Sample records for laser-supported detonation waves

  1. Laser-supported detonation waves and pulsed laser propulsion

    SciTech Connect

    Kare, J. (Lawrence Livermore National Laboratory, Livermore, California 94550 (United States))

    1990-07-30

    A laser thermal rocket uses the energy of a large remote laser, possibly ground-based, to heat an inert propellant and generate thrust. Use of a pulsed laser allows the design of extremely simple thrusters with very high performance compared to chemical rockets. The temperatures, pressures, and fluxes involved in such thrusters (10{sup 4} K, 10{sup 2} atmospheres, 10{sup 7} w/cm{sup 2}) typically result in the creation of laser-supported detonation (LSD) waves. The thrust cycle thus involves a complex set of transient shock phenomena, including laser-surface interactions in the ignition of the LSD wave, laser-plasma interactions in the LSD wave itself, and high-temperature nonequilibrium chemistry behind the LSD wave. The SDIO Laser Propulsion Program is investigating these phenomena as part of an overall effort to develop the technology for a low-cost Earth-to-orbit laser launch system. We will summarize the Program's approach to developing a high performance thruster, the double-pulse planar thruster, and present an overview of some results obtained to date, along with a discussion of the many research question still outstanding in this area.

  2. Laser-supported detonation waves and pulsed laser propulsion

    SciTech Connect

    Kare, J.T.

    1989-01-01

    A laser thermal rocket uses the energy of a large remote laser, possibly ground-based, to heat an inert propellant and generate thrust. Use of a pulsed laser allows the design of extremely simple thrusters with very high performance compared to chemical rockets. The temperatures, pressures, and fluxes involved in such thrusters (10{sup 4} K, 10{sup 2} atmospheres, 10{sup 7} w/cm{sup 2}) typically result in the creation of laser-supported detonation (LSD) waves. The thrust cycle thus involves a complex set of transient shock phenomena, including laser-surface interactions in the ignition if the LSD wave, laser-plasma interactions in the LSD wave itself, and high-temperature nonequilibrium chemistry behind the LSD wave. The SDIO Laser Propulsion Program is investigating these phenomena as part of an overall effort to develop the technology for a low-cost Earth-to-orbit laser launch system. We will summarize the program's approach to developing a high performance thruster, the double-pulse planar thruster, and present an overview of some results obtained to date, along with a discussion of the many research questions still outstanding in this area. 16 refs., 7 figs.

  3. Numerical Analysis on Non-Equilibrium Mechanism of Laser-Supported Detonation Wave Using Multiply-Charged Ionization

    SciTech Connect

    Shiraishi, Hiroyuki [Department of Mechanical Engineering, Daido Institute of Technology (Japan)

    2006-05-02

    Laser-Supported Detonation (LSD), one type of Laser-Supported Plasma (LSP), is considered as the most important phenomena because it can generate high pressure and high temperature for laser absorption. In this study, I have numerically simulated the 1-D LSD waves propagating through a helium gas, in which Multiply-charged ionization model is considered for describing an accurate ionization process.

  4. Fundamental Properties of Non-equilibrium Laser-Supported Detonation Wave

    SciTech Connect

    Shiraishi, Hiroyuki [Department of Mechanical Engineering, Daido Institute of Technology, 10-3 Taki-haru-cho, Minami-ku, Nagoya (Japan)

    2004-03-30

    For developing laser propulsion, it is very important to analyze the mechanism of Laser-Supported Detonation (LSD), because it can generate high pressure and high temperature to be used by laser propulsion can be categorized as one type of hypersonic reacting flows, where exothermicity is supplied not by chemical reaction but by radiation absorption. I have numerically simulated the 1-D and Quasi-1-D LSD waves propagating through an inert gas, which absorbs CO2 gasdynamic laser, using a 2-temperature model. Calculated results show the fundamental properties of the non-equilibrium LSD Waves.

  5. Internal structure of laser supported detonation waves by two-wavelength Mach-Zehnder interferometer

    SciTech Connect

    Shimamura, Kohei; Kawamura, Koichi; Fukuda, Akio; Wang Bin; Yamaguchi, Toshikazu; Komurasaki, Kimiya [Department of Advanced Energy, University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba 277-8561 (Japan); Hatai, Keigo; Fukui, Akihiro; Arakawa, Yoshihiro [Department of Aeronautics and Astronautics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan)

    2011-04-15

    Characteristics of the internal structure of the laser supported detonation (LSD) waves, such as the electron density n{sub e} and the electron temperature T{sub e} profiles behind the shock wave were measured using a two-wavelength Mach-Zehnder interferometer along with emission spectroscopy. A TEA CO{sub 2} laser with energy of 10 J/pulse produced explosive laser heating in atmospheric air. Results show that the peak values of n{sub e} and T{sub e} were, respectively, about 2 x 10{sup 24} m{sup -3} and 30 000 K, during the LSD regime. The temporal variation of the laser absorption coefficient profile estimated from the measured properties reveals that the laser energy was absorbed perfectly in a thin layer behind the shock wave during the LSD regime, as predicted by Raizer's LSD model. However, the absorption layer was much thinner than a plasma layer, the situation of which was not considered in Raizer's model. The measured n{sub e} at the shock front was not zero while the LSD was supported, which implies that the precursor electrons exist ahead of the shock wave.

  6. Numerical Analysis on Thermal Non-Equilibrium Process of Laser-Supported Detonation Wave in Axisymmetric Nozzle

    SciTech Connect

    Shiraishi, Hiroyuki [Daido Institute of Technology, Dept. of Mechanical Engineering 10-3 Takiharu-cho, Minami-ku, Nagoya 457-8530 (Japan)

    2008-04-28

    Numerical Analyses on Laser-Supported Plasma (LSP) have been performed for researching the mechanism of laser absorption occurring in the laser propulsion system. Above all, Laser-Supported Detonation (LSD), categorized as one type of LSP, is considered as one of the most important phenomena because it can generate high pressure and high temperature for performing highly effective propulsion. For simulating generation and propagation of LSD wave, I have performed thermal non-equilibrium analyses by Navier-stokes equations, using a CO{sub 2} gasdynamic laser into an inert gas, where the most important laser absorption mechanism for LSD propagation is Inverse Bremsstrahlung. As a numerical method, TVD scheme taken into account of real gas effects and thermal non-equilibrium effects by using a 2-temperature model, is applied. In this study, I analyze a LSD wave propagating through a conical nozzle, where an inner space of an actual laser propulsion system is simplified.

  7. Calculation of laser induced impulse based on the laser supported detonation wave model with dissociation, ionization and radiation

    SciTech Connect

    Gan, Li, E-mail: ligan0001@gmail.com; Mousen, Cheng; Xiaokang, Li [College of Aerospace Science and Engineering, National University of Defense Technology, Changsha (China)] [College of Aerospace Science and Engineering, National University of Defense Technology, Changsha (China)

    2014-03-15

    In the laser intensity range that the laser supported detonation (LSD) wave can be maintained, dissociation, ionization and radiation take a substantial part of the incidence laser energy. There is little treatment on the phenomenon in the existing models, which brings obvious discrepancies between their predictions and the experiment results. Taking into account the impact of dissociation, ionization and radiation in the conservations of mass, momentum and energy, a modified LSD wave model is developed which fits the experimental data more effectively rather than the existing models. Taking into consideration the pressure decay of the normal and the radial rarefaction, the laser induced impulse that is delivered to the target surface is calculated in the air; and the dependencies of impulse performance on laser intensity, pulse width, ambient pressure and spot size are indicated. The results confirm that the dissociation is the pivotal factor of the appearance of the momentum coupling coefficient extremum. This study focuses on a more thorough understanding of LSD and the interaction between laser and matter.

  8. Calculation of laser induced impulse based on the laser supported detonation wave model with dissociation, ionization and radiation

    NASA Astrophysics Data System (ADS)

    Li, Gan; Cheng, Mousen; Li, Xiaokang

    2014-03-01

    In the laser intensity range that the laser supported detonation (LSD) wave can be maintained, dissociation, ionization and radiation take a substantial part of the incidence laser energy. There is little treatment on the phenomenon in the existing models, which brings obvious discrepancies between their predictions and the experiment results. Taking into account the impact of dissociation, ionization and radiation in the conservations of mass, momentum and energy, a modified LSD wave model is developed which fits the experimental data more effectively rather than the existing models. Taking into consideration the pressure decay of the normal and the radial rarefaction, the laser induced impulse that is delivered to the target surface is calculated in the air; and the dependencies of impulse performance on laser intensity, pulse width, ambient pressure and spot size are indicated. The results confirm that the dissociation is the pivotal factor of the appearance of the momentum coupling coefficient extremum. This study focuses on a more thorough understanding of LSD and the interaction between laser and matter.

  9. Numerical Analysis of Threshold between Laser-Supported Detonation and Combustion Wave Using Thermal Non-Equilibrium and Multi-Charged Ionization Model

    NASA Astrophysics Data System (ADS)

    Shiraishi, Hiroyuki; Kumagai, Yuya

    Laser-supported Detonation (LSD), which is one type of Laser-supported Plasma (LSP), is an important phenomenon because it can generate high pressures and temperatures for laser absorption. In this study, using thermal-non-equilibrium model, we numerically simulate LSPs, which are categorized as either LSDs or laser-supported combustion-waves (LSCs). For the analysis model, a two-temperature (heavy particle and electron-temperature) model has been used because the electronic mode excites first in laser absorption and a thermal non-equilibrium state easily arises. In the numerical analysis of the LSDs, laser absorption models are particularly important. Therefore, a multi-charged ionization model is considered to evaluate precisely the propagation and the structure transition of the LSD waves in the proximity of the LSC-LSD threshold. In the new model, the transition of the LSD construction near the threshold, which is indicated by the ionization delay length, becomes more practical.

  10. 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.

  11. Influence of the gaseous form on the precursor heating layer of a laser-supported detonation wave using half self-emission half shadowgraph visualization

    NASA Astrophysics Data System (ADS)

    Shimamura, Kohei; Michigami, Keisuke; Ofoso, Joseph; Komursaki, Kimiya

    2012-10-01

    After breakdown one of the possible mechanisms of occurrence of laser-produced plasma is noted as laser-supported detonation (LSD) wave. This wave consisting of the shock wave and the beam absorbing plasma travels at 1-10 km/s along the beam channel in the direction opposite to the laser incidence. The laser heating structure is recognized as the ZND model of chemical detonation. However, Shimamura et. al, showed that the plasma proceeds the shock wave during LSD regime. The role of shock compression is relatively smaller than preheating by laser. The conventional model is inconsistent with our paper. To investigate the heating structure of a LSD wave, half self-emission half shadowgraph (HSHS) methods provides the self-emission image from the plasma on the top half and the shadowgraph image of the induced shock wave on the bottom half simultaneously. A TEA CO2 laser was used at 10 J incident energy. The locations of both wave fronts were detected from the brightness distribution of the HSHS images. As a result, the propagation of ionization front precedes that of shock wave front by the order of 10-4 m in air and N2. Preheating layer of N2 is shorter than that of air because O2 in air has the lowest ionization energy. Thus, a characteristic of preionization layer depends on the ionization properties because photoionization by the UV radiation generate the seed electrons ahead of shock wave.

  12. Review of Propulsion Applications of Detonation Waves

    Microsoft Academic Search

    K. Kailasanath

    2000-01-01

    Applications of detonations to propulsion are reviewed. First, the advantages of the detonation cycle over the constant pressure combustion cycle, typical of conventional propulsion engines, are discussed. Then the early studies of standing normal detonations, intermittent (or pulsed) detonations, rotating detonations, and oblique shock-induced detonations are reviewed. This is followed by a brief discussion of detonation thrusters, laser- supported detonations

  13. Understanding curved detonation waves

    SciTech Connect

    Bukiet, B.G. (New Jersey Inst. of Tech., Newark, NJ (United States). Dept. of Mathematics); Menikoff, R. (Los Alamos National Lab., NM (United States))

    1992-01-01

    A wave curve is the set of final states to which an initial state may be connected by a traveling wave. In gas dynamics, for example, the wave curve consists of the shock Hugoniot curve for compressive waves and the rarefaction curve for expansive waves. In this paper, we discuss the wave curve for an undriven planar detonation and for general planar detonations. We then extend the wave curve concept to detonations in converging and diverging geometry. We also discuss the application of these wave curves to the numerical computation of detonation problems.

