in the front of the detonation wave was estimated to be near the unreacted state determined from an extrapolation of low-pressure unreacted Hugoniot data for both TNT and PBX-9502 explosives. Computer calculations based on an ignition and growth model of a Zeldovich-von Neumann-Doering (ZND) detonation wave show good agreement with the measurements. By using the unreacted Hugoniot and a JWL equation of state for the reaction products, we estimated the initial reaction rate in the high explosive after the detonation wave front interacted with the foil to be 40 μs-1 for CP, 60 μs-1 for TNT, and 80 μs-1 for PBX-9502. The shape of the profiles indicates the reaction rate decreases as reaction proceeds.

  4. Chemical Energy Release in Several Recently Discovered Detonation and Deflagration Flows

    NASA Astrophysics Data System (ADS)

    Tarver, Craig M.

    2010-10-01

    Several recent experiments on complex detonation and deflagration flows are analyzed in terms of the chemical energy release required to sustain these flows. The observed double cellular structures in detonating gaseous nitromethane-oxygen and NO2-fuel (H2, CH4, and C2H6) mixtures are explained by the amplification of two distinct pressure wave frequencies by two exothermic reactions, the faster reaction forming vibrationally excited NO* and the slower reaction forming highly vibrationally excited N2**. The establishment of a Chapman-Jouguet (C-J) deflagration behind a weak shock wave, the C-J detonation established after a head-on collision with a shock front, and the C-J detonation conditions established in reactive supersonic flows are quantitatively calculated using the chemical energy release of a H2 + Cl2 mixture. For these three reactive flows, these calculations illustrate that different fractions of the exothermic chemical energy are used to sustain steady-state propagation. C-J detonation calculations on the various initial states using the CHEETAH chemical equilibrium code are shown to be in good agreement with experimental detonation velocity measurements for the head-on collision and supersonic flow detonations.

  5. Equation of State for Detonation Product Gases

    NASA Astrophysics Data System (ADS)

    Nagayama, Kunihito; Kubota, Shiro

    2013-06-01

    Based on the empirical linear relationship between detonation velocity and loading density, an approximate description for the Chapman-Jouguet state for detonation product gases of solid phase high explosives has been developed. Provided that the Grüneisen parameter is a function only of volume, systematic and closed system of equations for the Grüneisen parameter and CJ volume have been formulated. These equations were obtained by combining this approximation with the Jones-Stanyukovich-Manson relation together with JWL isentrope for detonation of crystal density PETN. A thermodynamic identity between the Grüneisen parameter and another non-dimensional material parameter introduced by Wu and Jing can be used to derive the enthalpy-pressure-volume equation of state for detonation gases. This Wu-Jing parameter is found to be the ratio of the Grüneisen parameter and the adiabatic index. Behavior of this parameter as a function of pressure was calculated and revealed that their change with pressure is very gradual. By using this equation of state, several isentropes down from the Chapman-Jouguet states reached by four different lower initial density PETN have been calculated and compared with available cylinder expansion tests.

  6. Momentum and Heat Transfer Models for Detonation in Nitromethane with Metal Particles

    NASA Astrophysics Data System (ADS)

    Ripley, R. C.; Zhang, F.; Lien, F.-S.

    2009-12-01

    Models for momentum and heat exchange have been derived from the results of previous 3D mesoscale simulations of detonation in packed aluminum particles saturated with nitromethane, where the shock interaction timescale was resolved. In these models, particle acceleration and heating within the shock and detonation zone are expressed in terms of velocity and temperature transmission factors, which are a function of the metal to explosive density ratio, solid volume fraction and ratio of particle size to detonation zone thickness. These models are incorporated as source terms in the governing equations for continuum dense two-phase flow, and then applied to macroscopic simulation of detonation of nitromethane/aluminum in lightly-cased cylinders. Heterogeneous detonation features such as velocity deficit, enhanced pressure, and critical diameter effects are demonstrated. Various spherical particle diameters from 3-350 μm are utilized where most of the particles react in the expanding detonation products. Results for detonation velocity, pressure history, failure and U-shaped critical diameter behavior are compared to existing experiments.

  7. Helium in double-detonation models of type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Boyle, Aoife; Sim, Stuart A.; Hachinger, Stephan; Kerzendorf, Wolfgang

    2017-03-01

    The double-detonation explosion model has been considered a candidate for explaining astrophysical transients with a wide range of luminosities. In this model, a carbon-oxygen white dwarf star explodes following detonation of a surface layer of helium. One potential signature of this explosion mechanism is the presence of unburned helium in the outer ejecta, left over from the surface helium layer. In this paper we present simple approximations to estimate the optical depths of important He I lines in the ejecta of double-detonation models. We use these approximations to compute synthetic spectra, including the He I lines, for double-detonation models obtained from hydrodynamical explosion simulations. Specifically, we focus on photospheric-phase predictions for the near-infrared 10 830 Å and 2 μm lines of He I. We first consider a double detonation model with a luminosity corresponding roughly to normal SNe Ia. This model has a post-explosion unburned He mass of 0.03 M⊙ and our calculations suggest that the 2 μm feature is expected to be very weak but that the 10 830 Å feature may have modest opacity in the outer ejecta. Consequently, we suggest that a moderate-to-weak He I 10 830 Å feature may be expected to form in double-detonation explosions at epochs around maximum light. However, the high velocities of unburned helium predicted by the model ( 19 000 km s-1) mean that the He I 10 830 Å feature may be confused or blended with the C I 10 690 Å line forming at lower velocities. We also present calculations for the He I 10 830 Å and 2 μm lines for a lower mass (low luminosity) double detonation model, which has a post-explosion He mass of 0.077 M⊙. In this case, both the He I features we consider are strong and can provide a clear observational signature of the double-detonation mechanism.

  8. The Use of Steady and Unsteady Detonation Waves for Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Adelman, Henry G.; Menees, Gene P.; Cambier, Jean-Luc; Bowles, Jeffrey V.; Cavolowsky, John A. (Technical Monitor)

    1995-01-01

    Detonation wave enhanced supersonic combustors such as the Oblique Detonation Wave Engine (ODWE) are attractive propulsion concepts for hypersonic flight. These engines utilize detonation waves to enhance fuel-air mixing and combustion. The benefits of wave combustion systems include shorter and lighter engines which require less cooling and generate lower internal drag. These features allow air-breathing operation at higher Mach numbers than the diffusive burning scramjet delaying the need for rocket engine augmentation. A comprehensive vehicle synthesis code has predicted the aerodynamic characteristics and structural size and weight of a typical single-stage-to-orbit vehicle using an ODWE. Other studies have focused on the use of unsteady or pulsed detonation waves. For low speed applications, pulsed detonation engines (PDE) have advantages in low weight and higher efficiency than turbojets. At hypersonic speeds, the pulsed detonations can be used in conjunction with a scramjet type engine to enhance mixing and provide thrust augmentation.

  9. A review of direct numerical simulations of astrophysical detonations and their implications

    DOE PAGES

    Parete-Koon, Suzanne T.; Smith, Christopher R.; Papatheodore, Thomas L.; ...

    2013-04-11

    Multi-dimensional direct numerical simulations (DNS) of astrophysical detonations in degenerate matter have revealed that the nuclear burning is typically characterized by cellular structure caused by transverse instabilities in the detonation front. Type Ia supernova modelers often use one- dimensional DNS of detonations as inputs or constraints for their whole star simulations. While these one-dimensional studies are useful tools, the true nature of the detonation is multi-dimensional. The multi-dimensional structure of the burning influences the speed, stability, and the composition of the detonation and its burning products, and therefore, could have an impact on the spectra of Type Ia supernovae. Considerablemore » effort has been expended modeling Type Ia supernovae at densities above 1x10 7 g∙cm -3 where the complexities of turbulent burning dominate the flame propagation. However, most full star models turn the nuclear burning schemes off when the density falls below 1x10 7 g∙cm -3 and distributed burning begins. The deflagration to detonation transition (DDT) is believed to occur at just these densities and consequently they are the densities important for studying the properties of the subsequent detonation. In conclusion, this work reviews the status of DNS studies of detonations and their possible implications for Type Ia supernova models. It will cover the development of Detonation theory from the first simple Chapman-Jouguet (CJ) detonation models to the current models based on the time-dependent, compressible, reactive flow Euler equations of fluid dynamics.« less

  10. Integrated Pulse Detonation Propulsion and Magnetohydrodynamic Power

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.

    2001-01-01

    The prospects for realizing an integrated pulse detonation propulsion and magnetohydrodynamic (MHD) power system are examined. First, energy requirements for direct detonation initiation of various fuel-oxygen and fuel-air mixtures are deduced from available experimental data and theoretical models. Second, the pumping power requirements for effective chamber scavenging are examined through the introduction of a scavenging ratio parameter and a scavenging efficiency parameter. A series of laboratory experiments were carried out to investigate the basic engineering performance characteristics of a pulse detonation-driven MHD electric power generator. In these experiments, stoichiometric oxy-acetylene mixtures seeded with a cesium hydroxide/methanol spray were detonated at atmospheric pressure in a 1-m-long tube having an i.d. of 2.54 cm. Experiments with a plasma diagnostic channel attached to the end of the tube confirmed the attainment of detonation conditions (p2/p1 approximately 34 and D approximately 2,400 m/sec) and enabled the direct measurement of current density and electrical conductivity (approximately = 6 S/m) behind the detonation wave front, In a second set of experiments, a 30-cm-long continuous electrode Faraday channel, having a height of 2.54 cm and a width of 2 cm, was attached to the end of the tube using an area transition duct. The Faraday channel was inserted in applied magnetic fields of 0.6 and 0.95 T, and the electrodes were connected to an active loading circuit to characterize power extraction dependence on load impedance while also simulating higher effective magnetic induction. The experiments indicated peak power extraction at a load impedance between 5 and 10 Omega. The measured power density was in reasonable agreement with a simple electrodynamic model incorporating a correction for near-electrode potential losses. The time-resolved thrust characteristics of the system were also measured, and it was found that the NM interaction

  11. Integrated Pulse Detonation Propulsion and Magnetohydrodynamic Power

    NASA Technical Reports Server (NTRS)

    Litchford, R. J.; Lyles, Garry M. (Technical Monitor)

    2001-01-01

    The prospects for realizing an integrated pulse detonation propulsion and magnetohydrodynamic (MHD) power system are examined. First, energy requirements for direct detonation initiation of various fuel-oxygen and fuel-air mixtures are deduced from available experimental data and theoretical models. Second, the pumping power requirements for effective chamber scavenging are examined through the introduction of a scavenging ratio parameter and a scavenging efficiency parameter. A series of laboratory experiments were carried out to investigate the basic engineering performance characteristics of a pulse detonation-driven MHD electric power generator. In these experiments, stoichiometric oxy-acetylene mixtures seeded with a cesium hydroxide/methanol spray were detonated at atmospheric pressure in a 1-m-long tube having an i.d. of 2.54 cm. Experiments with a plasma diagnostic channel attached to the end of the tube confirmed the attainment of detonation conditions (p(sub 2)/p(sub 1) approx. 34 and D approx. 2,400 m/sec) and enabled the direct measurement of current density and electrical conductivity (=6 S/m) behind the detonation wave front. In a second set of experiments, a 30-cm-long continuous electrode Faraday channel, having a height of 2.54 cm and a width of 2 cm, was attached to the end of the tube using an area transition duct. The Faraday channel was inserted in applied magnetic fields of 0.6 and 0.95 T. and the electrodes were connected to an active loading circuit to characterize power extraction dependence on load impedance while also simulating higher effective magnetic induction. The experiments indicated peak power extraction at a load impedance between 5 and 10 Ohm. The measured power density was in reasonable agreement with a simple electrodynamic model incorporating a correction for near-electrode potential losses. The time-resolved thrust characteristics of the system were also measured, and it was found that the MHD interaction exerted a

  12. Quenching tank: Accidental drowning in hot quenching oil.

    PubMed

    Mugadlimath, Anand B; Sane, Mandar Ramchandra; Zine, Kailash U; Hiremath, Rekha M

    2017-06-01

    We describe an unusual case of drowning in fluid other than water in an industrial setting. A 26-year-old man was working in an industry which performs surface treatment of mechanical steel parts with quenching oil. He fell into the quenching oil (which was hot due to immersion of red hot metal parts), and as he was working alone in the particular section, there was a fatal outcome. A medico-legal autopsy was performed. The causes of death were found to be multiple, with the association of drowning, extensive superficial burns and asphyxia due to laryngeal oedema. To our knowledge, it is the first report of drowning in hot quenching oil, and only nine previous observations of drowning in industrial environments have been reported in the international literature. Even though rare, these kinds of accidental deaths can be prevented in dangerous industries with proper precautions and strict adherence to standard operating procedures.

  13. Numerical modelling of underwater detonation of non-ideal condensed-phase explosives

    NASA Astrophysics Data System (ADS)

    Schoch, Stefan; Nikiforakis, Nikolaos

    2015-01-01

    The interest in underwater detonation tests originated from the military, since the expansion and subsequent collapse of the explosive bubble can cause considerable damage to surrounding structures or vessels. In military applications, the explosive is typically represented as a pre-burned material under high pressure, a reasonable assumption due to the short reaction zone lengths, and complete detonation of the unreacted explosive. Hence, numerical simulations of underwater detonation tests have been primarily concerned with the prediction of target loading and the damage incurred rather than the accurate modelling of the underwater detonation process. The mining industry in contrast has adopted the underwater detonation test as a means to experimentally characterise the energy output of their highly non-ideal explosives depending on explosive type and charge configuration. This characterisation requires a good understanding of how the charge shape, pond topography, charge depth, and additional charge confinement affect the energy release, some of which can be successfully quantified with the support of accurate numerical simulations. In this work, we propose a numerical framework which is able to capture the non-ideal explosive behaviour and in addition is capable of capturing both length scales: the reaction zone and the pond domain. The length scale problem is overcome with adaptive mesh refinement, which, along with the explosive model, is validated against experimental data of various TNT underwater detonations. The variety of detonation and bubble behaviour observed in non-ideal detonations is demonstrated in a parameter study over the reactivity of TNT. A representative underwater mining test containing an ammonium-nitrate fuel-oil ratestick charge is carried out to demonstrate that the presented method can be readily applied alongside experimental underwater detonation tests.

  14. Munitions having an insensitive detonator system for initiating large failure diameter explosives

    DOEpatents

    Perry, III, William Leroy

    2015-08-04

    A munition according to a preferred embodiment can include a detonator system having a detonator that is selectively coupled to a microwave source that functions to selectively prime, activate, initiate, and/or sensitize an insensitive explosive material for detonation. The preferred detonator can include an explosive cavity having a barrier within which an insensitive explosive material is disposed and a waveguide coupled to the explosive cavity. The preferred system can further include a microwave source coupled to the waveguide such that microwaves enter the explosive cavity and impinge on the insensitive explosive material to sensitize the explosive material for detonation. In use the preferred embodiments permit the deployment and use of munitions that are maintained in an insensitive state until the actual time of use, thereby substantially preventing unauthorized or unintended detonation thereof.

  15. Equations of state for explosive detonation products: The PANDA model

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kerley, G.I.

    1994-05-01

    This paper discusses a thermochemical model for calculating equations of state (EOS) for the detonation products of explosives. This model, which was first presented at the Eighth Detonation Symposium, is available in the PANDA code and is referred to here as ``the Panda model``. The basic features of the PANDA model are as follows. (1) Statistical-mechanical theories are used to construct EOS tables for each of the chemical species that are to be allowed in the detonation products. (2) The ideal mixing model is used to compute the thermodynamic functions for a mixture of these species, and the composition ofmore » the system is determined from assumption of chemical equilibrium. (3) For hydrocode calculations, the detonation product EOS are used in tabular form, together with a reactive burn model that allows description of shock-induced initiation and growth or failure as well as ideal detonation wave propagation. This model has been implemented in the three-dimensional Eulerian code, CTH.« less

  16. Near-Failure Detonation Behavior of Vapor-Deposited Hexanitrostilbene (HNS) Films

    NASA Astrophysics Data System (ADS)

    Knepper, Robert; Wixom, Ryan; Tappan, Alexander

    2015-06-01

    Physical vapor deposition is an attractive method to produce sub-millimeter explosive samples for studying detonation behavior at near-failure conditions. In this work, we examine hexanitrostilbene (HNS) films deposited onto polycarbonate substrates using vacuum thermal sublimation. Deposition conditions are varied in order to alter porosity in the films, and the resulting microstructures are quantified by analyzing ion-polished cross-sections using scanning electron microscopy. The effects of these changes in microstructure on detonation velocity and the critical thickness needed to sustain detonation are determined. The polycarbonate substrates can act as recording plates for detonation experiments, and films near the critical thickness display distinct patterns in the dent tracks that indicate instabilities in the detonation front when approaching failure conditions. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  17. Equation of State of Detonation Products for TNT by Aquarium Technique

    NASA Astrophysics Data System (ADS)

    Han, Yong

    2017-06-01

    During explosive detonation, the detonation pressure (P) and temperature (T) will decay quickly with the expansion of detonation products, and the damage effect is determined by the thermodynamic state of detonation products under high pressure. The traditional and important method for calibrating the parameters of thermodynamic state is cylinder test, but the results showed that when the cylinder expanded to a certain distance, the cylinder wall would break up and the detonation products would jet out, which would affect the accuracy of the calibration parameters of thermodynamic state. In this paper, the aquarium technique was used to study the detonation product thermodynamic state of TNT explosive, obtaining the shock wave track under the water and the trace of the interface between water and detonation products in the specific position with the high speed rotating mirror camera. By thermodynamic calculation program BKW and VHL, the parameters of equation of state were obtained. Using the parameters and the dynamic software LS-DYNA, the underwater explosion of TNT was simulated. Comparison with experimental results shows that the thermodynamic state parameters which is calculated by VHL is more accurate than that of BKW. It is concluded that the aquarium test is a more effective method to calibrate the thermodynamic state than cylinder test.

  18. Structure and Stability of One-Dimensional Detonations in Ethylene-Air Mixtures

    NASA Technical Reports Server (NTRS)

    Yungster, S.; Radhakrishnan, K.; Perkins, High D. (Technical Monitor)

    2003-01-01

    The propagation of one-dimensional detonations in ethylene-air mixtures is investigated numerically by solving the one-dimensional Euler equations with detailed finite-rate chemistry. The numerical method is based on a second-order spatially accurate total-variation-diminishing scheme and a point implicit, first-order-accurate, time marching algorithm. The ethylene-air combustion is modeled with a 20-species, 36-step reaction mechanism. A multi-level, dynamically adaptive grid is utilized, in order to resolve the structure of the detonation. Parametric studies over an equivalence ratio range of 0.5 less than phi less than 3 for different initial pressures and degrees of detonation overdrive demonstrate that the detonation is unstable for low degrees of overdrive, but the dynamics of wave propagation varies with fuel-air equivalence ratio. For equivalence ratios less than approximately 1.2 the detonation exhibits a short-period oscillatory mode, characterized by high-frequency, low-amplitude waves. Richer mixtures (phi greater than 1.2) exhibit a low-frequency mode that includes large fluctuations in the detonation wave speed; that is, a galloping propagation mode is established. At high degrees of overdrive, stable detonation wave propagation is obtained. A modified McVey-Toong short-period wave-interaction theory is in excellent agreement with the numerical simulations.

  19. Development of an Actuator for Flow Control Utilizing Detonation

    NASA Technical Reports Server (NTRS)

    Lonneman, Patrick J.; Cutler, Andrew D.

    2004-01-01

    Active flow control devices including mass injection systems and zero-net-mass flux actuators (synthetic jets) have been employed to delay flow separation. These devices are capable of interacting with low-speed, subsonic flows, but situations exist where a stronger crossflow interaction is needed. Small actuators that utilize detonation of premixed fuel and oxidizer should be capable of producing supersonic exit jet velocities. An actuator producing exit velocities of this magnitude should provide a more significant interaction with transonic and supersonic crossflows. This concept would be applicable to airfoils on high-speed aircraft as well as inlet and diffuser flow control. The present work consists of the development of a detonation actuator capable of producing a detonation in a single shot (one cycle). Multiple actuator configurations, initial fill pressures, oxidizers, equivalence ratios, ignition energies, and the addition of a turbulence generating device were considered experimentally and computationally. It was found that increased initial fill pressures and the addition of a turbulence generator aided in the detonation process. The actuators successfully produced Chapman-Jouguet detonations and wave speeds on the order of 3000 m/s.

  20. Detonation-to-shock wave transmission at a contact discontinuity

    NASA Astrophysics Data System (ADS)

    Peace, J. T.; Lu, F. K.

    2018-02-01

    The one-dimensional interaction of a detonation wave with a contact discontinuity was investigated analytically and experimentally for oxyhydrogen detonations. The analytical and experimental results showed that the transmitted shock through the contact surface and into a non-combustible gas can either be amplified or attenuated depending on the reflection type at the contact surface and on the ratio of acoustic impedance across it. Experiments were performed with a detonation-driven shock tube facility to determine the transmitted shock velocity into a non-combustible He/air mixture. The oxyhydrogen equivalence ratio in the detonation section was varied from 0.5 to 1.5, and the driven section He mole fraction was varied from 0.0 to 1.0 to test a broad range of acoustic impedance ratios ranging from approximately 0.36 to 1.69. The analytical results were shown to have acceptable agreement with the measured transmitted shock wave velocity in the case of a reflected rarefaction from the contact surface. Additionally, the results indicated that the detonation wave reaction zone properties could have an important role that influences the transmitted shock properties in the case of a reflected shock from the contact surface.

  1. Density Gradient Separation of Detonation Soot for Nanocarbon Characterization

    NASA Astrophysics Data System (ADS)

    Ringstrand, Bryan; Jungjohann, Katie; Seifert, Sonke; Firestone, Millicent; Podlesak, David

    2017-06-01

    Detonation of high explosives (HE) can expand our understanding of chemical bonding at extreme conditions as well as the opportunity to prepare carbon nanomaterials. In order to understand detonation mechanisms, nanocarbon characterization contained within the soot is paramount. Thus, benign purification methods for detonation soot are important for its characterization. Progress towards a non-traditional approach to detonation soot processing is presented. Purification of soot using heavy liquid media such as sodium polytungstate to separate soot components based on their density was tested based on the premise that different nanocarbons possess different densities [ ρ = 1.79 g/cm3 (graphene) and ρ = 3.05 g/cm3 (nanodiamond)]. Analysis using XRD, SAXS, WAXS, Raman, XPS, TEM, and NMR provided information about particle morphology and carbon hybridization. Detonation synthesis offers an avenue for the discovery of new carbon frameworks. In addition, understanding reactions at extreme conditions provides for more accurate predictions of HE performance, explosion intent, and simulation refinement. These results are of interest to both the nanoscience and shock physics communities. We acknowledge the support of the U.S. Department of Energy LANL/LDRD Program (LANL #20150050DR). LA-UR-17-21502.

  2. Momentum and Heat Transfer Models for Detonation in Nitromethane with Metal Particles

    NASA Astrophysics Data System (ADS)

    Ripley, Robert; Zhang, Fan; Lien, Fue-Sang

    2009-06-01

    Models for momentum and heat exchange have been derived from the results of previous 3D mesoscale simulations of detonation in packed aluminum particles saturated with nitromethane, where the shock interaction timescale was resolved. In these models, particle acceleration and heating within the shock and detonation zone have been expressed in terms of velocity and temperature transmission factors, which are a function of metal to explosive density ratio, metal volume fraction and ratio of particle size to detonation zone thickness. These models are incorporated as source terms in the governing equations for continuum dense two-phase flow and macroscopic simulation is then applied to detonation of nitromethane/aluminum in lightly-cased cylinders. Heterogeneous detonation features such as velocity deficit, enhanced pressure, and critical diameter effects are reproduced. Various spherical particle diameters from 3 -- 30 μm are utilized where most of the particles react in the expanding detonation products. Results for detonation velocity, pressure history, failure and U-shaped critical diameter behavior are compared to the existing experiments.

  3. Development and qualification testing of a laser-ignited, all-secondary (DDT) detonator

    NASA Technical Reports Server (NTRS)

    Blachowski, Thomas J.; Krivitsky, Darrin Z.; Tipton, Stephen

    1994-01-01

    The Indian Head Division, Naval Surface Warfare Center (IHDIV, NSWC) is conducting a qualification program for a laser-ignited, all-secondary (DDT) explosive detonator. This detonator was developed jointly by IHDIV, NSWC and the Department of Energy's EG&G Mound Applied Technologies facility in Miamisburg, Ohio to accept a laser initiation signal and produce a fully developed shock wave output. The detonator performance requirements were established by the on-going IHDIV, NSWC Laser Initiated Transfer Energy Subsystem (LITES) advanced development program. Qualification of the detonator as a component utilizing existing military specifications is the selected approach for this program. The detonator is a deflagration-to-detonator transfer (DDT) device using a secondary explosive, HMX, to generate the required shock wave output. The prototype development and initial system integration tests for the LITES and for the detonator were reported at the 1992 International Pyrotechnics Society Symposium and at the 1992 Survival and Flight Equipment National Symposium. Recent results are presented for the all-fire sensitivity and qualification tests conducted at two different laser initiation pulses.

  4. Pressure profiles in detonation cells with rectangular and diagonal structures

    NASA Astrophysics Data System (ADS)

    Hanana, M.; Lefebvre, M. H.

    Experimental results presented in this work enable us to classify the three-dimensional structure of the detonation into two fundamental types: a rectangular structure and a diagonal structure. The rectangular structure is well documented in the literature and consists of orthogonal waves travelling independently from each another. The soot record in this case shows the classical diamond detonation cell exhibiting `slapping waves'. The experiments indicate that the diagonal structure is a structure with the triple point intersections moving along the diagonal line of the tube cross section. The axes of the transverse waves are canted at 45 degrees to the wall, accounting for the lack of slapping waves. It is possible to reproduce these diagonal structures by appropriately controlling the experimental ignition procedure. The characteristics of the diagonal structure show some similarities with detonation structure in round tube. Pressure measurements recorded along the central axis of the cellular structure show a series of pressure peaks, depending on the type of structure and the position inside the detonation cell. Pressure profiles measured for the whole length of the two types of detonation cells show that the intensity of the shock front is higher and the length of the detonation cell is shorter for the diagonal structures.

  5. Weakly nonlinear dynamics of near-CJ detonation waves

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bdzil, J.B.; Klein, R.

    1993-01-01

    The renewed interest in safety issues for large scale industrial devices and in high speed combustion has driven recent intense efforts to gain a deeper theoretical understanding of detonation wave dynamics. Linear stability analyses, weakly nonlinear bifurcation calculations as well as full scale multi-dimensional direct numerical simulations have been pursued for a standard model problem based on the reactive Euler equations for an ideal gas with constant specific heat capacities and simplified chemical reaction models. Most of these studies are concerned with overdriven detonations. This is true despite the fact that the majority of all detonations observed in nature aremore » running at speeds close to the Chapman-Jouguet (CJ) limit value. By focusing on overdriven waves one removes an array of difficulties from the analysis that is associated with the sonic flow conditions in the wake of a CJ-detonation. In particular, the proper formulation of downstream boundary conditions in the CJ-case is a yet unsolved analytical problem. A proper treatment of perturbations in the back of a Chapman-Jouguet detonation has to account for two distinct weakly nonlinear effects in the forward acoustic wave component. The first is a nonlinear interactionof highly temperature sensitive chemistry with the forward acoustic wave component in a transonic boundary layer near the end of the reaction zone. The second is a cumulative three-wave-resonance in the sense of Majda et al. which is active in the near-sonic burnt gas flow and which is essentially independent of the details of the chemical model. In this work, we consider detonations in mixtures with moderate state sensitivity of the chemical reactions. Then, the acoustic perturbations do not influence the chemistry at the order considered and we may concentrate on the second effect; the three-wave resonance.« less

  6. Weakly nonlinear dynamics of near-CJ detonation waves

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bdzil, J.B.; Klein, R.

    1993-02-01

    The renewed interest in safety issues for large scale industrial devices and in high speed combustion has driven recent intense efforts to gain a deeper theoretical understanding of detonation wave dynamics. Linear stability analyses, weakly nonlinear bifurcation calculations as well as full scale multi-dimensional direct numerical simulations have been pursued for a standard model problem based on the reactive Euler equations for an ideal gas with constant specific heat capacities and simplified chemical reaction models. Most of these studies are concerned with overdriven detonations. This is true despite the fact that the majority of all detonations observed in nature aremore » running at speeds close to the Chapman-Jouguet (CJ) limit value. By focusing on overdriven waves one removes an array of difficulties from the analysis that is associated with the sonic flow conditions in the wake of a CJ-detonation. In particular, the proper formulation of downstream boundary conditions in the CJ-case is a yet unsolved analytical problem. A proper treatment of perturbations in the back of a Chapman-Jouguet detonation has to account for two distinct weakly nonlinear effects in the forward acoustic wave component. The first is a nonlinear interactionof highly temperature sensitive chemistry with the forward acoustic wave component in a transonic boundary layer near the end of the reaction zone. The second is a cumulative three-wave-resonance in the sense of Majda et al. which is active in the near-sonic burnt gas flow and which is essentially independent of the details of the chemical model. In this work, we consider detonations in mixtures with moderate state sensitivity of the chemical reactions. Then, the acoustic perturbations do not influence the chemistry at the order considered and we may concentrate on the second effect; the three-wave resonance.« less

  7. 29 CFR 1926.908 - Use of detonating cord.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... physical condition of the bore hole and stemming and the type of explosives used. (b) Detonating cord shall... cord extending out of a bore hole or from a charge shall be cut from the supply spool before loading the remainder of the bore hole or placing additional charges. (d) Detonating cord shall be handled and...

  8. 29 CFR 1926.908 - Use of detonating cord.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... physical condition of the bore hole and stemming and the type of explosives used. (b) Detonating cord shall... cord extending out of a bore hole or from a charge shall be cut from the supply spool before loading the remainder of the bore hole or placing additional charges. (d) Detonating cord shall be handled and...

  9. Isotope-Labeled Composition B for Tracing Detonation Signatures

    NASA Astrophysics Data System (ADS)

    Manner, Virginia; Podlesak, David; Huber, Rachel; Amato, Ronald; Giambra, Anna; Bowden, Patrick; Hartline, Ernest; Dattelbaum, Dana

    2017-06-01

    To better understand how solid carbon forms and evolves during detonation, we have prepared Composition B with 13 C and 15 N-labeled 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and 2,4,6-trinitrotoluene (TNT) in order to trace the formation of soot from the carbon and nitrogen atoms in these explosives. Isotope-labeling of explosives has been performed in the recent past for a variety of reasons, including environmental remediation and reaction mechanism studies. Because it is expensive and time consuming to prepare these materials, and our detection equipment only requires trace amounts of isotopes, we have prepared fully-labeled materials and substituted them into unlabeled RDX and TNT at less than the 1% level. We will discuss the preparation and full characterization of this labeled Composition B, the detonation tests performed, along with the results of the post-detonation soot analysis. Various detonation models predict differing amounts and forms of carbon and nitrogen; these isotopically-labeled precursors have allowed these models to be tested.

  10. Rotary wave-ejector enhanced pulse detonation engine

    NASA Astrophysics Data System (ADS)

    Nalim, M. R.; Izzy, Z. A.; Akbari, P.

    2012-01-01

    The use of a non-steady ejector based on wave rotor technology is modeled for pulse detonation engine performance improvement and for compatibility with turbomachinery components in hybrid propulsion systems. The rotary wave ejector device integrates a pulse detonation process with an efficient momentum transfer process in specially shaped channels of a single wave-rotor component. In this paper, a quasi-one-dimensional numerical model is developed to help design the basic geometry and operating parameters of the device. The unsteady combustion and flow processes are simulated and compared with a baseline PDE without ejector enhancement. A preliminary performance assessment is presented for the wave ejector configuration, considering the effect of key geometric parameters, which are selected for high specific impulse. It is shown that the rotary wave ejector concept has significant potential for thrust augmentation relative to a basic pulse detonation engine.

  11. Numerical study of chemically reacting viscous flow relevant to pulsed detonation engines

    NASA Astrophysics Data System (ADS)

    Yi, Tae-Hyeong

    2005-11-01

    A computational fluid dynamics code for two-dimensional, multi-species, laminar Navier-Stokes equations is developed to simulate a recently proposed engine concept for a pulsed detonation based propulsion system and to investigate the feasibility of the engine of the concept. The governing equations that include transport phenomena such as viscosity, thermal conduction and diffusion are coupled with chemical reactions. The gas is assumed to be thermally perfect and in chemically non-equilibrium. The stiffness due to coupling the fluid dynamics and the chemical kinetics is properly taken care of by using a time-operator splitting method and a variable coefficient ordinary differential equation solver. A second-order Roe scheme with a minmod limiter is explicitly used for space descretization, while a second-order, two-step Runge-Kutta method is used for time descretization. In space integration, a finite volume method and a cell-centered scheme are employed. The first-order derivatives in the equations of transport properties are discretized by a central differencing with Green's theorem. Detailed chemistry is involved in this study. Two chemical reaction mechanisms are extracted from GRI-Mech, which are forty elementary reactions with thirteen species for a hydrogen-air mixture and twenty-seven reactions with eight species for a hydrogen-oxygen mixture. The code is ported to a high-performance parallel machine with Message-Passing Interface. Code validation is performed with chemical kinetic modeling for a stoichiometric hydrogen-air mixture, an one-dimensional detonation tube, a two-dimensional, inviscid flow over a wedge and a viscous flow over a flat plate. Detonation is initiated using a numerically simulated arc-ignition or shock-induced ignition system. Various freestream conditions are utilized to study the propagation of the detonation in the proposed concept of the engine. Investigation of the detonation propagation is performed for a pulsed detonation

  12. [The Diagnostics of Detonation Flow External Field Based on Multispectral Absorption Spectroscopy Technology].

    PubMed

    Lü, Xiao-jing; Li, Ning; Weng, Chun-sheng

    2016-03-01

    Compared with traditional sampling-based sensing method, absorption spectroscopy technology is well suitable for detonation flow diagnostics, since it can provide with us fast response, nonintrusive, sensitive solution for situ measurements of multiple flow-field parameters. The temperature and concentration test results are the average values along the laser path with traditional absorption spectroscopy technology, while the boundary of detonation flow external field is unknown and it changes all the time during the detonation engine works, traditional absorption spectroscopy technology is no longer suitable for detonation diagnostics. The trend of line strength with temperature varies with different absorption lines. By increasing the number of absorption lines in the test path, more information of the non-uniform flow field can be obtained. In this paper, based on multispectral absorption technology, the reconstructed model of detonation flow external field distribution was established according to the simulation results of space-time conservation element and solution element method, and a diagnostic method of detonation flow external field was given. The model deviation and calculation error of the least squares method adopted were studied by simulation, and the maximum concentration and temperature calculation error was 20.1% and 3.2%, respectively. Four absorption lines of H2O were chosen and detonation flow was scanned at the same time. The detonation external flow testing system was set up for the valveless gas-liquid continuous pulse detonation engine with the diameter of 80 mm. Through scanning H2O absorption lines with a high frequency of 10 kHz, the on-line detection of detonation external flow was realized by direct absorption method combined with time-division multiplexing technology, and the reconstruction of dynamic temperature distribution was realized as well for the first time, both verifying the feasibility of the test method. The test results

  13. Explosive Products EOS: Adjustment for detonation speed and energy release

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Menikoff, Ralph

    2014-09-05

    Propagating detonation waves exhibit a curvature effect in which the detonation speed decreases with increasing front curvature. The curvature effect is due to the width of the wave profile. Numerically, the wave profile depends on resolution. With coarse resolution, the wave width is too large and results in a curvature effect that is too large. Consequently, the detonation speed decreases as the cell size is increased. We propose a modification to the products equation of state (EOS) to compensate for the effect of numerical resolution; i.e., to increase the CJ pressure in order that a simulation propagates a detonation wavemore » with a speed that is on average correct. The EOS modification also adjusts the release isentrope to correct the energy release.« less

  14. Towards Integrated Pulse Detonation Propulsion and MHD Power

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.; Thompson, Bryan R.; Lineberry, John T.

    1999-01-01

    The interest in pulse detonation engines (PDE) arises primarily from the advantages that accrue from the significant combustion pressure rise that is developed in the detonation process. Conventional rocket engines, for example, must obtain all of their compression from the turbopumps, while the PDE provides additional compression in the combustor. Thus PDE's are expected to achieve higher I(sub sp) than conventional rocket engines and to require smaller turbopumps. The increase in I(sub sp) and the decrease in turbopump capacity must be traded off against each other. Additional advantages include the ability to vary thrust level by adjusting the firing rate rather than throttling the flow through injector elements. The common conclusion derived from these aggregated performance attributes is that PDEs should result in engines which are smaller, lower in cost, and lighter in weight than conventional engines. Unfortunately, the analysis of PDEs is highly complex due to their unsteady operation and non-ideal processes. Although the feasibility of the basic PDE concept has been proven in several experimental and theoretical efforts, the implied performance improvements have yet to be convincingly demonstrated. Also, there are certain developmental issues affecting the practical application of pulse detonation propulsion systems which are yet to be fully resolved. Practical detonation combustion engines, for example, require a repetitive cycle of charge induction, mixing, initiation/propagation of the detonation wave, and expulsion/scavenging of the combustion product gases. Clearly, the performance and power density of such a device depends upon the maximum rate at which this cycle can be successfully implemented. In addition, the electrical energy required for direct detonation initiation can be significant, and a means for direct electrical power production is needed to achieve self-sustained engine operation. This work addresses the technological issues associated

  15. Composite accidental axions

    NASA Astrophysics Data System (ADS)

    Redi, Michele; Sato, Ryosuke

    2016-05-01

    We present several models where the QCD axion arises accidentally. Confining gauge theories can generate axion candidates whose properties are uniquely determined by the quantum numbers of the new fermions under the Standard Model. The Peccei-Quinn symmetry can emerge accidentally if the gauge theory is chiral. We generalise previous constructions in a unified framework. In some cases these models can be understood as the deconstruction of 5-dimensional gauge theories where the Peccei-Quinn symmetry is protected by locality but more general constructions are possible.

  16. Fundamental Structure of High-Speed Reacting Flows: Supersonic Combustion and Detonation

    DTIC Science & Technology

    2016-04-30

    AFRL-AFOSR-VA-TR-2016-0195 Fundamental Structure of High-Speed Reacting Flows: Supersonic Combustion and Detonation Kenneth Yu MARYLAND UNIV COLLEGE...MARCH 2016 4. TITLE AND SUBTITLE FUNDAMENTAL STRUCTURE OF HIGH-SPEED REACTING FLOWS: SUPERSONIC COMBUSTION AND DETONATION 5a. CONTRACT NUMBER...public release. Final Report on Fundamental Structure of High-Speed Reacting Flows: Supersonic Combustion and Detonation Grant

  17. Shock wave and flame front induced detonation in a rapid compression machine

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Qi, Y.; Xiang, S.; Mével, R.; Wang, Z.

    2018-05-01

    The present study focuses on one mode of detonation initiation observed in a rapid compression machine (RCM). This mode is referred to as shock wave and flame front-induced detonation (SWFID). Experimental high-speed imaging and two-dimensional numerical simulations with skeletal chemistry are combined to unravel the dominant steps of detonation initiation under SWFID conditions. It is shown that the interaction between the shock wave generated by the end-gas auto-ignition and the spherical flame creates a region of high pressure and temperature which enables the acceleration of the flame front and the detonation onset. The experimental observation lacks adequate spatial and temporal resolution despite good reproducibility of the detonation onset. Based on the numerical results, phenomenological interpretation of the event within the framework of shock wave refraction indicates that the formation of a free-precursor shock wave at the transition between regular and irregular refraction may be responsible for detonation onset. The present results along with previous findings on shock wave reflection-induced detonation in the RCM indicate that super-knock occurs after the interaction of the shock wave generated by end-gas auto-ignition with the RCM walls, preignition flame, or another shock wave.

  18. Initiation structure of oblique detonation waves behind conical shocks

    NASA Astrophysics Data System (ADS)

    Yang, Pengfei; Ng, Hoi Dick; Teng, Honghui; Jiang, Zonglin

    2017-08-01

    The understanding of oblique detonation dynamics has both inherent basic research value for high-speed compressible reacting flow and propulsion application in hypersonic aerospace systems. In this study, the oblique detonation structures formed by semi-infinite cones are investigated numerically by solving the unsteady, two-dimensional axisymmetric Euler equations with a one-step irreversible Arrhenius reaction model. The present simulation results show that a novel wave structure, featured by two distinct points where there is close-coupling between the shock and combustion front, is depicted when either the cone angle or incident Mach number is reduced. This structure is analyzed by examining the variation of the reaction length scale and comparing the flow field with that of planar, wedge-induced oblique detonations. Further simulations are performed to study the effects of chemical length scale and activation energy, which are both found to influence the formation of this novel structure. The initiation mechanism behind the conical shock is discussed to investigate the interplay between the effect of the Taylor-Maccoll flow, front curvature, and energy releases from the chemical reaction in conical oblique detonations. The observed flow fields are interpreted by means of the energetic limit as in the critical regime for initiation of detonation.

  19. Epidemiology of accidental radiation exposures.

    PubMed Central

    Cardis, E

    1996-01-01

    Much of the information on the health effects of radiation exposure available to date comes from long-term studies of the atomic bombings in Hiroshima and Nagasaki. Accidental exposures, such as those resulting from the Chernobyl and Kyshtym accidents, have as yet provided little information concerning health effects of ionizing radiation. This paper will present the current state of our knowledge concerning radiation effects, review major large-scale accidental radiation exposures, and discuss information that could be obtained from studies of accidental exposures and the types of studies that are needed. PMID:8781398

  20. Synchro-ballistic recording of detonation phenomena

    NASA Astrophysics Data System (ADS)

    Critchfield, Robert R.; Asay, Blaine W.; Bdzil, John B.; Davis, William C.; Ferm, Eric N.; Idar, Deanne J.

    1997-12-01

    Synchro-ballistic use of rotating-mirror streak cameras allows for detailed recording of high-speed events of known velocity and direction. After an introduction to the synchro-ballistic technique, this paper details two diverse applications of the technique as applied in the field of high-explosives research. In the first series of experiments detonation-front shape is recorded as the arriving detonation shock wave tilts an obliquely mounted mirror, causing reflected light to be deflected from the imaging lens. These tests were conducted for the purpose of calibrating and confirming the asymptotic detonation shock dynamics (DSD) theory of Bdzil and Stewart. The phase velocities of the events range from ten to thirty millimeters per microsecond. Optical magnification is set for optimal use of the film's spatial dimension and the phase velocity is adjusted to provide synchronization at the camera's maximum writing speed. Initial calibration of the technique is undertaken using a cylindrical HE geometry over a range of charge diameters and of sufficient length-to- diameter ratio to insure a stable detonation wave. The final experiment utilizes an arc-shaped explosive charge, resulting in an asymmetric denotation-front record. The second series of experiments consists of photographing a shaped-charge jet having a velocity range of two to nine millimeters per microsecond. To accommodate the range of velocities it is necessary to fire several tests, each synchronized to a different section of the jet. The experimental apparatus consists of a vacuum chamber to preclude atmospheric ablation of the jet tip with shocked-argon back lighting to produce a shadow-graph image.

  1. Determination of detonation wave boundary angles via hydrocode simulations using CREST

    NASA Astrophysics Data System (ADS)

    Whitworth, N. J.; Childs, M.

    2017-01-01

    A key input parameter to Detonation Shock Dynamics models is the angle that the propagating detonation wave makes with the charge edge. This is commonly referred to as the boundary angle, and is a property of the explosive/confiner material combination. Such angles can be determined: (i) experimentally from measured detonation wave-shapes, (ii) theoretically, or (iii) via hydrocode simulations using a reactive burn model. Of these approaches: (i) is difficult because of resolution, (ii) breaks down for certain configurations, while (iii) requires a well validated model. In this paper, the CREST reactive burn model, which has previously been successful in modelling a wide range of explosive phenomena, is used to simulate recent Detonation Confinement Sandwich Tests conducted at LANL using the insensitive high explosive PBX 9502. Simulated detonation wave-shapes in PBX 9502 for a number of different confiner materials and combinations closely match those recorded from the experiments. Boundary angles were subsequently extracted from the simulated results via a wave-shape analysis toolkit. The results shown demonstrate the usefulness of CREST in determining detonation wave boundary angles for a range of explosive/confiner material combinations.

  2. Effects of injection nozzle exit width on rotating detonation engine

    NASA Astrophysics Data System (ADS)

    Sun, Jian; Zhou, Jin; Liu, Shijie; Lin, Zhiyong; Cai, Jianhua

    2017-11-01

    A series of numerical simulations of RDE modeling real injection nozzles with different exit widths are performed in this paper. The effects of nozzle exit width on chamber inlet state, plenum flowfield and detonation propagation are analyzed. The results are compared with that using an ideal injection model. Although the ideal injection model is a good approximation method to model RDE inlet, the two-dimensional effects of real nozzles are ignored in the ideal injection model so that some complicated phenomena such as the reflected waves caused by the nozzle walls and the reversed flow into the nozzles can not be modeled accurately. Additionally, the ideal injection model overpredicts the block ratio. In all the cases that stabilize at one-wave mode, the block ratio increases as the nozzle exit width gets smaller. The dual-wave mode case also has a relatively high block ratio. A pressure oscillation in the plenum with the same main frequency with the rotating detonation wave is observed. A parameter σ is applied to describe the non-uniformity in the plenum. σ increases as the nozzle exit width gets larger. Under some condition, the heat release on the interface of fresh premixed gas layer and detonation products can be strong enough to induce a new detonation wave. A spontaneous mode-transition process is observed for the smallest exit width case. Due to the detonation products existing in the premixed gas layer before the detonation wave, the detonation wave will propagate through reactants and products alternately, and therefore its strength will vary with time, especially near the chamber inlet. This tendency gets weaker as the injection nozzle exit width increases.

  3. [Research on diagnosis of gas-liquid detonation exhaust based on double optical path absortion spectroscopy technique].

    PubMed

    Lü, Xiao-Jing; Li, Ning; Weng, Chun-Sheng

    2014-03-01

    The effect detection of detonation exhaust can provide measurement data for exploring the formation mechanism of detonation, the promotion of detonation efficiency and the reduction of fuel waste. Based on tunable diode laser absorption spectroscopy technique combined with double optical path cross-correlation algorithm, the article raises the diagnosis method to realize the on-line testing of detonation exhaust velocity, temperature and H2O gas concentration. The double optical path testing system is designed and set up for the valveless pulse detonation engine with the diameter of 80 mm. By scanning H2O absorption lines of 1343nm with a high frequency of 50 kHz, the on-line detection of gas-liquid pulse detonation exhaust is realized. The results show that the optical testing system based on tunable diode laser absorption spectroscopy technique can capture the detailed characteristics of pulse detonation exhaust in the transient process of detonation. The duration of single detonation is 85 ms under laboratory conditions, among which supersonic injection time is 5.7 ms and subsonic injection time is 19.3 ms. The valveless pulse detonation engine used can work under frequency of 11 Hz. The velocity of detonation overflowing the detonation tube is 1,172 m x s(-1), the maximum temperature of detonation exhaust near the nozzle is 2 412 K. There is a transitory platform in the velocity curve as well as the temperature curve. H2O gas concentration changes between 0-7% during detonation under experimental conditions. The research can provide measurement data for the detonation process diagnosis and analysis, which is of significance to advance the detonation mechanism research and promote the research of pulse detonation engine control technology.

  4. 5 CFR 870.206 - Accidental death and dismemberment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Accidental death and dismemberment. 870....206 Accidental death and dismemberment. (a) (1) Accidental death and dismemberment coverage is an automatic part of Basic and Option A insurance for employees. (2) There is no accidental death and...

  5. 5 CFR 870.206 - Accidental death and dismemberment.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 2 2014-01-01 2014-01-01 false Accidental death and dismemberment. 870....206 Accidental death and dismemberment. (a)(1) Accidental death and dismemberment coverage is an automatic part of Basic and Option A insurance for employees. (2) There is no accidental death and...

  6. 5 CFR 870.206 - Accidental death and dismemberment.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 2 2011-01-01 2011-01-01 false Accidental death and dismemberment. 870....206 Accidental death and dismemberment. (a)(1) Accidental death and dismemberment coverage is an automatic part of Basic and Option A insurance for employees. (2) There is no accidental death and...

  7. 5 CFR 870.206 - Accidental death and dismemberment.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 2 2013-01-01 2013-01-01 false Accidental death and dismemberment. 870....206 Accidental death and dismemberment. (a)(1) Accidental death and dismemberment coverage is an automatic part of Basic and Option A insurance for employees. (2) There is no accidental death and...

  8. 5 CFR 870.206 - Accidental death and dismemberment.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 2 2012-01-01 2012-01-01 false Accidental death and dismemberment. 870....206 Accidental death and dismemberment. (a)(1) Accidental death and dismemberment coverage is an automatic part of Basic and Option A insurance for employees. (2) There is no accidental death and...

  9. A Hydrocarbon Fuel Flash Vaporization System for a Pulsed Detonation Engine

    DTIC Science & Technology

    2006-12-01

    Experiments were performed in the Air Force Research Laboratory (AFRL) Pulsed Detonation Research Facility at Wright Patterson AFB, Ohio. The PDE ...AFRL-MN-EG-TP-2006-7420 A HYDROCARBON FUEL FLASH VAPORIZATION SYSTEM FOR A PULSED DETONATION ENGINE (PREPRINT) K. Colin Tucker...85,7<&/$66,),&$7,212) E7(/(3+21(180%(5 ,QFOXGHDUHDFRGH A Hydrocarbon Fuel Flash Vaporization System for a Pulsed Detonation Engine K

  10. Experimental study on transmission of an overdriven detonation wave from propane/oxygen to propane/air

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, J.; Lai, W.H.; Chung, K.

    2008-08-15

    Two sets of experiments were performed to achieve a strong overdriven state in a weaker mixture by propagating an overdriven detonation wave via a deflagration-to-detonation transition (DDT) process. First, preliminary experiments with a propane/oxygen mixture were used to evaluate the attenuation of the overdriven detonation wave in the DDT process. Next, experiments were performed wherein a propane/oxygen mixture was separated from a propane/air mixture by a thin diaphragm to observe the transmission of an overdriven detonation wave. Based on the characteristic relations, a simple wave intersection model was used to calculate the state of the transmitted detonation wave. The resultsmore » showed that a rarefaction effect must be included to ensure that there is no overestimate of the post-transmission wave properties when the incident detonation wave is overdriven. The strength of the incident overdriven detonation wave plays an important role in the wave transmission process. The experimental results showed that a transmitted overdriven detonation wave occurs instantaneously with a strong incident overdriven detonation wave. The near-CJ state of the incident wave leads to a transmitted shock wave, and then the transition to the overdriven detonation wave occurs downstream. The attenuation process for the overdriven detonation wave decaying to a near-CJ state occurs in all tests. After the attenuation process, an unstable detonation wave was observed in most tests. This may be attributed to the increase in the cell width in the attenuation process that exceeds the detonability cell width limit. (author)« less

  11. Detonation propagation in annular arcs of condensed phase explosives

    NASA Astrophysics Data System (ADS)

    Ioannou, Eleftherios; Schoch, Stefan; Nikiforakis, Nikolaos; Michael, Louisa

    2017-11-01

    We present a numerical study of detonation propagation in unconfined explosive charges shaped as an annular arc (rib). Steady detonation in a straight charge propagates at constant speed, but when it enters an annular section, it goes through a transition phase and eventually reaches a new steady state of constant angular velocity. This study examines the speed of the detonation wave along the annular charge during the transition phase and at steady state, as well as its dependence on the dimensions of the annulus. The system is modeled using a recently proposed diffuse-interface formulation which allows for the representation of a two-phase explosive and of an additional inert material. The explosive considered is the polymer-bonded TATB-based LX-17 and is modeled using two Jones-Wilkins-Lee (JWL) equations of state and the ignition and growth reaction rate law. Results show that steady state speeds are in good agreement with experiment. In the transition phase, the evolution of outer detonation speed deviates from the exponential bounded growth function suggested by previous studies. We propose a new description of the transition phase which consists of two regimes. The first regime is caused by local effects at the outer edge of the annulus and leads to a dependence of the outer detonation speed on the angular position along the arc. The second regime is induced by effects originating from the inner edge of the annular charge and leads to the deceleration of the outer detonation until steady state is reached. The study concludes with a parametric study where the dependence of the steady state and the transition phase on the dimensions of the annulus is investigated.

  12. On the theory of the propagation of detonation in gaseous systems

    NASA Technical Reports Server (NTRS)

    Zeldovich, Y B

    1950-01-01

    The existing theory of detonation is critically examined. It is shown that the considerations with which the steady value of the velocity of detonation is chosen are not convincing. In connection with the problem of the process of the chemical reaction in a detonation wave, the objections raised against the conceptions of Le Chatelier and Vieille of the 19th century with regard to the ignition of the gas by the shock wave are refuted. On the basis of this concept, it is possible to give a rigorous foundation for the existing method of computing the detonation velocity. The distributions of the temperature, the pressure, and the velocity in the detonation wave front as the chemical reaction proceeds, are considered. On the assumption of the absence of losses, the pure compression of the gas in the shock wave at the start of the chemical reaction develops a temperature that is near the temperature of combustion of the given mixture at constant pressure.

  13. a Transient Semi-Metallic Layer in Detonating Nitromethane

    NASA Astrophysics Data System (ADS)

    Reed, Evan J.; Manaa, M. Riad; Fried, Laurence E.; Glaesemann, Kurt; Joannopoulos, John D.

    2007-12-01

    We present the first ever glimpse behind a detonation shock front in a chemically reactive quantum molecular dynamics simulation of the explosive nitromethane (CH3NO2). We discover that the wide-bandgap insulator nitromethane undergoes chemical decomposition and a transformation into a semi-metallic state for a limited distance behind the detonation front. We find this transformation is associated with the production of charged decomposition species.

  14. Multiple-cycle Simulation of a Pulse Detonation Engine Ejector

    NASA Technical Reports Server (NTRS)

    Yungster, S.; Perkins, H. D.

    2002-01-01

    This paper presents the results of a study involving single and multiple-cycle numerical simulations of various PDE-ejector configurations utilizing hydrogen-oxygen mixtures. The objective was to investigate the thrust, impulse and mass flow rate characteristics of these devices. The results indicate that ejector systems can utilize the energy stored in the strong shock wave exiting the detonation tube to augment the impulse obtained from the detonation tube alone. Impulse augmentation ratios of up to 1.9 were achieved. The axial location of the converging-diverging ejectors relative to the end of the detonation tube were shown to affect the performance of the system.

  15. Detonation failure characterization of non-ideal explosives

    NASA Astrophysics Data System (ADS)

    Janesheski, Robert S.; Groven, Lori J.; Son, Steven

    2012-03-01

    Non-ideal explosives are currently poorly characterized, hence limiting the modeling of them. Current characterization requires large-scale testing to obtain steady detonation wave characterization for analysis due to the relatively thick reaction zones. Use of a microwave interferometer applied to small-scale confined transient experiments is being implemented to allow for time resolved characterization of a failing detonation. The microwave interferometer measures the position of a failing detonation wave in a tube that is initiated with a booster charge. Experiments have been performed with ammonium nitrate and various fuel compositions (diesel fuel and mineral oil). It was observed that the failure dynamics are influenced by factors such as chemical composition and confiner thickness. Future work is planned to calibrate models to these small-scale experiments and eventually validate the models with available large scale experiments. This experiment is shown to be repeatable, shows dependence on reactive properties, and can be performed with little required material.

  16. Eigenvalue Detonation of Combined Effects Aluminized Explosives

    NASA Astrophysics Data System (ADS)

    Capellos, Christos; Baker, Ernest; Balas, Wendy; Nicolich, Steven; Stiel, Leonard

    2007-06-01

    This paper reports on the development of theory and performance for recently developed combined effects aluminized explosives. Traditional high energy explosives used for metal pushing incorporate high loading percentages of HMX or RDX, whereas blast explosives incorporate some percentage of aluminum. However, the high blast explosives produce increased blast energies, with reduced metal pushing capability due to late time aluminum reaction. Metal pushing capability refers to the early volume expansion work produced during the first few volume expansions associated with cylinder wall velocities and Gurney energies. Our Recently developed combined effects aluminized explosives (PAX-29C, PAX-30, PAX-42) are capable of achieving excellent metal pushing and high blast energies. Traditional Chapman-Jouguet detonation theory does not explain the observed detonation states achieved by these combined effects explosives. This work demonstrates, with the use of cylinder expansion data and thermochemical code calculations (JAGUAR and CHEETAH), that eigenvalue detonation theory explains the observed behavior.

  17. Characterizing detonator output using dynamic witness plates

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Murphy, Michael John; Adrian, Ronald J

    2009-01-01

    A sub-microsecond, time-resolved micro-particle-image velocimetry (PIV) system is developed to investigate the output of explosive detonators. Detonator output is directed into a transparent solid that serves as a dynamic witness plate and instantaneous shock and material velocities are measured in a two-dimensional plane cutting through the shock wave as it propagates through the solid. For the case of unloaded initiators (e.g. exploding bridge wires, exploding foil initiators, etc.) the witness plate serves as a surrogate for the explosive material that would normally be detonated. The velocity-field measurements quantify the velocity of the shocked material and visualize the geometry of themore » shocked region. Furthermore, the time-evolution of the velocity-field can be measured at intervals as small as 10 ns using the PIV system. Current experimental results of unloaded exploding bridge wire output in polydimethylsiloxane (PDMS) witness plates demonstrate 20 MHz velocity-field sampling just 300 ns after initiation of the wire.« less

  18. Approximate Equation of State for Overdriven and Reflected Detonation Products

    NASA Astrophysics Data System (ADS)

    Liu, Zhi-Yue; Itoh, Shigeru

    2001-06-01

    Approximate Equation of State for Overdriven and Reflected Detonation Products Zhi-Yue Liu and Shigeru Itoh Shock Wave and Condensed Matter Research Center, Kumamoto University, 2-39-1 Kurokami, Kumamoto, 860-8555, Japan ABSTRACT There are several types of equations of state (EOS) to describe the isentropic expansion behavior of the detonation products after the explosive is exploded. Of which, Jones-Wilkins-Lee (or JWL) equation and polytropic gas (or gamma-law) equation are most popularly employed owing to either the completely experimental calibration or simple form in expression. However, both equations fail to correctly describe the behavior of detonation products above the Chapman-Jouguet (C-J) state. For this reason, a new form of equation of state is proposed for overcoming this deficiency. The new equation of state is simply a linear combination of JWL and gamma-law equations. The coefficient appeared in the EOS can be obtained by fitting to the data from the overdriven detonation experiments. Results show that this form of EOS not only gives the satisfactory description to the variation of the detonation products in overdriven or reflected state also can simply be incorporated into the hydrodynamic computer codes.

  19. Detonation-flame arrester devices for gasoline cargo vapor recovery systems

    NASA Technical Reports Server (NTRS)

    Bjorklund, R. A.; Ryason, P. R.

    1980-01-01

    Empirical data on the deflagration-to-detonation run-up distance for flowing mixtures of gasoline and air in 15.2-cm- (6.0-in.-) diameter piping simulating a vapor recovery system are presented. The quenching capability of eight selected flame control devices subjected to repeated stable detonations was evaluated. The successful detonation-flame arresters were: (1) spiral-wound, crimped aluminum ribbon, (2) foamed nickel-chrome metal, (3) vertically packed bed of aluminum Ballast rings, and (4) water-trap or hydraulic back-pressure valve. Installation configurations for two of the more applicable arresters, the spiral-wound, crimped stainless-steel ribbon and the vertically packed bed of aluminum Ballast rings, were further optimized by a series of parametric tests. The final configuration of these two arresters was demonstrated with repeated detonation tests at conditions that simulated vapor recovery system operation. On these tests, the combustible mixture of gasoline and air continued to flow through the piping for periods up to 120 seconds after the initial detonation had been arrested. There was no indication of continuous burning or reignition occurring on either side of the test arresters.

  20. Ferrite core coupled slapper detonator apparatus and method

    DOEpatents

    Boberg, Ralph E.; Lee, Ronald S.; Weingart, Richard C.

    1989-01-01

    Method and apparatus are provided for coupling a temporally short electric power pulse from a thick flat-conductor power cable into a thin flat-conductor slapper detonator circuit. A first planar and generally circular loop is formed from an end portion of the power cable. A second planar and generally circular loop, of similar diameter, is formed from all or part of the slapper detonator circuit. The two loops are placed together, within a ferrite housing that provides a ferrite path that magnetically couples the two loops. Slapper detonator parts may be incorporated within the ferrite housing. The ferrite housing may be made vacuum and water-tight, with the addition of a hermetic ceramic seal, and provided with an enclosure for protecting the power cable and parts related thereto.

  1. Ferrite core coupled slapper detonator apparatus and method

    DOEpatents

    Boberg, R.E.; Lee, R.S.; Weingart, R.C.

    1989-08-01

    Method and apparatus are provided for coupling a temporally short electric power pulse from a thick flat-conductor power cable into a thin flat-conductor slapper detonator circuit. A first planar and generally circular loop is formed from an end portion of the power cable. A second planar and generally circular loop, of similar diameter, is formed from all or part of the slapper detonator circuit. The two loops are placed together, within a ferrite housing that provides a ferrite path that magnetically couples the two loops. Slapper detonator parts may be incorporated within the ferrite housing. The ferrite housing may be made vacuum and water-tight, with the addition of a hermetic ceramic seal, and provided with an enclosure for protecting the power cable and parts related thereto. 10 figs.

  2. Thermal stability of detonation-produced micro and nanodiamonds

    NASA Astrophysics Data System (ADS)

    Efremov, V. P.; Zakatilova, E. I.; Maklashova, I. V.; Shevchenko, N. V.

    2018-01-01

    Detonation nanodiamonds are produced at utilization of high explosives. When an explosive blasts in a water environment, the detonation products contain microdiamonds, and in a gaseous medium, nanodiamonds. It is known that with decreasing size the influence of the surface energy of particles on their properties increases. Thus, it is interesting to compare the properties of detonation nano and microdiamonds. In this study, we have examined the thermal stability of diamond materials by synchronous thermal analysis. The experiments were performed at atmospheric pressure in argon flow for different heating rates in a range from room temperature to 1500 °C. Samples of initial and annealed micro and nanomaterials were studied using electron microscopy, x-ray and x-ray-fluorescence analysis. It was established that thermal and structural properties of micro and nanodiamonds differ substantially.

  3. Coupling Detonation Shock Dynamics in a Consistent Manner to Equations of State

    NASA Astrophysics Data System (ADS)

    Belfield, William

    2017-06-01

    In hydrocode simulations, detonating high explosives (HE) are often modelled using programmed burn. Each HE cell is assigned a ``burn time'' at which it should begin to behave as HE products in the subsequent simulation. Traditionally, these burn times were calculated using a Huygens construction to propagate the detonation wave at a constant speed corresponding to the planar Chapman-Jouguet (CJ) velocity. The Detonation Shock Dynamics (DSD) model improves upon this approach by treating the local detonation velocity as a function of wave curvature, reflecting that the detonation speed is not constant in reality. However, without alterations being made, this variable detonation velocity is inconsistent with the CJ velocity associated with the HE products equation of state (EOS). Previous work has shown that the inconsistency can be resolved by modifying the HE product EOS, but this treatment is empirical in nature and has only been applied to the JWL EOS. This work investigates different methods to resolve the inconsistency that are applicable both to JWL and to tabular HE product EOS, and their impact on hydrocode simulations.

  4. Small-scale Detonation Velocity Measurement of Select CL-20 Cocrystals

    NASA Astrophysics Data System (ADS)

    Vuppuluri, Vasant; Gunduz, I. Emre; Son, Steven F.

    2017-06-01

    The challenge of developing novel energetic materials makes cocrystallization using existing energetic molecules useful. Cocrystallization of CL-20 with other high explosives such as HMX has been demonstrated previously to yield novel energetic materials and may have favorable detonation performance. However, detonation performance characterization of these cocrystals is challenging due to limited availability of material. Also, the contribution of bonding energy between coformers contained within the cocrystal is not well-understood. We present the comparison of steady detonation velocities of CL-20 cocrystals to their corresponding physical mixtures using microwave interferometry. With less than 1.5 g of the cocrystal material contained within 6.52 mm diameter charges, shot-to-shot variation in detonation velocity of only about 100 m/s are achievable with this technique. This variation is adequate to resolve relatively small differences between physical mixed explosive molecules and cocrystals.

  5. Use of noise attenuation modeling in managing missile motor detonation activities.

    PubMed

    McFarland, Michael J; Watkins, Jeffrey W; Kordich, Micheal M; Pollet, Dean A; Palmer, Glenn R

    2004-03-01

    The Sound Intensity Prediction System (SIPS) and Blast Operation Overpressure Model (BOOM) are semiempirical sound models that are employed by the Utah Test and Training Range (UTTR) to predict whether noise levels from the detonation of large missile motors will exceed regulatory thresholds. Field validation of SIPS confirmed that the model was effective in limiting the number of detonations of large missile motors that could potentially result in a regulatory noise exceedance. Although the SIPS accurately predicted the impact of weather on detonation noise propagation, regulators have required that the more conservative BOOM model be employed in conjunction with SIPS in evaluating peak noise levels in populated areas. By simultaneously considering the output of both models, in 2001, UTTR detonated 104 missile motors having net explosive weights (NEW) that ranged between 14,960 and 38,938 lb without a recorded public noise complaint. Based on the encouraging results, the U.S. Department of Defense is considering expanding the application of these noise models to support the detonation of missile motors having a NEW of 81,000 lb. Recent modeling results suggest that, under appropriate weather conditions, missile motors containing up to 96,000 lb NEW can be detonated at the UTTR without exceeding the regulatory noise limit of 134 decibels (dB).

  6. A lethal danger in the home: turpentine poisoning.

    PubMed

    Güzel, Ahmet; Açıkgöz, Mehmet

    2015-01-01

    Turpentine is an oleoresin obtained from various species of pine. In turpentine poisoning, various signs and symptoms of toxicity may develop, including hematuria, renal failure, loss of vision, chest pain, vomiting, severe coughing, gastroesophageal hemorrhage, hypotension, swelling of the throat and even death. We report a case of turpentine ingestion in a 9-year-old boy. The patient was admitted to our clinic with suspected intoxication after accidentally drinking from a glass that held a turpentine oil preparation used by his father for hair care. The patient displayed no significant signs and symptoms other than bradycardia and hypotension. Laboratory investigations revealed no abnormalities. The patient was hospitalized for close monitoring and observation. During a two-and-a-half-day observation period, hypotension was corrected with administration of dopamine and intravenous fluids. In this report, we wish to draw attention to the dangerous effects of plant-derived drugs.

  7. HERMES: A Model to Describe Deformation, Burning, Explosion, and Detonation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Reaugh, J E

    2011-11-22

    HERMES (High Explosive Response to MEchanical Stimulus) was developed to fill the need for a model to describe an explosive response of the type described as BVR (Burn to Violent Response) or HEVR (High Explosive Violent Response). Characteristically this response leaves a substantial amount of explosive unconsumed, the time to reaction is long, and the peak pressure developed is low. In contrast, detonations characteristically consume all explosive present, the time to reaction is short, and peak pressures are high. However, most of the previous models to describe explosive response were models for detonation. The earliest models to describe the responsemore » of explosives to mechanical stimulus in computer simulations were applied to intentional detonation (performance) of nearly ideal explosives. In this case, an ideal explosive is one with a vanishingly small reaction zone. A detonation is supersonic with respect to the undetonated explosive (reactant). The reactant cannot respond to the pressure of the detonation before the detonation front arrives, so the precise compressibility of the reactant does not matter. Further, the mesh sizes that were practical for the computer resources then available were large with respect to the reaction zone. As a result, methods then used to model detonations, known as {beta}-burn or program burn, were not intended to resolve the structure of the reaction zone. Instead, these methods spread the detonation front over a few finite-difference zones, in the same spirit that artificial viscosity is used to spread the shock front in inert materials over a few finite-difference zones. These methods are still widely used when the structure of the reaction zone and the build-up to detonation are unimportant. Later detonation models resolved the reaction zone. These models were applied both to performance, particularly as it is affected by the size of the charge, and to situations in which the stimulus was less than that needed for

  8. Research on filling process of fuel and oxidant during detonation based on absorption spectrum technology

    NASA Astrophysics Data System (ADS)

    Lv, Xiao-Jing; Li, Ning; Weng, Chun-Sheng

    2014-12-01

    Research on detonation process is of great significance for the control optimization of pulse detonation engine. Based on absorption spectrum technology, the filling process of fresh fuel and oxidant during detonation is researched. As one of the most important products, H2O is selected as the target of detonation diagnosis. Fiber distributed detonation test system is designed to enable the detonation diagnosis under adverse conditions in detonation process. The test system is verified to be reliable. Laser signals at different working frequency (5Hz, 10Hz and 20Hz) are detected. Change of relative laser intensity in one detonation circle is analyzed. The duration of filling process is inferred from the change of laser intensity, which is about 100~110ms. The peak of absorption spectrum is used to present the concentration of H2O during the filling process of fresh fuel and oxidant. Absorption spectrum is calculated, and the change of absorption peak is analyzed. Duration of filling process calculated with absorption peak consisted with the result inferred from the change of relative laser intensity. The pulse detonation engine worked normally and obtained the maximum thrust at 10Hz under experiment conditions. The results are verified through H2O gas concentration monitoring during detonation.

  9. Build Up and Operation of an Axial Turbine Driven by a Rotary Detonation Engine

    DTIC Science & Technology

    2012-03-01

    RDEs) offer advantages over pulsed detonation engines ( PDEs ) due to a steadier exhaust and fewer total system losses. All previous research on...turbine integration with detonation combustors has focused on utilizing PDEs to drive axial and centrifugal turbines. The objective of this thesis was... detonation engine ............................................. 5 Figure 4. Schematic of the rotating detonation wave structure for an unwrapped view of an

  10. Detonation onset following shock wave focusing

    NASA Astrophysics Data System (ADS)

    Smirnov, N. N.; Penyazkov, O. G.; Sevrouk, K. L.; Nikitin, V. F.; Stamov, L. I.; Tyurenkova, V. V.

    2017-06-01

    The aim of the present paper is to study detonation initiation due to focusing of a shock wave reflected inside a cone. Both numerical and experimental investigations were conducted. Comparison of results made it possible to validate the developed 3-d transient mathematical model of chemically reacting gas mixture flows incorporating hydrogen - air mixtures. The results of theoretical and numerical experiments made it possible improving kinetic schemes and turbulence models. Several different flow scenarios were detected in reflection of shock waves all being dependent on incident shock wave intensity: reflecting of shock wave with lagging behind combustion zone, formation of detonation wave in reflection and focusing, and intermediate transient regimes.

  11. Explosive detonation causes an increase in soil porosity leading to increased TNT transformation.

    PubMed

    Yu, Holly A; Nic Daeid, Niamh; Dawson, Lorna A; DeTata, David A; Lewis, Simon W

    2017-01-01

    Explosives are a common soil contaminant at a range of sites, including explosives manufacturing plants and areas associated with landmine detonations. As many explosives are toxic and may cause adverse environmental effects, a large body of research has targeted the remediation of explosives residues in soil. Studies in this area have largely involved spiking 'pristine' soils using explosives solutions. Here we investigate the fate of explosives present in soils following an actual detonation process and compare this to the fate of explosives spiked into 'pristine' undetonated soils. We also assess the effects of the detonations on the physical properties of the soils. Our scanning electron microscopy analyses reveal that detonations result in newly-fractured planes within the soil aggregates, and novel micro Computed Tomography analyses of the soils reveal, for the first time, the effect of the detonations on the internal architecture of the soils. We demonstrate that detonations cause an increase in soil porosity, and this correlates to an increased rate of TNT transformation and loss within the detonated soils, compared to spiked pristine soils. We propose that this increased TNT transformation is due to an increased bioavailability of the TNT within the now more porous post-detonation soils, making the TNT more easily accessible by soil-borne bacteria for potential biodegradation. This new discovery potentially exposes novel remediation methods for explosive contaminated soils where actual detonation of the soil significantly promotes subsequent TNT degradation. This work also suggests previously unexplored ramifications associated with high energy soil disruption.

  12. Explosive detonation causes an increase in soil porosity leading to increased TNT transformation

    PubMed Central

    Yu, Holly A.; Nic Daeid, Niamh; Dawson, Lorna A.; DeTata, David A.; Lewis, Simon W.

    2017-01-01

    Explosives are a common soil contaminant at a range of sites, including explosives manufacturing plants and areas associated with landmine detonations. As many explosives are toxic and may cause adverse environmental effects, a large body of research has targeted the remediation of explosives residues in soil. Studies in this area have largely involved spiking ‘pristine’ soils using explosives solutions. Here we investigate the fate of explosives present in soils following an actual detonation process and compare this to the fate of explosives spiked into ‘pristine’ undetonated soils. We also assess the effects of the detonations on the physical properties of the soils. Our scanning electron microscopy analyses reveal that detonations result in newly-fractured planes within the soil aggregates, and novel micro Computed Tomography analyses of the soils reveal, for the first time, the effect of the detonations on the internal architecture of the soils. We demonstrate that detonations cause an increase in soil porosity, and this correlates to an increased rate of TNT transformation and loss within the detonated soils, compared to spiked pristine soils. We propose that this increased TNT transformation is due to an increased bioavailability of the TNT within the now more porous post-detonation soils, making the TNT more easily accessible by soil-borne bacteria for potential biodegradation. This new discovery potentially exposes novel remediation methods for explosive contaminated soils where actual detonation of the soil significantly promotes subsequent TNT degradation. This work also suggests previously unexplored ramifications associated with high energy soil disruption. PMID:29281650

  13. Shock Interaction of Metal Particles in Condensed Explosive Detonation

    NASA Astrophysics Data System (ADS)

    Ripley, Robert; Zhang, Fan; Lien, Fue-Sang

    2005-07-01

    For detonation propagation in a condensed explosive with metal particles, a macro-scale physical model describing the momentum transfer between the explosive and particles has yet to be completely established. Previous 1D and 2D meso-scale modeling studies indicated that significant momentum transfer from the explosive to the particles occurs as the leading shock front crosses the particles, thus influencing the initiation and detonation structure. In this work, 3D meso-scale modeling is conducted to further study the two-phase momentum transfer during the shock diffraction and subsequent detonation in liquid nitromethane containing packed metal particles. Detonation of the condensed explosive is computed using an Arrhenius reaction model and a hybrid EOS model that combines the Mie-Gruneisen equation for reactants and the JWL equation for products. The compressible particles are modeled using the Tait EOS, where the material strength is negligible. The effect of particle packing configuration and inter-particle spacing is shown by parametric studies. Finally, a physical description of the momentum transfer is discussed.