  14. Understanding curved detonation waves

    SciTech Connect

    Bukiet, B.G. [New Jersey Inst. of Tech., Newark, NJ (United States). Dept. of Mathematics; Menikoff, R. [Los Alamos National Lab., NM (United States)

    1992-10-01

    A wave curve is the set of final states to which an initial state may be connected by a traveling wave. In gas dynamics, for example, the wave curve consists of the shock Hugoniot curve for compressive waves and the rarefaction curve for expansive waves. In this paper, we discuss the wave curve for an undriven planar detonation and for general planar detonations. We then extend the wave curve concept to detonations in converging and diverging geometry. We also discuss the application of these wave curves to the numerical computation of detonation problems.

  15. Detonation waves in trinitrotoluene

    Microsoft Academic Search

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

    1999-01-01

    .   Fabry-Perot, ORVIS, and VISAR laser interferometry are used to obtain nanosecond time resolved particle velocity histories\\u000a of the free surfaces of copper and tantalum discs accelerated by detonating trinitrotoluene (TNT) charges and of the interfaces\\u000a between TNT detonation products and lithium fluoride crystals. TNT detonation reaction zone profiles are measured for self-sustaining\\u000a detonation and piston supported overdriven (supracompressed) waves.

  16. Detonation waves in triaminotrinitrobenzene

    Microsoft Academic Search

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

    1997-01-01

    FabryâPerot laser interferometry is used to obtain nanosecond time resolved particle velocity histories of the free surfaces of copper, tantalum, or magnesium disks driven by detonating triaminotrinitrobenzene (TATB)-based charges and of the interfaces between detonating TATB and transparent salt crystals. Detonation reaction zone profiles are measured for self-sustaining detonation waves propagating through various thicknesses of LX-17 (92.5% TATB and 7.5%

  17. Detonation waves in triaminotrinitrobenzene

    Microsoft Academic Search

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

    1997-01-01

    Fabry–Perot laser interferometry is used to obtain nanosecond time resolved particle velocity histories of the free surfaces of copper, tantalum, or magnesium disks driven by detonating triaminotrinitrobenzene (TATB)-based charges and of the interfaces between detonating TATB and transparent salt crystals. Detonation reaction zone profiles are measured for self-sustaining detonation waves propagating through various thicknesses of LX-17 (92.5% TATB and 7.5%

  18. Detonation waves in triaminotrinitrobenzene

    NASA Astrophysics Data System (ADS)

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

    1997-10-01

    Fabry-Perot laser interferometry is used to obtain nanosecond time resolved particle velocity histories of the free surfaces of copper, tantalum, or magnesium disks driven by detonating triaminotrinitrobenzene (TATB)-based charges and of the interfaces between detonating TATB and transparent salt crystals. Detonation reaction zone profiles are measured for self-sustaining detonation waves propagating through various thicknesses of LX-17 (92.5% TATB and 7.5% KelF binder) and pure ultrafine particle size TATB. The experimental records are compared to particle velocity histories calculated with the DYNA2D hydrodynamic code using the ignition and growth reactive flow model. The calculations yield excellent agreement with the experimental records for LX-17 using an unreacted von Neumann spike pressure of 33.7 GPa, a reaction rate law which releases 70% of the chemical energy within 100 ns, and the remaining 30% over 300 additional ns, and a reaction product equation of state fit to cylinder test and supracompression data with a Chapman-Jouguet (C-J) pressure of 25 GPa. The late time energy release is attributed to diffusion controlled solid carbon particle formation. Ultrafine TATB, pressed to a lower density (1.80 g/cm3) than LX-17 (1.905 g/cm3), exhibits lower unreacted spike and C-J pressures than LX-17 but similar reaction rates.

  19. Detonation waves in triaminotrinitrobenzene

    SciTech Connect

    Tarver, C.M.; Kury, J.W.; Breithaupt, R.D. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    1997-10-01

    Fabry{endash}Perot laser interferometry is used to obtain nanosecond time resolved particle velocity histories of the free surfaces of copper, tantalum, or magnesium disks driven by detonating triaminotrinitrobenzene (TATB)-based charges and of the interfaces between detonating TATB and transparent salt crystals. Detonation reaction zone profiles are measured for self-sustaining detonation waves propagating through various thicknesses of LX-17 (92.5{percent} TATB and 7.5{percent} KelF binder) and pure ultrafine particle size TATB. The experimental records are compared to particle velocity histories calculated with the DYNA2D hydrodynamic code using the ignition and growth reactive flow model. The calculations yield excellent agreement with the experimental records for LX-17 using an unreacted von Neumann spike pressure of 33.7 GPa, a reaction rate law which releases 70{percent} of the chemical energy within 100 ns, and the remaining 30{percent} over 300 additional ns, and a reaction product equation of state fit to cylinder test and supracompression data with a Chapman{endash}Jouguet (C{endash}J) pressure of 25 GPa. The late time energy release is attributed to diffusion controlled solid carbon particle formation. Ultrafine TATB, pressed to a lower density (1.80g/cm{sup 3}) than LX-17 (1.905g/cm{sup 3}), exhibits lower unreacted spike and C{endash}J pressures than LX-17 but similar reaction rates. {copyright} {ital 1997 American Institute of Physics.}

  20. 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.

  1. Photoionization in the Precursor of Laser Supported Detonation by Ultraviolet Radiation

    SciTech Connect

    Shimamura, Kohei; Michigami, Keisuke; Wang, Bin; Komurasaki, Kimiya [Department of Advanced Energy, University of Tokyo 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba, 277-8561 (Japan); Arakawa, Yoshihiro [Department of Aeronautics and Astronautics, University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan)

    2011-11-10

    The propagation mechanism of laser-supported detonation (LSD) is important for designing laser propulsion for a detonation type thruster. The purpose of this work to was to confirm that photo-ionization in precursor is the predominant LSD sustainment mechanism. First of all, we tried to investigate the dependency of LSD duration on ambient gas species, air and argon. We took a series of high-speed images using the laser shadow-graphy. Besides, to estimate the UV photons emitted from the plasma, we used plasma emission spectroscopy and determined the electron temperature and density. As a result, the LSD duration of argon plasma and air plasma are 0.7 {mu}s and 0.3 {mu}s, resp. Besides, argon plasma emitted 10{sup 10} to 10{sup 14} photons/seconds, which was higher than air plasma. These results reveal that LSD propagation depends on the photon-contributing photoionization. The threshold photon-emission rate of LSD termination gives the elucidation of the LSD termination condition.

  2. Detonation waves in pentaerythritol tetranitrate

    SciTech Connect

    Tarver, C.M.; Breithaupt, R.D.; Kury, J.W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    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}Jouguet (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.}

  3. Airbreathing Rotating Detonation Wave Engine Cycle Analysis

    E-print Network

    Texas at Arlington, University of

    Airbreathing Rotating Detonation Wave Engine Cycle Analysis Eric M. Braun, Frank K. Lu, Donald R analysis of an airbreathing, rotating detonation wave engine (RDWE) is developed. The engine consists constant RDWE Rotating detonation wave engine Graduate Research Associate, Aerodynamics Research Center

  4. Microwave velocity measurements of marginal detonation waves

    Microsoft Academic Search

    D H Edwards; G Hooper; R J Meddins

    1970-01-01

    A prerequisite to a study of a detonation wave structure is the establishment of an equilibrium frontal configuration, which is repeatable at equi-spaced distances along the detonation tube, together with a constant average wave velocity. A microwave interferometer is described which is capable of giving a continuous monitor of the velocity of a marginal planar detonation wave propagating in a

  5. Sharp shock model for propagating detonation waves

    SciTech Connect

    Bukiet, B.; Menikoff, R.

    1989-01-01

    Recent analyses of the reactive Euler equations have led to an understanding of the effect of curvature on an underdriven detonation wave. This advance can be incorporated into an improved sharp shock model for propagating detonation waves in hydrodynamic calculations. We illustrate the model with two simple examples: time dependent propagation of a diverging detonation wave in 1-D, and the steady 2-D propagation of a detonation wave in a rate stick. Incorporating this model into a 2-D front tracking code is discussed. 20 refs., 3 figs.

  6. INTRODUCTION In detonation wave computations involving

    E-print Network

    Bukiet, Bruce

    be used to compute the burned Hugoniot and wave curves. One can then solve the Riemann problem. Solving be solved to compute the curved detonation Hugo­ niot. By finding the Hugoniot (and the related 1 #12; wave

  7. Detonation waves in pentaerythritol tetranitrate

    Microsoft Academic Search

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

    1997-01-01

    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

  8. The dynamics of spinning detonation waves

    Microsoft Academic Search

    H. Jones

    1976-01-01

    The fluid motion of chemically reacting gases in a weak detonation wave is examined with a view to finding a dynamical theory of the spin phenomenon. It is shown that a reacting gas in which the rate of reaction increases with temperature is unstable with respect to wave motion. The amplitude of any wave tends to increase exponentially with time

  9. On the Existence of Pathological Detonation Waves

    SciTech Connect

    Tarver, C M

    2003-07-11

    Pathological detonation waves with velocities greater than Chapman-Jouguet (C-J) have been proposed theoretically but never observed experimentally in gaseous, liquid or solid explosives. Two types of pathological chemical reaction zones have been identified within the Zeldovich-von Neumann-Doring (ZND) model: an exothermic chemical decomposition with a mole decrease during from the von Neumann spike state to the C-J state and an exothermic reaction followed by an endothermic reaction (eigenvalue detonation). The high temperatures reached in detonation reaction zones cause sufficient radial and atom formation to insure overall mole increases in gaseous H{sub 2} + O{sub 2} detonations. Aluminized explosives exhibit a slight mole decrease when the solid aluminum particles are oxidized, but this does not negate the large mole increase that occurs during explosive decomposition. Porous solid explosives whose products form with more cold compression energy than that of the solid are an unlikely possibility for pathological detonation. Eigenvalue detonations have been postulated for H{sub 2} + Cl{sub 2} gas phase detonations and for plastic bonded solid explosives if endothermic binder decomposition follows exothermic explosive decomposition. Chemical kinetic and physical arguments are presented to eliminate these possible pathological detonations. In the case of H{sub 2} + Cl{sub 2}, highly vibrationally excited HCl molecules dissociate Cl{sub 2} molecules during the exothermic portion of the reaction zone rather than later in the flow process. In the plastic bonded explosives, the binders are located on the surfaces of explosive particles and thus are exposed to ''hot spots'' created by the three-dimensional Mach stem shock front. Any remaining binder material rapidly reacts in collisions with the high, vibrationally excited reaction products formed during explosive decomposition. Therefore eigenvalue detonations are extremely unlikely to occur in gaseous, liquid or solid explosives.

  10. Effect of Resolution on Propagating Detonation Wave

    SciTech Connect

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-07-10

    Simulations of the cylinder test are used to illustrate the effect of mesh resolution on a propagating detonation wave. For this study we use the xRage code with the SURF burn model for PBX 9501. The adaptive mesh capability of xRage is used to vary the resolution of the reaction zone. We focus on two key properties: the detonation speed and the cylinder wall velocity. The latter is related to the release isentrope behind the detonation wave. As the reaction zone is refined (2 to 15 cells for cell size of 62 to 8?m), both the detonation speed and final wall velocity change by a small amount; less than 1 per cent. The detonation speed decreases with coarser resolution. Even when the reaction zone is grossly under-resolved (cell size twice the reaction-zone width of the burn model) the wall velocity is within a per cent and the detonation speed is low by only 2 per cent.