  14. Comparative Analysis of a High Bypass Turbofan Using a Pulsed Detonation Combustor

    DTIC Science & Technology

    2007-03-01

    Thrust Specific Fuel Consumption . . . . . . . . . . . . . 67 xiii List of Abbreviations Abbreviation Page PDE Pulsed Detonation Engine...past ten years to develop pulsed det- onation engines ( PDE ) as a means of aircraft propulsion. Detonation combustion holds the promise of a more...aviation engine, and detonation creates more of it than previous aircraft engines. It is hoped that a marriage of the PDE with traditional

  15. On the propagation mechanism of a detonation wave in a round tube with orifice plates

    NASA Astrophysics Data System (ADS)

    Ciccarelli, G.; Cross, M.

    2016-09-01

    This study deals with the investigation of the detonation propagation mechanism in a circular tube with orifice plates. Experiments were performed with hydrogen air in a 10-cm-inner-diameter tube with the second half of the tube filled with equally spaced orifice plates. A self-sustained Chapman-Jouguet (CJ) detonation wave was initiated in the smooth first half of the tube and transmitted into the orifice-plate-laden second half of the tube. The details of the propagation were obtained using the soot-foil technique. Two types of foils were used between obstacles, a wall-foil placed on the tube wall, and a flat-foil (sooted on both sides) placed horizontally across the diameter of the tube. When placed after the first orifice plate, the flat foil shows symmetric detonation wave diffraction and failure, while the wall foil shows re-initiation via multiple local hot spots created when the decoupled shock wave interacts with the tube wall. At the end of the tube, where the detonation propagated at an average velocity much lower than the theoretical CJ value, the detonation propagation is much more asymmetric with only a few hot spots on the tube wall leading to local detonation initiation. Consecutive foils also show that the detonation structure changes after each obstacle interaction. For a mixture near the detonation propagation limit, detonation re-initiation occurs at a single wall hot spot producing a patch of small detonation cells. The local overdriven detonation wave is short lived, but is sufficient to keep the global explosion front propagating. Results associated with the effect of orifice plate blockage and spacing on the detonation propagation mechanism are also presented.

  16. Parametric Study of High Frequency Pulse Detonation Tubes

    NASA Technical Reports Server (NTRS)

    Cutler, Anderw D.

    2008-01-01

    This paper describes development of high frequency pulse detonation tubes similar to a small pulse detonation engine (PDE). A high-speed valve injects a charge of a mixture of fuel and air at rates of up to 1000 Hz into a constant area tube closed at one end. The reactants detonate in the tube and the products exit as a pulsed jet. High frequency pressure transducers are used to monitor the pressure fluctuations in the device and thrust is measured with a balance. The effects of injection frequency, fuel and air flow rates, tube length, and injection location are considered. Both H2 and C2H4 fuels are considered. Optimum (maximum specific thrust) fuel-air compositions and resonant frequencies are identified. Results are compared to PDE calculations. Design rules are postulated and applications to aerodynamic flow control and propulsion are discussed.

  17. Computer modeling of electrical performance of detonators

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Furnberg, C.M.; Peevy, G.R.; Brigham, W.P.

    1995-05-01

    An empirical model of detonator electrical performance which describes the resistance of the exploding bridgewire (EBW) or exploding foil initiator (EFI or slapper) as a function of energy, deposition will be described. This model features many parameters that can be adjusted to obtain a close fit to experimental data. This has been demonstrated using recent experimental data taken with the cable discharge system located at Sandia National Laboratories. This paper will be a continuation of the paper entitled ``Cable Discharge System for Fundamental Detonator Studies`` presented at the 2nd NASA/DOD/DOE Pyrotechnic Workshop.

  18. Pressure and Thrust Measurements of a High-Frequency Pulsed-Detonation Actuator

    NASA Technical Reports Server (NTRS)

    Nguyen, Namtran C.; Cutler, Andrew D.

    2008-01-01

    This paper describes the development of a small-scale, high-frequency pulsed detonation actuator. The device utilized a fuel mixture of H2 and air, which was injected into the device at frequencies of up to 1200 Hz. Pulsed detonations were demonstrated in an 8-inch long combustion volume, at approx.600 Hz, for the lambda/4 mode. The primary objective of this experiment was to measure the generated thrust. A mean value of thrust was measured up to 6.0 lb, corresponding to specific impulse of 2611 s. This value is comparable to other H2-fueled pulsed detonation engines (PDEs) experiments. The injection and detonation frequency for this new experimental case was approx.600 Hz, and was much higher than typical PDEs, where frequencies are usually less than 100 Hz. The compact size of the model and high frequency of detonation yields a thrust-per-unit-volume of approximately 2.0 lb/cu in, and compares favorably with other experiments, which typically have thrust-per-unit-volume values of approximately 0.01 lb/cu in.

  19. Diagnostic Imaging of Detonation Waves for Waveshaper Development

    DTIC Science & Technology

    2009-07-01

    it is difficult to determine the depth of the detonation wave (due to the translucency of the sensitised nitromethane) and when it reaches the bottom...Charges For Use against Concrete Targerts, DSTO Client Report, DSTO-CR-2005-0164, 2005. [2] M. J. Murphy, R. M. Kuklo, T. A. Rambur, L. L. Switzer & M...Resnyansky, S. A. Weckert & T. Delaney, Shaping of Detonation Waves in Shaped Charges for Use against Concrete Targets: Part II, in preparation

  20. Effect of slow energy releasing on divergent detonation of Insensitive High Explosives

    NASA Astrophysics Data System (ADS)

    Hu, Xiaomian; Pan, Hao; Huang, Yong; Wu, Zihui

    2014-03-01

    There exists a slow energy releasing (SER) process in the slow reaction zone located behind the detonation wave due to the carbon cluster in the detonation products of Insensitive High Explosives (IHEs), and the process will affect the divergent detonation wave's propagation and the driving process of the explosives. To study the potential effect, a new artificial burn model including the SER process based on the programmed burn model is proposed in the paper. Quasi-steady analysis of the new model indicates that the nonlinearity of the detonation speed as a function of front curvature owes to the significant change of the reaction rate and the reaction zone length at the sonic state. What's more, in simulating the detonation of IHE JB-9014, the new model including the slow reaction can predict a slower jump-off velocity, in good agreement with the result of the test.

  1. Propagation of gaseous detonation waves in a spatially inhomogeneous reactive medium

    NASA Astrophysics Data System (ADS)

    Mi, XiaoCheng; Higgins, Andrew J.; Ng, Hoi Dick; Kiyanda, Charles B.; Nikiforakis, Nikolaos

    2017-05-01

    Detonation propagation in a compressible medium wherein the energy release has been made spatially inhomogeneous is examined via numerical simulation. The inhomogeneity is introduced via step functions in the reaction progress variable, with the local value of energy release correspondingly increased so as to maintain the same average energy density in the medium and thus a constant Chapman-Jouguet (CJ) detonation velocity. A one-step Arrhenius rate governs the rate of energy release in the reactive zones. The resulting dynamics of a detonation propagating in such systems with one-dimensional layers and two-dimensional squares are simulated using a Godunov-type finite-volume scheme. The resulting wave dynamics are analyzed by computing the average wave velocity and one-dimensional averaged wave structure. In the case of sufficiently inhomogeneous media wherein the spacing between reactive zones is greater than the inherent reaction zone length, average wave speeds significantly greater than the corresponding CJ speed of the homogenized medium are obtained. If the shock transit time between reactive zones is less than the reaction time scale, then the classical CJ detonation velocity is recovered. The spatiotemporal averaged structure of the waves in these systems is analyzed via a Favre-averaging technique, with terms associated with the thermal and mechanical fluctuations being explicitly computed. The analysis of the averaged wave structure identifies the super-CJ detonations as weak detonations owing to the existence of mechanical nonequilibrium at the effective sonic point embedded within the wave structure. The correspondence of the super-CJ behavior identified in this study with real detonation phenomena that may be observed in experiments is discussed.

  2. Pulse Detonation Rocket Magnetohydrodynamic Power Experiment

    NASA Technical Reports Server (NTRS)

    Litchford, R. J.; Jones, J. E.; Dobson, C. C.; Cole, J. W.; Thompson, B. R.; Plemmons, D. H.; Turner, M. W.

    2003-01-01

    The production of onboard electrical power by pulse detonation engines is problematic in that they generate no shaft power; however, pulse detonation driven magnetohydrodynamic (MHD) power generation represents one intriguing possibility for attaining self-sustained engine operation and generating large quantities of burst power for onboard electrical systems. To examine this possibility further, a simple heat-sink apparatus was developed for experimentally investigating pulse detonation driven MHD generator concepts. The hydrogen oxygen fired driver was a 90 cm long stainless steel tube having a 4.5 cm square internal cross section and a short Schelkin spiral near the head end to promote rapid formation of a detonation wave. The tube was intermittently filled to atmospheric pressure and seeded with a CsOH/methanol prior to ignition by electrical spark. The driver exhausted through an aluminum nozzle having an area contraction ratio of A*/A(sub zeta) = 1/10 and an area expansion ratio of A(sub zeta)/A* = 3.2 (as limited by available magnet bore size). The nozzle exhausted through a 24-electrode segmented Faraday channel (30.5 cm active length), which was inserted into a 0.6 T permanent magnet assembly. Initial experiments verified proper drive operation with and without the nozzle attachment, and head end pressure and time resolved thrust measurements were acquired. The exhaust jet from the nozzle was interrogated using a polychromatic microwave interferometer yielding an electron number density on the order of 10(exp 12)/cm at the generator entrance. In this case, MHD power generation experiments suffered from severe near-electrode voltage drops and low MHD interaction; i.e., low flow velocity, due to an inherent physical constraint on expansion with the available magnet. Increased scaling, improved seeding techniques, higher magnetic fields, and higher expansion ratios are expected to greatly improve performance.

  3. Characterization of Detonator Performance as a Function of Porosity via the Hayes Effect via Rogowski Coil

    NASA Astrophysics Data System (ADS)

    Nakamoto, Teagan; Parrack, Kristina; Smith, Dalton; Trujillo, Chris; Wilde, Zak; Gibson, John; Lodes, Rylie; Malcolm, Hayden

    2017-06-01

    Researchers experimented with a novel diagnostic to study the effects of porosity on detonator performance. The new diagnostic takes advantage of the detonation electric effect observed by Hayes (1966). Detonation-produced electrical charges induce a current in the detonator wire that may be detected by use of a Rogowski coil developed and tailored for the purpose. Data collected by the Rogowski coil were then used to characterize detonations. Researchers tested PETN charges of various porosity levels (as characterized by measured particle size and surface area) to study the effect of porosity on detonation characteristics. This novel method was compared with and verified by the well-established technique of using PVDF gauges for detonator response characterization.

  4. Characterization of Detonation Soot Produced During Steady and Overdriven Conditions for Three High Explosive Formulations

    NASA Astrophysics Data System (ADS)

    Podlesak, David; Amato, Ronald; Dattelbaum, Dana; Firestone, Millicent; Gustavsen, Richard; Huber, Rachel; Ringstrand, Bryan

    2015-06-01

    The detonation of high explosives (HE) produces a dense fluid of molecular gases and solid carbon. The solid detonation carbon contains various carbon allotropes such as detonation nanodiamonds, ``onion-like'' carbon, graphite and amorphous carbon, with the formation of the different forms dependent upon pressure, temperature and the environmental conditions of the detonation. We have collected solid carbon residues from controlled detonations of three HE formulations (Composition B-3, PBX 9501, and PBX 9502). Soot was collected from experiments designed to produce both steady and overdriven conditions, and from detonations in both an ambient (air) atmosphere and in an inert Ar atmosphere. Structural studies to glean the features of the solid carbon products have been performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Raman spectroscopy, small-angle X-ray scattering (SAXS), and X-Ray Pair Distribution Function measurements (PDF). Bulk soot was also analyzed for elemental and isotopic compositions. We will discuss differences in the structure and composition of the detonation carbon as a function of formulation, detonation conditions, and the surrounding atmosphere.

  5. Modeling Initiation in Exploding Bridgewire Detonators

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hrousis, C A

    2005-05-18

    One- and two-dimensional models of initiation in detonators are being developed for the purpose of evaluating the performance of aged and modified detonator designs. The models focus on accurate description of the initiator, whether it be an EBW (exploding bridgewire) that directly initiates a high explosive powder or an EBF (exploding bridgefoil) that sends an inert flyer into a dense HE pellet. The explosion of the initiator is simulated using detailed MHD equations of state as opposed to specific action-based phenomenological descriptions. The HE is modeled using the best available JWL equations of state. Results to date have been promising,more » however, work is still in progress.« less

  6. A gasdynamic gun driven by gaseous detonation

    NASA Astrophysics Data System (ADS)

    Li, Jinping; Chen, Hong; Zhang, Shizhong; Zhang, Xiaoyuan; Yu, Hongru

    2016-01-01

    A gasdynamic gun driven by gaseous detonation was developed to address the disadvantages of the insufficient driving capability of high-pressure gas and the constraints of gunpowder. The performance of this gasdynamic gun was investigated through experiments and numerical simulations. Much more powerful launching capability was achieved by this gun relative to a conventional high-pressure gas gun, owing to the use of the chemical energy of the driver gas. To achieve the same launching condition, the initial pressure required for this gun was an order of magnitude lower than that for a gun driven by high-pressure H2. Because of the presence of the detonation, however, a more complex internal ballistic process of this gun was observed. Acceleration of projectiles for this gun was accompanied by a series of impulse loads, in contrast with the smooth acceleration for a conventional one, which indicates that this gun should be used conditionally. The practical feasibility of this gun was verified by experiments. The experiments demonstrated the convenience of taking advantage of the techniques developed for detonation-driven shock tubes and tunnels.

  7. Multistage reaction pathways in detonating high explosives

    NASA Astrophysics Data System (ADS)

    Li, Ying; Kalia, Rajiv; Nakano, Aiichiro; Vashishta, Priya; CACS Collaboration; ALCF Team

    2015-06-01

    Atomistic mechanisms underlying the reaction time and intermediate reaction products of detonating high explosives far from equilibrium have been elusive. This is because detonation is one of the hardest multiscale physics problems, in which diverse length and time scales play important roles. Here, large spatiotemporal-scale reactive molecular dynamics simulations validated by quantum molecular dynamics simulations reveal a two-stage reaction mechanism during the detonation of cyclotrimethylenetrinitramine crystal. Rapid production of N2 and H2O within 10 ps is followed by delayed production of CO molecules beyond ns. We found that further decomposition towards the final products is inhibited by the formation of large metastable carbon- and oxygen-rich clusters with fractal geometry. In addition, we found distinct uni-molecular and intermolecular reaction pathways, respectively, for the rapid N2 and H2O productions. This work was supported by the Office of Naval Research Grant No. N000014-12-1-0555 and the Basic Research Program of Defense Threat Reduction Agency (DTRA) Grant No. HDTRA1-08-1-0036. All the simulations were performed at USC and Argonne LCF.

  8. Detonation Performance Analyses for Recent Energetic Molecules

    NASA Astrophysics Data System (ADS)

    Stiel, Leonard; Samuels, Philip; Spangler, Kimberly; Iwaniuk, Daniel; Cornell, Rodger; Baker, Ernest

    2017-06-01

    Detonation performance analyses were conducted for a number of evolving and potential high explosive materials. The calculations were completed for theoretical maximum densities of the explosives using the Jaguar thermo-chemical equation of state computer programs for performance evaluations and JWL/JWLB equations of state parameterizations. A number of recently synthesized materials were investigated for performance characterizations and comparisons to existing explosives, including TNT, RDX, HMX, and Cl-20. The analytic cylinder model was utilized to establish cylinder and Gurney velocities as functions of the radial expansions of the cylinder for each explosive. The densities and heats of formulation utilized in the calculations are primarily experimental values from Picatinny Arsenal and other sources. Several of the new materials considered were predicted to have enhanced detonation characteristics compared to conventional explosives. In order to confirm the accuracy of the Jaguar and analytic cylinder model results, available experimental detonation and Gurney velocities for representative energetic molecules and their formulations were compared with the corresponding calculated values. Close agreement was obtained with most of the data. Presently at NATO.

  9. The analysis of thermal stability of detonation nanodiamond

    NASA Astrophysics Data System (ADS)

    Efremov, V. P.; Zakatilova, E. I.

    2016-11-01

    The detonation nanodiamond is a new perspective material. Ammunition recycling with use of high explosives and obtaining nanodiamond as the result of the detonation synthesis have given a new motivation for searching of their application areas. In this work nanodiamond powder has been investigated by the method of synchronous thermal analysis. Experiments have been carried out at atmospheric pressure in the environment of argon. Nanodiamond powder has been heated in the closed corundum crucible at the temperature range of 30-1500 °C. The heating rates were varied from 2 K/min to 20 K/min. After the heat treatment, the samples have been studied by the x-ray diffraction and the electron microscopy. As one of the results of this work, it has been found that the detonation nanodiamond has not started the transition into graphite at the temperature below 800 °C.

  10. Reflection Patterns Generated by Condensed-Phase Oblique Detonation Interaction with a Rigid Wall

    NASA Astrophysics Data System (ADS)

    Short, Mark; Chiquete, Carlos; Bdzil, John; Meyer, Chad

    2017-11-01

    We examine numerically the wave reflection patterns generated by a detonation in a condensed phase explosive inclined obliquely but traveling parallel to a rigid wall as a function of incident angle. The problem is motivated by the characterization of detonation-material confiner interactions. We compare the reflection patterns for two detonation models, one where the reaction zone is spatially distributed, and the other where the reaction is instantaneous (a Chapman-Jouguet detonation). For the Chapman-Jouguet model, we compare the results of the computations with an asymptotic study recently conducted by Bdzil and Short for small detonation incident angles. We show that the ability of a spatially distributed reaction energy release to turn flow streamlines has a significant impact on the nature of the observed reflection patterns. The computational approach uses a shock-fit methodology.

  11. 30 CFR 75.1312 - Explosives and detonators in underground magazines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... magazines. 75.1312 Section 75.1312 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... Blasting § 75.1312 Explosives and detonators in underground magazines. (a) The quantity of explosives kept..., explosives and detonators taken underground shall be kept in— (1) Separate, closed magazines at least 5 feet...

  12. Material properties effects on the detonation spreading and propagation of diaminoazoxyfurazan (DAAF)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Francois, Elizabeth Green; Morris, John S; Novak, Alan M

    2010-01-01

    Recent dynamic testing of Diaminoazoxyfurazan (DAAF) has focused on understanding the material properties affecting the detonation propagation, spreading, behavior and symmetry. Small scale gap testing and wedge testing focus on the sensitivity to shock with the gap test including the effects of particle size and density. Floret testing investigates the detonation spreading as it is affected by particle size, density, and binder content. The polyrho testing illustrates the effects of density and binder content on the detonation velocity. Finally the detonation spreading effect can be most dramatically seen in the Mushroom and Onionskin tests where the variations due to densitymore » gradients, pressing methods and geometry can be seen on the wave breakout behavior.« less

  13. Numerical Modeling of Pulse Detonation Rocket Engine Gasdynamics and Performance

    NASA Technical Reports Server (NTRS)

    Morris, C. I.

    2003-01-01

    Pulse detonation engines (PDB) have generated considerable research interest in recent years as a chemical propulsion system potentially offering improved performance and reduced complexity compared to conventional gas turbines and rocket engines. The detonative mode of combustion employed by these devices offers a theoretical thermodynamic advantage over the constant-pressure deflagrative combustion mode used in conventional engines. However, the unsteady blowdown process intrinsic to all pulse detonation devices has made realistic estimates of the actual propulsive performance of PDES problematic. The recent review article by Kailasanath highlights some of the progress that has been made in comparing the available experimental measurements with analytical and numerical models.

  14. The Physical Effects of Detonation in a Closed Cylindrical Chamber

    NASA Technical Reports Server (NTRS)

    Draper, C S

    1935-01-01

    Detonation in the internal-combustion engine is studied as a physical process. It is shown that detonation is accompanied by pressure waves within the cylinder charge. Sound theory is applied to the calculation of resonant pressure-wave frequencies. Apparatus is described for direct measurement of pressure-wave frequencies. Frequencies determined from two engines of different cylinder sizes are shown to agree with the values calculated from sound theory. An outline of the theoretically possible modes of vibration in a right circular cylinder with flat ends is included. An appendix by John P. Elting gives a method of calculating pressure in the sound wave following detonation.

  15. NOx Emissions from a Rotating Detonation-wave Engine

    NASA Astrophysics Data System (ADS)

    Kailasanath, Kazhikathra; Schwer, Douglas

    2016-11-01

    Rotating detonation-wave engines (RDE) are a form of continuous detonation-wave engines. They potentially provide further gains in performance than an intermittent or pulsed detonation-wave engine (PDE). The overall flow field in an idealized RDE, primarily consisting of two concentric cylinders, has been discussed in previous meetings. Because of the high pressures involved and the lack of adequate reaction mechanisms for this regime, previous simulations have typically used simplified chemistry models. However, understanding the exhaust species concentrations in propulsion devices is important for both performance considerations as well as estimating pollutant emissions. Progress towards addressing this need will be discussed in this talk. In this approach, an induction parameter model is used for simulating the detonation but a more detailed finite-chemistry model including NOx chemistry is used in the expansion flow region, where the pressures are lower and the uncertainties in the chemistry model are greatly reduced. Results show that overall radical concentrations in the exhaust flow are substantially lower than from earlier predictions with simplified models. Results to date show that NOx emissions are not a problem for the RDE due to the short residence times and the nature of the flow field. Furthermore, simulations show that the amount of NOx can be further reduced by tailoring the fluid dynamics within the RDE.

  16. [Accidental hanging during auto-erotic practices].

    PubMed

    Vieira, D N; da Silva, A G

    1989-01-01

    An unusual case of accidental hanging during autoerotic practices in a 25-year-old male student is described and the autoerotic asphyxia syndrome briefly discussed. The authors stressed the importance of a correct diagnostic of accidental death in these cases.

  17. Numerical Simulation of Flow in Fluidic Valves in Rotating Detonation Engines

    NASA Astrophysics Data System (ADS)

    Gopalakrishnan, Nandini

    Rotating detonation engines (RDE) have received considerable research attention in recent times for use in propulsion systems. The cycle frequency of operation of an RDE can be as high as 10,000 Hz. Conventional mechanical valves cannot operate at such high frequencies, leading to the need for propellant injectors or valves with no moving parts. A fluidic valve is such a valve and is the focus of this study. The valve consists of an orifice connected to a constant area plenum cavity which operates at constant pressure. The fluidic valve supplies propellants to the detonation tube through the orifice. Hydrogen - oxygen detonation is studied in a tube with fluidic valves. A detailed 19-step chemical reaction mechanism has been used to model detonation and the flow simulated in ANSYS Fluent. This research aims to determine the location of contact surface in the cavity and the time taken for the contact surface to leave the valve after a shock wave has passed through it. This will help us understand if the steady-state flow in the cavity is comprised of detonation products or fresh propellants.

  18. Detonation corner turning in vapor-deposited explosives using the micromushroom test

    NASA Astrophysics Data System (ADS)

    Tappan, Alexander S.; Yarrington, Cole D.; Knepper, Robert

    2017-06-01

    Detonation corner turning describes the ability of a detonation wave to propagate into unreacted explosive that is not immediately in the path normal to the wave. The classic example of corner turning is cylindrical and involves a small diameter explosive propagating into a larger diameter explosive as described by Los Alamos' Mushroom test (e.g. (Hill, Seitz et al. 1998)), where corner turning is inferred from optical breakout of the detonation wave. We present a complimentary method to study corner turning in millimeter-scale explosives through the use of vapor deposition to prepare the slab (quasi-2D) analog of the axisymmetric mushroom test. Because the samples are in a slab configuration, optical access to the explosive is excellent and direct imaging of the detonation wave and ``dead zone'' that results during corner turning is possible. Results are compared for explosives that demonstrate a range of behaviors, from pentaerythritol tetranitrate (PETN), which has corner turning properties that are nearly ideal; to HNAB (hexanitroazobenzene), which has corner turning properties that reveal a substantial dead zone. Results are discussed in the context of microstructure and detonation failure thickness.

  19. Experimental study of detonation of large-scale powder-droplet-vapor mixtures

    NASA Astrophysics Data System (ADS)

    Bai, C.-H.; Wang, Y.; Xue, K.; Wang, L.-F.

    2018-05-01

    Large-scale experiments were carried out to investigate the detonation performance of a 1600-m3 ternary cloud consisting of aluminum powder, fuel droplets, and vapor, which were dispersed by a central explosive in a cylindrically stratified configuration. High-frame-rate video cameras and pressure gauges were used to analyze the large-scale explosive dispersal of the mixture and the ensuing blast wave generated by the detonation of the cloud. Special attention was focused on the effect of the descending motion of the charge on the detonation performance of the dispersed ternary cloud. The charge was parachuted by an ensemble of apparatus from the designated height in order to achieve the required terminal velocity when the central explosive was detonated. A descending charge with a terminal velocity of 32 m/s produced a cloud with discernably increased concentration compared with that dispersed from a stationary charge, the detonation of which hence generates a significantly enhanced blast wave beyond the scaled distance of 6 m/kg^{1/3}. The results also show the influence of the descending motion of the charge on the jetting phenomenon and the distorted shock front.

  20. Three Dimensional Analysis of Induced Detonation of Cased Explosive

    DTIC Science & Technology

    2014-10-16

    hardness and ductility . RHA steel is largely used in military applications to manufacture armoured vehicles. The Johnson Cook (JC) constitutive...armour (RHA) steel were investigated through the LS-DYNA. The investigation focused on shock to detonation simulations of Composition B, with the... hot spots caused by the compression of the explosive from the initial shockwave. Detonation was also caused by pressure waves reflecting against the

  1. Anatomy of a diffracting detonation in a circular arc of explosive

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bdzil, John Bohdan

    Using high-resolution numerical simulation, study diffraction of a detonation as it traverses a 270° finite-thickness condensed-phase explosive arc. This geometry admits a steady solution in a frame rotating with angular speed ω 0, which thereby facilitates a detailed analysis of how the loss of energy from the detonation reaction zone due to the diffraction process slows the propagation of the detonation. There exists a region of subsonic flow, between the detonation shock and the curve of sonic flow (labelled the DDZ), which is responsible for setting ω 0. Although the DDZ spans the entire thickness for thin arcs, it ismore » localized to a region near the inside surface as the arc is thickened. Furthermore the explosive energy release near this inside surface plays a disproportionate role in the diffraction process.« less

  2. Shock-to-detonation transition of nitromethane: Time-resolved emission spectroscopy measurements

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bouyer, Viviane; Darbord, Isabelle; Herve, Philippe

    2006-01-01

    The objective of this work is to improve the knowledge of the shock-to-detonation transition of nitromethane. The study is based on a spectral analysis in the range 0.3-0.85 {mu}m, with a 28-nm resolution, during experiments of plane shock impacts on explosive targets at 8.6 GPa. The time-resolved radiant spectra show that the detonation front, the reaction products produced during the superdetonation, and the detonation products are semitransparent. The temperature and absorption coefficient profiles are determined from the measured spectra by a mathematical inversion method based on the equation of radiative transfer with Rayleigh scattering regime. Shocked nitromethane reaches at leastmore » 2500 K, showing the existence of local chemical reactions after shock entrance. Levels of temperature of superdetonation and steady-state detonation are also determined.« less

  3. Anatomy of a diffracting detonation in a circular arc of explosive

    DOE PAGES

    Bdzil, John Bohdan

    2018-02-08

    Using high-resolution numerical simulation, study diffraction of a detonation as it traverses a 270° finite-thickness condensed-phase explosive arc. This geometry admits a steady solution in a frame rotating with angular speed ω 0, which thereby facilitates a detailed analysis of how the loss of energy from the detonation reaction zone due to the diffraction process slows the propagation of the detonation. There exists a region of subsonic flow, between the detonation shock and the curve of sonic flow (labelled the DDZ), which is responsible for setting ω 0. Although the DDZ spans the entire thickness for thin arcs, it ismore » localized to a region near the inside surface as the arc is thickened. Furthermore the explosive energy release near this inside surface plays a disproportionate role in the diffraction process.« less

  4. Time resolved small angle X-ray scattering experiments performed on detonating explosives at the advanced photon source: Calculation of the time and distance between the detonation front and the x-ray beam

    DOE PAGES

    Gustavsen, Richard L.; Dattelbaum, Dana Mcgraw; Watkins, Erik Benjamin; ...

    2017-03-10

    Time resolved Small Angle X-ray Scattering (SAXS) experiments on detonating explosives have been conducted at Argonne National Laboratory's Advanced Photon Source Dynamic Compression Sector. The purpose of the experiments is to measure the SAXS patterns at tens of ns to a few μs behind the detonation front. Corresponding positions behind the detonation front are of order 0.1–10 mm. From the scattering patterns, properties of the explosive products relative to the time behind the detonation front can be inferred. Lastly, this report describes how the time and distance from the x-ray probe location to the detonation front is calculated, as wellmore » as the uncertainties and sources of uncertainty associated with the calculated times and distances.« less

  5. Time resolved small angle X-ray scattering experiments performed on detonating explosives at the advanced photon source: Calculation of the time and distance between the detonation front and the x-ray beam

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gustavsen, Richard L.; Dattelbaum, Dana Mcgraw; Watkins, Erik Benjamin

    Time resolved Small Angle X-ray Scattering (SAXS) experiments on detonating explosives have been conducted at Argonne National Laboratory's Advanced Photon Source Dynamic Compression Sector. The purpose of the experiments is to measure the SAXS patterns at tens of ns to a few μs behind the detonation front. Corresponding positions behind the detonation front are of order 0.1–10 mm. From the scattering patterns, properties of the explosive products relative to the time behind the detonation front can be inferred. Lastly, this report describes how the time and distance from the x-ray probe location to the detonation front is calculated, as wellmore » as the uncertainties and sources of uncertainty associated with the calculated times and distances.« less

  6. A Performance Map for Ideal Air Breathing Pulse Detonation Engines

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.

    2001-01-01

    The performance of an ideal, air breathing Pulse Detonation Engine is described in a manner that is useful for application studies (e.g., as a stand-alone, propulsion system, in combined cycles, or in hybrid turbomachinery cycles). It is shown that the Pulse Detonation Engine may be characterized by an averaged total pressure ratio, which is a unique function of the inlet temperature, the fraction of the inlet flow containing a reacting mixture, and the stoichiometry of the mixture. The inlet temperature and stoichiometry (equivalence ratio) may in turn be combined to form a nondimensional heat addition parameter. For each value of this parameter, the average total enthalpy ratio and total pressure ratio across the device are functions of only the reactant fill fraction. Performance over the entire operating envelope can thus be presented on a single plot of total pressure ratio versus total enthalpy ratio for families of the heat addition parameter. Total pressure ratios are derived from thrust calculations obtained from an experimentally validated, reactive Euler code capable of computing complete Pulse Detonation Engine limit cycles. Results are presented which demonstrate the utility of the described method for assessing performance of the Pulse Detonation Engine in several potential applications. Limitations and assumptions of the analysis are discussed. Details of the particular detonative cycle used for the computations are described.

  7. Schlieren Imaging of a Single-Ejector, Multi-Tube Pulsed Detonation Engine (Postprint)

    DTIC Science & Technology

    2009-01-01

    studies have shown the potential of an ejector to almost double the thrust of a pulsed detonation engine ( PDE ) tube [1-3]. Axial misalignment of the... Detonation Research Facility in the Air Force Research Laboratory were used for this study. The PDE utilizes automotive valving to feed up to four... detonation tubes. The damped thrust stand was setup to measure PDE thrust alone for baseline tests or total thrust from ejector and PDE . This

  8. Characterization of detonation soot produced during steady and overdriven conditions for three high explosive formulations

    NASA Astrophysics Data System (ADS)

    Podlesak, David W.; Huber, Rachel C.; Amato, Ronald S.; Dattelbaum, Dana M.; Firestone, Millicent A.; Gustavsen, Richard L.; Johnson, Carl E.; Mang, Joseph T.; Ringstrand, Bryan S.

    2017-01-01

    The detonation of high explosives (HE) produces a dense fluid of molecular gases and solid carbon. The solid detonation carbon contains various carbon allotropes such as detonation nanodiamonds, onion-like carbon, graphite and amorphous carbon, with the formation of the different forms dependent upon pressure, temperature and the environmental conditions of the detonation. We have collected solid carbon residues from controlled detonations of three HE formulations (Composition B-3, PBX 9501, and PBX 9502). Soot was collected from experiments designed to produce both steady and overdriven conditions, and from detonations in both an ambient (air) atmosphere and in an inert Ar atmosphere. Differences in solid carbon residues were quantified using X-ray photoelectron spectroscopy and carbon isotope measurements. Environmental conditions, HE formulation, and peak pressures influenced the amount of and isotopic composition of the carbon in the soot. Detonations in an Ar atmosphere produced greater amounts of carbon soot with lower δ13C values than those in ambient air. Therefore, solid carbon residues continued to evolve after detonation due to excess oxygen in the ambient air detonations. As well, higher peak pressures in overdriven conditions produced less carbon soot with, in general, higher δ13C values. Consequently, while overdriven conditions only produced peak pressures for a limited duration, it was enough to influence the composition of the solid carbon residues.

  9. Detonation Processes USSR

    DTIC Science & Technology

    1960-06-06

    scientists of various countries. The Investigators addressed themselves at once to the question as to what physical process causes combustion to...same values for the r poducts of com- bustion, D is the velocity of the detonation front AB, and w is the velocity of the products of com- ,bustton... mixed with oxi- dizer and mixture is preheated; 3 -- reaction zone; 4 -- products of combustion. Let us return to the single-headed spin and consider

  10. A Semi-analytic Criterion for the Spontaneous Initiation of Carbon Detonations in White Dwarfs

    NASA Astrophysics Data System (ADS)

    Garg, Uma; Chang, Philip

    2017-02-01

    Despite over 40 years of active research, the nature of the white dwarf progenitors of SNe Ia remains unclear. However, in the last decade, various progenitor scenarios have highlighted the need for detonations to be the primary mechanism by which these white dwarfs are consumed, but it is unclear how these detonations are triggered. In this paper we study how detonations are spontaneously initiated due to temperature inhomogeneities, e.g., hotspots, in burning nuclear fuel in a simplified physical scenario. Following the earlier work by Zel’Dovich, we describe the physics of detonation initiation in terms of the comparison between the spontaneous wave speed and the Chapman-Jouguet speed. We develop an analytic expression for the spontaneous wave speed and utilize it to determine a semi-analytic criterion for the minimum size of a hotspot with a linear temperature gradient between a peak and base temperature for which detonations in burning carbon-oxygen material can occur. Our results suggest that spontaneous detonations may easily form under a diverse range of conditions, likely allowing a number of progenitor scenarios to initiate detonations that burn up the star.

  11. A Semi-analytic Criterion for the Spontaneous Initiation of Carbon Detonations in White Dwarfs

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Garg, Uma; Chang, Philip, E-mail: umagarg@uwm.edu, E-mail: chang65@uwm.edu

    Despite over 40 years of active research, the nature of the white dwarf progenitors of SNe Ia remains unclear. However, in the last decade, various progenitor scenarios have highlighted the need for detonations to be the primary mechanism by which these white dwarfs are consumed, but it is unclear how these detonations are triggered. In this paper we study how detonations are spontaneously initiated due to temperature inhomogeneities, e.g., hotspots, in burning nuclear fuel in a simplified physical scenario. Following the earlier work by Zel’Dovich, we describe the physics of detonation initiation in terms of the comparison between the spontaneousmore » wave speed and the Chapman–Jouguet speed. We develop an analytic expression for the spontaneous wave speed and utilize it to determine a semi-analytic criterion for the minimum size of a hotspot with a linear temperature gradient between a peak and base temperature for which detonations in burning carbon–oxygen material can occur. Our results suggest that spontaneous detonations may easily form under a diverse range of conditions, likely allowing a number of progenitor scenarios to initiate detonations that burn up the star.« less

  12. 30 CFR 75.1313 - Explosives and detonators outside of magazines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosives and detonators outside of magazines... § 75.1313 Explosives and detonators outside of magazines. (a) The quantity of explosives outside a magazine for use in a working section or other area where blasting is to be performed shall— (1) Not exceed...

  13. Controlled Detonation Dynamics in Additively Manufactured High Explosives

    NASA Astrophysics Data System (ADS)

    Schmalzer, Andrew; Tappan, Bryce; Bowden, Patrick; Manner, Virginia; Clements, Brad; Menikoff, Ralph; Ionita, Axinte; Branch, Brittany; Dattelbaum, Dana; Espy, Michelle; Patterson, Brian; Wu, Ruilian; Mueller, Alexander

    2017-06-01

    The effect of structure in explosives has long been a subject of interest to explosives engineers and scientists. Through structure, detonation dynamics in explosives can be manipulated, introducing a new level of safety and directed performance into these previously difficult to control materials. New advances in additive manufacturing (AM) allow the deliberate introduction of exact internal structures at dimensions approaching the mesoscale of these energetic materials. We show through simulation and experiment that this structure can be used to control detonation behavior by manipulating complex shockwave interactions. We use high-speed video and shorting mag-wires to determine the detonation velocity in AM generated explosive structures, demonstrating, for the first time, a method of controlling the directional propagation of reactive flow through the controlled introduction of structure within a high explosive. With ongoing improvement in the AM methods available coupled with guidance through modeling and simulations, more complex interactions are being explored. LANL LDRD Office.

  14. 76 FR 64820 - Safety Zone; Mainardi/Kinsey Wedding Fireworks, Lake Erie, Lakewood, OH

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-19

    ... detonations, dangerous detonations, dangerous projectiles, and falling or burning debris that may cause death... cause finds that those procedures are ``impracticable, unnecessary, or contrary to the public interest.'' Under 5 U.S.C. 553(b)(B), the Coast Guard finds that good cause exists for not publishing a notice of...

  15. THE EFFECTS OF CURVATURE AND EXPANSION ON HELIUM DETONATIONS ON WHITE DWARF SURFACES

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Moore, Kevin; Bildsten, Lars; Townsley, Dean M.

    2013-10-20

    Accreted helium layers on white dwarfs have been highlighted for many decades as a possible site for a detonation triggered by a thermonuclear runaway. In this paper, we find the minimum helium layer thickness that will sustain a steady laterally propagating detonation and show that it depends on the density and composition of the helium layer, specifically {sup 12}C and {sup 16}O. Detonations in these thin helium layers have speeds slower than the Chapman-Jouget (CJ) speed from complete helium burning, v{sub CJ} = 1.5 × 10{sup 9} cm s{sup –1}. Though gravitationally unbound, the ashes still have unburned helium (≈80%more » in the thinnest cases) and only reach up to heavy elements such as {sup 40}Ca, {sup 44}Ti, {sup 48}Cr, and {sup 52}Fe. It is rare for these thin shells to generate large amounts of {sup 56}Ni. We also find a new set of solutions that can propagate in even thinner helium layers when {sup 16}O is present at a minimum mass fraction of ≈0.07. Driven by energy release from α captures on {sup 16}O and subsequent elements, these slow detonations only create ashes up to {sup 28}Si in the outer detonated He shell. We close by discussing how the unbound helium burning ashes may create faint and fast 'Ia' supernovae as well as events with virtually no radioactivity, and speculate on how the slower helium detonation velocities impact the off-center ignition of a carbon detonation that could cause a Type Ia supernova in the double detonation scenario.« less

  16. Effect of microstructure on the detonation initiation in energetic materials

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Jackson, T. L.

    2017-12-01

    In this work we examine the role of the microstructure on detonation initiation of energetic materials. We solve the reactive Euler equations, with the energy equation augmented by a power deposition term. The deposition term is based on simulations of void collapse at the microscale, modeled at the mesoscale as hot-spots, while the reaction rate at the mesoscale is modeled using density-based kinetics. We carry out two-dimensional simulations of random packs of HMX crystals in a binder. We show that mean particle size, size distribution, and particle shape have a major effect on the transition between detonation and no-detonation, thus highlighting the importance of the microstructure for shock-induced initiation.

  17. Parametric Investigation of Thrust Augmentation by Ejectors on a Pulsed Detonation Tube

    NASA Technical Reports Server (NTRS)

    Wilson, Jack; Sgondea, Alexandru; Paxson, Daniel E.; Rosenthal, Bruce N.

    2006-01-01

    A parametric investigation has been made of thrust augmentation of a 1 in. diameter pulsed detonation tube by ejectors. A set of ejectors was used which permitted variation of the ejector length, diameter, and nose radius, according to a statistical design of experiment scheme. The maximum augmentation ratios for each ejector were fitted using a polynomial response surface, from which the optimum ratios of ejector diameter to detonation tube diameter, and ejector length and nose radius to ejector diameter, were found. Thrust augmentation ratios above a factor of 2 were measured. In these tests, the pulsed detonation device was run on approximately stoichiometric air-hydrogen mixtures, at a frequency of 20 Hz. Later measurements at a frequency of 40 Hz gave lower values of thrust augmentation. Measurements of thrust augmentation as a function of ejector entrance to detonation tube exit distance showed two maxima, one with the ejector entrance upstream, and one downstream, of the detonation tube exit. A thrust augmentation of 2.5 was observed using a tapered ejector.

  18. [THREE CASES OF ACCIDENTAL AUTO-INJECTION OF ADRENALINE].

    PubMed

    Yanagida, Noriyuki; Iikura, Katsuhito; Ogura, Kiyotake; Wang, Ling-jen; Asaumi, Tomoyuki; Sato, Sakura; Ebisawa, Motohiro

    2015-12-01

    Reports on accidental auto-injection of adrenaline are few. We encountered three cases of accidental injection of adrenaline. In this study, we have examined and reported the clinical courses and symptoms of our cases. CASE 1 involved a female physician in her 50s who had attended an explanatory meeting on auto-injection of adrenaline. She mistook EpiPen® to be the EpiPen trainer and accidentally injected herself with 0.3 mg EpiPen®. Her systolic/diastolic pressure peaked at 7 min to reach 144/78 mmHg and decreased to 120/77 mmHg at 14 min. Except for palpitation after 7 min, the only subjective symptom was local pain at the injection site. CASE 2 was noted in a 6-year-old boy. He accidentally pierced his right forefinger with 0.15 mg EpiPen®, and after 20 min, his right forefinger was swollen. The swelling improved 80 min after the accidental injection. CASE 3 was noted in a 4-year-old girl. She accidentally injected herself with 0.15 mg EpiPen®. Her systolic/diastolic pressure peaked at 23 min to reach 123/70 mmHg and decreased to 96/86 mmHg at 28 min. Severe adverse effects of accidental auto-injection of adrenaline were not observed in these three cases. Our findings suggest that while handling adrenaline auto-injectors, we should keep in mind the possibility of accidental injection.

  19. Deflagrations, Detonations, and the Deflagration-to-Detonation Transition in Methane-Air Mixtures

    DTIC Science & Technology

    2011-04-27

    we attempt to answer the question: Given a large enough volume of flammable mixture of NG and air, can a weak spark ignition develop into a...detonation? Large -scale numerical simulations, in conjunction with experimental work conducted at the National Institute for Occupational Safety and...12 2.3.3. Flame Acceleration and DDT in Channels with Obstacles . . . . . . . . . . . . . 14 2.3.4. DDT in Large Spaces

  20. Swept-Ramp Detonation Initiation Performance in a High-Pressure Pulse Detonation Combustor

    DTIC Science & Technology

    2010-12-01

    conditions at sea level, but at elevated temperatures of 300–500°F in the combustor. The current work was motivated by a need to experimentally...The current work was motivated by a need to experimentally evaluate the detonation initiation performance of a PDC at elevated combustor pressures...High-Speed Propulsion Technologies (After [3]) .....................2 Figure 2. Stationary One-Dimensional Combustion Wave Model (From [7

  1. Initiation and structures of gaseous detonation

    NASA Astrophysics Data System (ADS)

    Vasil'ev, A. A.; Vasiliev, V. A.

    2018-03-01

    The analysis of the initiation of a detonation wave (DW) and the emergence of a multi-front structure of the DW-front are presented. It is shown that the structure of the DW arises spontaneously at the stage of a strong overdriven of the wave. The hypothesis of the gradual enhancement of small perturbations on an initially smooth initiating blast wave, traditionally used in the numerical simulation of multi-front detonation, does not agree with the experimental data. The instability of the DW is due to the chemical energy release of the combustible mixture Q. A technique for determining the Q-value of mixture was proposed, based on reconstruction of the trajectory of the expanding wave from the position of the strong explosion model. The wave trajectory at the critical initiation of a multifront detonation in a combustible mixture is compared with the trajectory of an explosive wave from the same initiator in an inert mixture whose gas-dynamic parameters are equivalent to the parameters of the combustible mixture. The energy release of a mixture is defined as the difference in the joint energy release of the initiator and the fuel mixture during the critical initiation and energy release of the initiator when the blast wave is excited in an inert mixture. Observable deviations of the experimental profile of Q from existing model representations were found.

  2. Pulse Detonation Propulsion

    DTIC Science & Technology

    2010-01-01

    constant-pressure ( Brayton ) cycle used in gas turbines and ramjets. The advantages of PDE for air- breathing propulsion are simplicity and easy scaling...constant-volume, and detonative combustion cycles will be referred to as Brayton , Humphrey, and PDE cycles. The efficiency of thermodynamic cycles O’ODD...efficiency of Brayton cycle, as 0G HH =′ , i.e., 0==constpχ (3) Constant-volume combustion (point E in Fig. 1) results in temperature K 2647/0E

  3. Thrust Augmentation Measurements Using a Pulse Detonation Engine Ejector

    NASA Technical Reports Server (NTRS)

    Santoro, Robert J.; Pal, Sibtosh

    2003-01-01

    The present NASA GRC-funded three-year research project is focused on studying PDE driven ejectors applicable to a hybrid Pulse Detonation/Turbofan Engine. The objective of the study is to characterize the PDE-ejector thrust augmentation. A PDE-ejector system has been designed to provide critical experimental data for assessing the performance enhancements possible with this technology. Completed tasks include demonstration of a thrust stand for measuring average thrust for detonation tube multi-cycle operation, and design of a 72-in.-long, 2.25-in.-diameter (ID) detonation tube and modular ejector assembly. This assembly will allow testing of both straight and contoured ejector geometries. Initial ejectors that have been fabricated are 72-in.-long-constant-diameter tubes (4-, 5-, and 6-in.-diameter) instrumented with high-frequency pressure transducers. The assembly has been designed such that the detonation tube exit can be positioned at various locations within the ejector tube. PDE-ejector system experiments with gaseous ethylene/ nitrogen/oxygen propellants will commence in the very near future. The program benefits from collaborations with Prof. Merkle of University of Tennessee whose PDE-ejector analysis helps guide the experiments. The present research effort will increase the TRL of PDE-ejectors from its current level of 2 to a level of 3.

  4. Exhaust Gas Emissions from a Rotating Detonation-wave Engine

    NASA Astrophysics Data System (ADS)

    Kailasanath, Kazhikathra; Schwer, Douglas

    2015-11-01

    Rotating detonation-wave engines (RDE) are a form of continuous detonation-wave engines. They potentially provide further gains in performance than an intermittent or pulsed detonation-wave engine (PDE). The overall flow field in an idealized RDE, primarily consisting of two concentric cylinders, has been discussed in previous meetings. Because of the high pressures involved and the lack of adequate reaction mechanisms for this regime, previous simulations have typically used simplified chemistry models. However, understanding the exhaust species concentrations in propulsion devices is important for both performance considerations as well as estimating pollutant emissions. Progress towards addressing this need will be discussed in this talk. In this approach, an induction parameter model is used for simulating the detonation but a more detailed finite-chemistry model including NOx chemistry is used in the expansion flow region, where the pressures are lower and the uncertainties in the chemistry model are greatly reduced. Results show that overall radical concentrations in the exhaust flow are substantially lower than from earlier predictions with simplified models. The performance of a baseline hydrogen/air RDE increased from 4940 s to 5000 s with the expansion flow chemistry, due to recombination of radicals and more production of H2O, resulting in additional heat release. Work sponsored by the Office of Naval Research.

  5. Thermodynamic Calculations of Hydrogen-Oxygen Detonation Parameters for Various Initial Pressures

    NASA Technical Reports Server (NTRS)

    Bollinger, Loren E.; Edse, Rudolph

    1961-01-01

    Composition, temperature, pressure and density behind a stable detonation wave and its propagation rate have been calculated for seven hydrogen-oxygen mixture at 1, 5, 25 and 100 atm initial pressure, and at an initial temperature of 40C. For stoichiometric mixtures that calculations also include an initial temperature of 200C. According to these calculations the detonation velocities of hydrogen-oxygen mixtures increase with increasing initial pressure, but decrease slightly when the initial temperature is raised from 40 to 200 C. The calculated detonation velocities agree satisfactorily with values determined experimentally. These values will be published in the near future.

  6. Effect of Mixture Pressure and Equivalence Ratio on Detonation Cell Size for Hydrogen-Air Mixtures

    DTIC Science & Technology

    2015-06-01

    National Labs ( BNL ) built and tested several detonation tubes with hydrogen and air detonations. BNL’s main detonation tubes were called the High...K and the ability to change to mixture pressure from one atmosphere to just less than three atmospheres. Before BNL designed their detonation tubes...gas driver initiation system was that the diaphragm had to be replaced after each test. In order to save time from replacing the diaphragms, BNL

  7. Formation of double front detonations of a condensed-phase explosive with powdered aluminium

    NASA Astrophysics Data System (ADS)

    Kim, Wuhyun; Gwak, Min-cheol; Yoh, Jack J.

    2018-03-01

    The performance characteristics of aluminised high explosive are considered by varying the aluminium (Al) mass fraction in a hybrid non-ideal detonation model. Since the time scales of the characteristic induction and combustion of high explosives and Al particles differ, the process of energy release behind the leading detonation wave front occurs over an extended period of time. Two cardinal observations are reported: a decrease in detonation velocity with an increase in Al mass fraction and a double front detonation (DFD) feature when anaerobic Al reaction occurs behind the front. In order to simulate the performance characteristics due to the varying Al mass fraction, the tetrahexamine tetranitramine (HMX) is considered as a base high explosive when formulating the multiphase conservation laws of mass, momentum, and energy exchanges between particles and HMX product gases. While experimental studies have been reported on the effect of Al mass fraction on both gas-phase and solid-phase detonations, the numerical investigations have been limited to only gas-phase detonation for the varying Al particles in the mixture. In the current study, a two-phase model is utilised for understanding the volumetric effects of Al mass fraction in condensed phase detonations. A series of unconfined and confined rate sticks are considered for characterising the performance of aluminised HMX with a maximum Al mass fraction of 50%. The simulated results are compared with the experimental data for 5-25% mass fractions, and the higher mass fraction behaviours are consistent with the experimental observations.

  8. Rotating Detonation Combustion: A Computational Study for Stationary Power Generation

    NASA Astrophysics Data System (ADS)

    Escobar, Sergio

    The increased availability of gaseous fossil fuels in The US has led to the substantial growth of stationary Gas Turbine (GT) usage for electrical power generation. In fact, from 2013 to 2104, out of the 11 Tera Watts-hour per day produced from fossil fuels, approximately 27% was generated through the combustion of natural gas in stationary GT. The thermodynamic efficiency for simple-cycle GT has increased from 20% to 40% during the last six decades, mainly due to research and development in the fields of combustion science, material science and machine design. However, additional improvements have become more costly and more difficult to obtain as technology is further refined. An alternative to improve GT thermal efficiency is the implementation of a combustion regime leading to pressure-gain; rather than pressure loss across the combustor. One concept being considered for such purpose is Rotating Detonation Combustion (RDC). RDC refers to a combustion regime in which a detonation wave propagates continuously in the azimuthal direction of a cylindrical annular chamber. In RDC, the fuel and oxidizer, injected from separated streams, are mixed near the injection plane and are then consumed by the detonation front traveling inside the annular gap of the combustion chamber. The detonation products then expand in the azimuthal and axial direction away from the detonation front and exit through the combustion chamber outlet. In the present study Computational Fluid Dynamics (CFD) is used to predict the performance of Rotating Detonation Combustion (RDC) at operating conditions relevant to GT applications. As part of this study, a modeling strategy for RDC simulations was developed. The validation of the model was performed using benchmark cases with different levels of complexity. First, 2D simulations of non-reactive shock tube and detonation tubes were performed. The numerical predictions that were obtained using different modeling parameters were compared with

  9. Investigation on Novel Methods to Increase Specific Thrust in Pulse Detonation Engines via Imploding Detonations

    DTIC Science & Technology

    2009-12-01

    Malliakos. Detonation cell size measurements in high-temperature hydrogen- air-steam mixtures at the bnl high-temperature combustion facility. Technical...Report NUREG/CR-6391, BNL -NUREG-52482, Brookhaven National Laboratory, 1997. [13] W.B. Benedick, R. Knystautas, and J.H.S. Lee. Large-scale

  10. A detonation wave in the system liquid-gas bubbles

    NASA Astrophysics Data System (ADS)

    Sychev, A. I.

    1985-06-01

    The shock-wave ignition of a system consisting of a liquid (H2O) and bubbles of an explosive gas mixture (C2H2+2.5O2) is investigated experimentally and analytically. The possibility of the existence of a detonation wave, a supersonic self-sustaining process, in a gas-liquid system is demonstrated. The conditions for the existence of a detonation wave are determined, and the initiation mechanism is analyzed.

  11. Characterizing the growth to detonation in HNS with small-scale PDV "cutback" experiments

    NASA Astrophysics Data System (ADS)

    Wixom, Ryan R.; Yarrington, Cole D.; Knepper, Robert; Tappan, Alexander S.; Olles, Joseph D.; Damm, David L.

    2017-01-01

    For many decades, cutback experiments have been used to characterize the equation of state and growth to steady detonation in explosive formulations. More recently, embedded gauges have been used to capture the growth to steady detonation in gas-gun impacted samples. Data resulting from these experiments are extremely valuable for parameterizing equation of state and reaction models used in hydrocode simulations. Due to the extremely fast growth to detonation in typical detonator explosives, cutback and embedded gauge experiments are particularly difficult, if not impossible. Using frequency shifted photonic Doppler velocimetry (PDV) we have measured particle velocity histories from vapor-deposited explosive films impacted with electrically driven flyers. By varying the sample thickness and impact conditions we were able to capture the growth from inert shock to full detonation pressure within distances as short as 100 µm. These data are being used to assess and improve burn-model parameterization and equations of state for simulating shock initiation.

  12. Development of Detonation Modeling Capabilities for Rocket Test Facilities: Hydrogen-Oxygen-Nitrogen Mixtures

    NASA Technical Reports Server (NTRS)

    Allgood, Daniel C.

    2016-01-01

    The objective of the presented work was to develop validated computational fluid dynamics (CFD) based methodologies for predicting propellant detonations and their associated blast environments. Applications of interest were scenarios relevant to rocket propulsion test and launch facilities. All model development was conducted within the framework of the Loci/CHEM CFD tool due to its reliability and robustness in predicting high-speed combusting flow-fields associated with rocket engines and plumes. During the course of the project, verification and validation studies were completed for hydrogen-fueled detonation phenomena such as shock-induced combustion, confined detonation waves, vapor cloud explosions, and deflagration-to-detonation transition (DDT) processes. The DDT validation cases included predicting flame acceleration mechanisms associated with turbulent flame-jets and flow-obstacles. Excellent comparison between test data and model predictions were observed. The proposed CFD methodology was then successfully applied to model a detonation event that occurred during liquid oxygen/gaseous hydrogen rocket diffuser testing at NASA Stennis Space Center.

  13. Parallel Adaptive Simulation of Detonation Waves Using a Weighted Essentially Non-Oscillatory Scheme

    NASA Astrophysics Data System (ADS)

    McMahon, Sean

    The purpose of this thesis was to develop a code that could be used to develop a better understanding of the physics of detonation waves. First, a detonation was simulated in one dimension using ZND theory. Then, using the 1D solution as an initial condition, a detonation was simulated in two dimensions using a weighted essentially non-oscillatory scheme on an adaptive mesh with the smallest lengthscales being equal to 2-3 flamelet lengths. The code development in linking Chemkin for chemical kinetics to the adaptive mesh refinement flow solver was completed. The detonation evolved in a way that, qualitatively, matched the experimental observations, however, the simulation was unable to progress past the formation of the triple point.

  14. Development of a Gas-Fed Pulse Detonation Research Engine

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.; Hutt, John (Technical Monitor)

    2001-01-01

    In response to the growing need for empirical data on pulse detonation engine performance and operation, NASA Marshall Space Flight Center has developed and placed into operation a low-cost gas-fed pulse detonation research engine. The guiding design strategy was to achieve a simple and flexible research apparatus, which was inexpensive to build and operate. As such, the engine was designed to operate as a heat sink device, and testing was limited to burst-mode operation with run durations of a few seconds. Wherever possible, maximum use was made of standard off-the-shelf industrial or automotive components. The 5-cm diameter primary tube is about 90-cm long and has been outfitted with a multitude of sensor and optical ports. The primary tube is fed by a coaxial injector through an initiator tube, which is inserted directly into the injector head face. Four auxiliary coaxial injectors are also integrated into the injector head assembly. All propellant flow is controlled with industrial solenoid valves. An automotive electronic ignition system was adapted for use, and spark plugs are mounted in both tubes so that a variety of ignition schemes can be examined. A microprocessor-based fiber-optic engine control system was developed to provide precise control over valve and ignition timing. Initial shakedown testing with hydrogen/oxygen mixtures verified the need for Schelkin spirals in both the initiator and primary tubes to ensure rapid development of the detonation wave. Measured pressure wave time-of-flight indicated detonation velocities of 2.4 km/sec and 2.2 km/sec in the initiator and primary tubes, respectively. These values implied a fuel-lean mixture corresponding to an H2 volume fraction near 0.5. The axial distribution for the detonation velocity was found to be essentially constant along the primary tube. Time-resolved thrust profiles were also acquired for both underfilled and overfilled tube conditions. These profiles are consistent with previous time

  15. Laser-shocked energetic materials with metal additives: evaluation of chemistry and detonation performance.

    PubMed

    Gottfried, Jennifer L; Bukowski, Eric J

    2017-01-20

    A focused, nanosecond-pulsed laser has been used to ablate, atomize, ionize, and excite milligram quantities of metal-doped energetic materials that undergo exothermic reactions in the laser-induced plasma. The subsequent shock wave expansion in the air above the sample has been monitored using high-speed schlieren imaging in a recently developed technique, laser-induced air shock from energetic materials (LASEM). The method enables the estimation of detonation velocities based on the measured laser-induced air-shock velocities and has previously been demonstrated for organic military explosives. Here, the LASEM technique has been extended to explosive formulations with metal additives. A comparison of the measured laser-induced air-shock velocities for TNT, RDX, DNTF, and LLM-172 doped with Al or B to the detonation velocities predicted by the thermochemical code CHEETAH for inert or active metal participation demonstrates that LASEM has potential for predicting the early time (<10  μs) participation of metal additives in detonation events. The LASEM results show that while Al is mostly inert at early times in the detonation event (confirmed from large-scale detonation testing), B is active-and reducing the amount of hydrogen present during the early chemical reactions increases the resulting estimated detonation velocities.

  16. Simple Model for Detonation Energy and Rate

    NASA Astrophysics Data System (ADS)

    Lauderbach, Lisa M.; Souers, P. Clark

    2017-06-01

    A simple model is used to derive the Eyring equation for the size effect and detonation rate, which depends on a constant energy density. The rate derived from detonation velocities is then converted into a rate constant to be used in a reactive flow model. The rate might be constant if the size effect curve is straight, but the rate constant will change with the radius of the sample and cannot be a constant. This is based on many careful cylinder tests have been run recently on LX-17 with inner copper diameters ranging from 12.7 to 101.6 mm. Copper wall velocities at scaled displacements of 6, 12.5 and 19 mm equate to values at relative volumes of 2.4, 4.4 and 7.0. At each point, the velocities from 25.4 to 101.6 mm are constant within error whereas the 12.7 mm velocities are lower. Using the updated Gurney model, the energy densities at the three larger sizes are also constant. Similar behavior has been seen in LX-14, LX-04, and an 83% RDX mix. A rough saturation has also been in old ANFO data for diameters of 101.6 mm and larger. Although the energy densities saturate, the detonation velocities continue to increase with size. These observations suggest that maximum energy density is a constant for a given explosive of a given density. The correlation of energy density with detonation velocity is not good because the latter depends on the total energy of the sample. This work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  17. Density-based kinetics for mesoscale simulations of detonation initiation in energetic materials

    NASA Astrophysics Data System (ADS)

    Jackson, Thomas Luther; Zhang, Ju

    2017-07-01

    In this work we present one- and two-dimensional mesoscale simulations of detonation initiation in energetic materials. We solve the reactive Euler equations, with the energy equation augmented by a power deposition term. The reaction rate at the mesoscale is modelled using a density-based kinetics scheme, adapted from standard 'Ignition and Growth' models. The deposition term is based on previous results of simulations of void collapse at the microscale, modelled at the mesoscale as hot spots. For an isolated hot spot in a homogeneous medium, it is found that a critical size of the hot spots exists. If the hot spots exceed the critical size, initiation of detonation can be achieved. For sub-critical hot-spot sizes, we show that it takes a collection of hot spots to achieve detonation. We also carry out two-dimensional mesoscale simulations of random packs of HMX crystals in a binder, and show that the transition between no detonation and detonation depends on the number density of the hot spots, the initial radius of the hot spot, the post-shock pressure of an imposed shock, and the amplitude of the power deposition term.

  18. DDT Characteristics of Laser Driven Exploding Bridgewire Detonators

    NASA Astrophysics Data System (ADS)

    Welle, Eric

    2005-07-01

    The initiation and performance characteristics of Laser Exploding Bridgewire (LEBW) detonators loaded with CL-20, CP and BNCP were examined. LEBW devices, in name, as well as in function, exhibit similarities to their electrically driven counterparts with the exception that the means for energy deposition into the driving metal media results from photon absorption instead of electrical joule heating. CP and BNCP were chosen due to their well-known propensity to rapidly undergo a deflagration-to-detonation transition (DDT) and CL-20 was chosen to explore its utility as a DDT explosive. The explosive loading within the LEBW detonators were similar in nature to traditional EBW devices with regard to %TMD loading of the initial increment as well as quantity of energetic materials. Comparisons of the energy fluences required for initiation of the explosives will be discussed. Additionally, streak camera measurements will be reviewed that were conducted at what would be considered ``hard-fire'' fluence levels as well as conditions closer to the mean firing fluence levels of initiation.

  19. Detonation Energies of Explosives by Optimized JCZ3 Procedures

    NASA Astrophysics Data System (ADS)

    Stiel, Leonard; Baker, Ernest

    1997-07-01

    Procedures for the detonation properties of explosives have been extended for the calculation of detonation energies at adiabatic expansion conditions. Advanced variable metric optimization routines developed by ARDEC are utilized to establish chemical reaction equilibrium by the minimization of the Helmholtz free energy of the system. The use of the JCZ3 equation of state with optimized Exp-6 potential parameters leads to lower errors in JWL detonation energies than the TIGER JCZ3 procedure and other methods tested for relative volumes to 7.0. For the principal isentrope with C-J parameters and freeze conditions established at elevated pressures with the JCZ3 equation of state, best results are obtained if an alternate volumetric relationship is utilized at the highest expansions. Efficient subroutines (designated JAGUAR) have been developed which incorporate the ability to automatically generate JWL and JWLB equation of state parameters. abstract.

  20. Structure of Biocompatible Coatings Produced from Hydroxyapatite Nanoparticles by Detonation Spraying

    NASA Astrophysics Data System (ADS)

    Nosenko, Valentyna; Strutynska, Nataliia; Vorona, Igor; Zatovsky, Igor; Dzhagan, Volodymyr; Lemishko, Sergiy; Epple, Matthias; Prymak, Oleg; Baran, Nikolai; Ishchenko, Stanislav; Slobodyanik, Nikolai; Prylutskyy, Yuriy; Klyui, Nickolai; Temchenko, Volodymyr

    2015-12-01

    Detonation-produced hydroxyapatite coatings were studied by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Raman spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. The source material for detonation spraying was a B-type carbonated hydroxyapatite powder. The coatings consisted of tetracalcium phosphate and apatite. The ratio depended slightly on the degree of crystallinity of the initial powder and processing parameters of the coating preparation. The tetracalcium phosphate phase was homogeneous; the apatite phase contained defects localized on the sixfold axis and consisted of hydroxyapatite and oxyapatite. Technological factors contributing to the transformation of hydroxyapatite powder structure during coating formation by detonation spraying are discussed.

  1. Structure of Biocompatible Coatings Produced from Hydroxyapatite Nanoparticles by Detonation Spraying.

    PubMed

    Nosenko, Valentyna; Strutynska, Nataliia; Vorona, Igor; Zatovsky, Igor; Dzhagan, Volodymyr; Lemishko, Sergiy; Epple, Matthias; Prymak, Oleg; Baran, Nikolai; Ishchenko, Stanislav; Slobodyanik, Nikolai; Prylutskyy, Yuriy; Klyui, Nickolai; Temchenko, Volodymyr

    2015-12-01

    Detonation-produced hydroxyapatite coatings were studied by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Raman spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. The source material for detonation spraying was a B-type carbonated hydroxyapatite powder. The coatings consisted of tetracalcium phosphate and apatite. The ratio depended slightly on the degree of crystallinity of the initial powder and processing parameters of the coating preparation. The tetracalcium phosphate phase was homogeneous; the apatite phase contained defects localized on the sixfold axis and consisted of hydroxyapatite and oxyapatite. Technological factors contributing to the transformation of hydroxyapatite powder structure during coating formation by detonation spraying are discussed.

  2. The characterization and evaluation of accidental explosions

    NASA Technical Reports Server (NTRS)

    Strehlow, R. A.; Baker, W. E.

    1975-01-01

    Accidental explosions are discussed from a number of viewpoints. First, all accidental explosions, intentional explosions and natural explosions are characterized by type. Second, the nature of the blast wave produced by an ideal (point source or HE) explosion is discussed to form a basis for describing how other explosion processes yield deviations from ideal blast wave behavior. The current status blast damage mechanism evaluation is also discussed. Third, the current status of our understanding of each different category of accidental explosions is discussed in some detail.

  3. Linear stability analysis of detonations via numerical computation and dynamic mode decomposition

    NASA Astrophysics Data System (ADS)

    Kabanov, Dmitry I.; Kasimov, Aslan R.

    2018-03-01

    We introduce a new method to investigate linear stability of gaseous detonations that is based on an accurate shock-fitting numerical integration of the linearized reactive Euler equations with a subsequent analysis of the computed solution via the dynamic mode decomposition. The method is applied to the detonation models based on both the standard one-step Arrhenius kinetics and two-step exothermic-endothermic reaction kinetics. Stability spectra for all cases are computed and analyzed. The new approach is shown to be a viable alternative to the traditional normal-mode analysis used in detonation theory.

  4. Numerical simulation of double front detonations in a non-ideal explosive with varying aluminum concentration

    NASA Astrophysics Data System (ADS)

    Kim, Wuhyun; Gwak, Min-Cheol; Yoh, Jack; Seoul National University Team

    2017-06-01

    The performance characteristics of aluminized HMX are considered by varying the aluminum (Al) concentration in a hybrid non-ideal detonation model. Two cardinal observations are reported: a decrease in detonation velocity with an increase in Al concentration and a double front detonation (DFD) feature when aerobic Al reaction occurs behind the front. While experimental studies have been reported on the effect of Al concentration on both gas-phase and solid-phase detonations, the numerical investigations were limited to only gas-phase detonation for the varying Al concentration. In the current study, a two-phase model is utilized for understanding the volumetric effects of Al concentration in the condensed phase detonations. A series of unconfined and confined rate sticks are considered for characterizing the performance of aluminized HMX with a maximum Al concentration of 50%. The simulated results are compared with the experimental data for 5%-25% concentrations, and the formation of DFD structure under varying Al concentration (0%-50%) in HMX is investigated.

  5. Pressure and Thrust Measurements of a High-Frequency Pulsed Detonation Tube

    NASA Technical Reports Server (NTRS)

    Nguyen, N.; Cutler, A. D.

    2008-01-01

    This paper describes measurements of a small-scale, high-frequency pulsed detonation tube. The device utilized a mixture of H2 fuel and air, which was injected into the device at frequencies of up to 1200 Hz. Pulsed detonations were demonstrated in an 8-inch long combustion volume, at about 600 Hz, for the quarter wave mode of resonance. The primary objective of this experiment was to measure the generated thrust. A mean value of thrust was measured up to 6.0 lb, corresponding to H2 flow based specific impulse of 2970 s. This value is comparable to measurements in H2-fueled pulsed detonation engines (PDEs). The injection and detonation frequency for this new experimental case was much higher than typical PDEs, where frequencies are usually less than 100 Hz. The compact size of the device and high frequency of detonation yields a thrust-per-unit-volume of approximately 2.0 pounds per cubic inch, and compares favorably with other experiments, which typically have thrust-per-unit-volume of order 0.01 pound per cubic inch. This much higher volumetric efficiency results in a potentially much more practical device than the typical PDE, for a wide range of potential applications, including high-speed boundary layer separation control, for example in hypersonic engine inlets, and propulsion for small aircraft and missiles.

  6. Phenomenology of spectrally and temporally resolved infrared emissions from bomb detonations

    NASA Astrophysics Data System (ADS)

    Gross, Kevin; Dills, Anthony; Tuttle, Ron; Perram, Glen

    2002-10-01

    The remote sensing of infrared signatures from exothermic reactions during military operations, including missile launches, muzzle flashes, and bomb detonations has been studied using fast FTIR techniques. Battle space characterization includes the ability to classify the munitions type, size, and other characteristics. One possible approach to munitions classification is to understand the spectral and temporal signatures from explosive ordinance. To investigate this possibility, experimental data has been collected remotely from ground-based sensors, processed, and analyzed for several conventional munitions. Field observations of 56 detonation events included a set of aircraft delivered ordnance and a series of static ground detonations for a variety of bomb sizes, types and environmental conditions. The emission is well represented by a gray body with continuously decreasing temperature and characteristic decay times of 1-4 s, providing only limited variability with detonation conditions. However, the fireball size times the emissivity as a function of time can be determined from the spectra without imaging and provides a more sensitive signature. The degree of temporal overlap as a function of frequency for a pair of detonation events provides a very sensitive discriminator for explosion conditions. The temporal overlap decreases with increasing emission frequency for all the observed events, indicating more information content at higher frequencies. Finally, the temporal nature of the emissions has been analyzed, providing a significant reduction in the dimensionality of the data.

  7. 21 CFR 1002.20 - Reporting of accidental radiation occurrences.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Reporting of accidental radiation occurrences... SERVICES (CONTINUED) RADIOLOGICAL HEALTH RECORDS AND REPORTS Manufacturers' Reports on Accidental Radiation Occurrences § 1002.20 Reporting of accidental radiation occurrences. (a) Manufacturers of electronic products...

  8. 21 CFR 1002.20 - Reporting of accidental radiation occurrences.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Reporting of accidental radiation occurrences... SERVICES (CONTINUED) RADIOLOGICAL HEALTH RECORDS AND REPORTS Manufacturers' Reports on Accidental Radiation Occurrences § 1002.20 Reporting of accidental radiation occurrences. (a) Manufacturers of electronic products...

  9. 21 CFR 1002.20 - Reporting of accidental radiation occurrences.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Reporting of accidental radiation occurrences... SERVICES (CONTINUED) RADIOLOGICAL HEALTH RECORDS AND REPORTS Manufacturers' Reports on Accidental Radiation Occurrences § 1002.20 Reporting of accidental radiation occurrences. (a) Manufacturers of electronic products...

  10. Experimental Study of a Pulse Detonation Engine Driven Ejector

    NASA Technical Reports Server (NTRS)

    Santoro, Robert J.; Pal, Sibtosh; Shehadeh, R.; Saretto, S.; Lee, S.-Y.

    2005-01-01

    Results of an experimental effort on pulse detonation driven ejectors are presented and discussed. The experiments were conducted using a pulse detonation engine (PDE)/ejector setup that was specifically designed for the study. The results of various experiments designed to probe different aspects of the PDE/ejector setup are reported. The baseline PDE was operated using ethylene (C2H4) as the fuel and an oxygen/nitrogen (O2 + N2) mixture at an equivalence ratio of one. The PDE only experiments included propellant mixture characterization using a laser absorption technique, high fidelity thrust measurements using an integrated spring-damper system, and shadowgraph imaging of the detonation/shock wave structure emanating from the tube. The baseline PDE thrust measurement results are in excellent agreement with experimental and modeling results reported in the literature. These PDE setup results were then used as a basis for quantifying thrust augmentation for various PDE/ejector setups with constant diameter ejector tubes and various detonation tube/ejector tube overlap distances. The results show that for the geometries studied here, a maximum thrust augmentation of 24% is achieved. Further increases are possible by tailoring the ejector geometry based on CFD predictions conducted elsewhere. The thrust augmentation results are complemented by shadowgraph imaging of the flowfield in the ejector tube inlet area and high frequency pressure transducer measurements along the length of the ejector tube.

  11. Atomistic Simulations of Detonation Instabilities in Condensed Phase Systems

    NASA Astrophysics Data System (ADS)

    Kober, Edward; Heim, Andrew; Germann, Timothy; Jensen, Niels

    2007-06-01

    We report the results of simulations of condensed phase detonation phenomena using a model diatomic system: 2AB -> A2 + B2. The initial set of parameters for this system corresponded to the Model 0 set of C. White et al, which exhibits a steady, Chapman-Jouget (CJ) detonation structure with a reaction zone length of 30-100 å. This has a highly compressed CJ state (V/V0˜0.5) that does not consist of discrete molecular species. The potential form was modified so that a more molecular CJ state resulted, consistent with the models for conventional organic explosives. The new system has a less dense CJ state (V/V0˜0.8), and the reaction zone was substantially extended. The reaction rate fits Arrhenius-type kinetics with an activation energy of ˜2 eV, with a minor density dependence. In contrast, the original Model 0 system had a lower activation energy (˜1 eV) with a stronger density dependence. The new system exhibits quite marked two dimensional instability structures with well-defined wavelengths similar to what has been observed for gas-phase detonations and for nitromethane. Depending on the exothermicity and the width of the periodic simulations, these instabilities can result in either detonation failure or quasi-steady propagation. The observed propagation velocities are several per cent higher than CJ values derived from thermodynamic analyses.

  12. Quantification of uncertainties for application in detonation simulation

    NASA Astrophysics Data System (ADS)

    Zheng, Miao; Ma, Zhibo

    2016-06-01

    Numerical simulation has become an important means in designing detonation systems, and the quantification of its uncertainty is also necessary to reliability certification. As to quantifying the uncertainty, it is the most important to analyze how the uncertainties occur and develop, and how the simulations develop from benchmark models to new models. Based on the practical needs of engineering and the technology of verification & validation, a framework of QU(quantification of uncertainty) is brought forward in the case that simulation is used on detonation system for scientific prediction. An example is offered to describe the general idea of quantification of simulation uncertainties.