  11. Testing of a Continuous Detonation Wave Engine with Swirled Injection

    E-print Network

    Texas at Arlington, University of

    , also known as the rotating detonation wave engine (RDWE).1­23 CDWE testing was initiatedTesting of a Continuous Detonation Wave Engine with Swirled Injection Eric M. Braun Nathan L. Dunn detonation wave engines with swirl to improve mixing were developed. The reactants were ignited

  12. Shock waves, explosions, and detonations

    Microsoft Academic Search

    J. R. Bowen; N. Manson; A. K. Oppenheim; R. Soloukhin

    1983-01-01

    Shock wave interactions are considered, taking into account the study of shock-induced signals and coherent effects in solids by molecular dynamics, oblique shock waves in two-phase flow, equilibrium shock wave properties in dusty and clean air, shock waves in water induced by focused laser radiation, the ignition of small particles behind shock waves, the reflection of shock waves at rigid

  13. The flow field in a rotating detonation-wave engine

    NASA Astrophysics Data System (ADS)

    Kailasanath, Kazhikathra; Schwer, Douglas

    2011-11-01

    Rotating detonation-wave engines (RDE) are a form of continuous detonation-wave engine. They potentially provide further gains than an intermittent or pulsed detonation-wave engine (PDE). However, significantly less work has been on this concept when compared to the PDE. In this talk, we present the detailed flow field in an idealized RDE, primarily consisting of two concentric cylinders. A premixed detonable mixture is injected into the annulus between the two concentric cylinders. Once a detonation is initiated, it keeps travelling around in the annulus as long as there is fresh detonable mixture ahead of it. Hence, the injection process is critically important to the stability and performance of the RDE. Furthermore, we show that the flow field is quite complex consisting of multiple shock waves and the outflow is primarily axial, although the detonation-wave is travelling around circumferentially. Sponsored by the NRL 6.1 Computational Physics Task Area.

  14. Analytical study of laser supported combustion waves in hydrogen

    NASA Technical Reports Server (NTRS)

    Kemp, N. H.; Root, R. G.

    1977-01-01

    A one-dimensional energy equation, with constant pressure and area, was used to model the LSC wave. This equation balances convection, conduction, laser energy absorption, radiation energy loss and radiation energy transport. Solutions of this energy equation were obtained to give profiles of temperature and other properties, as well as the relation between laser intensity and mass flux through the wave. The flow through the LSC wave was then conducted through a variable pressure, variable area streamtube to accelerate it to high speed, with the propulsion application in mind. A numerical method for coupling the LSC wave model to the streamtube flow was developed, and a sample calculation was performed. The result shows that 42% of the laser power has been radiated away by the time the gas reaches the throat. It was concluded that in the radially confined flows of interest for propulsion applications, transverse velocities would be less important than in the unconfined flows where air experiments have been conducted.

  15. The quasi-steady regime in critically initiated detonation waves

    Microsoft Academic Search

    D. H. Edwards; G. Hooper; J. M. Morgan; G. O. Thomas

    1978-01-01

    Experimental work is described on the initiation of spherical detonation waves, in oxyacetylene with various diluents, using an exploding wire and a lead azide pellet as sources. The transition of the spherical blast wave to a detonation, when the source energy is either above or at the critical value, is studied by three methods. Changes in wave structure are inferred

  16. Detonation Wave Structure of Gases at Elevated Initial Pressures

    Microsoft Academic Search

    R. G. SCHMITT; P. B. BUTLER

    1995-01-01

    The characteristic “structure” of gaseous detonation waves, defined here as the spatial variation of the pressure, temperature, density, species concentrations, and velocity within the detonation wave is examined theoretically at elevated initial pressures. The approach taken in this work is to extend the Zel'dovich-von Neumann-Doering (ZND) theory of gas-phase detonation to use real-gas equations of state, Chemkin Real Gas, a

  17. Laser-supported ionization wave in under-dense gases and foams

    SciTech Connect

    Gus'kov, S. Yu. [P. N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow 119991 (Russian Federation); Limpouch, J. [FNSPE, Czech Technical University in Prague, 115 19 Prague 1 (Czech Republic); Nicolaie, Ph.; Tikhonchuk, V. T. [Centre Lasers Intenses et Applications, Universite Bordeaux - CNRS - CEA, Talence 33405 (France)

    2011-10-15

    Propagation of laser-supported ionization wave in homogeneous and porous materials with a mean density less than the critical plasma density is studied theoretically in the one-dimensional geometry. It is shown that the velocity of the ionization wave in a foam is significantly decreased in comparison with the similar wave in a homogeneous fully ionized plasma of the same density. That difference is attributed to the ionization and hydro-homogenization processes forming an under-critical density environment in the front of ionization wave. The rate of energy transfer from laser to plasma is found to be in a good agreement with available experimental data.

  18. Propagation of Axially Symmetric Detonation Waves

    Microsoft Academic Search

    Robert L. Druce; F Roeske; P. Clark Souers; Craig M. Tarver; Charles T. S. Chow; Ronald S. Lee; Estella M. McGuire; George E. Overturf III; Peter A. Vitello

    2002-01-01

    We have studied the non-ideal propagation of detonation waves in LX-10 and in the insensitive explosive TATB. Explosively-driven, 5.8-mm-diameter, 0.125-mm-thick aluminum flyer plates were used to initiate 38-mm-diameter, hemispherical samples of LX-10 pressed to a density of 1.86 g\\/cm³ and of TATB at a density of 1.80 g\\/cm³. The TATB powder was a grade called ultrafine (UFTATB), having an arithmetic

  19. DDT and detonation waves in dust-air mixtures

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Grönig, H.; van de Ven, A.

    This paper summarizes the studies of DDT and stable detonation waves in dust-air mixtures at the Stosswellenlabor of RWTH Aachen. The DDT process and propagation mechanism for stable heterogeneous dust detonations in air are essentially the same as in the oxygen environment studied previously. The dust DDT process in tubes is composed of a reaction compression stage followed by a reaction shock stage as the pre-detonation process. The transverse waves that couple the shock wave and the chemical energy release are responsible for the propagation of a stable dust-air detonation. However, the transverse wave spacing of dust-air mixtures is much larger. Therefore, DDT and propagation of a stable detonation in most industrial and agricultural, combustible dust-air mixtures require a tube that has a large diameter between 0.1 m and 1 m and a sufficient length-diameter ratio beyond 100, when an appropriately strong initiation energy is used. Two dust detonation tubes, 0.14 m and 0.3 m in diameter, were used for observation of the above-mentioned results in cornstarch, anthraquinone and aluminum dust suspended in air. Smoked-foil technique was also used to measure the cellular structure of dust detonations in the 0.3 m detonation tube.

  20. Blast waves generated by planar detonations

    NASA Astrophysics Data System (ADS)

    Thibault, P. A.; Penrose, J. D.; Shepherd, J. E.; Benedick, W. B.; Ritzel, D. V.

    This paper presents experimental and theoretical studies of blast waves generated by gaseous and HE detonations in long cylindrical tubes. The experimental studies were performed using the 1.8 m diameter shock tube facilities at the Defence Research Establishment Suffield and at the New Mexico Engineering Research Institute. Two gaseous explosives, acetylene-oxygen and hydrogen-air, and one solid explosive, 120g nitroguanidine, were used in order to verify the validity of energy scaling in the far-field. The above experimental work is supported by one- and two-dimensional numerical computations which are based on the Flux Corrected Transport (FCT) algorithm. The experimental results are also analyzed in terms of a simple analytical blast model.

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

    Microsoft Academic Search

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

    2007-01-01

    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,

  2. Propagation of Axially Symmetric Detonation Waves

    SciTech Connect

    Druce, R L; Roeske, F; Souers, P C; Tarver, C M; Chow, C T S; Lee, R S; McGuire, E M; Overturf, G E; Vitello, P A

    2002-06-26

    We have studied the non-ideal propagation of detonation waves in LX-10 and in the insensitive explosive TATB. Explosively-driven, 5.8-mm-diameter, 0.125-mm-thick aluminum flyer plates were used to initiate 38-mm-diameter, hemispherical samples of LX-10 pressed to a density of 1.86 g/cm{sup 3} and of TATB at a density of 1.80 g/cm{sup 3}. The TATB powder was a grade called ultrafine (UFTATB), having an arithmetic mean particle diameter of about 8-10 {micro}m and a specific surface area of about 4.5 m{sup 2}/g. Using PMMA as a transducer, output pressure was measured at 5 discrete points on the booster using a Fabry-Perot velocimeter. Breakout time was measured on a line across the booster with a streak camera. Each of the experimental geometries was calculated using the Ignition and Growth Reactive Flow Model, the JWL++ Model and the Programmed Burn Model. Boosters at both ambient and cold (-20 C and -54 C) temperatures have been experimentally and computationally studied. A comparison of experimental and modeling results is presented.

  3. Reactive Flow Modeling of the Interaction of TATB Detonation Waves with Inert Materials

    Microsoft Academic Search

    Craig M. Tarver; Estella M. McGuire

    2002-01-01

    The Ignition & Growth model for the shock initiation and detonation of solid explosives is applied to calculating the main features of detonation waves in the triaminotrinitrobenzene (TATB) based high explosives LX-17, PBX 9502 and EDC-35. Under detonation conditions, TATB based explosives exhibit reaction zone lengths of 2 to 3 mm depending on the interactions between the detonation wave and

  4. Oblique detonation waves stabilized in rectangular-cross-section bent tubes

    Microsoft Academic Search

    Yusuke Kudo; Yuuto Nagura; Jiro Kasahara; Yuya Sasamoto; Akiko Matsuo

    2011-01-01

    Oblique detonation waves, which are generated by a fundamental detonation phenomenon occurring in bent tubes, may be applied to fuel combustion in high-efficiency engines such as a pulse detonation engine (PDE) and a rotating detonation engine (RDE). The present study has experimentally demonstrated that steady-state oblique detonation waves propagated stably through rectangular-cross-section bent tubes by visualizing these waves using a

  5. 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.

  6. Observations on Gaseous Detonation Waves using a Microwave Interferometer

    Microsoft Academic Search

    D. H. Edwards; E. M. Job; T. R. Lawrence

    1962-01-01

    CONSIDERABLE attention has been devoted to the study of the structure of the reaction zone in gaseous detonation waves with the view of providing information on the duration and quantitative variations occurring in the gas parameters. In order to make these variations amenable to experimental study the waves are usually generated in mixtures at reduced initial pressures so as to

  7. Links between detonation wave propagation and reactive flow models.

    SciTech Connect

    Swift, D. C. (Damian C.); White, S. J. (Stephen J.)