  13. Fast Reactions of Aluminum and Explosive Decomposition Products in a Post-Detonation Environment

    NASA Astrophysics Data System (ADS)

    Tappan, Bryce; Manner, Virginia; Lloyd, Joseph; Pemberton, Steven; Explosives Applications; Special Projects Team

    2011-06-01

    In order to determine the reaction behavior of Al in HMX/cast-cured binder formulations shortly after the passage of the detonation, a series of cylinder tests was performed on formulations with varying amounts of 2 μm spherical Al as well as LiF (an inert surrogate for Al). In these studies, both detonation velocity and cylinder expansion velocity are measured in order to determine exactly how and when Al contributes to the explosive event, particularly in the presence of oxidizing/energetic binders. The U.S. Army ARDEC at Picatinny has recently coined the term ``combined effects explosives'' for these materials as they demonstrate both high metal pushing capability and high blast ability. This study is aimed at developing a fundamental understanding of the reaction of Al with explosives decomposition products, where both the detonation and post-detonation environment are analyzed. Reaction rates of Al metal are determined via comparison of predicted performance based on thermoequilibrium calculations. The JWL equation of state, detonation velocities, wall velocities, and parameters at the C-J plane are some of the parameters that will be discussed.

  14. Qualification of a multi-diagnostic detonator-output characterization procedure utilizing PMMA witness blocks

    NASA Astrophysics Data System (ADS)

    Biss, Matthew; Murphy, Michael; Lieber, Mark

    2017-06-01

    Experiments were conducted in an effort to qualify a multi-diagnostic characterization procedure for the performance output of a detonator when fired into a poly(methyl methacrylate) (PMMA) witness block. A suite of optical diagnostics were utilized in combination to both bound the shock wave interaction state at the detonator/PMMA interface and characterize the nature of the shock wave decay in PMMA. The diagnostics included the Shock Wave Image Framing Technique (SWIFT), a photocathode tube streak camera, and photonic Doppler velocimetry (PDV). High-precision, optically clear witness blocks permitted dynamic flow visualization of the shock wave in PMMA via focused shadowgraphy. SWIFT- and streak-imaging diagnostics captured the spatiotemporally evolving shock wave, providing a two-dimensional temporally discrete image set and a one-dimensional temporally continuous image, respectively. PDV provided the temporal velocity history of the detonator output along the detonator axis. Through combination of the results obtained, a bound was able to be placed on the interface condition and a more-physical profile representing the shock wave decay in PMMA for an exploding-bridgewire detonator was achieved.

  15. Laser-shocked energetic materials with metal additives: evaluation of detonation performance

    NASA Astrophysics Data System (ADS)

    Gottfried, Jennifer; Bukowski, Eric

    A focused, nanosecond-pulsed laser with sufficient energy to exceed the breakdown threshold of a material generates a laser-induced plasma with high peak temperatures, pressures, and shock velocities. Depending on the laser parameters and material properties, nanograms to micrograms of material is ablated, atomized, ionized and excited in the laser-induced plasma. The subsequent shock wave expansion into the air above the sample has been monitored using high-speed schlieren imaging in a recently developed technique, laser-induced air shock from energetic materials (LASEM). The estimated detonation velocities using LASEM agree well with published experimental values. A comparison of the measured shock velocities for various energetic materials including RDX, DNTF, and LLM-172 doped with Al or B to the detonation velocities predicted by CHEETAH for inert or active metal participation demonstrates that LASEM has potential for predicting the early time participation of metal additives in detonation events. The LASEM results show that reducing the amount of hydrogen present in B formulations increases the resulting detonation velocities

  16. Explosively generated shock wave processing of metal powders by instrumented detonics

    NASA Astrophysics Data System (ADS)

    Sharma, A. D.; Sharma, A. K.; Thakur, N.

    2013-06-01

    The highest pressures generated by dynamic processes resulting either from high velocity impact or by spontaneous release of high energy rate substances in direct contact with a metal find superior applications over normal mechanical means. The special feature of explosive loading to the powder materials over traditional methods is its controlled detonation pressure which directly transmits shock energy to the materials which remain entrapped inside powder resulting into several micro-structural changes and hence improved mechanical properties. superalloy powders have been compacted nearer to the theoretical density by shock wave consolidation. In a single experimental set-up, compaction of metal powder and measurement of detonation velocity have been achieved successfully by using instrumented detonics. The thrust on the work is to obtain uniform, crack-free and fracture-less compacts of superalloys having intact crystalline structure as has been examined from FE-SEM, XRD and mechanical studies. Shock wave processing is an emerging technique and receiving much attention of the materials scientists and engineers owing to its excellent advantages over traditional metallurgical methods due to short processing time, scaleup advantage and controlled detonation pressure.

  17. Fast Hydrogen-Air Flames for Turbulence Driven Deflagration to Detonation Transition

    NASA Astrophysics Data System (ADS)

    Chambers, Jessica; Ahmed, Kareem

    2016-11-01

    Flame acceleration to Detonation produces several combustion modes as the Deflagration-to-Detonation Transition (DDT) is initiated, including fast deflagration, auto-ignition, and quasi-detonation. Shock flame interactions and turbulence levels in the reactant mixture drive rapid flame expansion, formation of a leading shockwave and post-shock conditions. An experimental study to characterize the developing shock and flame front behavior of propagating premixed hydrogen-air flames in a square channel is presented. To produce each flame regime, turbulence levels and flame propagation velocity are controlled using perforated plates in several configurations within the experimental facility. High speed optical diagnostics including Schlieren and Particle Image Velocimetry are used to capture the flow field. In-flow pressure measurements acquired post-shock, detail the dynamic changes that occur in the compressed gas directly ahead of the propagating flame. Emphasis on characterizing the turbulent post-shock environment of the various flame regimes helps identify the optimum conditions to initiate the DDT process. The study aims to further the understanding of complex physical mechanisms that drive transient flame conditions for detonation initiation. American Chemical Society.

  18. Environmentally Benign Stab Detonators

    DTIC Science & Technology

    2006-07-11

    composition. In addition we will work with our DoD partner TACOM-ARDEC in identifying and testing more environmentally suitable replacement transfer...components identified is shown in Figure 1 below. Figure 1. Photo of M55 stab detonator Al cup with initiation train and components. Common...primer mixes, such as NOL-130, are made up of lead styphnate (basic) 40%, lead azide ( dextrinated ) 20%, barium nitrate 20%, antimony sulfide 15%, and

  19. Keep Away from Danger: Dangerous Objects in Dynamic and Static Situations

    PubMed Central

    Anelli, Filomena; Nicoletti, Roberto; Bolzani, Roberto; Borghi, Anna M.

    2013-01-01

    Behavioral and neuroscience studies have shown that objects observation evokes specific affordances (i.e., action possibilities) and motor responses. Recent findings provide evidence that even dangerous objects can modulate the motor system evoking aversive affordances. This sounds intriguing since so far the majority of behavioral, brain imaging, and transcranial magnetic stimulation studies with painful and dangerous stimuli strictly concerned the domain of pain, with the exception of evidence suggesting sensitivity to objects’ affordances when neutral objects are located in participants’ peripersonal space. This study investigates whether the observation of a neutral or dangerous object in a static or dynamic situation differently influences motor responses, and the time-course of the dangerous objects’ processing. In three experiments we manipulated: object dangerousness (neutral vs. dangerous); object category (artifact vs. natural); manual response typology (press vs. release a key); object presentation (Experiment 1: dynamic, Experiments 2 and 3: static); object movement direction (Experiment 1: away vs. toward the participant) or size (Experiments 2 and 3: big vs. normal vs. small). The task required participants to decide whether the object was an artifact or a natural object, by pressing or releasing one key. Results showed a facilitation for neutral over dangerous objects in the static situation, probably due to an affordance effect. Instead, in the dynamic condition responses were modulated by the object movement direction, with a dynamic affordance effect elicited by neutral objects and an escape-avoidance effect provoked by dangerous objects (neutral objects were processed faster when they moved toward-approached the participant, whereas dangerous objects were processed faster when they moved away from the participant). Moreover, static stimuli influenced the manual response typology. These data indicate the emergence of dynamic affordance and

  20. Keep away from danger: dangerous objects in dynamic and static situations.

    PubMed

    Anelli, Filomena; Nicoletti, Roberto; Bolzani, Roberto; Borghi, Anna M

    2013-01-01

    Behavioral and neuroscience studies have shown that objects observation evokes specific affordances (i.e., action possibilities) and motor responses. Recent findings provide evidence that even dangerous objects can modulate the motor system evoking aversive affordances. This sounds intriguing since so far the majority of behavioral, brain imaging, and transcranial magnetic stimulation studies with painful and dangerous stimuli strictly concerned the domain of pain, with the exception of evidence suggesting sensitivity to objects' affordances when neutral objects are located in participants' peripersonal space. This study investigates whether the observation of a neutral or dangerous object in a static or dynamic situation differently influences motor responses, and the time-course of the dangerous objects' processing. In three experiments we manipulated: object dangerousness (neutral vs. dangerous); object category (artifact vs. natural); manual response typology (press vs. release a key); object presentation (Experiment 1: dynamic, Experiments 2 and 3: static); object movement direction (Experiment 1: away vs. toward the participant) or size (Experiments 2 and 3: big vs. normal vs. small). The task required participants to decide whether the object was an artifact or a natural object, by pressing or releasing one key. Results showed a facilitation for neutral over dangerous objects in the static situation, probably due to an affordance effect. Instead, in the dynamic condition responses were modulated by the object movement direction, with a dynamic affordance effect elicited by neutral objects and an escape-avoidance effect provoked by dangerous objects (neutral objects were processed faster when they moved toward-approached the participant, whereas dangerous objects were processed faster when they moved away from the participant). Moreover, static stimuli influenced the manual response typology. These data indicate the emergence of dynamic affordance and

  1. Development and application of theoretical models for Rotating Detonation Engine flowfields

    NASA Astrophysics Data System (ADS)

    Fievisohn, Robert

    As turbine and rocket engine technology matures, performance increases between successive generations of engine development are becoming smaller. One means of accomplishing significant gains in thermodynamic performance and power density is to use detonation-based heat release instead of deflagration. This work is focused on developing and applying theoretical models to aid in the design and understanding of Rotating Detonation Engines (RDEs). In an RDE, a detonation wave travels circumferentially along the bottom of an annular chamber where continuous injection of fresh reactants sustains the detonation wave. RDEs are currently being designed, tested, and studied as a viable option for developing a new generation of turbine and rocket engines that make use of detonation heat release. One of the main challenges in the development of RDEs is to understand the complex flowfield inside the annular chamber. While simplified models are desirable for obtaining timely performance estimates for design analysis, one-dimensional models may not be adequate as they do not provide flow structure information. In this work, a two-dimensional physics-based model is developed, which is capable of modeling the curved oblique shock wave, exit swirl, counter-flow, detonation inclination, and varying pressure along the inflow boundary. This is accomplished by using a combination of shock-expansion theory, Chapman-Jouguet detonation theory, the Method of Characteristics (MOC), and other compressible flow equations to create a shock-fitted numerical algorithm and generate an RDE flowfield. This novel approach provides a numerically efficient model that can provide performance estimates as well as details of the large-scale flow structures in seconds on a personal computer. Results from this model are validated against high-fidelity numerical simulations that may require a high-performance computing framework to provide similar performance estimates. This work provides a designer a new

  2. Evaluation of the Deuterium Isotope Effect in the Detonation of Aluminum Containing Explosives

    DOE PAGES

    Tappan, Bryce C.; Bowden, Patrick R.; Manner, Virginia W.; ...

    2017-12-04

    During or shortly after a detonation in condensed explosives, the reaction rates and the physical mechanism controlling aluminum reaction is poorly understood. We utilize the kinetic isotope effect to probe Al reactions in detonation product gases in aluminized, protonated and deuterated high explosives using high-fidelity detonation velocity and cylinder wall expansion velocity measurements. By observation of the profile of cylinder wall velocity versus time, we are able to determine the timing of aluminum contribution to energy release in product gases and observe the presence or absence of rate changes isotopic substitution. By comparison of the Al oxidation with lithium fluoridemore » (LiF), data indicate that Al oxidation occurs on an extremely fast time scale, with post-detonation kinetic isotope effects observed in carbon containing formulations.« less

  3. Evaluation of the Deuterium Isotope Effect in the Detonation of Aluminum Containing Explosives

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tappan, Bryce C.; Bowden, Patrick R.; Manner, Virginia W.

    During or shortly after a detonation in condensed explosives, the reaction rates and the physical mechanism controlling aluminum reaction is poorly understood. We utilize the kinetic isotope effect to probe Al reactions in detonation product gases in aluminized, protonated and deuterated high explosives using high-fidelity detonation velocity and cylinder wall expansion velocity measurements. By observation of the profile of cylinder wall velocity versus time, we are able to determine the timing of aluminum contribution to energy release in product gases and observe the presence or absence of rate changes isotopic substitution. By comparison of the Al oxidation with lithium fluoridemore » (LiF), data indicate that Al oxidation occurs on an extremely fast time scale, with post-detonation kinetic isotope effects observed in carbon containing formulations.« less

  4. Airbreathing Pulse Detonation Engine Performance

    NASA Technical Reports Server (NTRS)

    Povinelli, Louis A.; Yungster, Shaye

    2002-01-01

    This paper presents performance results for pulse detonation engines taking into account the effects of dissociation and recombination. The amount of sensible heat recovered through recombination in the PDE chamber and exhaust process was found to be significant. These results have an impact on the specific thrust, impulse and fuel consumption of the PDE.

  5. Airbreathing Pulse Detonation Engine Performance

    NASA Technical Reports Server (NTRS)

    Povinelli, Louis A.; Yungster, Shaye

    2002-01-01

    This paper presents performance results for pulse detonation engines (PDE) taking into account the effects of dissociation and recombination. The amount of sensible heat recovered through recombination in the PDE chamber and exhaust process was found to be significant. These results have an impact on the specific thrust, impulse and fuel consumption of the PDE.

  6. Detonation shock dynamics with an acceleration relation for nitromethane and TATB

    NASA Astrophysics Data System (ADS)

    Swift, Damian; Kraus, Richard; Mulford, Roberta; White, Stephen

    2015-06-01

    The propagation of curved detonation waves has been treated phenomenologically through models of the speed D of a detonation wave as a function of its curvature K, in the Whitham-Bdzil-Lambourn model, also known as detonation shock dynamics. D(K) relations, and the edge angle with adjacent material, have been deduced from the steady shape of detonation waves in long rods and slabs of explosive. Nonlinear D(K) relations have proven necessary to interpret data from charges of different diameter, and even then the D(K) relation may not transfer between diameters. This is an indication that the D(K) relation oversimplifies the kinematics. It is also possible to interpret wave-shape data in terms of an acceleration relation, as used in Brun's Jouguet relaxe model. One form of acceleration behavior is to couple an asymptotic D(K) relation with a time-dependent relaxation toward it from the instantaneous, local speed. This approach is also capable of modeling overdriving of a detonation by a booster. Using archival data for the TATB-based explosive EDC35 and for nitromethane, we found that a simple linear asymptotic D(K) relation with a constant relaxation rate was able to reproduce the experimental wave-shapes better, with fewer parameters, than a nonlinear instantaneous D(K) relation. This work was performed in part under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  7. Risk Factors for new accidental falls in elderly patients at traumatology ambulatory center.

    PubMed

    Porto Gautério, Daiane; Zortea, Bruna; Costa Santos, Silvana Sidney; da Silva Tarouco, Bárbara; Lopes, Manoel José; João Fonseca, Cesar

    2015-01-01

    To identify the risks factors for new accidental falls in elderly patients attended in the Traumatology Ambulatory of a University hospital in Rio Grande do Sul, Brazil. Quantitative study of the type of multiple cases. Performed at the traumatology ambulatory, amongst fifteen elders that attended the inclusion criteria: age of sixty or more; patient at the traumatology ambulatory because of a fall motivated by accident, oriented and in conditions of answer an interview of data collectors. The data collection was made between April and June, 2013, with the Elderly Nursing Core Set scale (Lopes & Fonseca). The data analysis was made by a descriptive structure, which helped identify the existence of relation patterns among the cases. The risk factors for new accidental falls identified with larger incidence amongst the elders studied were: impaired balance (15/15), age above 65 (11/15), use of antihypertensive drugs (9/15), absence of non-slip material at home environment (7/15), in seven cases; rugs scattered at the floor of the house (6/15). The combination of intrinsic and extrinsic factors that include the environmental risks is considered a much more relevant cause to occur the new falls. The minimization of the home dangers, allied to the control of the elder intrinsic factors, may reduce the risks of causes. In that sense, is necessary that the nursing team make available more attention to the elderly assisted at the ambulatories, mainly those with sequelae due to fall accidents.

  8. Detonability of turbulent white dwarf plasma: Hydrodynamical models at low densities

    NASA Astrophysics Data System (ADS)

    Fenn, Daniel

    The origins of Type Ia supernovae (SNe Ia) remain an unsolved problem of contemporary astrophysics. Decades of research indicate that these supernovae arise from thermonuclear runaway in the degenerate material of white dwarf stars; however, the mechanism of these explosions is unknown. Also, it is unclear what are the progenitors of these objects. These missing elements are vital components of the initial conditions of supernova explosions, and are essential to understanding these events. A requirement of any successful SN Ia model is that a sufficient portion of the white dwarf plasma must be brought under conditions conducive to explosive burning. Our aim is to identify the conditions required to trigger detonations in turbulent, carbon-rich degenerate plasma at low densities. We study this problem by modeling the hydrodynamic evolution of a turbulent region filled with a carbon/oxygen mixture at a density, temperature, and Mach number characteristic of conditions found in the 0.8+1.2 solar mass (CO0812) model discussed by Fenn et al. (2016). We probe the ignition conditions for different degrees of compressibility in turbulent driving. We assess the probability of successful detonations based on characteristics of the identified ignition kernels, using Eulerian and Lagrangian statistics of turbulent flow. We found that material with very short ignition times is abundant in the case that turbulence is driven compressively. This material forms contiguous structures that persist over many ignition time scales, and that we identify as prospective detonation kernels. Detailed analysis of the kernels revealed that their central regions are densely filled with material characterized by short ignition times and contain the minimum mass required for self-sustained detonations to form. It is conceivable that ignition kernels will be formed for lower compressibility in the turbulent driving. However, we found no detonation kernels in models driven 87.5 percent

  9. Method and system for making integrated solid-state fire-sets and detonators

    DOEpatents

    O'Brien, Dennis W.; Druce, Robert L.; Johnson, Gary W.; Vogtlin, George E.; Barbee, Jr., Troy W.; Lee, Ronald S.

    1998-01-01

    A slapper detonator comprises a solid-state high-voltage capacitor, a low-jitter dielectric breakdown switch and trigger circuitry, a detonator transmission line, an exploding foil bridge, and a flier material. All these components are fabricated in a single solid-state device using thin film deposition techniques.

  10. Metallized Gelled Propellants Combustion Experiments in a Pulse Detonation Engine

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan; Jurns, John; Breisacher, Kevin; Kearns, Kim

    2006-01-01

    A series of combustion tests were performed with metallized gelled JP 8/aluminum fuels in a Pulse Detonation Engine (PDE). Nanoparticles of aluminum were used in the 60 to 100 nanometer diameter. Gellants were also of a nanoparticulate type composed of hydrocarbon alkoxide materials. Using simulated air (a nitrogen-oxygen mixture), the ignition potential of metallized gelled fuels with nanoparticle aluminum was investigated. Ignition of the JP 8/aluminum was possible with less than or equal to a 23-wt% oxygen loading in the simulated air. JP 8 fuel alone was unable to ignite with less than 30 percent oxygen loaded simulated air. The tests were single shot tests of the metallized gelled fuel to demonstrate the capability of the fuel to improve fuel detonability. The tests were conducted at ambient temperatures and with maximal detonation pressures of 1340 psia.

  11. Shock-to-detonation transition of RDX and NTO based composite high explosives: experiments and modeling

    NASA Astrophysics Data System (ADS)

    Baudin, Gerard; Roudot, Marie; Genetier, Marc

    2013-06-01

    Composite HMX and NTO based high explosives (HE) are widely used in ammunitions. Designing modern warheads needs robust and reliable models to compute shock ignition and detonation propagation inside HE. Comparing to a pressed HE, a composite HE is not porous and the hot-spots are mainly located at the grain - binder interface leading to a different behavior during shock-to-detonation transition. An investigation of how shock-to-detonation transition occurs inside composite HE containing RDX and NTO is proposed in this lecture. Two composite HE have been studied. The first one is HMX - HTPB 82:18. The second one is HMX - NTO - HTPB 12:72:16. These HE have been submitted to plane sustained shock waves at different pressure levels using a laboratory powder gun. Pressure signals are measured using manganin gauges inserted at several distances inside HE. The corresponding run-distances to detonation are determined using wedge test experiments where the plate impact is performed using a powder gun. Both HE exhibit a single detonation buildup curve in the distance - time diagram of shock-to-detonation transition. This feature seems a common shock-to-detonation behavior for composite HE without porosity. This behavior is also confirmed for a RDX - HTPB 85:15 based composite HE. Such a behavior is exploited to determine the heterogeneous reaction rate versus the shock pressure using a method based on the Cauchy-Riemann problem inversion. The reaction rate laws obtained allow to compute both run-distance to detonation and pressure signals.

  12. High speed radiometric measurements of IED detonation fireballs

    NASA Astrophysics Data System (ADS)

    Spidell, Matthew T.; Gordon, J. Motos; Pitz, Jeremey; Gross, Kevin C.; Perram, Glen P.

    2010-04-01

    Continuum emission is predominant in fireball spectral phenomena and in some demonstrated cases, fine detail in the temporal evolution of infrared spectral emissions can be used to estimate size and chemical composition of the device. Recent work indicates that a few narrow radiometric bands may reveal forensic information needed for the explosive discrimination and classification problem, representing an essential step in moving from "laboratory" measurements to a rugged, fieldable system. To explore phenomena not observable in previous experiments, a high speed (10μs resolution) radiometer with four channels spanning the infrared spectrum observed the detonation of nine home made explosive (HME) devices in the < 100lb class. Radiometric measurements indicate that the detonation fireball is well approximated as a single temperature blackbody at early time (0 < t <~ 3ms). The effective radius obtained from absolute intensity indicates fireball growth at supersonic velocity during this time. Peak fireball temperatures during this initial detonation range between 3000.3500K. The initial temperature decay with time (t <~ 10ms) can be described by a simple phenomenological model based on radiative cooling. After this rapid decay, temperature exhibits a small, steady increase with time (10 <~ t <~ 50ms) and peaking somewhere between 1000.1500K-likely the result of post-detonation combustion-before subsequent cooling back to ambient conditions . Radius derived from radiometric measurements can be described well (R2 > 0.98) using blast model functional forms, suggesting that energy release could be estimated from single-pixel radiometric detectors. Comparison of radiometer-derived fireball size with FLIR infrared imagery indicate the Planckian intensity size estimates are about a factor of two smaller than the physical extent of the fireball.

  13. Parametric Investigation of Thrust Augmentation by Ejectors on a Pulsed Detonation Tube

    NASA Technical Reports Server (NTRS)

    Wilson, Jack; Sgondea, Alexandru; Paxson, Daniel E.; Rosenthal, Bruce N.

    2005-01-01

    A parametric investigation has been made of thrust augmentation of a 1 inch diameter pulsed detonation tube by ejectors. A set of ejectors was used which permitted variation of the ejector length, diameter, and nose radius, according to a statistical design of experiment scheme. The maximum augmentations for each ejector were fitted using a polynomial response surface, from which the optimum ejector diameters, and nose radius, were found. Thrust augmentations above a factor of 2 were measured. In these tests, the pulsed detonation device was run on approximately stoichiometric air-hydrogen mixtures, at a frequency of 20 Hz. Later measurements at a frequency of 40 Hz gave lower values of thrust augmentation. Measurements of thrust augmentation as a function of ejector entrance to detonation tube exit distance showed two maxima, one with the ejector entrance upstream, and one downstream, of the detonation tube exit. A thrust augmentation of 2.5 was observed using a tapered ejector.

  14. The Danger Instincts

    PubMed Central

    Rippon, T. S.

    1928-01-01

    (I) Theory Rivers' theory of the “danger instincts” is a key to the problem of moral and prevention of war neuroses. (II) Causes of War Neuroses These are believed to be largely mental, e.g., conflict between the instinct of self-preservation and the sense of duty. (III) Instinct of Self-Preservation This subject presents difficulties, because people react in so many different ways; a man may be impelled to run away, or to become aggressive or even motionless when in danger. (IV) Importance The importance of knowing all the reactions of the normal man to danger is, first—the need to know the normal before considering the abnormal states; second—the chemical warfare of the future will involve increased emotional stress; third—in such war, there will be an additional strain of inactivity during a gas attack. (V) The Danger Instincts as described by Rivers Reaction by flight. Aggression. Manipulative activity. Immobility and collapse. Emotional states associated with reactions. Conflict between different tendencies the reason for collapse when in danger. (VI) Evidence supporting Rivers' Theories Relative severity of war neurosis in pilots, observers, balloon officers, Army officers and submarine crews. Investigation on reactions of pilots to danger and fear. (VII) Rivers' Theory applied to Moral (Mental Hygiene) Knowledge of normal reactions to danger enables the medical officer to help to maintain moral by:—(a) Preparing the mind to meet danger. Explaining that fear is a natural emotion under certain circumstances. Need for self-control but not shame. (b) Prevention of repression. (c) Counter-suggestion and panic. (VIII) Concluding Statement on Cowardice Difficulty in distinguishing cowardice from neurosis. Definition suggested. Medical tests. PMID:19986246

  15. Diamonds in detonation soot

    NASA Technical Reports Server (NTRS)

    Greiner, N. Roy; Phillips, Dave; Johnson, J. D.; Volk, Fred

    1990-01-01

    Diamonds 4 to 7 nm in diameter have been identified and partially isolated from soot formed in detonations of carbon-forming composite explosives. The morphology of the soot has been examined by transmission electron microscopy (TEM), and the identity of the diamond has been established by the electron diffraction pattern of the TEM samples and by the X-ray diffraction (XRD) pattern of the isolated solid. Graphite is also present in the form of ribbons of turbostatic structure with a thickness of 2 to 4 nm. A fraction, about 25 percent of the soot by weight, was recovered from the crude soot after oxidation of the graphite with fuming perchloric acid. This fraction showed a distinct XRD pattern of diamond and the diffuse band of amorphous carbon. The IR spectrum of these diamonds closely matches that of diamonds recovered from meteorites (Lewis et al., 1987), perhaps indicating similar surface properties after the oxidation. If these diamonds are produced in the detonation itself or during the initial expansion, they exhibit a phenomenal crystal growth rate (5 nm/0.00001 s equal 1.8 m/hr) in a medium with a very low hydrogen/carbon ratio. Because the diamonds will be carried along with the expanding gases, they will be accelerated to velocities approaching 8 km/s.

  16. Post-Detonation Energy Release from TNT-Aluminum Explosives

    NASA Astrophysics Data System (ADS)

    Zhang, Fan; Anderson, John; Yoshinaka, Akio

    2007-06-01

    Detonation and post-detonation energy release from TNT and TNT-aluminum composite have been experimentally studied in an air-filled chamber, 26 m^3 in volume and 3 m in diameter. While TNT has a high oxygen deficiency, experiments with 1.1 kg to 4 kg charges yield energy releases reaching only 86% of theoretical equilibrium values, possibly due to the non-uniform mixing between the detonation products and air. In order to improve mixing and further increase afterburning energy, large mass fractions of large aluminum particles are combined with TNT. The effect of particle distribution is also investigated in two composite configurations, whereby the aluminum particles are uniformly mixed in cast TNT or arranged in a shell surrounding a TNT cylinder. It is shown that the TNT-aluminum composite outperforms pure TNT, while improved performance is achieved for the shell configuration due to enhanced spatial mixing of hot fuels with oxidizing gases. Comparisons with the equilibrium theory and a liquid-based aluminized composite explosive (with an oxygen deficiency less than that of TNT) are conducted to further explore the mixing and afterburning mechanism.

  17. Equation of State for Gaseous Products of Detonation

    NASA Astrophysics Data System (ADS)

    Rightley, Maria

    1998-11-01

    There have been many equations of state (EOS) proposed for gaseous products of detonation, from simple theoretically-based EOS to empirically-based EOS with many adjustable parameters. How well these EOS approximate the real behavior depends on the material which is detonated. Gases, for example, are much easier to represent simply than are condensed or solid materials. If we concentrate solely on the particular class of condensed materials known as high explosives (HE) and their products of detonation, the most common formulation is the Jones-Wilkins-Lee (JWL) EOS. It has six adjustable parameters, and is as popular as it is in some part due to the fact that it can represent well the experiments which are primary source for HE EOS data, the explosive cylinder test. This test uses a cylinder of copper filled with an HE, which is then initiated, and the expansion is recorded. The obtained expansion profile is then used to calibrate the EOS, generally the JWL form. The work presented here will describe the rereading of some old film data, as well as recalibration of that data for the JWL EOS, and progress with modified EOS forms.

  18. Thrust Augmentation Measurements Using a Pulse Detonation Engine Ejector

    NASA Technical Reports Server (NTRS)

    Santoro, Robert J.; Pal, Sibtosh

    2005-01-01

    Results of an experimental effort on pulse detonation driven ejectors are presented and discussed. The experiments were conducted using a pulse detonation engine (PDE)/ejector setup that was specifically designed for the study and operated at frequencies up to 50 Hz. The results of various experiments designed to probe different aspects of the PDE/ejector setup are reported. The baseline PDE was operated using ethylene (C2H4) as the fuel and an oxygen/nitrogen O2 + N2) mixture at an equivalence ratio of one. The PDE only experiments included propellant mixture characterization using a laser absorption technique, high fidelity thrust measurements using an integrated spring-damper system, and shadowgraph imaging of the detonation/shock wave structure emanating from the tube. The baseline PDE thrust measurement results at each desired frequency agree with experimental and modeling results reported in the literature. These PDE setup results were then used as a basis for quantifying thrust augmentation for various PDE/ejector setups with constant diameter ejector tubes and various ejector lengths, the radius of curvature for the ejector inlets and various detonation tube/ejector tube overlap distances. For the studied experimental matrix, the results showed a maximum thrust augmentation of 106% at an operational frequency of 30 Hz. The thrust augmentation results are complemented by shadowgraph imaging of the flowfield in the ejector tube inlet area and high frequency pressure transducer measurements along the length of the ejector tube.

  19. Detonation equation of state at LLNL, 1995. Revision 3

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Souers, P.C.; Wu, B.; Haselman, L.C. Jr.

    1996-02-01

    JWL`s and 1-D Look-up tables are shown to work for ``one-track`` experiments like cylinder shots and the expanding sphere. They fail for ``many-track`` experiments like the compressed sphere. As long as the one-track experiment has dimensions larger than the explosive`s reaction zone and the explosive is near-ideal, a general JWL with R{sub 1} = 4.5 and R{sub 2} = 1.5 can be constructed, with both {omega} and E{sub o} being calculated from thermochemical codes. These general JWL`s allow comparison between various explosives plus recalculation of the JWL for different densities. The Bigplate experiment complements the cylinder test by providing continuousmore » oblique angles of shock incidence from 0{degrees} to 70{degrees}. Explosive reaction zone lengths are determined from metal plate thicknesses, extrapolated run-to-detonation distances, radius size effects and detonation front curvature. Simple theories of the cylinder test, Bigplate, the cylinder size effect and detonation front curvature are given. The detonation front lag at the cylinder edge is shown to be proportional to the half-power of the reaction zone length. By calibrating for wall blow-out, a full set of reaction zone lengths from PETN to ANFO are obtained. The 1800--2100 K freezing effect is shown to be caused by rapid cooling of the product gases. Compiled comparative data for about 80 explosives is listed. Ten Chapters plus an Appendix.« less

  20. Simulation of detonation of ammonium nitrate fuel oil mixture confined by aluminum: edge angles for DSD

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Short, Mark; Quirk, James J; Kiyanda, Charles B

    2010-01-01

    Non-ideal high explosives are typically porous, low-density materials with a low detonation velocity (3--5 km/s) and long detonation reaction zone ({approx} cms). As a result, the interaction of a non-ideal high explosive with an inert confiner can be markedly different than for a conventional high explosive. Issues arise, for example, with light stiff confiners where the confiner can drive the high explosive (HE) through a Prandtl-Meyer fan at the HE/confiner interface rather than the HE driving the confiner. For a non-ideal high explosive confined by a high sound speed inert such that the detonation velocity is lower than the inertmore » sound speed, the flow is subsonic and thus shockless in the confiner. In such cases, the standard detonation shock dynamics methodology, which requires a positive edge-angle be specified at the HE/confiner interface in order that the detonation shape be divergent, cannot be directly utilized. In order to study how detonation shock dynamics can be utilized in such cases, numerical simulations of the detonation of ammonium nitrate-fuel oil (ANFO) confined by aluminum 6061 are conducted.« less

  1. The equation of state of predominant detonation products

    NASA Astrophysics Data System (ADS)

    Zaug, Joseph; Crowhurst, Jonathan; Bastea, Sorin; Fried, Laurence

    2009-06-01

    The equation of state of detonation products, when incorporated into an experimentally grounded thermochemical reaction algorithm can be used to predict the performance of explosives. Here we report laser based Impulsive Stimulated Light Scattering measurements of the speed of sound from a variety of polar and nonpolar detonation product supercritical fluids and mixtures. The speed of sound data are used to improve the exponential-six potentials employed within the Cheetah thermochemical code. We will discuss the improvements made to Cheetah in terms of predictions vs. measured performance data for common polymer blended explosives. Accurately computing the chemistry that occurs from reacted binder materials is one important step forward in our efforts.

  2. Characterization of Detonation Products of RSI-007 Explosive

    NASA Astrophysics Data System (ADS)

    Ager, Timothy; Neel, Christopher; Chhabildas, Lalit

    2011-06-01

    PDV and VISAR have been employed to characterize the detonation products of a production quality RSI-007 explosive. The explosive was part of an exploding foil initiator (EFI) detonator assembly in which the explosive was contained within a Kovar (Fe-Ni-Co alloy) cup. The free surface of the Kovar serves as the witness plate for the interferometry measurements. Detailed shock reverberations are recorded on the witness plate and the isentropic release path of the explosive is inferred though the velocity history. Two separate window materials are bonded to the Kovar cup in subsequent experiments and are used to further determine the release state in different pressure regimes. Presenter

  3. Characterization of detonation products of RSI-007 explosive

    NASA Astrophysics Data System (ADS)

    Ager, Timothy; Neel, Christopher; Breaux, Bradley; Vineski, Christopher; Welle, Eric; Lambert, David; Chhabildas, Lalit

    2012-03-01

    PDV and VISAR have been employed to characterize the detonation products of a high-purity CL-20 based explosive. The explosive was part of an exploding foil initiator (EFI) detonator assembly in which the explosive was contained within a Kovar (Fe-Ni-Co alloy) cup. The back surface of the Kovar serves as the witness plate for interferometry measurements. Detailed reverberations corresponding to shock arrival and release are recorded on the witness plate and the isentropic release path of the explosive is inferred though the velocity history. Two separate window materials are bonded to the Kovar cup in subsequent experiments and are used to further refine the release states.

  4. EPIDEMIOLOGY OF ACCIDENTAL POISONING

    PubMed Central

    Bissell, D. M.; McInnes, Robert S.

    1960-01-01

    In San Jose, California, studies of cases of accidental poisoning showed that the greatest hazard was to children 1 through 3 years of age. Drugs accounted for half the cases, household products for another third, and insecticides and rodenticides and others for the remainder. Most often poison material was within easy reach of the children. An analysis of families in which an accident occurred indicated that accidental poisoning might happen to any family. Since there was little after-effect of poisoning in cases in which treatment was obtained promptly, education directed toward getting prompt treatment seems most advisable. Community agencies interested in poison control need to focus their attention on parents of pre-school children. PMID:13801023

  5. Low Velocity Detonation of Nitromethane Affected by Precursor Shock Waves Propagating in Various Container Materials

    NASA Astrophysics Data System (ADS)

    Hamashima, H.; Osada, A.; Itoh, S.; Kato, Y.

    2007-12-01

    It is well known that some liquid explosives have two detonation behaviors, high velocity detonation (HVD) or low velocity detonation (LVD) can propagate. A physical model to describe the propagation mechanism of LVD in liquid explosives was proposed that LVD is not a self-reactive detonation, but rather a supported-reactive detonation from the cavitation field generated by precursor shock waves. However, the detailed structure of LVD in liquid explosives has not yet been clarified. In this study, high-speed photography was used to investigate the effects of the precursor shock waves propagating in various container materials for LVD in nitromethane (NM). Stable LVD was not observed in all containers, although transient LVD was observed. A very complicated structure of LVD was observed: the interaction of multiple precursor shock waves, multiple oblique shock waves, and the cavitation field.