    2002-01-01

    An accurate reactive flow model is necessary to be able to predict the initiation properties of explosives by complicated shock structures, but a very fine the spatial resolution is needed in reactive flow to reproduce the detailed dynamics of a detonation wave. However, it is not often necessary to use a reactive flow model to simulate the motion of a fully-developed detonation wave. In many situations the same results can be obtained with a coarse computational mesh using programmed burn techniques. In the WBL model [Lambourn89,Swift93], an eikonal detonation wave propagates through a body of explosive at a speed which depends on the curvature of the wave. The model describes the motion of the leading shock of the detonation wave. Here we use the level set method for integrating the WBL equations in time [Collyer98,Bdzil93,Osher88,Aslam98]. This method is attractive because complicated detonation wave shapes can be represented simply. It was found possible to initialize the level set field by a set of source points derived from a reactive flow simulation, by taking 'trigger states' from the reactive flow. The level set scheme was generalized further to take account of motion of the material behind the detonation wave, allowing it to be used for simulations coupled with reactive flow, where detonation may propagate through preshocked and moving material. The modified level set scheme was implemented in 1D and 2D Lagrangian hydrocodes. Trial calculations were performed of initiation and detonation in the TATB-based explosive LX-17, using the Lee - Tarver model. A CJ detonation was simulated in order to verify that the modified level set algorithm operated correctly. The detonation speed was in very good agreement with the expected value. Single-shock initiation was simulated. The position - time history of the leading shock from the coupled model was in excellent agreement with full reactive flow; the pressure profiles were similar but not identical, because of the difference in material properties behind the WBL wave and the omission of the von Neumann spike from the WBL profiles. As a more interesting test, we simulated the shock-to-detonation transition on reflection of a weak shock from a rigid boundary. The position - time history of the leading shock was in good agreement. The pressure profiles varied much more than in the single-shock case, because the WBL calculation used the same propagation parameters and for simplicity imposed the same state at the end of the detonation zone as was used in the single-shock simulation. We have previously used quasisteady flow analysis to derive a reaction rate from experimental measurements of the relation between detonation speed and wave curvature, or vice versa [Swift93]. Reactive flow models have been developed for HMX-based explosives based on mesoscale representations of the components of the explosive [Mulford01], and using a temperature-dependent reaction rate which should be valid over a wide range of loading conditions. The quasisteady analysis scheme was extended to allow arbitrary reaction models to be investigated.

  8. Characterization of Detonation Wave Propagation in LX17 Near the Critical Diameter

    Microsoft Academic Search

    T. D. Tran; C. M. Tarver; J. Maienschein; P. Lewis; R Pastrone; R. S. Lee; F. Roeske

    2002-01-01

    A new Detonation Profile Test (DPT) was developed to measure simultaneously the detonation wave breakout profile and the average detonation velocity at the breakout surface. The test evaluated small cylindrical samples with diameter up to 19.08 mm and length up to 33 mm. The experiment involved initiating a LX-17 cylindrical specimen and recording the wave breakout using a fast streaking

  9. Triggering of Detonation upon Flame Interaction with an Expansion Wave

    Microsoft Academic Search

    V. A. Subbotin

    2003-01-01

    The transition of a deflagration wave into an abruptly expanding part of a plane channel, where a quasi-steady supersonic underexpanded jet of an unburned gas is formed, is studied for a propane–oxygen mixture using schlieren pictures. Two explosion-initiation modes (weak and strong) are registered. In the first case, almost instantaneous onset of the detonation wave occurs when the flame front

  10. Dynamic mode decomposition analysis of detonation waves

    NASA Astrophysics Data System (ADS)

    Massa, L.; Kumar, R.; Ravindran, P.

    2012-06-01

    Dynamic mode decomposition is applied to study the self-excited fluctuations supported by transversely unstable detonations. The focus of this study is on the stability of the limit cycle solutions and their response to forcing. Floquet analysis of the unforced conditions reveals that the least stable perturbations are almost subharmonic with ratio between global mode and fundamental frequency ?i/?f = 0.47. This suggests the emergence of period doubling modes as the route to chaos observed in larger systems. The response to forcing is analyzed in terms of the coherency of the four fundamental energy modes: acoustic, entropic, kinetic, and chemical. Results of the modal decomposition suggest that the self-excited oscillations are quite insensitive to vortical forcing, and maintain their coherency up to a forcing turbulent Mach number of 0.3.

  11. 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.

  12. Initiation of detonation in TATB by a diverging shock wave

    Microsoft Academic Search

    Yu. A. Aminov; A. V. Vershinin; V. P. Voronina; N. S. Es’kov; O. V. Kostitsyin; B. G. Loboiko; G. N. Rykovanov; M. A. Strizhenok

    1999-01-01

    The development of detonation is examined in a low sensitivity explosive initiated by a diverging shock wave through an inert\\u000a barrier. It is shown experimentally and by calculation that, in the case where the properties of the material and the geometric\\u000a factors begin to have an effect, the initial zone within which an explosive material under conditions close to critical

  13. Ignition of petn particles by a gas-detonation wave

    Microsoft Academic Search

    V. V. Grigor’ev; L. A. Lukyanchikov; É. P. Pruuel

    1997-01-01

    Ignition ofPETN particles by a gas-detonation wave in a gas suspension has been studied experimentally. The critical pressure at which the\\u000a total rate ofPETN decomposition increases sharply has been found using a method of multiwave pyrometry with variation in the pressure of the\\u000a initial gas mixture from 0.1 to 0.4MPa. It is shown that this can occur owing to a

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

    SciTech Connect

    Li, J.; Lai, W.H. [National Cheng Kung University, Institute of Aeronautics and Astronautics, Tainan (China); Chung, K. [National Cheng Kung University, Aerospace Science and Technology Research Center, Tainan (China); Lu, F.K. [University of Texas at Arlington, Mechanical and Aerospace Engineering Department, Aerodynamics Research Center, TX 76019 (United States)

    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 results 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)

  15. 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.

  16. Rigorous asymptotic stability of a Chapman-Jouguet detonation wave in the limit of small resolved heat release

    Microsoft Academic Search

    Tong Liy

    1997-01-01

    We study the rigorous asymptotic stability of a Chapman-Jouguet (CJ) detonation wave in the limit of small resolved heat release (SRHR). We show that the solution exists globally and that the solution converges uniformly to a shifted CJ detonation wave as t!C1 for initial data which are small perturbations of the CJ detonation wave. A CJ detonation wave is characterized

  17. Nonlinear dynamics of self-sustained supersonic reaction waves: Fickett's detonation analogue

    E-print Network

    Matei I. Radulescu; Justin Tang

    2011-08-03

    The present study investigates the spatio-temporal variability in the dynamics of self-sustained supersonic reaction waves propagating through an excitable medium. The model is an extension of Fickett's detonation model with a state dependent energy addition term. Stable and pulsating supersonic waves are predicted. With increasing sensitivity of the reaction rate, the reaction wave transits from steady propagation to stable limit cycles and eventually to chaos through the classical Feigenbaum route. The physical pulsation mechanism is explained by the coherence between internal wave motion and energy release. The results obtained clarify the physical origin of detonation wave instability in chemical detonations previously observed experimentally.

  18. 39th AIAA Fluid Dynamics Conference & Exhibit, 2225 June 2009, San Antonio, Texas Determining Shock and Detonation Wave Propagation

    E-print Network

    Texas at Arlington, University of

    of the propagation speed of a shock or detonation wave as in shock or detonation tube experiments typically makes use Shock and Detonation Wave Propagation Time Using Wavelet Methods Frank K. Lu , and A. Albert Ortiz Wavelet envelope correlation coefficient ¯u Average wave propagation speed L Distance between two

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

    E-print Network

    Liu, Qingming; Zhang, Yunming; Li, Shuzhuan

    2015-01-01

    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 exist 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.

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

    SciTech Connect

    Jackson, Scott I [Los Alamos National Laboratory; Klyanda, Charles B [Los Alamos National Laboratory; Short, Mark [Los Alamos National Laboratory

    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 understanding 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.

  1. Microwave Diagnostics of Shock Wave and Detonation Processes

    NASA Astrophysics Data System (ADS)

    Mikhaylov, Anatoly; Belsky, Vladimir; Bogdanov, Evgeny; Rodionov, Alexey; Sedov, Alexander; Khvorostin, Vladimir; Russian Federal Nuclear Center-Vniief 607190, Sarov, Nizhniy Novgorod Reg., Russia Team

    2013-06-01

    The physical bases of laser and microwave Doppler interferometry are the same - measurements of the Doppler shift of probing electromagnetic frequency, reflected from a moving surface. However, using probing wavelength 4 orders of magnitude longer, microwave diagnostics has some specific advantages as compared with laser diagnostics, namely: measurements inside the microwave-transparent media, which spectrum is much more wide than the spectrum of optically transparent media; for microwave measurements the reflecting surfaces of media, but all jumps of medium parameters - density, dielectric permittivity, conductivity; for microwave technique due to its wavelength all practically important hydrodynamical jumps are smooth. The results of application of the microwave technique were presented in the paper, which demonstrate capabilities of diagnostics of various dynamic processes using single equipment, namely: liners and massive objects launching; shock-to-detonation transition in HE; propagation of steady detonation waves; laminar HE combustion etc. In all conducted investigations the using of the microwave technique gives a big amount of interesting experimental information which is inaccessible for the other traditional experimental techniques.

  2. Modelling and solutions to the linear stability of a detonation wave in the kinetic frame

    Microsoft Academic Search

    M. Pandolfi Bianchi; A. J. Soares

    2011-01-01

    The analysis of linear stability of a steady detonation wave is formulated for the first time at the kinetic level in the frame of the Boltzmann equation extended to reacting gases. Within this context and for a reversible reaction, the stability problem is carried out, in agreement with most classical papers on gas detonation, through a normal mode approach for

  3. Rotating Detonation Wave Propulsion: Experimental Challenges, Modeling, and Engine Concepts (Invited)

    E-print Network

    Texas at Arlington, University of

    THE primary form of chemical energy conversion for jet and liquid rocket propulsion comes fromRotating Detonation Wave Propulsion: Experimental Challenges, Modeling, and Engine Concepts energy release from detonations for propulsion or as a power source.1a This interest actually predates

  4. Experimentation and direct numerical simulation of self-similar convergent detonation wave

    NASA Astrophysics Data System (ADS)

    Sorin, R.; Matignon, C.; Bozier, O.

    The propagation of self similar convergent detonation wave in TATB-based explosive composition was studied both experimentally and numerically. The device constists in a 50 mm cylinder of TATB surrounded by an HMX tube. The detonation in HMX overdrives the detonation in TATB which adapts to the propagation velocity with a convergent front at centerline. We measured a curvature of ? = -21.2 m-1 for propagation velocity of 8750 m/s, which extends the knowledge of the (Dn,?) law. A wide ranged EOS/reaction rate model inspired from previous work of Wescott et al. was calibrated to reproduce both the run-to-detonation distance and the newly extended (Dn,?) law for the 1D sligthly curved detonation theory. 2D Direct Numerical Simulations (DNS) were made on fine resolved mesh grid for the experimental configuration and for various driver velocities. The simulation reproduces the experimental data both qualitatively (overall detonation structure) and quantitatively (? = -25.4 m-1).

  5. Mathematical modeling of a rotating detonation wave in a hydrogen-oxygen mixture

    Microsoft Academic Search

    S. A. Zhdan; F. A. Bykovskii; E. F. Vedernikov

    2007-01-01

    A two-dimensional unsteady mathematical model of spin detonation in an annular cylindrical ramjet-type combustor is formulated.\\u000a The wave dynamics in the combustor filled by a hydrogen-oxygen mixture is studied numerically.

  6. Exploratory Study of Conductivity in Detonation Waves D. R. Wilson,

    E-print Network

    Texas at Arlington, University of

    from those early investigations are not directly pertinent to combustion applications at higher use of a facility used previously to study the conductivity of high-enthalpy, seeded air plasmas.7 of detonation were achieved. This detonated gas passed through a test section that enabled the average conduc

  7. Importance of unsteady force and heating to particle interaction with shock/detonation waves

    NASA Astrophysics Data System (ADS)

    Ling, Yue; Haselbacher, Andreas; Balachandar, S.

    2012-03-01

    Particle interaction with shock/detonation waves is a fundamental phenomenon. In many practical applications, shock/detonation waves interact with a very large number of particles and the scales of interest are typically much larger than particle size. Therefore, fully resolving the flow around all the particles is impractical. Therefore, rigorous models for momentum and energy exchange in the interaction is very important. Detonation/shock-particle interaction is strongly time-dependent, so unsteady mechanisms play important roles in momentum and energy transfer. A model that includes unsteady contributions to force and heating is proposed. The model is used to investigate the interaction between an aluminum particle and a nitromethane CJ detonation wave. The results computed by the present model show good agreement with DNS results. The standard drag and heat-transfer correlations that ignore unsteady mechanisms lead to significant errors.