  6. Low Velocity Detonation of Nitromethane Affected by Precursor Shock Waves Propagating in Various Container Materials

    NASA Astrophysics Data System (ADS)

    Hamashima, Hideki; Osada, Akinori; Kato, Yukio; Itoh, Shigeru

    2007-06-01

    It is well known that some liquid explosives have two detonation behaviors, high velocity detonation (HVD) or low velocity detonation (LVD) can propagate. A physical model to describe the propagation mechanism of LVD in liquid explosives was proposed that LVD is not a self-reactive detonation, but rather a supported-reactive detonation from the cavitation field generated by precursor shock waves. However, the detailed structure of LVD in liquid explosives has not yet been clarified. In this study, high-speed photography was used to investigate the effects of the precursor shock waves propagating in various container materials for LVD in nitromethane (NM). Stable LVD was not observed in all containers, although transient LVD was observed. A very complicated structure of LVD was observed: the interaction of multiple precursor shock waves, multiple oblique shock waves, and the cavitation field.

  7. Method and system for making integrated solid-state fire-sets and detonators

    DOEpatents

    O`Brien, D.W.; Druce, R.L.; Johnson, G.W.; Vogtlin, G.E.; Barbee, T.W. Jr.; Lee, R.S.

    1998-03-24

    A slapper detonator comprises a solid-state high-voltage capacitor, a low-jitter dielectric breakdown switch and trigger circuitry, a detonator transmission line, an exploding foil bridge, and a flier material. All these components are fabricated in a single solid-state device using thin film deposition techniques. 13 figs.

  8. Performance and environmental impact assessment of pulse detonation based engine systems

    NASA Astrophysics Data System (ADS)

    Glaser, Aaron J.

    Experimental research was performed to investigate the feasibility of using pulse detonation based engine systems for practical aerospace applications. In order to carry out this work a new pulse detonation combustion research facility was developed at the University of Cincinnati. This research covered two broad areas of application interest. The first area is pure PDE applications where the detonation tube is used to generate an impulsive thrust directly. The second focus area is on pulse detonation based hybrid propulsion systems. Within each of these areas various studies were performed to quantify engine performance. Comparisons of the performance between detonation and conventional deflagration based engine cycles were made. Fundamental studies investigating detonation physics and flow dynamics were performed in order to gain physical insight into the observed performance trends. Experimental studies were performed on PDE-driven straight and diverging ejectors to determine the system performance. Ejector performance was quantified by thrust measurements made using a damped thrust stand. The effects of PDE operating parameters and ejector geometric parameters on thrust augmentation were investigated. For all cases tested, the maximum thrust augmentation is found to occur at a downstream ejector placement. The optimum ejector geometry was determined to have an overall length of LEJECT/DEJECT =5.61, including an intermediate-straight section length of LSTRT /DEJECT=2, and diverging exhaust section with 4 deg half-angle. A maximum thrust augmentation of 105% was observed while employing the optimized ejector geometry and operating the PDE at a fill-fraction of 0.6 and a frequency of 10 Hz. When operated at a fill-fraction of 1.0 and a frequency of 30 Hz, the thrust augmentation of the optimized PDE-driven ejector system was observed to be 71%. Static pressure was measured along the interior surface of the ejector, including the inlet and exhaust sections. The

  9. Effect of actuating voltage and discharge gap on plasma assisted detonation initiation process

    NASA Astrophysics Data System (ADS)

    Siyin, ZHOU; Xueke, CHE; Wansheng, NIE; Di, WANG

    2018-06-01

    The influence of actuating voltage and discharge gap on plasma assisted detonation initiation by alternating current dielectric barrier discharge was studied in detail. A loose coupling method was used to simulate the detonation initiation process of a hydrogen–oxygen mixture in a detonation tube under different actuating voltage amplitudes and discharge gap sizes. Both the discharge products and the detonation forming process assisted by the plasma were analyzed. It was found that the patterns of the temporal and spatial distributions of discharge products in one cycle keep unchanged as changing the two discharge operating parameters. However, the adoption of a higher actuating voltage leads to a higher active species concentration within the discharge zone, and atom H is the most sensitive to the variations of the actuating voltage amplitude among the given species. Adopting a larger discharge gap results in a lower concentration of the active species, and all species have the same sensitivity to the variations of the gap. With respect to the reaction flow of the detonation tube, the corresponding deflagration to detonation transition (DDT) time and distance become slightly longer when a higher actuating voltage is chosen. The acceleration effect of plasma is more prominent with a smaller discharge gap, and the benefit builds gradually throughout the DDT process. Generally, these two control parameters have little effect on the amplitude of the flow field parameters, and they do not alter the combustion degree within the reaction zone.

  10. Turbulent Mixing and Afterburn in Post-Detonation Flow with Dense Particle Clouds

    NASA Astrophysics Data System (ADS)

    Menon, Suresh

    2015-06-01

    Reactive metal particles are used as additives in most explosives to enhance afterburn and augment the impact of the explosive. The afterburn is highly dependent on the particle dispersal and mixing in the post-detonation flow. The post-detonation flow is generally characterized by hydrodynamic instabilities emanating from the interaction of the blast waves with the detonation product gases and the ambient air. Further, influenced by the particles, the flow evolves and develops turbulent structures, which play vital role in determining mixing and combustion. Past studies in the field in open literature are reviewed along with some recent studies conducted using three dimensional numerical simulations of particle dispersal and combustion in the post-detonation flow. Spherical nitromethane charges enveloped by particle shells of varying thickness are considered along with dense loading effects. In dense flows, the particles block the flow of the gases and therefore, the role of the inter-particle interactions on particle dispersal cannot be ignored. Thus, both dense and dilute effects must be modeled simultaneously to simulate the post-detonation flow. A hybrid equation of state is employed to study the evolution of flow from detonation initiation till the late time mixing and afterburn. The particle dispersal pattern in each case is compared with the available experimental results. The burn rate and the energy release in each case is quantified and the effect of total mass of the particles and the particle size is analyzed in detail. Strengths and limitations of the various methods used for such studies as well as the uncertainties in the modeling strategies are also highlighted. Supported by Defense Threat Reduction Agency.

  11. Fast reactions of aluminum and explosive decomposition products in a post-detonation environment

    NASA Astrophysics Data System (ADS)

    Tappan, Bryce C.; Manner, Virginia W.; Lloyd, Joseph M.; Pemberton, Steven J.

    2012-03-01

    In order to determine the reaction behavior of Al in RDX or HMX/cast-cured binder formulations shortly after the passage of the detonation, a series of cylinder tests was performed on formulations comprising of varying binder systems and either 3.5 μm spherical Al or LiF (an inert salt with a similar molecular weight and density to Al). In these studies, both detonation velocity and cylinder expansion velocity are measured in order to determine exactly how and when Al contributes to the explosive event, particularly in the presence of oxidizing/energetic binders. The U.S. Army Research, Development and Engineering Laboratory at Picatinny have recently coined the term "combined effects" explosives for materials such as these; as they demonstrate both high metal pushing capability and high blast ability. This study is aimed at developing a fundamental understanding of the reaction of Al with explosives decomposition products, where both the detonation and early post-detonation environment are analyzed. Reaction rates of Al metal are investigated via comparison of predicted performance based on thermoequilibrium calculations. The detonation velocities, wall velocities, and parameters at the CJ plane are some of the parameters that will be discussed.

  12. Effect of Vertical Concentration Gradient on Globally Planar Detonation with Detailed Reaction Mechanism

    NASA Astrophysics Data System (ADS)

    Song, Qingguana; Wang, Cheng; Han, Yong; Gao, Dayuan; Duan, Yingliang

    2017-06-01

    Since detonation often initiates and propagates in the non-homogeneous mixtures, investigating its behavior in non-uniform mixtures is significant not only for the industrial explosion in the leakage combustible gas, but also for the experimental investigations with a vertical concentration gradient caused by the difference in the molecular weight of gas mixture. Objective of this work is to show the detonation behavior in the mixture with different concentration gradients with detailed chemical reaction mechanism. A globally planar detonation in H2-O2 system is simulated by a high-resolution code based on the fifth-order weighted essentially non-oscillatory (WENO) scheme in spatial discretization and the third-order Additive Runge-Kutta schemes in time discretization. The different shocked combustion modes appear in the rich-fuel and poor-fuel layers due to the concentration gradient effect. Globally, for the cases with the lower gradient detonation can be sustained in a way of the alternation of the multi-heads mode and single-head mode, whereas for the cases with the higher gradient detonation propagates with a single-head mode. Institute of Chemical Materials, CAEP.

  13. Accidental death in autoerotic maneuvers.

    PubMed

    Focardi, Martina; Gualco, Barbara; Norelli, GianAristide

    2008-03-01

    The authors from the Florence Forensic Department present a case that demonstrates the paradigms attached to accidental deaths while performing autoerotic maneuvers. The incidents of such practices are underestimated and are only the tip of the iceberg since they do not represent the cases that are never reported due to successful practice. After analyzing the statistic data, the authors describe the case and discuss about the element that prove the accidental nature of the death and the importance of the correct application of forensic methodology at the scene and in the mortuary.

  14. Tidal double detonation: a new mechanism for the thermonuclear explosion of a white dwarf induced by a tidal disruption event

    NASA Astrophysics Data System (ADS)

    Tanikawa, Ataru

    2018-03-01

    We suggest tidal double detonation as a new mechanism for the thermonuclear explosion of a white dwarf (WD) induced by a tidal disruption event (TDE). Tidal detonation is also a WD explosion induced by a TDE. In this case, helium (He) and carbon-oxygen (CO) detonation waves incinerate He WDs and CO WDs, respectively. On the other hand, for tidal double detonation, He detonation is first excited in the He shell of a CO WD, which then drives CO detonation in the CO core. We name this mechanism after the double detonation scenario in the context of type Ia supernovae. In this paper, by performing numerical simulations for CO WDs of mass 0.60 M⊙ with and without a He shell, we show that tidal double detonation occurs in the shallower encounter of a CO WD with an intermediate-mass black hole (IMBH) compared to simple tidal detonation. We expect tidal double detonation will increase the possibility of the occurrence of WD TDEs, which can help us to understand IMBHs.

  15. High-order shock-fitted detonation propagation in high explosives

    NASA Astrophysics Data System (ADS)

    Romick, Christopher M.; Aslam, Tariq D.

    2017-03-01

    A highly accurate numerical shock and material interface fitting scheme composed of fifth-order spatial and third- or fifth-order temporal discretizations is applied to the two-dimensional reactive Euler equations in both slab and axisymmetric geometries. High rates of convergence are not typically possible with shock-capturing methods as the Taylor series analysis breaks down in the vicinity of discontinuities. Furthermore, for typical high explosive (HE) simulations, the effects of material interfaces at the charge boundary can also cause significant computational errors. Fitting a computational boundary to both the shock front and material interface (i.e. streamline) alleviates the computational errors associated with captured shocks and thus opens up the possibility of high rates of convergence for multi-dimensional shock and detonation flows. Several verification tests, including a Sedov blast wave, a Zel'dovich-von Neumann-Döring (ZND) detonation wave, and Taylor-Maccoll supersonic flow over a cone, are utilized to demonstrate high rates of convergence to nontrivial shock and reaction flows. Comparisons to previously published shock-capturing multi-dimensional detonations in a polytropic fluid with a constant adiabatic exponent (PF-CAE) are made, demonstrating significantly lower computational error for the present shock and material interface fitting method. For an error on the order of 10 m /s, which is similar to that observed in experiments, shock-fitting offers a computational savings on the order of 1000. In addition, the behavior of the detonation phase speed is examined for several slab widths to evaluate the detonation performance of PBX 9501 while utilizing the Wescott-Stewart-Davis (WSD) model, which is commonly used in HE modeling. It is found that the thickness effect curve resulting from this equation of state and reaction model using published values is dramatically more steep than observed in recent experiments. Utilizing the present fitting

  16. Hybrid Solution-Adaptive Unstructured Cartesian Method for Large-Eddy Simulation of Detonation in Multi-Phase Turbulent Reactive Mixtures

    DTIC Science & Technology

    2012-03-27

    pulse- detonation engines ( PDE ), stage separation, supersonic cav- ity oscillations, hypersonic aerodynamics, detonation induced structural...ADAPTIVE UNSTRUCTURED CARTESIAN METHOD FOR LARGE-EDDY SIMULATION OF DETONATION IN MULTI-PHASE TURBULENT REACTIVE MIXTURES 5b. GRANT NUMBER FA9550...CCL Report TR-2012-03-03 Hybrid Solution-Adaptive Unstructured Cartesian Method for Large-Eddy Simulation of Detonation in Multi-Phase Turbulent

  17. Influence of Dense Inert Additives (W and Pb) on Detonation Conditions and Regime of Condensed Explosives

    NASA Astrophysics Data System (ADS)

    Imkhovik, Nikolay A.

    2010-10-01

    Results of experimental and theoretical studies of the unusual detonation properties of mixtures of high explosives (HEs) with high-density inert additives W and Pb were analyzed and systematized. Typical examples of the nonideal detonation of composite explosives for which the measured detonation pressure is substantially lower and the detonation velocity is higher than the values calculated within the framework of the hydrodynamic model, with the specific heat ratio for the detonation products of ∼6-8, are presented. Mechanisms of formation of anomalous pressure and mass velocity profiles, which explain the correlation between the Chapman-Jouguet pressure for HE-W and HE-Pb mixtures, the velocity of the free surface of duralumin target, and the depth of the dent imprinted in steel witness plates, are described.

  18. The stabilization of unstable detonation waves for the mixture of nitromethane/methanol

    NASA Astrophysics Data System (ADS)

    Utkin, A. V.; Koldunov, S. A.; Mochalova, V. M.; Torunov, S. I.; Lapin, S. M.

    2015-11-01

    Using a laser interferometer VISAR the measurements of the particle velocity profiles in detonation waves for nitromethane/methanol mixtures with additions of a sensitizer diethylenetriamine were conducted. It is shown that the detonation front in a mixture of nitromethane/methanol is unstable and sensitizer is an effective method for the flow stabilization. If the diluent concentration is less than 10%, the detonation front is stabilized by adding of 1% diethylenetriamine. At higher concentrations of methanol, the sensitizer does not reject instability, but the amplitude of oscillations decreases in several times. An increase of the limit concentration of methanol at the addition of diethylenetriamine to the mixture was found.

  19. 49 CFR 178.318 - Specification MC 201; container for detonators and percussion caps.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Specification MC 201; container for detonators and percussion caps. 178.318 Section 178.318 Transportation Other Regulations Relating to Transportation PIPELINE....318 Specification MC 201; container for detonators and percussion caps. ...

  20. On the Stability of the Detonation Wave Front in the High Explosive Liquid Mixture Tetranitromethane/Nitrobenzene

    NASA Astrophysics Data System (ADS)

    Fedorov, A. V.; Mikhaylov, A. L.; Men'Shikh, A. V.; Nazarov, D. V.; Finyushin, S. A.; Davydov, V. A.

    2010-10-01

    We performed experimental studies on the stability of the detonation wave front in mixtures of the liquids tetranitromethane (TNM) and nitrobenzene (NB). Tetranitromethane is an oxygen-rich explosive and nitrobenzene was used as a solvent or dilutant. (NB is not classed as an explosive but as an explosive would be oxygen poor and fuel rich.) The primary diagnostic was a laser velocimetry method with high temporal resolution. Data obtained were compared with the detonation parameters of the TNM/NB mixtures. In previous experimental work [1,2] it was shown that the detonation wave front in liquid explosives may be either smooth or rough. Rough detonation fronts have been reported in nitromethane, as well as nitromethane mixed with a solvent. Smooth detonation fronts have been reported in tetranitromethane. Previously, we conducted studies on the structure of the detonation wave front in liquid explosives containing tetranitromethane [3-5]. Smooth, stable fronts were recorded in pure tetranitromethane and in a 46/54 mixture of tetranitromethane and nitromethane. A pulsating, unstable detonation wave front was recorded in a 74/26 mixture of tetranitromethane and nitrobenzene. The goal of the present work is to extend our research on the structure of the detonation wave front in mixtures of tetranitromethane diluted with less energetic nitrobenzene. To this end, the following TNM/NB mixtures were studied: 95/5, 90/10, 85/15, 80/20, 74/26, and 50/50.

  1. Measurement of Detonation Velocity for a Nonideal Heterogeneous Explosive in Axisymmetric and Two-Dimensional Geometries

    NASA Astrophysics Data System (ADS)

    Higgins, Andrew

    2009-12-01

    Detonation in a heterogeneous explosive with a relatively sparse concentration of reaction centers ("hot spots") is investigated experimentally. The explosive system considered is nitromethane gelled with PMMA and with glass microballoons (GMB's) in suspension. The detonation velocity is measured as a function of the characteristic charge dimension (diameter or thickness) in both axisymmetric and two-dimensional geometries. The use of a unique, annular charge geometry (with the diameter of the annulus much greater than the annular gap thickness) permits quasi-two-dimensional detonations to be observed without undesirable lateral rarefactions that result from a finite aspect ratio. The results confirm the prior findings of Gois et al. (1996) which show that, for a low concentration of GMB's, detonation propagation does not exhibit the expected 2:1 scaling from axisymmetric to planar geometries. This reinforces the idea that detonation in highly nonideal explosives is not governed exclusively by global front curvature.

  2. Trauma is Danger

    DTIC Science & Technology

    2011-01-01

    self interactions and thereby neglect most traumatic injuries , the Danger model abandons this classical concept [ 2 ]. The Danger model theorizes that...June 2011 References 1. Keel M, Trentz O: Pathophysiology of polytrauma. Injury 2005, 36:691-709. 2 . Matzinger P: Tolerance, danger, and the extended... ischemia - reperfusion . J Exp Med 2005, 201:1135-1143. 27. Huang LF, Yao YM, Zhang LT, Dong N, Yu Y, Sheng ZY: The effect of high- mobility group box 1

  3. Double-detonation Sub-Chandrasekhar Supernovae: Synthetic Observables for Minimum Helium Shell Mass Models

    NASA Astrophysics Data System (ADS)

    Kromer, M.; Sim, S. A.; Fink, M.; Röpke, F. K.; Seitenzahl, I. R.; Hillebrandt, W.

    2010-08-01

    In the double-detonation scenario for Type Ia supernovae, it is suggested that a detonation initiates in a shell of helium-rich material accreted from a companion star by a sub-Chandrasekhar-mass white dwarf. This shell detonation drives a shock front into the carbon-oxygen white dwarf that triggers a secondary detonation in the core. The core detonation results in a complete disruption of the white dwarf. Earlier studies concluded that this scenario has difficulties in accounting for the observed properties of Type Ia supernovae since the explosion ejecta are surrounded by the products of explosive helium burning in the shell. Recently, however, it was proposed that detonations might be possible for much less massive helium shells than previously assumed (Bildsten et al.). Moreover, it was shown that even detonations of these minimum helium shell masses robustly trigger detonations of the carbon-oxygen core (Fink et al.). Therefore, it is possible that the impact of the helium layer on observables is less than previously thought. Here, we present time-dependent multi-wavelength radiative transfer calculations for models with minimum helium shell mass and derive synthetic observables for both the optical and γ-ray spectral regions. These differ strongly from those found in earlier simulations of sub-Chandrasekhar-mass explosions in which more massive helium shells were considered. Our models predict light curves that cover both the range of brightnesses and the rise and decline times of observed Type Ia supernovae. However, their colors and spectra do not match the observations. In particular, their B - V colors are generally too red. We show that this discrepancy is mainly due to the composition of the burning products of the helium shell of the Fink et al. models which contain significant amounts of titanium and chromium. Using a toy model, we also show that the burning products of the helium shell depend crucially on its initial composition. This leads us to

  4. Numerical simulation of a 100-ton ANFO detonation

    NASA Astrophysics Data System (ADS)

    Weber, P. W.; Millage, K. K.; Crepeau, J. E.; Happ, H. J.; Gitterman, Y.; Needham, C. E.

    2015-03-01

    This work describes the results from a US government-owned hydrocode (SHAMRC, Second-Order Hydrodynamic Automatic Mesh Refinement Code) that simulated an explosive detonation experiment with 100,000 kg of Ammonium Nitrate-Fuel Oil (ANFO) and 2,080 kg of Composition B (CompB). The explosive surface charge was nearly hemispherical and detonated in desert terrain. Two-dimensional axisymmetric (2D) and three-dimensional (3D) simulations were conducted, with the 3D model providing a more accurate representation of the experimental setup geometry. Both 2D and 3D simulations yielded overpressure and impulse waveforms that agreed qualitatively with experiment, including the capture of the secondary shock observed in the experiment. The 2D simulation predicted the primary shock arrival time correctly but secondary shock arrival time was early. The 2D-predicted impulse waveforms agreed very well with the experiment, especially at later calculation times, and prediction of the early part of the impulse waveform (associated with the initial peak) was better quantitatively for 2D compared to 3D. The 3D simulation also predicted the primary shock arrival time correctly, and secondary shock arrival times in 3D were closer to the experiment than in the 2D results. The 3D-predicted impulse waveform had better quantitative agreement than 2D for the later part of the impulse waveform. The results of this numerical study show that SHAMRC may be used reliably to predict phenomena associated with the 100-ton detonation. The ultimate fidelity of the simulations was limited by both computer time and memory. The results obtained provide good accuracy and indicate that the code is well suited to predicting the outcomes of explosive detonations.

  5. Non-detonable explosive simulators

    DOEpatents

    Simpson, Randall L.; Pruneda, Cesar O.

    1994-01-01

    A simulator which is chemically equivalent to an explosive, but is not detonable. The simulator has particular use in the training of explosives detecting dogs and calibrating sensitive analytical instruments. The explosive simulants may be fabricated by different techniques, a first involves the use of standard slurry coatings to produce a material with a very high binder to explosive ratio without masking the explosive vapor, and the second involves coating inert beads with thin layers of explosive molecules.

  6. Effect of the oxygen balance on ignition and detonation properties of liquid explosive mixtures

    NASA Astrophysics Data System (ADS)

    Genetier, Marc; Osmont, Antoine; Baudin, Gerard

    2013-06-01

    The objective is to compare ignition and detonation properties of various liquid high explosives having negative up to positive oxygen balance (OB): nitromethane (OB < 0), saccharose and hydrogen peroxide based mixture (quasi nil OB), hydrogen peroxide with more than 90% purity (OB > 0). The decomposition kinetic rates and the equations of state (EOS) for the liquid mixtures and detonation products (DP) are the input data for a detonation model. EOS are theoretically determined using the Woolfolk et al universal liquid polar shock law and thermochemical computations for DP. The decomposition kinetic rate laws are determined to reproduce the shock to detonation transition for the mixtures submitted to planar plate impacts. Such a model is not sufficient to compute open field explosions. The aerial overpressure is well reproduced in the first microseconds, however, after it becomes worse at large expansion of the fireball and the impulse is underestimated. The problem of the DP EOS alone is that it takes into account only the detonation, the secondary combustion DP - air being not considered. To solve this problem a secondary combustion model has been developed to take into account the OB effect. The detonation model has been validated on planar plate impact experiments. The secondary combustion parameters were deduced from thermochemical computations. The whole model has been used to predict the effects of the oxygen balance on open air blast effects of spherical charges.

  7. Pulse Detonation Rocket MHD Power Experiment

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.; Cook, Stephen (Technical Monitor)

    2002-01-01

    A pulse detonation research engine (MSFC (Marshall Space Flight Center) Model PDRE (Pulse Detonation Rocket Engine) G-2) has been developed for the purpose of examining integrated propulsion and magnetohydrodynamic power generation applications. The engine is based on a rectangular cross-section tube coupled to a converging-diverging nozzle, which is in turn attached to a segmented Faraday channel. As part of the shakedown testing activity, the pressure wave was interrogated along the length of the engine while running on hydrogen/oxygen propellants. Rapid transition to detonation wave propagation was insured through the use of a short Schelkin spiral near the head of the engine. The measured detonation wave velocities were in excess of 2500 m/s in agreement with the theoretical C-J velocity. The engine was first tested in a straight tube configuration without a nozzle, and the time resolved thrust was measured simultaneously with the head-end pressure. Similar measurements were made with the converging-diverging nozzle attached. The time correlation of the thrust and head-end pressure data was found to be excellent. The major purpose of the converging-diverging nozzle was to configure the engine for driving an MHD generator for the direct production of electrical power. Additional tests were therefore necessary in which seed (cesium-hydroxide dissolved in methanol) was directly injected into the engine as a spray. The exhaust plume was then interrogated with a microwave interferometer in an attempt to characterize the plasma conditions, and emission spectroscopy measurements were also acquired. Data reduction efforts indicate that the plasma exhaust is very highly ionized, although there is some uncertainty at this time as to the relative abundance of negative OH ions. The emission spectroscopy data provided some indication of the species in the exhaust as well as a measurement of temperature. A 24-electrode-pair segmented Faraday channel and 0.6 Tesla permanent

  8. Research on laser detonation pulse circuit with low-power based on super capacitor

    NASA Astrophysics Data System (ADS)

    Wang, Hao-yu; Hong, Jin; He, Aifeng; Jing, Bo; Cao, Chun-qiang; Ma, Yue; Chu, En-yi; Hu, Ya-dong

    2018-03-01

    According to the demand of laser initiating device miniaturization and low power consumption of weapon system, research on the low power pulse laser detonation circuit with super capacitor. Established a dynamic model of laser output based on super capacitance storage capacity, discharge voltage and programmable output pulse width. The output performance of the super capacitor under different energy storage capacity and discharge voltage is obtained by simulation. The experimental test system was set up, and the laser diode of low power pulsed laser detonation circuit was tested and the laser output waveform of laser diode in different energy storage capacity and discharge voltage was collected. Experiments show that low power pulse laser detonation based on super capacitor energy storage circuit discharge with high efficiency, good transient performance, for a low power consumption requirement, for laser detonation system and low power consumption and provide reference light miniaturization of engineering practice.

  9. Investigation of detonation velocity in heterogeneous explosive system using the reactive Burgers' analog

    NASA Astrophysics Data System (ADS)

    Di Labbio, G.; Kiyanda, C. B.; Mi, X.; Higgins, A. J.; Nikiforakis, N.; Ng, H. D.

    2016-06-01

    In this study, the applicability of the Chapman-Jouguet (CJ) criterion is tested numerically for heterogeneous explosive media using a simple detonation analog. The analog system consists of a reactive Burgers' equation coupled with an Arrhenius type reaction wave, and the heterogeneity of the explosive media is mimicked using a discrete energy source approach. The governing equation is solved using a second order, finite-volume approach and the average propagation velocity of the discrete detonation is determined by tracking the leading shock front. Consistent with previous studies, the averaged velocity of the leading shock front from the unsteady numerical simulations is also found to be in good agreement with the velocity of a CJ detonation in a uniform medium wherein the energy source is spatially homogenized. These simulations have thus implications for whether the CJ criterion is valid to predict the detonation velocity in heterogeneous explosive media.

  10. Design and Testing of an H2/O2 Predetonator for a Simulated Rotating Detonation Engine Channel

    DTIC Science & Technology

    2013-03-01

    Diameter PDE Pulse Detonation Engines RDE Rotating Detonation Engine WPAFB Wright Patterson Air Force Base ZND Zeldovich, von Neumann and Doring xv...DESIGN AND TESTING OF AN H2/O2 PREDETONATOR FOR A SIMULATED ROTATING DETONATION ENGINE CHANNEL THESIS Stephen J. Miller, 2Lt, USAF AFIT-ENY-13-M-23...RELEASE; DISTRIBUTION UNLIMITED AFIT-ENY-13-M-23 DESIGN AND TESTING OF AN H2/O2 PREDETONATOR FOR A SIMULATED ROTATING DETONATION ENGINE CHANNEL Stephen

  11. Smokeless Propellants as Vehicle Borne IED Main Charges: An Initial Threat Assessment

    DTIC Science & Technology

    2008-01-01

    uci: • danger clasa : (B) critical detonation height I 45 - 65 em. detonation danger , during fillin. material in mixing trough, in barrels as a in...Appendix A Examples ofMorphology Appendix B ATF List of Explosives Materials Appendix C Cabella Web Page Appendix D ATF Intelligence Report on Explosives...available for exploitation by violent extremist organizations and individuals. Discussion: Conventional explosive materials remain the most probable

  12. Dangerous Spaces, Dangerous Memories, Dangerous Emotions: Informal Education and Heteronormativity--A Manchester UK Youth Work Vignette

    ERIC Educational Resources Information Center

    Batsleer, Janet

    2012-01-01

    This article makes a connection between youth work spaces, emotions and some elements of memory, exploring the construction of spaces dangerous for social justice in both meanings of the term "dangerous for". It investigates the contribution to social justice of lesbian and gay youth work and other non-heteronormative youth work in a…

  13. Computational Study of Near-limit Propagation of Detonation in Hydrogen-air Mixtures

    NASA Technical Reports Server (NTRS)

    Yungster, S.; Radhakrishnan, K.

    2002-01-01

    A computational investigation of the near-limit propagation of detonation in lean and rich hydrogen-air mixtures is presented. The calculations were carried out over an equivalence ratio range of 0.4 to 5.0, pressures ranging from 0.2 bar to 1.0 bar and ambient initial temperature. The computations involved solution of the one-dimensional Euler equations with detailed finite-rate chemistry. The numerical method is based on a second-order spatially accurate total-variation-diminishing (TVD) scheme, and a point implicit, first-order-accurate, time marching algorithm. The hydrogen-air combustion was modeled with a 9-species, 19-step reaction mechanism. A multi-level, dynamically adaptive grid was utilized in order to resolve the structure of the detonation. The results of the computations indicate that when hydrogen concentrations are reduced below certain levels, the detonation wave switches from a high-frequency, low amplitude oscillation mode to a low frequency mode exhibiting large fluctuations in the detonation wave speed; that is, a 'galloping' propagation mode is established.

  14. Detonation suppression in hydrogen-air mixtures using porous coatings on the walls

    NASA Astrophysics Data System (ADS)

    Bivol, G. Yu.; Golovastov, S. V.; Golub, V. V.

    2018-05-01

    We considered the problem of detonation suppression and weakening of blast wave effects occurring during the combustion of hydrogen-air mixtures in confined spaces. The gasdynamic processes during combustion of hydrogen, an alternative environmentally friendly fuel, were also considered. Detonation decay and flame propagation in hydrogen-air mixtures were experimentally investigated in rectangular cross-section channels with solid walls and two types of porous coatings: steel wool and polyurethane foam. Shock wave pressure dynamics inside the section with porous coating were studied using pressure sensors; flame front propagation was studied using photodiodes and high-speed camera visualization. For all mixtures, the detonation wave formed before entering the section with porous coating. For both porous materials, the steady detonation wave decoupled in the porous section of the channel into a shock wave and flame front propagating with a velocity around the Chapman-Jouguet acoustic velocity. By the end of the porous section, shock wave pressure reductions of 70 and 85% were achieved for the polyurethane foam and steel wool, respectively. The dependence of the flame velocity on the mixture composition (equivalence ratio) is presented.

  15. About Assessment Criteria of Driver's Accidental Abilities

    ERIC Educational Resources Information Center

    Lobanova, Yuliya I.; Glushko, Kirill V.

    2016-01-01

    The article points at the importance of studying the human factor as a cause of accidents of drivers, especially in loosely structured traffic situations. The description of the experiment on the measurement of driver's accidental abilities is given. Under accidental ability is meant the capability to ensure the security of driving as a behavior…

  16. Accidental awareness during general anaesthesia - a narrative review.

    PubMed

    Tasbihgou, S R; Vogels, M F; Absalom, A R

    2018-01-01

    Unintended accidental awareness during general anaesthesia represents failure of successful anaesthesia, and so has been the subject of numerous studies during the past decades. As return to consciousness is both difficult to describe and identify, the reported incidence rates vary widely. Similarly, a wide range of techniques have been employed to identify cases of accidental awareness. Studies which have used the isolated forearm technique to identify responsiveness to command during intended anaesthesia have shown remarkably high incidences of awareness. For example, the ConsCIOUS-1 study showed an incidence of responsiveness around the time of laryngoscopy of 1:25. On the other hand, the 5th Royal College of Anaesthetists National Audit Project, which reported the largest ever cohort of patients who had experienced accidental awareness, used a system to identify patients who spontaneously self-reported accidental awareness. In this latter study, the incidence of accidental awareness was 1:19,600. In the recently published SNAP-1 observational study, in which structured postoperative interviews were performed, the incidence was 1:800. In almost all reported cases of intra-operative responsiveness, there was no subsequent explicit recall of intra-operative events. To date, there is no evidence that this occurrence has any psychological consequences. Among patients who experience accidental awareness and can later remember details of their experience, the consequences are better known. In particular, when awareness occurs in a patient who has been given neuromuscular blocking agents, it may result in serious sequelae such as symptoms of post-traumatic stress disorder and a permanent aversion to surgery and anaesthesia, and is feared by patients and anaesthetists. In this article, the published literature on the incidence, consequences and management of accidental awareness under general anaesthesia with subsequent recall will be reviewed. © 2017 The Association

  17. Numerical Analysis of a Rotating Detonation Engine in the Relative Reference Frame

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.

    2014-01-01

    A two-dimensional, computational fluid dynamic (CFD) simulation of a semi-idealized rotating detonation engine (RDE) is described. The simulation operates in the detonation frame of reference and utilizes a relatively coarse grid such that only the essential primary flow field structure is captured. This construction yields rapidly converging, steady solutions. Results from the simulation are compared to those from a more complex and refined code, and found to be in reasonable agreement. The performance impacts of several RDE design parameters are then examined. Finally, for a particular RDE configuration, it is found that direct performance comparison can be made with a straight-tube pulse detonation engine (PDE). Results show that they are essentially equivalent.

  18. Fluorescent single-digit detonation nanodiamond for biomedical applications

    NASA Astrophysics Data System (ADS)

    Nunn, Nicholas; d’Amora, Marta; Prabhakar, Neeraj; Panich, Alexander M.; Froumin, Natalya; Torelli, Marco D.; Vlasov, Igor; Reineck, Philipp; Gibson, Brant; Rosenholm, Jessica M.; Giordani, Silvia; Shenderova, Olga

    2018-07-01

    Detonation nanodiamonds (DNDs) have emerged as promising candidates for a variety of biomedical applications, thanks to different physicochemical and biological properties, such as small size and reactive surfaces. In this study, we propose carbon dot decorated single digit (4–5 nm diameter) primary particles of detonation nanodiamond as promising fluorescent probes. Due to their intrinsic fluorescence originating from tiny (1–2 atomic layer thickness) carbonaceous structures on their surfaces, they exhibit brightness suitable for in vitro imaging. Moreover, this material offers a unique, cost effective alternative to sub-10 nm nanodiamonds containing fluorescent nitrogen-vacancy color centers, which have not yet been produced at large scale. In this paper, carbon dot decorated nanodiamonds are characterized by several analytical techniques. In addition, the efficient cellular uptake and fluorescence of these particles are observed in vitro on MDA-MD-231 breast cancer cells by means of confocal imaging. Finally, the in vivo biocompatibility of carbon dot decorated nanodiamonds is demonstrated in zebrafish during the development. Our results indicate the potential of single-digit detonation nanodiamonds as biocompatible fluorescent probes. This unique material will find application in correlative light and electron microscopy, where small sized NDs can be attached to antibodies to act as a suitable dual marker for intracellular correlative microscopy of biomolecules.

  19. Study of particle evolution from Composition B-3 detonation by time-resolved small angle x-ray scattering

    NASA Astrophysics Data System (ADS)

    Huber, R.; Podlesak, D.; Dattelbaum, D.; Firestone, M.; Gustavsen, R.; Jensen, B.; Ringstrand, B.; Watkins, E.; Bagge-Hansen, M.; Hodgin, R.; Lauderbach, L.; Willey, T.; van Buuren, T.; Graber, T.; Rigg, P.; Sinclair, N.; Seifert, S.

    2017-06-01

    High explosive (HE) detonations produce an assortment of gases (CO, CO2, N2) and solid carbon products (nanodiamond, graphite). The evolution of solid carbon particles, within the chemical reaction zone, help to propel the detonation wave forward. Due to the violent nature and short reaction times during HE detonations, experimental observation are limited. Through time-resolved small angle x-ray scattering (TRSAXS) we are able to observed nanocarbon formation on nanosecond time scales. This TRSAXS setup is the first of its kind in the United States at Argonne National Laboratory at the Advanced Photon Source in the Dynamic Compression Sector. From the empirical and analytical analysis of the x-ray scattering of an in-line detonation we are able to temporally follow morphology and size. Two detonation geometries were studied for the HE Comp B-3 (40% TNT/60% RDX), producing steady and overdriven conditions. Steady wave particle evolution plateaued by 2 microseconds, where overdriven condition particle size decreases at the collision of the two shock fronts then plateaus. Post detonation soot is also analyzed to confirm size and shape of nanocarbon formation from Comp B-3 detonations. LA-UR-17-21443.

  20. Bonfire-safe low-voltage detonator

    DOEpatents

    Lieberman, M.L.

    1988-07-01

    A column of explosive in a low-voltage detonator which makes it bonfire-safe includes a first layer of an explosive charge of CP, or a primary explosive, and a second layer of a secondary organic explosive charge, such as PETN, which has a degradation temperature lower than the autoignition temperature of the CP or primary explosives. The first layer is composed of a pair of increments disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to and in contact with an electrical ignition device at one end of the bore. The second layer is composed of a plurality of increments disposed in the housing bore in a transition region of the explosive column next to and in contact with the first layer on a side opposite from the ignition device. The first layer is loaded under a sufficient high pressure, 25 to 40 kpsi, to achieve ignition, whereas the second layer is loaded under a sufficient low pressure, about 10 kpsi, to allow occurrence of DDT. Each increment of the first and second layers has an axial length-to-diameter ratio of one-half. 2 figs.

  1. Bonfire-safe low-voltage detonator

    DOEpatents

    Lieberman, Morton L.