  8. Detonation wave velocity and curvature of IRX-4 and PBXN-110

    SciTech Connect

    Lemar, E.R.; Forbes, J.W.; Sutherland, G.T. [Naval Surface Warfare Center, Indian Head Division, Silver Spring, Maryland 20903-5640 (United States)

    1996-05-01

    Detonation velocities and wave front curvatures were measured for bare cylindrical charges of IRX-4 and PBXN-110 charges. Steady detonation waves propagated in IRX-4 charges with diameters as small as 33 mm. The failure diameter of IRX-4 is between 25 and 33 mm. A fit of detonation velocity data gives 5.83 mm/{mu}s for IRX-4{close_quote}s infinite diameter velocity. Detonation wave curvature experiments have been done on 48 mm diameter cylindrical IRX-4 charges with lengths from 9 to 28 cm. The data have been fitted accurately over the entire charge diameters using the natural logarithm of a Bessel function. {copyright} {ital 1996 American Institute of Physics.}

  9. Simulation of laser interaction with ablative plasma and hydrodynamic behavior of laser supported plasma

    SciTech Connect

    Tong Huifeng; Yuan Hong [Institute of Fluid Physics, Chinese Academy of Engineering Physics, P.O. Box 919-101, Mianyang, Sichuan 621900 (China); Tang Zhiping [CAS Key Laboratory for Mechanical Behavior and Design of Materials, Department of Mechanics and Mechanical Engineering, University of Science and Technology of China, Hefei 230026 (China)

    2013-01-28

    When an intense laser beam irradiates on a solid target, ambient air ionizes and becomes plasma, while part of the target rises in temperature, melts, vaporizes, ionizes, and yet becomes plasma. A general Godunov finite difference scheme WENO (Weighted Essentially Non-Oscillatory Scheme) with fifth-order accuracy is used to simulate 2-dimensional axis symmetrical laser-supported plasma flow field in the process of laser ablation. The model of the calculation of ionization degree of plasma and the interaction between laser beam and plasma are considered in the simulation. The numerical simulations obtain the profiles of temperature, density, and velocity at different times which show the evolvement of the ablative plasma. The simulated results show that the laser energy is strongly absorbed by plasma on target surface and that the velocity of laser supported detonation (LSD) wave is half of the ideal LSD value derived from Chapman-Jouguet detonation theory.

  10. Simulation of laser interaction with ablative plasma and hydrodynamic behavior of laser supported plasma

    NASA Astrophysics Data System (ADS)

    Tong, Huifeng; Yuan, Hong; Tang, Zhiping

    2013-01-01

    When an intense laser beam irradiates on a solid target, ambient air ionizes and becomes plasma, while part of the target rises in temperature, melts, vaporizes, ionizes, and yet becomes plasma. A general Godunov finite difference scheme WENO (Weighted Essentially Non-Oscillatory Scheme) with fifth-order accuracy is used to simulate 2-dimensional axis symmetrical laser-supported plasma flow field in the process of laser ablation. The model of the calculation of ionization degree of plasma and the interaction between laser beam and plasma are considered in the simulation. The numerical simulations obtain the profiles of temperature, density, and velocity at different times which show the evolvement of the ablative plasma. The simulated results show that the laser energy is strongly absorbed by plasma on target surface and that the velocity of laser supported detonation (LSD) wave is half of the ideal LSD value derived from Chapman-Jouguet detonation theory.

  11. Detonation wave structure studies in high explosives by means of proton radiography

    NASA Astrophysics Data System (ADS)

    Kolesnikov, Sergei; Dudin, Sergei; Mintsev, Victor; Utkin, Alexander; Demidov, Victor; Fertman, Alexander; Golubev, Alexander; Katz, Mark; Markov, Nikolai; Sharkov, Boris; Smirnov, Gennady; Turtikov, Vladimir

    2007-06-01

    Proton radiography is the unique experimental technique for obtaining direct information about important material characteristics of real solid objects under dynamic conditions. The aim of the present work is the application of this method to the investigation of evolution of density in shock and detonation waves in high explosives (HE). Obtained information will be very useful for the improvement of existing detonation models and equations of state of HE. For this purpose a proton radiography facility for dynamic experiments on the basis of TWAC-ITEP accelerator is being constructed. A special containment chamber for explosive experiments was built. Static experiments with imitators of detonating HE charges were performed; as a result the proton radiographic images of imitators with time resolution of up to 10 ns were obtained. Dynamic experiments on the registration of detonation wave structure in pressed TNT are underway.

  12. Shock wave and detonation propagation through U-bend tubes

    Microsoft Academic Search

    S. M. Frolov; V. S. Aksenov; I. O. Shamshin

    2007-01-01

    The objective of the research outlined in this paper is to provide experimental and computational data on initiation, propagation, and stability of gaseous fuel–air detonations in tubes with U-bends implying their use for design optimization of pulse detonation engines (PDEs). The experimental results with the U-bends of two curvatures indicate that, on the one hand, the U-bend of the tube

  13. Particle response to shock waves in solids: dynamic witness plate/PIV method for detonations

    NASA Astrophysics Data System (ADS)

    Murphy, Michael J.; Adrian, Ronald J.

    2007-08-01

    Studies using transparent, polymeric witness plates consisting of polydimethlysiloxane (PDMS) have been conducted to measure the output of exploding bridge wire (EBW) detonators and exploding foil initiators (EFI). Polymeric witness plates are utilized to alleviate particle response issues that arise in gaseous flow fields containing shock waves and to allow measurements of shock-induced material velocities to be made using particle image velocimetry (PIV). Quantitative comparisons of velocity profiles across the shock waves in air and in PDMS demonstrate the improved response achieved by the dynamic witness plate method. Schlieren photographs complement the analysis through direct visualization of detonator-induced shock waves in the witness plates.

  14. 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.

  15. Characterization of Detonation Wave Propagation in LX-17 Near the Critical Diameter

    SciTech Connect

    Tran, T D; Tarver, C M; Maienschein, J; Lewis, P; Pastrone, R; Lee, R S; Roeske, F

    2002-06-14

    A new Detonation Profile Test (DPT) was developed to measure simultaneously the detonation wave breakout profile and the average detonation velocity at the breakout surface. The test evaluated small cylindrical samples with diameter up to 19.08 mm and length up to 33 mm. The experiment involved initiating a LX-17 cylindrical specimen and recording the wave breakout using a fast streaking electronic camera. The initiation was done using a PBX-9407 pellet (1.630 g/cm{sup 3}), which has a Chapman-Jouguet (C-J) pressure close to that of LX-17. The acceptor breakout surface had a 2 mm wide by 1 mm deep groove that provided a step in the recorded breakout profile for velocity determination. A 532-nm laser light illuminated the specimen surface. A streak camera looking perpendicular to the groove, recorded the extinction of the laser light as the detonation wave emerged from the surface. This technique provided a high-resolution spatial and temporal profile of the wave curvature as well as accurate timing of the propagating wave over the last millimeter of the sample. The measured groove depth and recorded travel time were then used to calculate the average detonation wave velocity. Results for 12.7 mm diameter unconfined LX-17 charges showed detonation velocity in the range between 6.79 and 7.06 km/s for parts up to 33 mm long. Since LX-17 can not sustain detonation at less than 7.3 km/s , these waves were definitely failing. Experiments with confined 12.7 mm diameter and unconfined 19.1 mm diameter samples showed wave velocities in the range of 7.4-7.6 km/s, values approaching steady state conditions at infinite diameter. Both unconfined and confined charges show no sensitivity to density variations in the range between 1.890-1.915 g/cm{sup 3}. Experiments with 15.88 mm and 19.08 mm diameters gave velocities in the range between 7.2-7.45 km/s, values close to that expected for failure. The velocity measurement has an estimated experimental error in the range of 2%, which is large enough to complicate data analysis. The Ignition and Growth model for LX-17 was compared to the results. The effects of density, confinement and charge diameter on wave breakout profiles and detonation wave velocity were accurately reproduced. A comparative analysis of the experimental breakout patterns and the calculated wave curvatures for the densities and dimensions was also determined.

  16. Atomistic Studies of Shock-Wave and Detonation Phenomena in Energetic Materials

    NASA Astrophysics Data System (ADS)

    Budzevich, Mikalai M.

    2011-07-01

    The major goal of this PhD project is to investigate the fundamental properties of energetic materials, including their atomic and electronic structures, as well as mechanical properties, and relate these to the fundamental mechanisms of shock wave and detonation propagation using state-of-the-art simulation methods. The first part of this PhD project was aimed at the investigation of static properties of energetic materials (EMs) with specific focus on 1,3,5-triamino-2,4,6-trinitrobenzene (TATB). The major goal was to calculate the isotropic and anisotropic equations of state for TATB within a range of compressions not accessible to experiment, and to make predictions of anisotropic sensitivity along various crystallographic directions. The second part of this PhD project was devoted to applications of a novel atomic-scale simulation method, referred to as the moving window molecular dynamics (MW-MD) technique, to study the fundamental mechanisms of condensed-phase detonation. Because shock wave is a leading part of the detonation wave, MW-MD was applied to demonstrate its effectiveness in resolving fast non-equilibrium processes taking place behind the shock-wave front during shock-induced solid-liquid phase transitions in crystalline aluminum. Next, MW-MD was used to investigate the fundamental mechanisms of detonation propagation in condensed energetic materials. Due to the chemical complexity of real EMs, a simplified AB model of a prototypical energetic material was used. The AB interatomic potential, which describes chemical bonds, as well as chemical reactions between atoms A and B in an AB solid, was modified to investigate the mechanism of the detonation wave propagation with different reactive activation barriers. The speed of the shock or detonation wave, which is an input parameter of MW-MD, was determined by locating the Chapman-Jouguet point along the reactive Hugoniot, which was simulated using the constant number of particles, volume, and temperature (NVT) ensemble in MD. Finally, the detonation wave structure was investigated as a function of activation barrier for the chemical reaction AB+B ? A+ BB. Different regimes of detonation propagation including 1-D laminar, 2-D cellular, and 3-D spinning and turbulent detonation regimes were identified.

  17. Computation of the critical gas layer thickness by means of the ratio to detonation wave propagation

    SciTech Connect

    Shebeko, Yu.N.; Korol'chenko, A.Ya.; Eremenko, O.Ya.

    1988-05-01

    The numerical modeling method of detonation wave propagation proposed in earlier work for gas volumes of finite thickness was used in this paper with a more adequate description of the chemical kinetics to compute the critical gas layer thickness of the mixtures 2H/sub 2/ + O/sub 2/, 29% H/sub 2/ + 71% air, 23% H/sub 2/ + 77% air, and 4H/sub 2/ + O/sub 2/. To model the detonation wave propagation, two-dimensional gas dynamic equations in the Lagrange description were taken, supplemented by the chemical kinetics equation in Arrhenius form. A formula was derived for computing specific heat liberation. Results are presented of computed detonation wave velocities for different values of the effective specific heat of combustion as well as for values of the Chapman-Jouguet velocity for the mixtures.

  18. Physical model for shock-wave initiation of detonation of plastic-bounded TATB-based explosive

    Microsoft Academic Search

    K. F. Grebenkin; A. L. Zherebtsov; M. V. Taranik; S. K. Tsarenkova; A. S. Shnitko

    2006-01-01

    A physical model for the macrokinetics of shock-wave initiation of detonation in plastic-bounded TATB-based explosive is proposed\\u000a that is based on the assumption of electronic energy transfer from hot spots. Results of numerical modeling of experiments\\u000a on shock-wave initiation of detonation of LX-17 are presented.

  19. Microwave interferometer for shock wave, detonation, and material motion measurements

    Microsoft Academic Search

    Gene H. McCall; Wayne L. Bongianni; Gilbert A. Miranda

    1985-01-01

    A microwave interferometer system which provides a continuous measurement of the position of interfaces, such as shock fronts, detonation fronts, or material surfaces, has been developed. The use of low-mass microcoaxial cable, some of which is commercially available, and stripline for conducting the microwave signal into the interior of an experiment makes the perturbation of the measuring system on the

  20. Equilibrium and stability properties of detonation waves in the hydrodynamic limit of a kinetic model

    NASA Astrophysics Data System (ADS)

    Marques, Wilson, Jr.; Jacinta Soares, Ana; Pandolfi Bianchi, Miriam; Kremer, Gilberto M.

    2015-06-01

    A shock wave structure problem, like the one which can be formulated for the planar detonation wave, is analyzed here for a binary mixture of ideal gases undergoing the symmetric reaction {{A}1}+{{A}1}\\rightleftharpoons {{A}2}+{{A}2}. The problem is studied at the hydrodynamic Euler limit of a kinetic model of the reactive Boltzmann equation. The chemical rate law is deduced in this frame with a second-order reaction rate, in a chemical regime such that the gas flow is not far away from the chemical equilibrium. The caloric and the thermal equations of state for the specific internal energy and temperature are employed to close the system of balance laws. With respect to other approaches known in the kinetic literature for detonation problems with a reversible reaction, this paper aims to improve some aspects of the wave solution. Within the mathematical analysis of the detonation model, the equation of the equilibrium Hugoniot curve of the final states is explicitly derived for the first time and used to define the correct location of the equilibrium Chapman–Jouguet point in the Hugoniot diagram. The parametric space is widened to investigate the response of the detonation solution to the activation energy of the chemical reaction. Finally, the mathematical formulation of the linear stability problem is given for the wave detonation structure via a normal-mode approach, when bidimensional disturbances perturb the steady solution. The stability equations with their boundary conditions and the radiation condition of the considered model are explicitly derived for small transversal deviations of the shock wave location. The paper shows how a second-order chemical kinetics description, derived at the microscopic level, and an analytic deduction of the equilibrium Hugoniot curve, lead to an accurate picture of the steady detonation with reversible reaction, as well as to a proper bidimensional linear stability analysis.

  1. Diffraction of a planar strong detonation wave by a moving three-dimensional thin body

    NASA Astrophysics Data System (ADS)

    Fengqing, Zhuang

    1986-03-01

    An analytic solution is obtained for the diffraction of a planar strong detonation wave by a three-dimensional thin body moving in the opposite direction. The planform and the thickness distribution of the body can be arbitrary and the speed of the body can be either supersonic or subsonic relative to the undisturbed stream ahead of the wave or to that behind the wave. The solution is a generalization of the previous solution of Ting and Gunzburger for the shock diffraction.

  2. Chemical reaction and equilibration mechanisms in detonation waves

    SciTech Connect

    Tarver, C.M. [Lawrence Livermore National Laboratory, P.O. Box 808, L-282, Livermore, California 94551 (United States)

    1998-07-01

    Experimental and theoretical evidence for the nonequilibrium Zeldovich-von Neumann-Doring (NEZND) theory of self-sustaining detonation is presented. High density, high temperature transition state theory is used to calculate unimolecular reaction rate constants for the initial decomposition of gaseous norbornene, liquid nitromethane, and solid, single crystal pentaerythritol tetranitrate as functions of shock temperature. The calculated rate constants are compared to those derived from experimental induction time measurements at various shock and detonation states. Uncertainties in the calculated shock and von Neumann spike temperatures are the main drawbacks to calculating these reaction rates. Nanosecond measurements of the shock temperatures of unreacted explosives are necessary to reduce these uncertainties. {copyright} {ital 1998 American Institute of Physics.}

  3. Operation Hardtack. Project 6. 4. Wave form of electromagnetic pulse from nuclear detonations

    Microsoft Academic Search

    F. Lavicka; G. Lang

    1985-01-01

    The wave form of the electromagnetic pulse resulting from nuclear detonations, especially at very high altitudes is analyzed. In particular, broadband measurements were made from 0 to 10 Mc at ranges up to 460 statue miles. The measurements were a continuation of those made during Operation Plumbbob, although improvements in equipment were incorporated wherever possible. The increased cataloging of EM-pulse

  4. Particle response to shock waves in solids: dynamic witness plate\\/PIV method for detonations

    Microsoft Academic Search

    Michael J. Murphy; Ronald J. Adrian

    2007-01-01

    Studies using transparent, polymeric witness plates consisting of polydimethlysiloxane (PDMS) have been conducted to measure the output of exploding bridge wire (EBW) detonators and exploding foil initiators (EFI). Polymeric witness plates are utilized to alleviate particle response issues that arise in gaseous flow fields containing shock waves and to allow measurements of shock-induced material velocities to be made using particle

  5. Parallel Algorithm for Detonation Wave Simulation P. Ravindran and F. K. Lu

    E-print Network

    Texas at Arlington, University of

    environment. 2 Governing Equations The time-dependent conservation equations are those for an inviscid, non-heatParallel Algorithm for Detonation Wave Simulation P. Ravindran and F. K. Lu Aerodynamics Research- tational time without compromising accuracy. The flow was assumed to be unsteady, inviscid and non-heat

  6. Shock-Wave and Detonation Studies at ITEP-TWAC Proton Radiography Facility

    NASA Astrophysics Data System (ADS)

    Kolesnikov, Sergey; Dudin, Sergey; Lavrov, Vladimir; Nikolaev, Dmitry; Mintsev, Victor; Shilkin, Nikolay; Ternovoi, Vladimir; Utkin, Alexander; Yakushev, Vladislav; Yuriev, Denis; Fortov, Vladimir; Golubev, Alexander; Kantsyrev, Alexey; Shestov, Lev; Smirnov, Gennady; Turtikov, Vladimir; Sharkov, Boris; Burtsev, Vasily; Zavialov, Nikolay; Kartanov, Sergey; Mikhailov, Anatoly; Rudnev, Alexey; Tatsenko, Mikhail; Zhernokletov, Mikhail

    2011-06-01

    In recent years studies of shock and detonation wave phenomena at extreme dynamic conditions were performed at proton radiography facility developed at the 800 MeV proton beam line of ITEP Terawatt Accelerator (ITEP-TWAC). The facility provides a multi-frame imaging capability at 50 ?m spatial and 70 ns temporal resolution. The results of latest studies conducted there are presented, including explosion and detonation of pressed and emulsion high explosives, shock-induced dense non-ideal plasma of argon and xenon and shock loading of non-uniform metal surfaces. New compact explosive generators developed specifically for a use at proton radiography facilities are also presented.

  7. Physical model for shock-wave initiation of detonation in pressed fine crystalline xplosives

    Microsoft Academic Search

    K. F. Grebenkin

    1998-01-01

    A physical model is proposed for the reaction kinetics of heterogeneous explosives under shock-wave initiation of detonation.\\u000a The model is based on the assumption that the molecular crystals of the explosive materials have semiconductor properties.\\u000a The model can account for the experimentally observed strong dependence of the shock-wave sensitivity of pressed explosives\\u000a on their initial density and temperature. The proposed

  8. Studies on Shock Attenuation in Plastic Materials and Applications in Detonation Wave Shaping

    NASA Astrophysics Data System (ADS)

    Khurana, Ritu; Gautam, P. C.; Rai, Rajwant; Kumar, Anil; Sharma, A. C.; Singh, Manjit, Dr

    2012-07-01

    Pressure in plastic materials attenuates due to change of impedance, phase change in the medium and plastic deformation. A lot of theoretical and experimental efforts have been devoted to the attenuation of shock wave produced by the impact of explosive driven flyer plate. However comparatively less work has been done on the attenuation of shock waves due to contact explosive detonation. Present studies deal with the attenuation of explosive driven shock waves in various plastic materials and its applications in design of Hybrid Detonation Wave Generator In present work shock attenuating properties of different polymers such as Perspex, Teflon, nylon, polypropylene and viton has been studied experimentally using rotating mirror streak camera and electrical position pins. High explosive RDX/TNT and OCTOL of diameter 75-100mm and thickness 20 to 50mm were detonated to induce shock wave in the test specimens. From experimental determined shock velocity at different locations the attenuation in shock pressure was calculated. The attenuation of shock velocity with thickness in the material indicates exponential decay according to relation US = UOexp(-ax). In few of the experiments manganin gauge of resistance 50 ohms was used to record stress time profile across shock wave. The shock attenuation data of Viton has successfully been used in the design of hybrid detonation wave generator using Octol as high explosive. While selecting a material it was ensured that the attenuated shock remains strong enough to initiate an acceptor explosive. Theoretical calculation were supported by Autodyne 2D hydro-code simulation which were validated with the experiments conducted using high speed streak photography and electrical shock arrival pins. Shock attenuation data of Perspex was used to establishing card gap test and wedge test in which test items is subjected to known pressure pulse by selecting the thickness of the plastic material.

  9. Experimental measurements of the detonation wave profile in a TATB based explosive

    NASA Astrophysics Data System (ADS)

    Bouyer, V.; Doucet, M.; Decaris, L.

    We report results of the experimental measurements of the detonation wave profile of the TATB based plastic bonded explosive T2 (97 w. % of TATB) using VISAR and Heterodyne Velocimetry (HV - same as Photon Doppler Velocimetry). The experiment consists in initiating a detonation wave in a 15 mm diameter cylinder of explosive using an explosive wire detonator and an explosive booster. In order to obtain the particle velocity history in the reaction zone, we measure particle velocity at the interaction of the detonation front with an aluminized window or the free surface velocity of a metallic foil. Lithium Fluoride (LIF), PMMA and steel have been tested. Several shots have been performed for different lengths of explosive. We compare the VISAR and HV measurements. With LIF and steel, VISAR and HV diagnostics give very similar profiles. The ZND profile obtained on LIF is resolved with both techniques. With PMMA, HV gives a more accurate profile than VISAR in the reaction zone. There is no evidence of the influence of the explosive cylinder length.

  10. Numerical investigation of shock wave reflections near the head ends of rotating detonation engines

    NASA Astrophysics Data System (ADS)

    Zhou, R.; Wang, J.-P.

    2013-09-01

    The influence of various chamber geometries on shock wave reflections near the head end of rotating detonation engines was investigated. A hydrogen/air one-step chemical reaction model was used. The results demonstrated that the variation in flow field along the radial direction was not obvious when the chamber width was small, but became progressively more obvious as the chamber width increased. The thrust increased linearly, and the detonation height and the fuel-based gross specific impulse were almost constant as the chamber width increased. Near the head end, shock waves reflected repeatedly between the inner and outer walls. Both regular and Mach reflections were found near the head end. The length of the Mach stem increased as the chamber length increased. When the chamber width, chamber length and injection parameters were the same, the larger inner radius resulted in more shock wave reflections between the inner and outer walls. The greater the ratio of the chamber width to the inner radius, the weaker the shock wave reflection near the head end. The detonation height on the outer wall and the thrust, both increased correspondingly, while the specific impulse was almost constant as the inner radius of the chamber increased. The numerical shock wave reflection phenomena coincided qualitatively with the experimental results.

  11. Deflagration-to-detonation transition by amplification of acoustic waves in type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Charignon, C.; Chièze, J.-P.

    2013-02-01

    Aims: We study a new mechanism for deflagration-to-detonation transition in thermonuclear supernovae (SNe Ia), based on the formation of shocks by amplification of sound waves in the steep density gradients of white dwarfs envelopes. We characterise, in terms of wavelength and amplitude, the perturbations which will ignite a detonation after their amplification. Methods: This study was performed using the well tested HERACLES code, a conservative hydrodynamical code, validated in the present specific application by an analytical description of the propagation of sound waves in white dwarfs. Thermonuclear combustion of the carbon oxygen fuel was treated with the ?-chain nuclear reactions network. Results: In planar geometry we found the critical parameter to be the height of shock formation. When it occurs in the inner dense regions (? > 106 g cm-3) detonation is inevitable but can take an arbitrarily long time. We found that ignition can be achieved for perturbation as low as Mach number: M ~ 0.005, with heating times compatible with typical explosion time scale (a few seconds). On the opposite no ignition occurs when shocks initiated by small amplitude or large wavelength form further away in less dense regions. We show finally that ignition is also achieved in a spherical self-gravitating spherical model of cold C+O white dwarf of 1.430 M?, but due to the spherical damping of sound waves it necessitates stronger perturbation (M ~ 0.02). Small perturbations (M ~ 0.003) could still trigger detonation if a small helium layer is considered. In the context of SNe Ia, one has to consider further the initial expansion of the white dwarf, triggered by the deflagration, prior to the transition to detonation. As the star expands, gradients get flatter and ignition requires increasingly strong perturbations.