    1990-01-01

    A column of explosive in a low-voltage detonator which makes it bonfire-safe includes a first layer of an explosive charge of CP, or a primary explosive, and a second layer of a secondary organic explosive charge, such as PETN, which has a degradation temperature lower than the autoignition temperature of the CP or primary explosives. The first layer is composed of a pair of increments disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to and in contact with an electrical ignition device at one end of the bore. The second layer is composed of a plurality of increments disposed in the housing bore in a transition region of the explosive column next to and in contact with the first layer on a side opposite from the ignition device. The first layer is loaded under a sufficient high pressure, 25 to 40 kpsi, to achieve ignition, whereas the second layer is loaded under a sufficient low pressure, about 10 kpsi, to allow occurrence of DDT. Each increment of the first and second layers has an axial length-to-diameter ratio of one-half.

  2. The Attenuation of a Detonation Wave by an Aircraft Engine Axial Turbine Stage

    NASA Technical Reports Server (NTRS)

    VanZante, Dale; Envia, Edmane; Turner, Mark G.

    2007-01-01

    A Constant Volume Combustion Cycle Engine concept consisting of a Pulse Detonation Combustor (PDC) followed by a conventional axial turbine was simulated numerically to determine the attenuation and reflection of a notional PDC pulse by the turbine. The multi-stage, time-accurate, turbomachinery solver TURBO was used to perform the calculation. The solution domain consisted of one notional detonation tube coupled to 5 vane passages and 8 rotor passages representing 1/8th of the annulus. The detonation tube was implemented as an initial value problem with the thermodynamic state of the tube contents, when the detonation wave is about to exit, provided by a 1D code. Pressure time history data from the numerical simulation was compared to experimental data from a similar configuration to verify that the simulation is giving reasonable results. Analysis of the pressure data showed a spectrally averaged attenuation of about 15 dB across the turbine stage. An evaluation of turbine performance is also presented.

  3. Transient analysis of a pulsed detonation combustor using the numerical propulsion system simulation

    NASA Astrophysics Data System (ADS)

    Hasler, Anthony Scott

    The performance of a hybrid mixed flow turbofan (with detonation tubes installed in the bypass duct) is investigated in this study and compared with a baseline model of a mixed flow turbofan with a standard combustion chamber as a duct burner. Previous studies have shown that pulsed detonation combustors have the potential to be more efficient than standard combustors, but they also present new challenges that must be overcome before they can be utilized. The Numerical Propulsion System Simulation (NPSS) will be used to perform the analysis with a pulsed detonation combustor model based on a numerical simulation done by Endo, Fujiwara, et. al. Three different cases will be run using both models representing a take-off situation, a subsonic cruise and a supersonic cruise situation. Since this study investigates a transient analysis, the pulse detonation combustor is run in a rig setup first and then its pressure and temperature are averaged for the cycle to obtain quasi-steady results.

  4. OGLE-2013-SN-079: A LONELY SUPERNOVA CONSISTENT WITH A HELIUM SHELL DETONATION

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Inserra, C.; Sim, S. A.; Smartt, S. J.

    2015-01-20

    We present observational data for a peculiar supernova discovered by the OGLE-IV survey and followed by the Public ESO Spectroscopic Survey for Transient Objects. The inferred redshift of z = 0.07 implies an absolute magnitude in the rest-frame I-band of M{sub I} ∼ –17.6 mag. This places it in the luminosity range between normal Type Ia SNe and novae. Optical and near infrared spectroscopy reveal mostly Ti and Ca lines, and an unusually red color arising from strong depression of flux at rest wavelengths <5000 Å. To date, this is the only reported SN showing Ti-dominated spectra. The data aremore » broadly consistent with existing models for the pure detonation of a helium shell around a low-mass CO white dwarf and ''double-detonation'' models that include a secondary detonation of a CO core following a primary detonation in an overlying helium shell.« less

  5. Ignition and growth modeling of detonation reaction zone experiments on single crystals of PETN and HMX

    NASA Astrophysics Data System (ADS)

    White, Bradley W.; Tarver, Craig M.

    2017-01-01

    It has long been known that detonating single crystals of solid explosives have much larger failure diameters than those of heterogeneous charges of the same explosive pressed or cast to 98 - 99% theoretical maximum density (TMD). In 1957, Holland et al. demonstrated that PETN single crystals have failure diameters of about 8 mm, whereas heterogeneous PETN charges have failure diameters of less than 0.5 mm. Recently, Fedorov et al. quantitatively determined nanosecond time resolved detonation reaction zone profiles of single crystals of PETN and HMX by measuring the interface particle velocity histories of the detonating crystals and LiF windows using a PDV system. The measured reaction zone time durations for PETN and HMX single crystal detonations were approximately 100 and 260 nanoseconds, respectively. These experiments provided the necessary data to develop Ignition and Growth (I&G) reactive flow model parameters for the single crystal detonation reaction zones. Using these parameters, the calculated unconfined failure diameter of a PETN single crystal was 7.5 +/- 0.5 mm, close to the 8 mm experimental value. The calculated failure diameter of an unconfined HMX single crystal was 15 +/- 1 mm. The unconfined failure diameter of an HMX single crystal has not yet been determined precisely, but Fedorov et al. detonated 14 mm diameter crystals confined by detonating a HMX-based plastic bonded explosive (PBX) without initially overdriving the HMX crystals.

  6. Non-detonable explosive simulators

    DOEpatents

    Simpson, R.L.; Pruneda, C.O.

    1994-11-01

    A simulator which is chemically equivalent to an explosive, but is not detonable. The simulator has particular use in the training of explosives detecting dogs and calibrating sensitive analytical instruments. The explosive simulants may be fabricated by different techniques, a first involves the use of standard slurry coatings to produce a material with a very high binder to explosive ratio without masking the explosive vapor, and the second involves coating inert beads with thin layers of explosive molecules. 5 figs.

  7. Characterizing the energy output generated by a standard electric detonator using shadowgraph imaging

    NASA Astrophysics Data System (ADS)

    Petr, V.; Lozano, E.

    2017-09-01

    This paper overviews a complete method for the characterization of the explosive energy output from a standard detonator. Measurements of the output of explosives are commonly based upon the detonation parameters of the chemical energy content of the explosive. These quantities provide a correct understanding of the energy stored in an explosive, but they do not provide a direct measure of the different modes in which the energy is released. This optically based technique combines high-speed and ultra-high-speed imaging to characterize the casing fragmentation and the detonator-driven shock load. The procedure presented here could be used as an alternative to current indirect methods—such as the Trauzl lead block test—because of its simplicity, high data accuracy, and minimum demand for test repetition. This technique was applied to experimentally measure air shock expansion versus time and calculating the blast wave energy from the detonation of the high explosive charge inside the detonator. Direct measurements of the shock front geometry provide insight into the physics of the initiation buildup. Because of their geometry, standard detonators show an initial ellipsoidal shock expansion that degenerates into a final spherical wave. This non-uniform shape creates variable blast parameters along the primary blast wave. Additionally, optical measurements are validated using piezoelectric pressure transducers. The energy fraction spent in the acceleration of the metal shell is experimentally measured and correlated with the Gurney model, as well as to several empirical formulations for blasts from fragmenting munitions. The fragment area distribution is also studied using digital particle imaging analysis and correlated with the Mott distribution. Understanding the fragmentation distribution plays a critical role when performing hazard evaluation from these types of devices. In general, this technique allows for characterization of the detonator within 6-8% error

  8. Experimental Measurements of the Chemical Reaction Zone of Detonating Liquid Explosives

    NASA Astrophysics Data System (ADS)

    Bouyer, Viviane; Sheffield, Stephen A.; Dattelbaum, Dana M.; Gustavsen, Richard L.; Stahl, David B.; Doucet, Michel; Decaris, Lionel

    2009-12-01

    We have a joint project between CEA-DAM Le Ripault and Los Alamos National Laboratory (LANL) to study the chemical reaction zone in detonating high explosives using several different laser velocimetry techniques. The short temporal duration of the von Neumann spike and early part of the reaction zone make these measurements difficult. Here, we report results obtained from detonation experiments using VISAR (velocity interferometer system for any reflector) and PDV (photon Doppler velocimetry) methods to measure the particle velocity history at a detonating nitromethane/PMMA interface. Experiments done at CEA were high-explosive-plane-wave initiated and those at LANL were gas-gun-projectile initiated with a detonation run of about 6 charge diameters in all experiments. The experiments had either glass or brass confinement. Excellent agreement of the interface particle velocity measurements at both Laboratories were obtained even though the initiation methods and the velocimetry systems were somewhat different. Some differences were observed in the peak particle velocity because of the ˜2 ns time resolution of the techniques—in all cases the peak was lower than the expected von Neumann spike. This is thought to be because the measurements were not high enough time resolution to resolve the spike.

  9. Effect of the oxygen balance on ignition and detonation properties of liquid explosive mixtures

    NASA Astrophysics Data System (ADS)

    Genetier, M.; Osmont, A.; Baudin, G.

    2014-05-01

    The objective is to compare the ignition and detonation properties of various liquid high explosives having negative up to positive oxygen balance (OB): nitromethane (OB < 0), saccharose and hydrogen peroxide based mixture (quasi nil OB), hydrogen peroxide with more than 90% purity (OB > 0). The decomposition kinetic rates and the equations of state (EOS) for the liquid mixtures and detonation products (DP) are the input data for a detonation model. EOS are theoretically determined using the Woolfolk et al. universal liquid polar shock law and thermochemical computations for DP. The decomposition kinetic rate laws are determined to reproduce the shock to detonation transition for the mixtures submitted to planar plate impacts. Such a model is not sufficient to compute open field explosions. The aerial overpressure is well reproduced in the first few microseconds, however, after it becomes worse at large expansion of the fireball and the impulse is underestimated. The problem of the DP EOS alone is that it takes only the detonation into account, the secondary combustion DP - air is not considered. To solve this problem a secondary combustion model has been developed to take the OB effect into account. The detonation model has been validated on planar plate impact experiments. The secondary combustion parameters were deduced from thermochemical computations. The whole model has been used to predict the effects of the oxygen balance on open air blast effects of spherical charges.

  10. Is red the colour of danger? Testing an implicit red-danger association.

    PubMed

    Pravossoudovitch, Karyn; Cury, Francois; Young, Steve G; Elliot, Andrew J

    2014-01-01

    Research using participant's self-reports has documented a link between red and danger. In this research, we used two different variants of a Stroop word evaluation task to test for the possibility of an implicit red-danger association using carefully controlled colour stimuli (equated on lightness and chroma). Experiment 1, using words as stimuli, yielded strong evidence of a link between red and danger, and weaker evidence of a green-safety association. Experiment 2, using symbols as stimuli, again yielded strong evidence of a link between red and danger; no green effects were observed. The findings were discussed in terms of the power and promise of red in signal communication.

  11. Carbon Condensation during High Explosive Detonation with Time Resolved Small Angle X-ray Scattering

    NASA Astrophysics Data System (ADS)

    Hammons, Joshua; Bagge-Hansen, Michael; Nielsen, Michael; Lauderbach, Lisa; Hodgin, Ralph; Bastea, Sorin; Fried, Larry; May, Chadd; Sinclair, Nicholas; Jensen, Brian; Gustavsen, Rick; Dattelbaum, Dana; Watkins, Erik; Firestone, Millicent; Ilavsky, Jan; van Buuren, Tony; Willey, Trevor; Lawrence Livermore National Lab Collaboration; Los Alamos National Laboratory Collaboration; Washington State University/Advanced Photon Source Team

    Carbon condensation during high-energy detonations occurs under extreme conditions and on very short time scales. Understanding and manipulating soot formation, particularly detonation nanodiamond, has attracted the attention of military, academic and industrial research. An in-situ characterization of these nanoscale phases, during detonation, is highly sought after and presents a formidable challenge even with today's instruments. Using the high flux available with synchrotron X-rays, pink beam small angle X-ray scattering is able to observe the carbon phases during detonation. This experimental approach, though powerful, requires careful consideration and support from other techniques, such as post-mortem TEM, EELS and USAXS. We present a comparative survey of carbon condensation from different CHNO high explosives. This work was performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344.

  12. Is Radiation Dangerous?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lincoln, Don

    Radiation is all around us, ranging from the non-dangerous to the lethal. In this video, Fermilab’s Dr. Don Lincoln talks about radiation and gives you the real deal on whether it is dangerous or not.

  13. Scaling and Multifractality in Road Accidental Distances

    NASA Astrophysics Data System (ADS)

    Qiu, Tian; Wan, Chi; Zou, Xiang-Xiang; Wang, Xiao-Fan

    Accidental distance dynamics is investigated, based on the road accidental data of the Great Britain. The distance distribution of all the districts as an ensemble presents a power law tail, which is different from that of the individual district. A universal distribution is found for different districts, by rescaling the distribution functions of individual districts, which can be well fitted by the Weibull distribution. The male and female drivers behave similarly in the distance distribution. The multifractal characteristic is further studied for the individual district and all the districts as an ensemble, and different behaviors are also revealed between them. The accidental distances of the individual district show a weak multifractality, whereas of all the districts present a strong multifractality when taking them as an ensemble.

  14. Relation Between Spark-Ignition Engine Knock, Detonation Waves, and Autoignition as Shown by High-Speed Photography

    NASA Technical Reports Server (NTRS)

    Miller, Cearcy D

    1946-01-01

    A critical review of literature bearing on the autoignition and detonation-wave theories of spark-ignition engine knock and on the nature of gas vibrations associated with combustion and knock results in the conclusion that neither the autoignition theory nor the detonation-wave theory is an adequate explanation of spark-ignition engine knock. A knock theory is proposed, combining the autoignition and detonation-wave theories, which introduces the idea that the detonation wave develops in autoignited or after-burning gases, and ascribes comparatively low-pitched heavy knocks to autoignition but high-pitched pinging knocks to detonation waves with the possibility of combinations of the two types of knocks. Analysis of five shots of knocking combustion, taken with the NACA high-speed motion-picture camera at the rate of 40,000 photographs per second reveals propagation speeds ranging from 3250 to more than 5500 feet per second. The range of propagation speeds from 3250 to more than 5500 feet per second is held to be considered with the proposed combined theory but not with either the simple autoignition theory or the simple detonation-wave theory.

  15. Course Management Systems for Learning: Beyond Accidental Pedagogy

    ERIC Educational Resources Information Center

    McGee, Patricia; Carmean, Colleen; Jafari, Ali

    2005-01-01

    "Course Management Systems for Learning: Beyond Accidental Pedagogy" is a comprehensive overview of standards, practices and possibilities of course management systems in higher education. "Course Management Systems for Learning: Beyond Accidental Pedagogy" focuses on what the current knowledge is (in best practices, research, standards and…

  16. Equations of state of detonation products: ammonia and methane

    NASA Astrophysics Data System (ADS)

    Lang, John; Dattelbaum, Dana; Goodwin, Peter; Garcia, Daniel; Coe, Joshua; Leiding, Jeffery; Gibson, Lloyd; Bartram, Brian

    2015-06-01

    Ammonia (NH3) and methane (CH4) are two principal product gases resulting from explosives detonation, and the decomposition of other organic materials under shockwave loading (such as foams). Accurate thermodynamic descriptions of these gases are important for understanding the detonation performance of high explosives. However, shock compression data often do not exist for molecular species in the dense gas phase, and are limited in the fluid phase. Here, we present equation of state measurements of elevated initial density ammonia and methane gases dynamically compressed in gas-gun driven plate impact experiments. Pressure and density of the shocked gases on the principal Hugoniot were determined from direct particle velocity and shock wave velocity measurements recorded using optical velocimetry (Photonic Doppler velocimetry (PDV) and VISAR (velocity interferometer system for any reflector)). Streak spectroscopy and 5-color pyrometry were further used to measure the emission from the shocked gases, from which the temperatures of the shocked gases were estimated. Up to 0.07 GPa, ammonia was not observed to ionize, with temperature remaining below 7000 K. These results provide quantitative measurements of the Hugoniot locus for improving equations of state models of detonation products.

  17. Theory of Mach reflection of detonation at glancing incidence

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bdzil, John Bohdan; Short, Mark

    In this paper, we present a theory for Mach reflection of a detonation undergoing glancing incidence reflection off of a rigid wall. Our focus is on condensed-phase explosives, which we describe with a constant adiabatic gamma equation of state and an irreversible and either state-independent or weakly state-dependent reaction rate. We consider two detonation models: (1) the instantaneous reaction heat-release Chapman–Jouguet (CJ) limit and (2) the spatially resolved reaction heat-release Zeldovich–von Neumann–Dmore » $$\\ddot{Ø}$$ring (ZND) limit, where here we only consider that a small fraction of the detonation energy release is spatially resolved (the SRHR limit). We observe a three-shock reflection in the CJ limit case, with a Mach shock that is curved. In addition, we develop an analytical expression for the triple-point track angle as a function of the angle of incidence. For the SRHR model, we observe a smooth lead shock, akin to von Neumann reflection, with no reflected shock in the reaction zone. Only at larger angles of incidence is a three-shock Mach reflection observed.« less

  18. Theory of Mach reflection of detonation at glancing incidence

    DOE PAGES

    Bdzil, John Bohdan; Short, Mark

    2016-12-06

    In this paper, we present a theory for Mach reflection of a detonation undergoing glancing incidence reflection off of a rigid wall. Our focus is on condensed-phase explosives, which we describe with a constant adiabatic gamma equation of state and an irreversible and either state-independent or weakly state-dependent reaction rate. We consider two detonation models: (1) the instantaneous reaction heat-release Chapman–Jouguet (CJ) limit and (2) the spatially resolved reaction heat-release Zeldovich–von Neumann–Dmore » $$\\ddot{Ø}$$ring (ZND) limit, where here we only consider that a small fraction of the detonation energy release is spatially resolved (the SRHR limit). We observe a three-shock reflection in the CJ limit case, with a Mach shock that is curved. In addition, we develop an analytical expression for the triple-point track angle as a function of the angle of incidence. For the SRHR model, we observe a smooth lead shock, akin to von Neumann reflection, with no reflected shock in the reaction zone. Only at larger angles of incidence is a three-shock Mach reflection observed.« less

  19. A Case for Basic Rotating Detonation Engine Research

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.

    2016-01-01

    A brief review is provided covering the benefits to air breathing and chemical rocket propulsion found from pressure gain combustion in general, and rotating detonation in particular. Challenges are also identified.

  20. Performance Impact of Deflagration to Detonation Transition Enhancing Obstacles

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.; Schauer, Frederick; Hopper, David

    2012-01-01

    A sub-model is developed to account for the drag and heat transfer enhancement resulting from deflagration-to-detonation (DDT) inducing obstacles commonly used in pulse detonation engines (PDE). The sub-model is incorporated as a source term in a time-accurate, quasi-onedimensional, CFD-based PDE simulation. The simulation and sub-model are then validated through comparison with a particular experiment in which limited DDT obstacle parameters were varied. The simulation is then used to examine the relative contributions from drag and heat transfer to the reduced thrust which is observed. It is found that heat transfer is far more significant than aerodynamic drag in this particular experiment.

  1. A glove-likeability study of specially-treated gloves in the detonator manufacturing and packaging industry

    DOE PAGES

    Cournoyer, Michael E.; Lawton, Cindy M.; Lounsbury, James B.; ...

    2016-03-22

    We use hand gloves (hereafter referred to as gloves) in the detonator manufacturing and packaging operations. As part of a process improvement program, new glove formulations have been considered that lower the overall risk of detonator operations by reducing ergonomic injury factors. Gloves with a specially treated surface for extra grip and control are now commercially available and have been recommended for use in detonator operations. A Glove Likeability Study demonstrated that detonator manufacturing and packaging workers prefer gloves with a specially treated surface over currently approved gloves made from latex and nitrile formulations. Glove material compatibility tests indicate thatmore » the recommended gloves are as compatible if not more compatible as the currently approved gloves for working with secondary explosives. Thus, these gloves with a specially treated surface for extra grip and control are now available for tasks where sensitivity and fingertip control are crucial. Replacement of the current gloves with gloves with a specially treated surface improves the safety configuration of detonator manufacturing and packaging operations.« less

  2. A glove-likeability study of specially-treated gloves in the detonator manufacturing and packaging industry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cournoyer, Michael E.; Lawton, Cindy M.; Lounsbury, James B.

    We use hand gloves (hereafter referred to as gloves) in the detonator manufacturing and packaging operations. As part of a process improvement program, new glove formulations have been considered that lower the overall risk of detonator operations by reducing ergonomic injury factors. Gloves with a specially treated surface for extra grip and control are now commercially available and have been recommended for use in detonator operations. A Glove Likeability Study demonstrated that detonator manufacturing and packaging workers prefer gloves with a specially treated surface over currently approved gloves made from latex and nitrile formulations. Glove material compatibility tests indicate thatmore » the recommended gloves are as compatible if not more compatible as the currently approved gloves for working with secondary explosives. Thus, these gloves with a specially treated surface for extra grip and control are now available for tasks where sensitivity and fingertip control are crucial. Replacement of the current gloves with gloves with a specially treated surface improves the safety configuration of detonator manufacturing and packaging operations.« less

  3. Imaging Detonations of Explosives

    DTIC Science & Technology

    2016-04-01

    made using a full-color single-camera pyrometer where wavelength resolution is achieved using the Bayer-type mask covering the sensor chip17 and a...many CHNO- based explosives (e.g., TNT [C7H5N3O6], the formulation C-4 [92% RDX, C3H6N6O6]), hot detonation products are mainly soot and permanent...unreferenced). Essentially, 2 light sensors (cameras), each filtered over a narrow wavelength region, observe an event over the same line of sight. The

  4. The effect of detonation wave incidence angle on the acceleration of flyers by explosives heavily laden with inert additives

    NASA Astrophysics Data System (ADS)

    Loiseau, Jason; Georges, William; Frost, David L.; Higgins, Andrew J.

    2017-01-01

    The incidence angle of a detonation wave in a conventional high explosive influences the acceleration and terminal velocity of a metal flyer by increasing the magnitude of the material velocity imparted by the transmitted shock wave as the detonation is tilted towards normal loading. For non-ideal explosives heavily loaded with inert additives, the detonation velocity is typically subsonic relative to the flyer sound speed, leading to shockless accelerations when the detonation is grazing. Further, in a grazing detonation the particles are initially accelerated in the direction of the detonation and only gain velocity normal to the initial orientation of the flyer at later times due to aerodynamic drag as the detonation products expand. If the detonation wave in a non-ideal explosive instead strikes the flyer at normal incidence, a shock is transmitted into the flyer and the first interaction between the particle additives and the flyer occurs due to the imparted material velocity from the passage of the detonation wave. Consequently, the effect of incidence angle and additive properties may play a more prominent role in the flyer acceleration. In the present study we experimentally compared normal detonation loadings to grazing loadings using a 3-mm-thick aluminum slapper to impact-initiate a planar detonation wave in non-ideal explosive-particle admixtures, which subsequently accelerated a second 6.4-mm-thick flyer. Flyer acceleration was measured with heterodyne laser velocimetry (PDV). The explosive mixtures considered were packed beds of glass or steel particles of varying sizes saturated with sensitized nitromethane, and gelled nitromethane mixed with glass microballoons. Results showed that the primary parameter controlling changes in flyer velocity was the presence of a transmitted shock, with additive density and particle size playing only secondary roles. These results are similar to the grazing detonation experiments, however under normal loading the

  5. The Accidental Transgressor: Morally Relevant Theory of Mind

    PubMed Central

    Killen, Melanie; Mulvey, Kelly Lynn; Richardson, Cameron; Jampol, Noah

    2014-01-01

    To test young children’s false belief theory of mind in a morally relevant context, two experiments were conducted. In Experiment 1, children (N = 162) at 3.5, 5.5, and 7.5 years of age were administered 3 tasks: prototypic moral transgression task, false belief theory of mind task (ToM), and an “accidental transgressor” task, which measured a morally relevant false belief theory of mind (MoToM). Children who did not pass false belief ToM were more likely to attribute negative intentions to an accidental transgressor than children who passed false belief ToM, and to use moral reasons when blaming the accidental transgressor. In Experiment 2, children (N = 46) who did not pass false belief ToM viewed it as more acceptable to punish the accidental transgressor than did participants who passed false belief ToM. Findings are discussed in light of research on the emergence of moral judgment and theory of mind. PMID:21377148

  6. Fine Tuning the CJ Detonation Speed of a High Explosive products Equation of State

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Menikoff, Ralph

    For high explosive (HE) simulations, inaccuracies of a per cent or two in the detonation wave speed can result from not suficiently resolving the reaction zone width or from small inaccuracies in calibrating the products equation of state (EOS) or from variation of HE lots. More accurate detonation speeds can be obtained by ne tuning the equation of state to compensate. Here we show that two simple EOS transformations can be used to adjust the CJ detonation speed by a couple of per cent with minimal effect on the CJ release isentrope. The two transformations are (1) a shift inmore » the energy origin and (2) a linear scaling of the speci c volume. The effectiveness of the transformations is demonstrated with simulations of the cylinder test for PBX 9502 starting with a products EOS for which the CJ detonation speed is 1 per cent too low.« less

  7. Measurement of Front Curvature and Detonation Velocity for a Nonideal Heterogeneous Explosive in Axisymmetric and Two-Dimensional Geometries

    NASA Astrophysics Data System (ADS)

    Higgins, Andrew

    2009-06-01

    Detonation in a heterogeneous explosive with a relatively sparse concentration of reaction centers (``hot spots'') is investigated experimentally. The explosive system considered is nitromethane gelled with PMMA and with glass microballoons (GMB's) in suspension. The detonation velocity is measured as a function of the characteristic charge dimension (diameter or thickness) in both axisymmetric and two-dimensional planar geometries. The use of a unique, annular charge geometry (with the diameter of the annulus much greater than the annular gap thickness) permits quasi-two-dimensional detonations to be observed without undesirable lateral rarefactions that result from a finite aspect ratio. The detonation front curvature is also measured directly using an electronic streak camera. The results confirm the prior findings of Gois et al. (1996) which showed that, for a low concentration of GMB's, detonation propagation does not exhibit the expected 2:1 scaling from axisymmetric to planar geometries. This reinforces the idea that detonation in highly nonideal explosives is not governed exclusively by front curvature.

  8. Investigation of the effect of the ejector on the performance of the pulse detonation engine nozzle extension

    NASA Astrophysics Data System (ADS)

    Korobov, A. E.; Golovastov, S. V.

    2015-11-01

    Influence of an ejector nozzle extension on gas flow at a pulse detonation engine was investigated numerically and experimentally. Detonation formation was organized in stoichiometric hydrogen-oxygen mixture in cylindrical detonation tube. Cylindrical ejector was constructed and mounted at the open end of the tube. Thrust, air consumption and parameters of the detonation were measured in single and multiple regimes of operation. Axisymmetric model was used in numerical investigation. Equations of Navies-Stokes were solved using a finite-difference scheme Roe of second order of accuracy. Initial conditions were estimated on a base of experimental data. Numerical results were validated with experiments data.

  9. A Kinetic Approach to Propagation and Stability of Detonation Waves

    NASA Astrophysics Data System (ADS)

    Monaco, R.; Bianchi, M. Pandolfi; Soares, A. J.

    2008-12-01

    The problem of the steady propagation and linear stability of a detonation wave is formulated in the kinetic frame for a quaternary gas mixture in which a reversible bimolecular reaction takes place. The reactive Euler equations and related Rankine-Hugoniot conditions are deduced from the mesoscopic description of the process. The steady propagation problem is solved for a Zeldovich, von Neuman and Doering (ZND) wave, providing the detonation profiles and the wave thickness for different overdrive degrees. The one-dimensional stability of such detonation wave is then studied in terms of an initial value problem coupled with an acoustic radiation condition at the equilibrium final state. The stability equations and their initial data are deduced from the linearized reactive Euler equations and related Rankine-Hugoniot conditions through a normal mode analysis referred to the complex disturbances of the steady state variables. Some numerical simulations for an elementary reaction of the hydrogen-oxygen chain are proposed in order to describe the time and space evolution of the instabilities induced by the shock front perturbation.

  10. Analysis of sheltering and evacuation strategies for a Chicago nuclear detonation scenario.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yoshimura, Ann S.; Brandt, Larry D.

    2011-09-01

    Development of an effective strategy for shelter and evacuation is among the most important planning tasks in preparation for response to a low yield, nuclear detonation in an urban area. Extensive studies have been performed and guidance published that highlight the key principles for saving lives following such an event. However, region-specific data are important in the planning process as well. This study examines some of the unique regional factors that impact planning for a 10 kt detonation in Chicago. The work utilizes a single scenario to examine regional impacts as well as the shelter-evacuate decision alternatives at selected exemplarymore » points. For many Chicago neighborhoods, the excellent assessed shelter quality available make shelter-in-place or selective transit to a nearby shelter a compelling post-detonation strategy.« less

  11. Shock-wave initiation of heated plastified TATB detonation

    NASA Astrophysics Data System (ADS)

    Kuzmitsky, Igor; Rudenko, Vladimir; Gatilov, Leonid; Koshelev, Alexandr

    1999-06-01

    Explosive, plastified TATB, attracts attention with its weak sensitivity to shock loads and high temperature stability ( Pthreshold ? 6.5 GPa and Tcrit ? 250 0Q). However, at its cooling to T 250 0Q plastified TATB becomes as sensitive to shock load as octogen base HE: the excitation threshold reduces down to Pthreshold 2.0 GPa. The main physical reason for the HE sensitivity change is reduction in density at heating and, hence, higher porosity of the product (approximately from 2Moreover, increasing temperature increases the growth rate of uhotf spots which additionally increases the shock sensitivity [1]. Heated TATB experiments are also conducted at VNIIEF. The detonation excitation was computed within 1D program system MAG using EOS JWL for HE and EP and LLNL kinetics [1,2,3]. Early successful results of using this kinetics to predict detonation excitation in heated plastified TATB in VNIIEF experiments with short and long loading pulses are presented. Parameters of the chemical zone of the stationary detonation wave in plastified TATB (LX-17) were computed with the data from [1]. Parameters Heated In shell Cooled Unheated ?0 , g/cm3 1.70 1.81 1.84 1.905 D , km/s 7.982 7.764 7.686 7.517 PN, GPa 45.4 45.8 35.7 32.9 PJ, GPa 27.0 27.3 27.2 26.4 ?x , mm 0.504 0.843 1.041 2.912 ?t , ns 63.1 108.6 135.5 387.4 [1] Effect of Confinement and Thermal Cycling on the Shock Initiation of LX-17 P.A. Urtiew, C.M. Tarver, J.L. Maienschein, and W.C. Tao. LLNL. Combustion and Flame 105: 43-53 (1996) [2] C.M. Tarver, P.A. Urtiew and W.C. Tao (LLNL) Effects of tandem and colliding shock waves on initiation of triaminotrinitrobenzene. J.Appl. Phys. 78(5), September 1995 [3] Craig M. Tarver, John W. Kury and R. Don Breithaupt Detonation waves in triaminotrinitrobenzene J. Appl. Phys. 82(8) , 15 October 1997.

  12. Structural evolution of detonation carbon in Composition B-3 by X-ray scattering

    NASA Astrophysics Data System (ADS)

    Firestone, Millicent; Dattelbaum, Dana; Gustavsen, Richard; Podlesak, David; Jensen, Brian; Watkins, Erik; Ringstrand, Bryan; Willey, Trevor; Lauderbach, Lisa; Hodgin, Ralph; Bagge-Hansen, Michael; van Buuren, Tony; Graber, Tim

    2015-06-01

    High explosive detonation products are primarily composed of solid carbon products. Prior electron microscopy studies have revealed that detonation carbon can contain a variety of unique carbon particles possessing novel morphologies, including core-shell, onions and ribbons. Despite these observations very little is known on what conditions leads to the production of novel carbon nanoparticles. A fuller understanding on conditions that generate such novel carbon materials would greatly benefit from time-resolved studies that probe particle formation and evolution through and beyond the chemical reaction zone. Here, we report initial experiments employing time-resolved X-ray scattering measurements to monitor the detonation carbon products formed from Composition B-3 (60% TNT, 40% RDX). Time-resolved SAXS (TRSAXS) studies were performed at the Dynamic Compression Sector (DCS, Sector 35) at the Advanced Photon Source (Argonne National Laboratory). In-situ formation of solid carbon behind the detonation front was probed on the nanosecond time scale. Analysis of the scattering patterns using model independent methods (Porod and Guinier) yielded insights into particle morphology and interfaces.

  13. Propagation of detonation wave in hydrogen-air mixture in channels with sound-absorbing surfaces

    NASA Astrophysics Data System (ADS)

    Bivol, G. Yu.; Golovastov, S. V.; Golub, V. V.

    2015-12-01

    The possibility of using sound-absorbing surfaces for attenuating the intensity of detonation waves propagating in hydrogen-air mixtures has been experimentally studied in a cylindrical detonation tube open at one end, with an explosive initiated by spark discharge at the closed end. Sound-absorbing elements were made of an acoustic-grade foamed rubber with density of 0.035 g/cm3 containing open pores with an average diameter of 0.5 mm. The degree of attenuation of the detonation wave front velocity was determined as dependent on the volume fraction of hydrogen in the gas mixture.

  14. Modeling of Multi-Tube Pulse Detonation Engine Operation

    NASA Technical Reports Server (NTRS)

    Ebrahimi, Houshang B.; Mohanraj, Rajendran; Merkle, Charles L.

    2001-01-01

    The present paper explores some preliminary issues concerning the operational characteristics of multiple-tube pulsed detonation engines (PDEs). The study is based on a two-dimensional analysis of the first-pulse operation of two detonation tubes exhausting through a common nozzle. Computations are first performed to assess isolated tube behavior followed by results for multi-tube flow phenomena. The computations are based on an eight-species, finite-rate transient flow-field model. The results serve as an important precursor to understanding appropriate propellant fill procedures and shock wave propagation in multi-tube, multi-dimensional simulations. Differences in behavior between single and multi-tube PDE models are discussed, The influence of multi-tube geometry and the preferred times for injecting the fresh propellant mixture during multi-tube PDE operation are studied.

  15. Far Field Modeling Methods For Characterizing Surface Detonations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Garrett, A.

    2015-10-08

    Savannah River National Laboratory (SRNL) analyzed particle samples collected during experiments that were designed to replicate tests of nuclear weapons components that involve detonation of high explosives (HE). SRNL collected the particle samples in the HE debris cloud using innovative rocket propelled samplers. SRNL used scanning electronic microscopy to determine the elemental constituents of the particles and their size distributions. Depleted uranium composed about 7% of the particle contents. SRNL used the particle size distributions and elemental composition to perform transport calculations that indicate in many terrains and atmospheric conditions the uranium bearing particles will be transported long distances downwind.more » This research established that HE tests specific to nuclear proliferation should be detectable at long downwind distances by sampling airborne particles created by the test detonations.« less

  16. Detonation models of fast combustion waves in nanoscale Al-MoO3 bulk powder media

    NASA Astrophysics Data System (ADS)

    Shaw, Benjamin D.; Pantoya, Michelle L.; Dikici, Birce

    2013-02-01

    The combustion of nanometric aluminum (Al) powder with an oxidiser such as molybdenum trioxide (MoO3) is studied analytically. This study focuses on detonation wave models and a Chapman-Jouget detonation model provides reasonable agreement with experimentally-observed wave speeds provided that multiphase equilibrium sound speeds are applied at the downstream edge of the detonation wave. The results indicate that equilibrium sound speeds of multiphase mixtures can play a critical role in determining speeds of fast combustion waves in nanoscale Al-MoO3 powder mixtures.

  17. Photographic investigation into the mechanism of combustion in irregular detonation waves

    NASA Astrophysics Data System (ADS)

    Kiyanda, C. B.; Higgins, A. J.

    2013-03-01

    Irregular detonations are supersonic combustion waves in which the inherent multi-dimensional structure is highly variable. In such waves, it is questionable whether auto-ignition induced by shock compression is the only combustion mechanism present. Through the use of high-speed schlieren and self-emitted light photography, the velocity of the different components of detonation waves in a {{ CH}}_4+2{ O}_2 mixture is analyzed. The observed burn-out of unreacted pockets is hypothesized to be due to turbulent combustion.

  18. Advanced Warheads Concepts: An Advanced Equation of State for Overdriven Detonation

    DTIC Science & Technology

    1991-05-01

    equation of state (Jones-Wilkens Lee-Baker ( JWLB )] for high explosive detonation products. JWLB is suitable for overdriven detonation and material...In order to achieve a suitable equation of state, an appropriate equation of state form ( JWLB ) was derived. A standard explosive (octol 75/25) was...resulting equation of slate form, named Jones-Wilkens-Lcc-Baker ( JWLB ), is as follows: L ’L RiVJ .RiV+AJE + C(1.W(oH-l) -RoV X-JA^VC’V + O) The

  19. Detonation mode and frequency analysis under high loss conditions for stoichiometric propane-oxygen

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jackson, Scott I.; Lee, Bok Jik; Shepherd, Joseph E.