  12. Particle response to shock waves in solids: dynamic witness plate\\/PIV method for detonations

    Microsoft Academic Search

    Michael J. Murphy; Ronald J. Adrian

    2007-01-01

    Studies using transparent, polymeric witness plates consisting of polydimethlysiloxane (PDMS) have been conducted to measure\\u000a the output of exploding bridge wire (EBW) detonators and exploding foil initiators (EFI). Polymeric witness plates are utilized\\u000a to alleviate particle response issues that arise in gaseous flow fields containing shock waves and to allow measurements of\\u000a shock-induced material velocities to be made using particle

  13. Initiation of detonation by steady planar incident shock waves

    NASA Astrophysics Data System (ADS)

    Edwards, D. H.; Thomas, G. O.; Williams, T. L.

    1981-11-01

    The initiation of detonation by planar shocks is studied in a vertical shock tube in which a removable diaphragm allows the generated shock to be transmitted into the gas mixture, without any reflection at the interface. Streak schlieren photography confirms that a quasi-steady shock reaction complex is formed prior to the shock acceleration phase. The steady phase enabled the induction delay time to be measured in a direct manner, and microwave interferometry, along with pressure transducers, gave an accurate value for the delay time. The shock acceleration was determined from the locus of the exothermic reaction zone, and it is shown that the time coherence of energy release between particles entering the shock front at different times leads to the formation of reactive centers which are characteristic of mild ignition. Ignition delay data obtained by the incident shock method for oxyacetylene, diluted with nitrogen, are compared with those obtained by the reflected shock technique and shown to have advantages in high heat capacity systems.

  14. The exhaust flow field of a rotating detonation-wave engine

    NASA Astrophysics Data System (ADS)

    Kailasanath, Kazhikathra; Schwer, Douglas

    2012-11-01

    Rotating detonation-wave engines (RDE) are a form of continuous detonation-wave engine. They potentially provide further gains than an intermittent or pulsed detonation-wave engine (PDE). However, significantly less work has been done on this concept when compared to the PDE. Last year, we presented the details of the injection system on the overall flow field in an RDE. In this talk, we focus on the effects of adding an exhaust plenum to this idealized RDE. While the overall exhaust flow shows that a recirculation zone sets up behind the RDE when a plenum is added, the net effect on the flow field within the RDE and on performance is found to be small. However, the slight modification to the flow field may impact the design of suitable nozzles for this device. This is explored further with the addition of a simple conical nozzle. This nozzle reduces the size of the recirculation zone and also reduces the temperature in the plume but has little effect on the flow field inside the RDE. Work Sponsored by ONR through NRL 6.1 Computational Physics Task Area.

  15. Microwave interferometer for shock wave, detonation, and material motion measurements

    SciTech Connect

    McCall, G.H.; Bongianni, W.L.; Miranda, G.A.

    1985-08-01

    A microwave interferometer system which provides a continuous measurement of the position of interfaces, such as shock fronts, detonation fronts, or material surfaces, has been developed. The use of low-mass microcoaxial cable, some of which is commercially available, and stripline for conducting the microwave signal into the interior of an experiment makes the perturbation of the measuring system on the experiment small. Other microwave systems have measured the time of peak amplitude of a reflected signal, but the present system with proper matching produces a continuous record of position as a function of time. It is believed that this technique can be used to replace most uses of electrical contact or fiber-optic pins in high-explosive experiments. The amount of data far exceeds that which it is possible to obtain from pins or optical fibers. The matching of the microcoax to the microwave generator has an important effect on the accuracy of the technique. The effect of matching on accuracy will be described in detail, and matching methods will be discussed. A position accuracy of 0.2 mm has been attained. Several methods for extracting position information as a function of time are possible. These techniques are discussed, and their application to the analysis of an experiment is demonstrated. The data from the interferometer system is compared to a streak camera record in a phased, shock-breakout experiment. Agreement is quite good, and the superiority of this method over the pin method is demonstrated by comparing details of the streak and interferometer records.

  16. Explosion Waves and Shock Waves. VII. The Velocity of Detonation in Cast T.N.T

    Microsoft Academic Search

    W. B. Cybulski; W. Payman; D. W. Woodhead

    1949-01-01

    The Buxton rotating-mirror camera has been used for the precise determination of velocities of detonation in cylinders of cast T.N.T. The method has an advantage over the indirect Dautriche method in that it affords a direct measure of the velocity. The effects on the velocity of detonation of the following variables have been studied in so far as each can

  17. Operation Hardtack. Project 6. 4. Wave form of electromagnetic pulse from nuclear detonations

    SciTech Connect

    Lavicka, F.; Lang, G.

    1985-09-01

    The wave form of the electromagnetic pulse resulting from nuclear detonations, especially at very high altitudes is analyzed. In particular, broadband measurements were made from 0 to 10 Mc at ranges up to 460 statue miles. The measurements were a continuation of those made during Operation Plumbbob, although improvements in equipment were incorporated wherever possible. The increased cataloging of EM-pulse wave-form data was very useful in the field of nuclear surveillance. The presence of a second stage in a thermonuclear device can be detected within certain range and system-bandwidth limitations. Correlations of first and second crossover points with total yield, noted in previously recorded wave forms, are supported by these test results. The agreement obtained from the Shot Holly sky wave crossover times indicates that these measurements are relatively independent of propagation and, therefore, more valuable than field strength for determining yield.

  18. The evolution and cellular structure of a detonation subsequent to a head-on interaction with a shock wave

    SciTech Connect

    Botros, Barbara B.; Zhu, YuJian; Lee, John H.S. [Department of Mechanical Engineering, McGill University, Montreal, Quebec (Canada); Ng, Hoi Dick; Ju, Yiguang [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

    2007-12-15

    This paper analyzes the results of a head-on collision between a detonation and a planar shock wave. The evolution of the detonation cellular structure subsequent to the frontal collision was examined through smoked foil experiments. It is shown that a large reduction in cell size is observed following the frontal collision, and that the detonation cell widths are correlated well with the chemical kinetic calculations from the ZND model. From chemical kinetic calculations, the density increase caused by shock compression appears to be the main factor leading to the significant reduction in cell size. It was found that depending on the initial conditions, the transition to the final cellular pattern can be either smooth or spotty. This phenomenon appears to be equivalent to Oppenheim's strong and mild reflected shock ignition experiments. The difference between these two transitions is, however, more related to the stability of the incident detonation and the strength of the perturbation generated by the incident shock. (author)

  19. Methods for processing experimental data in microwave diagnostics of shock waves and detonation

    NASA Astrophysics Data System (ADS)

    Sedov, Alexander; Rodionov, Alexey; Kanakov, Vladimir

    2013-06-01

    Microwave interferometry is a promising method of unperturbing diagnostics of short-time processes. It is a bit less effective than the optical methods in accuracy, but it provides a researcher with more capabilities, in particular, for measurements in optically opaque media. The classic methods for processing experimental interferograms using extremums allow to obtain data on motion of investigated objects with the resolution of a quarter of wavelength of probing radiation. It is insufficient for majority of practical applications. Use of the mathematical methods for processing output signals of the receiver allows to improve the method resolution significantly and to obtain motion measurement errors of 0.05...0.1 of wavelength or even less. This paper presents schemes of conduction and brief description of the methods for processing a series of tests, which were performed in RFNC-VNIIEF with use of radio interferometer having length of wave of probing radiation ? = 3.2 mm, namely: to measure velocity of stationary detonation; to measure depth of detonation initiation by shock wave; to investigate shock compressibility of dielectric materials; to investigate dynamics of constructions.

  20. Detonation Structure Simulation with AMROC Ralf Deiterding

    E-print Network

    Barr, Al

    combustion. In a self-sustaining detonation, shock and reac- tion zone propagate essentially is the propagation of detonation waves in gaseous media. Detonations are shock-induced combustion waves that inter combustion devices. It was found that detonation waves usually exhibit non-neglectable instationary multi

  1. Collision of plane thermonuclear detonation waves in a preliminarily compressed DT mixture

    NASA Astrophysics Data System (ADS)

    Khishchenko, K. V.; Charakhch'yan, A. A.

    2015-03-01

    The paper deals with a one-dimensional problem on symmetric irradiation of a plane DT fuel layer with a thickness 2 H and density ?0 ? 100? s (where ? s is the density of the DT fuel in the solid state at atmospheric pressure and a temperature of 4 K) by two identical monoenergetic proton beams with a kinetic energy of 1 MeV, an intensity of 1019 W/cm2, and a duration of 50 ps. The problem is solved in the framework of one-fluid two-temperature hydrodynamic model that takes into account the equation of state for hydrogen, electron and ion heat conductivities, kinetics of the DT reaction, plasma self-radiation, and plasma heating by ?-particles. The irradiation of the fuel results in the appearance of two counterpropagating detonation waves to the fronts of which rarefaction waves are adjacent. The efficiency of the DT reaction after the collision (reflection from the plane of symmetry) of the detonation waves depends on the spatial homogeneity of thermodynamic functions between the fronts of the reflected detonation waves. At H?0 ? 1 g/cm2, the gain factor is G ? 200, whereas at H?0 ? 5 g/cm2, it is G > 2000. As applied to a cylindrical target that is ignited from ends and in which the cylinder with the fuel is surrounded by a heavy magnetized shell, the obtained values of the burn-up and gain factors are maximum possible. To estimate the ignition energy E ig of a cylindrical target by using solutions to the one-dimensional problem, a quasi-one-dimensional model is developed. The model assumes that the main mechanism of target ignition is fuel heating by ?-particles. The trajectories of ?-particles are limited by a cylindrical surface with a given radius, which is a parameter of the model and is identified with the fuel radius in the target and the radii of the irradiating proton beams. This model reproduces the well-known theoretical dependence E ig ˜ ?{0/-2} and yields E ig = 160 kJ as a lower estimate of the ignition energy for ?0 = 100? s ? 22 g/cm3.

  2. Md and HD Simulations of Detonation Wave Refraction at the Border of Tatb-Like he and BE

    Microsoft Academic Search

    I. V. Derbenev; V. V. Dremov; F. A. Sapozhnikov; A. V. Karavaev; V. A. Bychenkov; L. V. Khardina; N. D. Sokolova; L. Soulard

    2009-01-01

    Here we present results of Molecular Dynamics (MD) and Hydro Dynamics (HD) investigations into the process of detonation wave refraction on the border with the inert material. The effects of broad reaction zone in TATB-like HE and high sound speed in inert material (Be) were of particular interest. To make possible direct comparison of MD and HD approaches the parameters

  3. Shock wave physics and detonation physics --- a stimulus for the emergence of numerous new branches in science and engineering

    Microsoft Academic Search

    Peter O. K. Krehl

    2011-01-01

    In the period of the Cold War (1945-1991), Shock Wave Physics and Detonation Physics (SWP&DP) --- until the beginning of WWII mostly confined to gas dynamics, high-speed aerodynamics, and military technology (such as aero- and terminal ballistics, armor construction, chemical explosions, supersonic gun, and other firearms developments) --- quickly developed into a large interdisciplinary field by its own. This rapid

  4. External Detonations

    Microsoft Academic Search

    Charles E. Needham

    \\u000a Previous chapters have dealt with blast loads on walls and exterior surfaces of buildings or structures. In this section I\\u000a will briefly discuss how blast wave energy enters a building through windows and doors and the internal loads caused by external\\u000a detonations. In general the walls floors and roof of a structure are much more substantial than the doors and

  5. Surface chemical reaction of laser ablated aluminum sample for detonation initiation

    SciTech Connect

    Kim, Chang-hwan; Yoh, Jack J. [School of Mechanical and Aerospace Engineering, Seoul National University, 599 Kwanakro, Kwanakgu, Seoul, Korea 151-742 (Korea, Republic of)

    2011-05-01

    We explore the evolution of metal plasma generated by high laser irradiances and its effect on the surrounding air by using shadowgraph images after laser pulse termination; hence the formation of laser supported detonation and combustion processes has been investigated. The essence of the paper is in observing initiation of chemical reaction between ablated aluminum plasma and oxygen from air by inducing high power laser pulse (>1000 mJ/pulse) and conduct a quantitative comparison of chemically reactive laser initiated waves with the classical detonation of exploding aluminum (dust) cloud in air. Findings in this work may lead to a new method of initiating detonation from metal sample in its bulk form without the need of mixing nano-particles with oxygen for initiation.