    In this paper, the propagation characteristics of galloping detonations were quantified with a high-time-resolution velocity diagnostic. Combustion waves were initiated in 30-m lengths of 4.1-mm inner diameter transparent tubing filled with stoichiometric propane–oxygen mixtures. Chemiluminescence from the resulting waves was imaged to determine the luminous wave front position and velocity every 83.3 μ. As the mixture initial pressure was decreased from 20 to 7 kPa, the wave was observed to become increasingly unsteady and transition from steady detonation to a galloping detonation. While wave velocities averaged over the full tube length smoothly decreased with initial pressure down to half ofmore » the Chapman–Jouguet detonation velocity (D CJ) at the quenching limit, the actual propagation mechanism was seen to be a galloping wave with a cycle period of approximately 1.0 ms, corresponding to a cycle length of 1.3–2.0 m or 317–488 tube diameters depending on the average wave speed. The long test section length of 7300 tube diameters allowed observation of up to 20 galloping cycles, allowing for statistical analysis of the wave dynamics. In the galloping regime, a bimodal velocity distribution was observed with peaks centered near 0.4 D CJ and 0.95 D CJ. Decreasing initial pressure increasingly favored the low velocity mode. Galloping frequencies ranged from 0.8 to 1.0 kHz and were insensitive to initial mixture pressure. Wave deflagration-to-detonation transition and detonation failure trajectories were found to be repeatable in a given test and also across different initial mixture pressures. The temporal duration of wave dwell at the low and high velocity modes during galloping was also quantified. It was found that the mean wave dwell duration in the low velocity mode was a weak function of initial mixture pressure, while the mean dwell time in the high velocity mode depended exponentially on initial mixture pressure. Analysis of the velocity

  20. Detonation mode and frequency analysis under high loss conditions for stoichiometric propane-oxygen

    DOE PAGES

    Jackson, Scott I.; Lee, Bok Jik; Shepherd, Joseph E.

    2016-03-24

    In this paper, the propagation characteristics of galloping detonations were quantified with a high-time-resolution velocity diagnostic. Combustion waves were initiated in 30-m lengths of 4.1-mm inner diameter transparent tubing filled with stoichiometric propane–oxygen mixtures. Chemiluminescence from the resulting waves was imaged to determine the luminous wave front position and velocity every 83.3 μ. As the mixture initial pressure was decreased from 20 to 7 kPa, the wave was observed to become increasingly unsteady and transition from steady detonation to a galloping detonation. While wave velocities averaged over the full tube length smoothly decreased with initial pressure down to half ofmore » the Chapman–Jouguet detonation velocity (D CJ) at the quenching limit, the actual propagation mechanism was seen to be a galloping wave with a cycle period of approximately 1.0 ms, corresponding to a cycle length of 1.3–2.0 m or 317–488 tube diameters depending on the average wave speed. The long test section length of 7300 tube diameters allowed observation of up to 20 galloping cycles, allowing for statistical analysis of the wave dynamics. In the galloping regime, a bimodal velocity distribution was observed with peaks centered near 0.4 D CJ and 0.95 D CJ. Decreasing initial pressure increasingly favored the low velocity mode. Galloping frequencies ranged from 0.8 to 1.0 kHz and were insensitive to initial mixture pressure. Wave deflagration-to-detonation transition and detonation failure trajectories were found to be repeatable in a given test and also across different initial mixture pressures. The temporal duration of wave dwell at the low and high velocity modes during galloping was also quantified. It was found that the mean wave dwell duration in the low velocity mode was a weak function of initial mixture pressure, while the mean dwell time in the high velocity mode depended exponentially on initial mixture pressure. Analysis of the velocity

  1. Double-HE-Layer Detonation-Confinement Sandwich Tests: The Effect of Slow-Layer Density

    NASA Astrophysics Data System (ADS)

    Hill, Larry

    2013-06-01

    Over a period of several years, we have explored the phenomenon in which slabs of high explosives (HEs) with differing detonation speeds are joined along one of their faces. Both are initiated (usually by a line-wave generator) at one edge. If there were no coupling between the layers, the detonation in the fast HE would outrun that in the slow HE. In reality, the detonation in the fast HE transmits an oblique shock into the slow HE, the phase speed of which is equal to the speed of the fast HE. This has one of two effects depending on the particulars. First, the oblique shock transmitted to the slow HE can pre-shock and deaden it, extinguishing the detonation in the slow HE. Second, the oblique shock can transversely initiate the slow layer, pulling its detonation along at the fast HE speed. When the second occurs, it does so at the ``penalty'' of a nominally dead layer, which forms in the slow HE adjacent to the material interface. We present the results of tests in which the fast layer was 3-mm-thick PBX 9501 (95 wt% HMX), and the slow layer was 8-mm-thick PBX 9502 (95 wt% TATB). The purpose was to observe the effect of slow layer density on the ``dead'' layer thickness. Very little effect was observed across the nominal PBX 9502 density range, 1.885-1.895 g/cc.

  2. Outdoor dissolution of detonation residues of three insensitive munitions (IM) formulations.

    PubMed

    Taylor, Susan; Dontsova, Katerina; Walsh, Marianne E; Walsh, Michael R

    2015-09-01

    We seek to understand the environmental fate of three new insensitive munitions, explosive formulations developed to reduce the incidence of unintended detonations. To this end, we measured the size distribution of residues from low order detonations of IMX 101, IMX 104, and PAX 21-filled munitions and are studying how these three formulations weather and dissolve outdoors. The largest pieces collected from the detonations were centimeter-sized and we studied 12 of these in the outdoors test. We found that the particles break easily and that the dissolution of 2,4-dinitroanisole (DNAN) is quasi-linear as a function of water volume. DNAN is the matrix and the least soluble major constituent of the three formulations. We used DNAN's linear dissolution rate to estimate the life span of the pieces. Particles ranging in mass from 0.3 to 3.5 g will completely dissolve in 3-21 years given 100 cm y(-1) precipitation rates. Published by Elsevier Ltd.

  3. Cable Discharge System for fundamental detonator studies

    NASA Technical Reports Server (NTRS)

    Peevy, Gregg R.; Barnhart, Steven G.; Brigham, William P.

    1994-01-01

    Sandia National Laboratories has recently completed the modification and installation of a cable discharge system (CDS) which will be used to study the physics of exploding bridgewire (EBW) detonators and exploding foil initiators (EFI or slapper). Of primary interest are the burst characteristics of these devices when subjected to the constant current pulse delivered by this system. The burst process involves the heating of the bridge material to a conductive plasma and is essential in describing the electrical properties of the bridgewire foil for use in diagnostics or computer models. The CDS described herein is capable of delivering up to an 8000 A pulse of 3 micron duration. Experiments conducted with the CDS to characterize the EBW and EFI burst behavior are also described. In addition, the CDS simultaneous VISAR capability permits updating the EFI electrical Gurney analysis parameters used in our computer simulation codes. Examples of CDS generated data for a typical EFI and EBW detonator are provided.

  4. Pulse Detonation Engines for High Speed Flight

    NASA Technical Reports Server (NTRS)

    Povinelli, Louis A.

    2002-01-01

    Revolutionary concepts in propulsion are required in order to achieve high-speed cruise capability in the atmosphere and for low cost reliable systems for earth to orbit missions. One of the advanced concepts under study is the air-breathing pulse detonation engine. Additional work remains in order to establish the role and performance of a PDE in flight applications, either as a stand-alone device or as part of a combined cycle system. In this paper, we shall offer a few remarks on some of these remaining issues, i.e., combined cycle systems, nozzles and exhaust systems and thrust per unit frontal area limitations. Currently, an intensive experimental and numerical effort is underway in order to quantify the propulsion performance characteristics of this device. In this paper, we shall highlight our recent efforts to elucidate the propulsion potential of pulse detonation engines and their possible application to high-speed or hypersonic systems.

  5. Measurement of carbon condensation using small-angle x-ray scattering during detonation of the high explosive hexanitrostilbene

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bagge-Hansen, M.; Lauderbach, L. M.; Hodgin, R.

    2015-06-24

    The dynamics of carboncondensation in detonating high explosives remains controversial. Detonation model validation requires data for processes occurring at nanometer length scales on time scales ranging from nanoseconds to microseconds. A new detonation endstation has been commissioned to acquire and provide time-resolved small-angle x-ray scattering (SAXS) from detonating explosives. Hexanitrostilbene (HNS) was selected as the first to investigate due to its ease of initiation using exploding foils and flyers, vacuum compatibility, high thermal stability, and stoichiometric carbon abundance that produces high carbon condensate yields. The SAXS data during detonation, collected with 300 ns time resolution, provide unprecedented signal fidelity overmore » a broad q-range. This fidelity permits the first analysis of both the Guinier and Porod/power-law regions of the scattering profile during detonation, which contains information about the size and morphology of the resultant carbon condensate nanoparticles. To bolster confidence in these data, the scattering angle and intensity were additionally cross-referenced with a separate, highly calibrated SAXS beamline. The data show that HNS produces carbon particles with a radius of gyration of 2.7 nm in less than 400 ns after the detonation front has passed, and this size and morphology are constant over the next several microseconds. These data directly contradict previous pioneering work on RDX/TNT mixtures and TATB, where observations indicate significant particle growth (50% or more) continues over several microseconds. As a result, the power-law slope is about –3, which is consistent with a complex disordered, irregular, or folded sp 2 sub-arrangement within a relatively monodisperse structure possessing radius of gyration of 2.7 nm after the detonation of HNS.« less

  6. Laws of attenuation of axially symmetrical shock waves in shells of detonating extended charges

    NASA Astrophysics Data System (ADS)

    Kuzin, E. N.; Zagarskih, V. I.; Efanov, V. V.

    2016-12-01

    The procedure and algorithms are proposed for an experimental and computational estimate of attenuation of radial shock waves occurring in shells of detonating extended charges during glancing detonation of their ammunition (explosives). Based on results of experimental, the semiempirical dependence characterizing the attenuation law for such waves is obtained.

  7. On investigation of optical and spin properties of NV centers in aggregates of detonation nanodiamonds

    NASA Astrophysics Data System (ADS)

    Bolshedvorskii, S. V.; Vorobyov, V. V.; Soshenko, V. V.; Zeleneev, A.; Sorokin, V. N.; Smolyaninov, A. N.; Akimov, A. V.

    2018-02-01

    Quickly developing application of nitrogen-vacancy color centers in diamond sets demands on cheap and high optical and spin properties nanodiamonds. Among other types, detonation nanodiamonds are easiest for production but often show no NV color centers inside. In this work we show, that aggregates of detonation nanodiamonds could be as good, or even better in terms of brightness and spin properties, than more expensive single crystal nanodiamonds. This way aggregates of detonation nanodiamonds could efficiently serve as cheap and bright source of single photon radiation or sensitive element of biocompatible sensor.

  8. Controlling the position of a stabilized detonation wave in a supersonic gas mixture flow in a plane channel

    NASA Astrophysics Data System (ADS)

    Levin, V. A.; Zhuravskaya, T. A.

    2017-03-01

    Stabilization of a detonation wave in a stoichiometric hydrogen-air mixture flowing at a supersonic velocity into a plane symmetric channel with constriction has been studied in the framework of a detailed kinetic mechanism of the chemical interaction. Conditions ensuring the formation of a thrust-producing f low with a stabilized detonation wave in the channel are determined. The inf luence of the inf low Mach number, dustiness of the combustible gas mixture supplied to the channel, and output cross-section size on the position of a stabilized detonation wave in the f low has been analyzed with a view to increasing the efficiency of detonation combustion of the gas mixture. It is established that thrust-producing flow with a stabilized detonation wave can be formed in the channel without any energy consumption.

  9. The Universal Role of Tubulence in the Propagation of Strong Shocks and Detonation Waves

    NASA Astrophysics Data System (ADS)

    Lee, John H.

    2001-06-01

    The passage of a strong shock wave usually results in irreversible physical and chemical changes in the medium. If the chemical reactions are sufficiently exothermic, the shock wave can be self-propagating, i.e., sustained by the chemical energy release via the expansion work of the reaction products. Although shocks and detonations can be globally stable and propagate at constant velocities (in the direction of motion), their structure may be highly unstable and exhibit large hydrodynamic fluctuations, i.e., turbulence. Recent investigations on plastic deformation of polycrystalline material behind shock waves have revealed particle velocity dispersion at the mesoscopic level, a result of vortical rotational motion similar to that of turbulent fluid flows at high Reynolds number.1 Strong ionizing shocks in noble gases2, as well as dissociating shock waves in carbon dioxide,3 also demonstrate a turbulent density fluctuation in the non-equilibrium shock transition zone. Perhaps the most thoroughly investigated unstable structure is that of detonation waves in gaseous explosives.4 Detonation waves in liquid explosives such as nitromethane also take on similar unstable structure as gaseous detonations.5 There are also indications that detonations in solid explosives have a similar unsteady structure under certain conditions. Thus, it appears that it is more of a rule than an exception that the structure of strong shocks and detonations are unstable and exhibit turbulent-like fluctuations as improved diagnostics now permit us to look more closely at the meso- and micro-levels. Increasing attention is now devoted to the understanding of the shock waves at the micro-scale level in recent years. This is motivated by the need to formulate physical and chemical models that contain the correct physics capable of describing quantitatively the shock transition process. It should be noted that, in spite of its unstable 3-D structure, the steady 1-D conservation laws (in the

  10. Overview of Pulse Detonation Propulsion Technology

    DTIC Science & Technology

    2001-04-01

    PROPULSION TECHNOLOGY M. L. Coleman CHEMICAL PROPULSION INFORMATION AGENCY THE JOHNS HOPKINS UNIVERSITY. WHITING SCHOOL OF ENGINEERING -COLUMBIA...U. 20 R. Santoro, "Advanced Propulsion Research: A Focus of the Penn State Propulsion Engineering Research Center," Chemical Propulsion Information...Detonation Engine ," AIAA 95-3155 (July 1995), U-A. NASA Marshall Space Flight Center Space Transportation Day 2000 Presentation Material, Advance Chemical

  11. Detonation Velocity Measurements from a Digital High-speed Rotating-mirror Framing Camera

    DTIC Science & Technology

    2012-09-01

    information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 2...The intense light emission produced throughout the energetic material detonation process, however, suggests the alternative use of optical measurement...edge, figure 1). As previously stated, the detonation wave position was typically measured as a result of its light emission . Here, however, it was

  12. Accidental poisoning with "Chinese chalk".

    PubMed

    Martínez-Navarrete, Juan; Loria-Castellanos, Jorge; Nava-Ocampo, Alejandro A

    2008-04-01

    We present a 1.5-year old, 11 kg, female infant with a history of bronchial hyper-responsiveness who accidentally ingested half of a "Chinese chalk". A day later, the infant showed vomiting, cough, fever, drowsiness, and irritability and her clinical conditions progressively worsened. She was admitted to the emergency department with cough, respiratory distress, and hepatomegaly. It has been reported that the chalk may contain deltamethrin and cypermethrin. The patient was successfully treated with supportive therapy. This report identifies "Chinese chalk" as a potential source of accidental poisoning in children and should be considered as part of the differential diagnoses in the emergency rooms since poisoning with these compounds may be misdiagnosed as organophosphate poisoning due to the presentation of similar symptoms.

  13. Development of a Detonation Diffuser

    DTIC Science & Technology

    2014-03-27

    detonation frequency is adjustable from 8 Hz to 40 Hz, and the ignition can be set to operate in “burst mode” firing for a predetermined number of cycles... resistance were tried, but the strain on the windows caused the coating to fracture. Without a scratch- resistant coating, the windows regularly suffered... abrasion from the Shock wave Strain waves 35 test articles. The heat from local explosions did burn away a small amount of the window surface

  14. Impact of Dissociation and Sensible Heat Release on Pulse Detonation and Gas Turbine Engine Performance

    NASA Technical Reports Server (NTRS)

    Povinelli, Louis A.

    2001-01-01

    A thermodynamic cycle analysis of the effect of sensible heat release on the relative performance of pulse detonation and gas turbine engines is presented. Dissociation losses in the PDE (Pulse Detonation Engine) are found to cause a substantial decrease in engine performance parameters.

  15. Numerical and Analytical Assessment of a Coupled Rotating Detonation Engine and Turbine Experiment

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.; Naples, Andrew

    2017-01-01

    An analysis is presented of an experimental rig comprising a rotating detonation engine (RDE) with bypass ejector flow coupled to a downstream turbine. The analysis used a validated computational fluid dynamics RDE simulation combined with straightforward algebraic mixing equations for the bypass flow. The objectives of the analysis were to supplement and interpret the necessarily sparse measurements from the rig, and to assess the performance of the RDE itself, which was not instrumented in this installation. The analysis is seen to agree reasonably well with available data. It shows that the RDE is operating in an unusual fashion, with subsonic flow throughout the exhaust plane. The detonation event itself is producing a total pressure rise relative to the pre-detonative pressure; however, the length of the device and the substantial flow restriction at the inlet yield an overall pressure loss. This is not surprising since the objective of the rig test was primarily aimed at investigating RDE turbine interactions, and not on performance optimization. Furthermore, the RDE was designed for fundamental detonation studies and not performance. Nevertheless, the analysis indicates that with some small alterations to the design, an RDE with an overall pressure rise is possible.

  16. Examination of Wave Speed in Rotating Detonation Engines Using Simplified Computational Fluid Dynamics

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.

    2018-01-01

    A simplified, two-dimensional, computational fluid dynamic (CFD) simulation, with a reactive Euler solver is used to examine possible causes for the low detonation wave propagation speeds that are consistently observed in air breathing rotating detonation engine (RDE) experiments. Intense, small-scale turbulence is proposed as the primary mechanism. While the solver cannot model this turbulence, it can be used to examine the most likely, and profound effect of turbulence. That is a substantial enlargement of the reaction zone, or equivalently, an effective reduction in the chemical reaction rate. It is demonstrated that in the unique flowfield of the RDE, a reduction in reaction rate leads to a reduction in the detonation speed. A subsequent test of reduced reaction rate in a purely one-dimensional pulsed detonation engine (PDE) flowfield yields no reduction in wave speed. The reasons for this are explained. The impact of reduced wave speed on RDE performance is then examined, and found to be minimal. Two other potential mechanisms are briefly examined. These are heat transfer, and reactive mixture non-uniformity. In the context of the simulation used for this study, both mechanisms are shown to have negligible effect on either wave speed or performance.

  17. Numerical and Analytical Assessment of a Coupled Rotating Detonation Engine and Turbine Experiment

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.; Naples, Andrew

    2017-01-01

    An analysis is presented of an experimental rig comprising a rotating detonation engine (RDE) with bypass flow coupled to a downstream turbine. The analysis used a validated computational fluid dynamics RDE simulation combined with straightforward algebraic mixing equations for the bypass flow. The objectives of the analysis were to supplement and interpret the necessarily sparse measurements from the rig, and to assess the performance of the RDE itself (which was not instrumented in this installation). The analysis is seen to agree reasonably well with available data. It shows that the RDE is operating in an unusual fashion, with subsonic flow throughout the exhaust plane. The detonation event itself is producing a total pressure rise relative to the pre-detonative pressure; however, the length of the device and the substantial flow restriction at the inlet yield an overall pressure loss. This is not surprising since the objective of the rig test was primarily aimed at investigating RDEturbine interactions, and not on performance optimization. Furthermore, the RDE was designed for fundamental detonation studies and not performance. Nevertheless, the analysis indicates that with some small alterations to the design, an RDE with an overall pressure rise is possible.

  18. Numerical and Analytical Assessment of a Coupled Rotating Detonation Engine and Turbine Experiment

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.; Naples, Andrew

    2017-01-01

    An analysis is presented of an experimental rig comprising a rotating detonation engine (RDE) with bypass ejector flow coupled to a downstream turbine. The analysis used a validated computational fluid dynamics RDE simulation combined with straightforward algebraic mixing equations for the bypass flow. The objectives of the analysis were to supplement and interpret the necessarily sparse measurements from the rig, and to assess the performance of the RDE itself, which was not instrumented in this installation. The analysis is seen to agree reasonably well with available data. It shows that the RDE is operating in an unusual fashion, with subsonic flow throughout the exhaust plane. The detonation event itself is producing a total pressure rise relative to the pre-detonative pressure; however, the length of the device and the substantial flow restriction at the inlet yield an overall pressure loss. This is not surprising since the objective of the rig test was primarily aimed at investigating RDE/turbine interactions, and not on performance optimization. Furthermore, the RDE was designed for fundamental detonation studies and not performance. Nevertheless, the analysis indicates that with some small alterations to the design, an RDE with an overall pressure rise is possible.

  19. Measurement of carbon condensates using small-angle x-ray scattering during detonation of the high explosive hexanitrostilbene

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bagge-Hansen, M.; Lauderbach, L.; Hodgin, R.

    2015-06-28

    The dynamics of carbon condensation in detonating high explosives remains controversial. Detonation model validation requires data for processes occurring at nanometer length scales on time scales ranging from nanoseconds to microseconds. A new detonation endstation has been commissioned to acquire and provide time-resolved small-angle x-ray scattering (SAXS) from detonating explosives. Hexanitrostilbene (HNS) was selected as the first to investigate due to its ease of initiation using exploding foils and flyers, vacuum compatibility, high thermal stability, and stoichiometric carbon abundance that produces high carbon condensate yields. The SAXS data during detonation, collected with 300 ns time resolution, provide unprecedented signal fidelity overmore » a broad q-range. This fidelity permits the first analysis of both the Guinier and Porod/power-law regions of the scattering profile during detonation, which contains information about the size and morphology of the resultant carbon condensate nanoparticles. To bolster confidence in these data, the scattering angle and intensity were additionally cross-referenced with a separate, highly calibrated SAXS beamline. The data show that HNS produces carbon particles with a radius of gyration of 2.7 nm in less than 400 ns after the detonation front has passed, and this size and morphology are constant over the next several microseconds. These data directly contradict previous pioneering work on RDX/TNT mixtures and TATB, where observations indicate significant particle growth (50% or more) continues over several microseconds. The power-law slope is about −3, which is consistent with a complex disordered, irregular, or folded sp{sup 2} sub-arrangement within a relatively monodisperse structure possessing radius of gyration of 2.7 nm after the detonation of HNS.« less

  20. Measurement of carbon condensates using small-angle x-ray scattering during detonation of the high explosive hexanitrostilbene

    DOE PAGES

    Bagge-Hansen, M.; Lauderbach, L.; Hodgin, R.; ...

    2015-06-24

    In this study, the dynamics of carbon condensation in detonating high explosives remains controversial. Detonation model validation requires data for processes occurring at nanometer length scales on time scales ranging from nanoseconds to microseconds. A new detonation end station has been commissioned to acquire and provide time-resolved small-angle x-ray scattering (SAXS) from detonating explosives. Hexanitrostilbene (HNS) was selected as the first to investigate due to its ease of initiation using exploding foils and flyers, vacuum compatibility, high thermal stability, and stoichiometric carbon abundance that produces high carbon condensate yields. The SAXS data during detonation, collected with 300 ns time resolution,more » provide unprecedented signal fidelity over a broad q-range. This fidelity permits the first analysis of both the Guinier and Porod/power-law regions of the scattering profile during detonation, which contains information about the size and morphology of the resultant carbon condensate nanoparticles. To bolster confidence in these data, the scattering angle and intensity were additionally cross-referenced with a separate, highly calibrated SAXS beamline. The data show that HNS produces carbon particles with a radius of gyration of 2.7 nm in less than 400 ns after the detonation front has passed, and this size and morphology are constant over the next several microseconds. These data directly contradict previous pioneering work on RDX/TNT mixtures and TATB, where observations indicate significant particle growth (50% or more) continues over several microseconds. The power-law slope is about -3, which is consistent with a complex disordered, irregular, or folded sp 2 sub-arrangement within a relatively monodisperse structure possessing radius of gyration of 2.7 nm after the detonation of HNS.« less

  1. Simulating the blast wave from detonation of a charge using a balloon of compressed air

    NASA Astrophysics Data System (ADS)

    Blanc, L.; Santana Herrera, S.; Hanus, J. L.

    2018-07-01

    This paper investigates a simple numerical method, based on the release of a pressurized spherical air volume, to predict or reproduce the main characteristics of the blast environment from the detonation of solid or gaseous charges. This approach aims to give an alternative to the use of a steady-state detonation model and a Jones-Wilkins-Lee equation of state to describe the expansion of the detonation products, especially when the explosive parameters are unknown and a TNT equivalent is used. The validity of the proposed approach is assessed through the comparison of predicted overpressure and impulse at different distances from the explosion with that of TNT and stoichiometric propane-oxygen explosions. It is also shown that, for gaseous detonations, a better agreement is obtained with the rationally optimized compressed balloon than with the use of a Jones-Wilkins-Lee model and a TNT equivalent mass.

  2. Simulating the blast wave from detonation of a charge using a balloon of compressed air

    NASA Astrophysics Data System (ADS)

    Blanc, L.; Santana Herrera, S.; Hanus, J. L.

    2017-11-01

    This paper investigates a simple numerical method, based on the release of a pressurized spherical air volume, to predict or reproduce the main characteristics of the blast environment from the detonation of solid or gaseous charges. This approach aims to give an alternative to the use of a steady-state detonation model and a Jones-Wilkins-Lee equation of state to describe the expansion of the detonation products, especially when the explosive parameters are unknown and a TNT equivalent is used. The validity of the proposed approach is assessed through the comparison of predicted overpressure and impulse at different distances from the explosion with that of TNT and stoichiometric propane-oxygen explosions. It is also shown that, for gaseous detonations, a better agreement is obtained with the rationally optimized compressed balloon than with the use of a Jones-Wilkins-Lee model and a TNT equivalent mass.

  3. Emerging Energetic Materials: Synthesis, Physicochemical, and Detonation Properties

    USDA-ARS?s Scientific Manuscript database

    This book summarizes the science and technology of new generation high energy and insensitive explosives. The objective is to provide the professionals with comprehensive information on synthesis, physicochemical, and detonation properties of the explosives. Potential technologies applicable for tre...

  4. Advancement Is Seldom Accidental.

    ERIC Educational Resources Information Center

    Frantzreb, Arthur C.

    1981-01-01

    Success in college goals and programs for institutional advancement is seldom accidental: success in philanthropic support is seen as 90 percent planning and 10 percent implementation. Trustee membership, long-range plans, the motivational case, experienced staff, adequate budgets, prospect research, supportive communication all meld into a plan…

  5. Legal considerations in a nuclear detonation.

    PubMed

    Sherman, Susan E

    2011-03-01

    This article summarizes public health legal issues that need to be considered in preparing for and responding to nuclear detonation. Laws at the federal, state, territorial, local, tribal, and community levels can have a significant impact on the response to an emergency involving a nuclear detonation and the allocation of scarce resources for affected populations. An understanding of the breadth of these laws, the application of federal, state, and local law, and how each may change in an emergency, is critical to an effective response. Laws can vary from 1 geographic area to the next and may vary in an emergency, affording waivers or other extraordinary actions under federal, state, or local emergency powers. Public health legal requirements that are commonly of concern and should be examined for flexibility, reciprocity, and emergency exceptions include liability protections for providers; licensing and credentialing of providers; consent and privacy protections for patients; occupational safety and employment protections for providers; procedures for obtaining and distributing medical countermeasures and supplies; property use, condemnation, and protection; restrictions on movement of individuals in an emergency area; law enforcement; and reimbursement for care.

  6. Detonation Shock Dynamics Calibration for Non-Ideal He: Anfo

    NASA Astrophysics Data System (ADS)

    Short, Mark; Salyer, Terry R.; Aslam, Tariq D.; Kiyanda, Charles B.; Morris, John S.; Zimmerly, Tony

    2009-12-01

    Linear Dn-κ detonation shock dynamics (DSD) fitting forms are obtained for four ammonium nitrate-fuel oil (ANFO) mixtures involving variations in the ammonium nitrate prill properties and ANFO stoichiometries.

  7. A Common Initiation Criterion for CL-20 EBW Detonators

    NASA Astrophysics Data System (ADS)

    Valancius, Cole; Garasi, Christopher; O'Malley, Patrick

    2014-11-01

    In an effort to better understand the initiation mechanisms of hexanitrohexaazaisowurtzitane (CL-20) based Exploding Bridgewire (EBW) detonators, a series of studies were performed comparing electrical input parameters and detonator performance. Traditional methods of analysis, such as burst current and action, do not allow performance to be compared across multiple firesets. A new metric, electrical burst energy density (Eρ) , allows an explosive train to be characterized across all possible electrical configurations (different firesets, different sized gold bridges, different cables and cable lengths); by testing one electrical configuration, performance across all others is understood. This discovery has implications for design and surveillance, and for the first time, presents a link between modeling of electrical circuits (such as in ALEGRA) and explosive performance.

  8. Detonation Velocity Calculations of Explosives with Slowly-Burning Constituents

    NASA Astrophysics Data System (ADS)

    Howard, W. Michael; Souers, P. Clark; Fried, Laurence E.

    1997-07-01

    The thermochemical code Equilbrium CHEETAH has been modified to allow partial reaction of constituents and partial flow of heat. Solid or liquid reactants are described by Einstein oscillators, whose temperatures can be changed to allow heat transfer. Hydroxy-terminated-poly-budadiene, mixed with RDX or HMX, does not react, as shown by the effect on the calculated detonation velocity. Aluminum and ammonium perchlorate in composites also do not react. Only partial heat flow also takes place in the unreacted materials. These results show that the usual assumption of total burn in a thermochemical code is probably incorrect, at least in the sonic reaction zone that drives the detonation velocity. A kinetic code would be the logical extension of this work.

  9. Semiconductor bridge (SCB) detonator

    DOEpatents

    Bickes, Jr., Robert W.; Grubelich, Mark C.

    1999-01-01

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length.

  10. Semiconductor bridge (SCB) detonator

    DOEpatents

    Bickes, R.W. Jr.; Grubelich, M.C.

    1999-01-19

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge (SCB) igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length. 3 figs.

  11. Measurement of carbon condensates using small-angle x-ray scattering during detonation of high explosives

    NASA Astrophysics Data System (ADS)

    Willey, T. M.; Bagge-Hansen, M.; Lauderbach, L.; Hodgin, R.; Hansen, D.; May, C.; van Buuren, T.; Dattelbaum, D. M.; Gustavsen, R. L.; Watkins, E. B.; Firestone, M. A.; Jensen, B. J.; Graber, T.; Bastea, S.; Fried, L.

    2017-01-01

    The lack of experimental validation for processes occurring at sub-micron length scales on time scales ranging from nanoseconds to microseconds hinders detonation model development. Particularly, quantification of late-time energy release requires measurement of carbon condensation kinetics behind detonation fronts. A new small-angle x-ray scattering (SAXS) endstation has been developed for use at The Dynamic Compression Sector to observe carbon condensation during detonation. The endstation and beamline demonstrate unprecedented fidelity; SAXS profiles can be acquired from single x-ray pulses, which in 24-bunch mode are about 80 ps in duration and arrive every 153.4 ns. This paper presents both the current temporal capabilities of this beamline, and the ability to distinguish different carbon condensate morphologies as they form behind detonation fronts. To demonstrate temporal capabilities, three shots acquired during detonation of hexanitrostilbene (HNS) are interleaved to show the evolution of the SAXS in about 50 ns steps. To show fidelity of the SAXS, the scattering from carbon condensates at several hundred nanoseconds varies with explosive: scattering from HNS is consistent with a complex morphology that we assert is associated with sp2 carbon., while Comp B scattering is consistent with soots containing three-dimensional diamond nanoparticles.

  12. Research Area 3 - Mathematical Sciences: Multiscale Modeling of the Mechanics of Advanced Energetic Materials Relevant to Detonation Prediction

    DTIC Science & Technology

    2015-08-24

    new energetic materials with enhanced energy release rates and reduced sensitivity to unintentional detonation . The following results have been...Mechanics of Advanced Energetic Materials Relevant to Detonation Prediction The views, opinions and/or findings contained in this report are those of the...modeling, molecular simulations, detonation prediction REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 10. SPONSOR/MONITOR’S

  13. Assessment of Blasting Performance Using Electronic Vis-à-Vis Shock Tube Detonators in Strong Garnet Biotite Sillimanite Gneiss Formations

    NASA Astrophysics Data System (ADS)

    Sharma, Suresh Kumar; Rai, Piyush

    2016-04-01

    This paper presents a comparative investigation of the shock tube and electronic detonating systems practised in bench blasting. The blast trials were conducted on overburden rocks of Garnet Biotite Sillimanite Gneiss formations in one of the largest metalliferous mine of India. The study revealed that the choice of detonating system was crucial in deciding the fragment size and its distribution within the blasted muck-piles. The fragment size and its distribution affected the digging rate of excavators. Also, the shape of the blasted muck-pile was found to be related to the degree of fragmentation. From the present work, it may be inferred that in electronic detonation system, timely release of explosive energy resulted in better overall blasting performance. Hence, the precision in delay time must be considered in designing blast rounds in such overburden rock formations. State-of-art image analysis, GPS based muck-pile profile plotting techniques were rigorously used in the investigation. The study revealed that a mean fragment size (K50) value for shock tube detonated blasts (0.55-0.59 m) was higher than that of electronically detonated blasts (0.43-0.45 m). The digging rate of designated shovels (34 m3) with electronically detonated blasts was consistently more than 5000 t/h, which was almost 13 % higher in comparison to shock tube detonated blasts. Furthermore, favourable muck-pile shapes were witnessed in electronically detonated blasts from the observations made on the dozer performance.

  14. Calculation of detonation initiation in a hydrogen/oxygen/argon mixture in by a small-diameter spherical projectile

    NASA Astrophysics Data System (ADS)

    Bedarev, I. A.; Temerbekov, V. M.; Fedorov, A. V.

    2018-03-01

    The initiation of detonation in a reactive mixture by a small-diameter spherical projectile launched at supersonic velocity was studied for a reduced kinetic scheme of chemical reactions. A mathematical technique based on the ANSYS Fluent package was developed for this purpose. Numerical and experimental data on the flow regimes and detonation cell sizes are compared. There is agreement between the calculated and experimental flow patterns and detonation cell sizes for each regime.

  15. Critical detonation thickness in vapor-deposited hexanitroazobenzene (HNAB) films with different preparation conditions

    NASA Astrophysics Data System (ADS)

    Tappan, Alexander; Knepper, Robert; Marquez, Michael; Ball, J.; Miller, Jill

    2013-06-01

    At Sandia National Laboratories, we have coined the term ``microenergetics'' to describe sub-millimeter energetic material studies aimed at gaining knowledge of combustion and detonation behavior at the mesoscale. Films of the high explosive hexanitroazobenzene (HNAB) have been deposited through physical vapor deposition. HNAB deposits in an amorphous state that crystallizes over time and modest heating accelerates this crystallization. HNAB films were prepared under different crystallization temperatures, and characterized with surface profilometry and scanning electron microscopy. The critical detonation thickness for HNAB at different crystallization conditions was determined in a configuration where charge width was large compared to film thickness, and thus side losses did not play a role in detonation propagation. The results of these experiments will be discussed in the context of small sample geometry, deposited film morphology, crystal structure, and density.

  16. 49 CFR 172.521 - DANGEROUS placard.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false DANGEROUS placard. 172.521 Section 172.521... SECURITY PLANS Placarding § 172.521 DANGEROUS placard. (a) Except for size and color, the DANGEROUS placard... B to this part, the DANGEROUS placard must have a red upper and lower triangle. The placard center...

  17. 49 CFR 172.521 - DANGEROUS placard.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false DANGEROUS placard. 172.521 Section 172.521... SECURITY PLANS Placarding § 172.521 DANGEROUS placard. (a) Except for size and color, the DANGEROUS placard... B to this part, the DANGEROUS placard must have a red upper and lower triangle. The placard center...

  18. 49 CFR 172.521 - DANGEROUS placard.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false DANGEROUS placard. 172.521 Section 172.521... SECURITY PLANS Placarding § 172.521 DANGEROUS placard. (a) Except for size and color, the DANGEROUS placard... B to this part, the DANGEROUS placard must have a red upper and lower triangle. The placard center...

  19. Degos disease: a new simulator of non-accidental injury.

    PubMed

    Moss, Celia; Wassmer, Evangeline; Debelle, Geoff; Hackett, Scott; Goodyear, Helen; Malcomson, Roger; Ryder, Clive; Sgouros, Spyros; Shahidullah, Hossain

    2009-08-01

    Recent high-profile cases have made paediatricians very aware of the serious implications of either missing or wrongly diagnosing non-accidental injury. Subdural fluid collections in non-mobile infants usually represent haemorrhage caused by non-accidental injury. We report a 6-month-old male who presented to the Accident and Emergency Department of Birmingham Heartlands Hospital with bilateral subdural fluid collections and skin ulcers resembling cigarette burns. Non-accidental injury was considered to be the most likely diagnosis. However, while under observation in hospital, the child's neurological condition deteriorated with progressive cerebral infarctions, and serial photographs of the skin lesions showed failure to heal. The revised diagnosis, confirmed histologically, was Degos disease, an extremely rare and often fatal occlusive vasculopathy. The child was treated palliatively and died 8 weeks after presentation. This report informs doctors of a new simulator of non-accidental injury to be considered in infants with otherwise unexplained subdural fluid collections.

  20. Type Ia supernovae: Pulsating delayed detonation models, IR light curves, and the formation of molecules

    NASA Technical Reports Server (NTRS)

    Hoflich, Peter; Khokhlov, A.; Wheeler, C.

    1995-01-01

    We computed optical and infrared light curves of the pulsating class of delayed detonation models for Type Ia supernovae (SNe Ia). It is demonstrated that observations of the IR light curves can be used to identify subluminous SNe Ia by testing whether secondary maxima occur in the IR. Our pulsating delayed detonation models are in agreement with current observations both for subluminous and normal bright SN Ia, namely SN1991bg, SN1992bo, and SN1992bc. Observations of molecular bands provide a test to distinguish whether strongly subluminous supernovae are a consequence of the pulsating mechanism occurring in a high-mass white dwarf (WD) or, alternatively, are formed by the helium detonation in a low-mass WD as was suggested by Woosley. In the latter case, no carbon is left after the explosion of low-mass WDs whereas a log of C/O-rich material is present in pulsating delayed detonation models.