  6. Parallel Adaptive Simulation of Weak and Strong Transverse-Wave Structures in H2-O2 Detonations

    SciTech Connect

    Deiterding, Ralf [ORNL] [ORNL

    2010-01-01

    Two- and three-dimensional simulation results are presented that investigate at great detail the temporal evolution of Mach reflection sub-structure patterns intrinsic to gaseous detonation waves. High local resolution is achieved by utilizing a distributed memory parallel shock-capturing finite volume code that employs block-structured dynamic mesh adaptation. The computational approach, the implemented parallelization strategy, and the software design are discussed.

  7. Shock wave physics and detonation physics — a stimulus for the emergence of numerous new branches in science and engineering

    Microsoft Academic Search

    Peter O. K. Krehl

    2011-01-01

    In the period of the Cold War (1945?1991), Shock Wave Physics and Detonation Physics\\u000a (SWP&DP) — until the beginning of WWII mostly confined to gas dynamics, high-speed\\u000a aerodynamics, and military technology (such as aero- and terminal ballistics, armor\\u000a construction, chemical explosions, supersonic gun, and other firearms developments) —\\u000a quickly developed into a large interdisciplinary field by its own. This rapid

  8. Fundamentals of rotating detonations

    NASA Astrophysics Data System (ADS)

    Hishida, Manabu; Fujiwara, Toshi; Wolanski, Piotr

    2009-04-01

    A rotating detonation propagating at nearly Chapman-Jouguet velocity is numerically stabilized on a two-dimensional simple chemistry flow model. Under purely axial injection of a combustible mixture from the head end of a toroidal section of coaxial cylinders, the rotating detonation is proven to give no average angular momentum at any cross section, giving an axial flow. The detonation wavelet connected with an oblique shock wave ensuing to the downstream has a feature of unconfined detonation, causing a deficit in its propagation velocity. Due to Kelvin-Helmholtz instability existing on the interface of an injected combustible, unburnt gas pockets are formed to enter the junction between the detonation and oblique shock waves, generating strong explosions propagating to both directions. Calculated specific impulse is as high as 4,700 s.

  9. Reaction Zone of Steady-State Detonation Waves in Dinitrodiazapentane and RDX

    NASA Astrophysics Data System (ADS)

    Kolesnikov, Sergey A.; Utkin, Alexander V.; Ananin, Alexander V.; Pershin, Sergey V.; Fortov, Vladimir E.

    2004-07-01

    The detonation waves structure of pressed high explosives (HE) dinitrodiazapentane (DNP) and RDX with different initial densities was investigated by the laser interferometric system VISAR. The experimental results are the profiles of surface velocity of foils placed at the boundary between a HE sample and a water "window". In DNP the Von Neumann spike was observed for all studied initial densities, and one of the most interesting features in these results is the unexpectedly large ratio (reaching two) of the von Neumann peak to C-J point parameters. Earlier it was found that in RDX with initial particle size of ˜80 ?m existed the critical initial density of 1.73 g/cm3 above which the monotone increase of parameters in the reaction zone was observed. Now it is shown that in acetone-recrystallized RDX with initial particle size of ˜5 ?m this critical density is much lower (˜1.30-1.35 g/cm3). Above this density the Von Neumann spike was observed. The experimental results are explained by chemical reaction in the shock front and influence of initial density, particle sizes and preparation conditions of samples on the efficiency of the "hot spots" and thus on the rate of this reaction.

  10. Numerical Optimisation in Non Reacting Conditions of the Injector Geometry for a Continuous Detonation Wave Rocket Engine

    NASA Astrophysics Data System (ADS)

    Gaillard, T.; Davidenko, D.; Dupoirieux, F.

    2015-06-01

    The paper presents the methodology and the results of a numerical study, which is aimed at the investigation and optimisation of different means of fuel and oxidizer injection adapted to rocket engines operating in the rotating detonation mode. As the simulations are achieved at the local scale of a single injection element, only one periodic pattern of the whole geometry can be calculated so that the travelling detonation waves and the associated chemical reactions can not be taken into account. Here, separate injection of fuel and oxidizer is considered because premixed injection is handicapped by the risk of upstream propagation of the detonation wave. Different associations of geometrical periodicity and symmetry are investigated for the injection elements distributed over the injector head. To analyse the injection and mixing processes, a nonreacting 3D flow is simulated using the LES approach. Performance of the studied configurations is analysed using the results on instantaneous and mean flowfields as well as by comparing the mixing efficiency and the total pressure recovery evaluated for different configurations.

  11. Md and HD Simulations of Detonation Wave Refraction at the Border of Tatb-Like he and BE

    NASA Astrophysics Data System (ADS)

    Derbenev, I. V.; Dremov, V. V.; Sapozhnikov, F. A.; Karavaev, A. V.; Bychenkov, V. A.; Khardina, L. V.; Sokolova, N. D.; Soulard, L.

    2009-12-01

    Here we present results of Molecular Dynamics (MD) and Hydro Dynamics (HD) investigations into the process of detonation wave refraction on the border with the inert material. The effects of broad reaction zone in TATB-like HE and high sound speed in inert material (Be) were of particular interest. To make possible direct comparison of MD and HD approaches the parameters of the models used in HD were determined from MD simulations, i.e. we used MD results to choose parameters for Be and HE equations of state and to evaluate parameters of elastic-plastic transition models for these materials. HD and MD results have been compared and analyzed.

  12. SOLVING CURVED DETONATION RIEMANN PROBLEMS Bruce Bukiet

    E-print Network

    Bukiet, Bruce

    the one parameter family of behind states comprising the burned Hugoniot and wave curves. For curved and show how the curved detonation jump conditions can be solved to compute the curved detonation Hugoniot

  13. Electronic Thermal Conductivity during Combustion-Wave Propagation from Hot Spots in Detonating TATB

    Microsoft Academic Search

    K. F. Grebenkin; A. L. Zherebtsov; M. V. Taranik

    2005-01-01

    A model for the electronic thermal conductivity of shock-compressed TATB is developed using experimental data on the growth kinetics of its electrical conductivity. It is shown that electronic thermal conduction can be the main mechanism of energy transfer from hot spots in detonating explosives.

  14. Simulation of detonation wave interaction using an ignition and growth model

    Microsoft Academic Search

    J. K. Clutter; D. Belk

    2002-01-01

    A kinetics based detonation model has been integrated with an existing object oriented hydrocode. The model has been demonstrated to correctly predict the shock initiation of explosives and captures key features such as the von Neumann pressure spike and reaction zone. Comparisons to experimental flyer plate data for both primary and secondary class explosives have been performed and key features

  15. A Virtual Test Facility for the Efficient Simulation of Solid Material Response under Strong Shock and Detonation Wave Loading

    SciTech Connect

    Deiterding, Ralf [ORNL

    2006-01-01

    A Virtual Test Facility (VTF) for studying the three-dimensional dynamic response of solid materials subject to strong shock and detonation waves has been constructed as part of the research program of the Center for Simulating the Dynamic Response of Materials at the California Institute of Technology. The compressible fluid flow is simulated with a Cartesian finite volume method and treating the solid as an embedded moving body, while a Lagrangian finite element scheme is employed to describe the structural response to the hydrodynamic pressure loading. A temporal splitting method is applied to update the position and velocity of the boundary between time steps. The boundary is represented implicitly in the fluid solver with a level set function that is constructed on-the-fly from the unstructured solid surface mesh. Block-structured mesh adaptation with time step refinement in the fluid allows for the efficient consideration of disparate fluid and solid time scales. We detail the design of the employed object-oriented mesh refinement framework AMROC and outline its effective extension for fluid-structure interaction problems. Further, we describe the parallelization of the most important algorithmic components for distributed memory machines and discuss the applied partitioning strategies. As computational examples for typical VTF applications, we present the dynamic deformation of a tantalum cylinder due to the detonation of an interior solid explosive and the impact of an explosion-induced shock wave on a multi-material soft tissue body.

  16. On the possibility of the realization of combustion and detonation waves in a system of nuclear isomers

    NASA Astrophysics Data System (ADS)

    Arutyunyan, R. V.; Akhrameev, E. V.; Bolshov, L. A.; Kondratenko, P. S.; Tkalya, E. V.

    2014-02-01

    The possible regimes of the propagation of a self-sustained fluorescence wave of long-lived nuclear isomers, which is initiated by transitions to the nearest short-lived level owing to the absorption of X-ray photons and inelastic collisions of electrons in a plasma, have been analyzed. It has been found that, when the energy exchange between the nuclear subsystem and plasma is due to absorption and emission of photons, the fluorescence wave can propagate in the fast (with a near-light velocity) deflagration regime induced by the radiative heat transfer mechanism. When the energy exchange between the subsystems is nonradiative, the (slower) detonation regime becomes significant. The implementation of each of the two regimes requires certain conditions on the characteristics of the system.

  17. Dynamics of detonations and explosions: Detonations; International Colloquium on Dynamics of Explosions and Reactive Systems, 12th, University of Michigan, Ann Arbor, July 23-28, 1989, Technical Papers

    Microsoft Academic Search

    A. L. Kuhl; J.-C. Leyer; A. A. Borisov; W. A. Sirignano

    1991-01-01

    The present volume on the dynamics of gaseous detonations, detonation initiation and transmission, multiphase detonations, and nonideal detonations and boundary effects, discusses the detonability of hydrocarbon fuels in air, the detonation of cryogenic gaseous hydrogen-oxygen mixtures, chemical kinetics-detonation structure correlations for gaseous explosives, the initiation of hydrogen-air detonations by turbulent fluorine-air jets, and the initiation of a detonation wave due

  18. Plane thermonuclear detonation waves initiated by proton beams and quasi-one-dimensional model of fast ignition

    NASA Astrophysics Data System (ADS)

    Charakhch'yan, Alexander A.; Khishchenko, Konstantin V.

    2015-03-01

    The one-dimensional (1D) problem on bilatiral irradiation by proton beams of the plane layer of condensed DT mixture with length $2H$ and density $\\rho_0 \\leqslant 100\\rho_s$, where $\\rho_s$ is the fuel solid-state density at atmospheric pressure and temperature of 4 K, is considered. The proton kinetic energy is 1 MeV, the beam intensity is $10^{19}$ W/cm$^2$ and duration is 50 ps. A mathematical model is based on the one-fluid two-temperature hydrodynamics with a wide-range equation of state of the fuel, electron and ion heat conduction, DT fusion reaction kinetics, self-radiation of plasma and plasma heating by alpha-particles. If the ignition occurs, a plane detonation wave, which is adjacent to the front of the rarefaction wave, appears. Upon reflection of this detonation wave from the symmetry plane, the flow with the linear velocity profile along the spatial variable $x$ and with a weak dependence of the thermodynamic functions of $x$ occurs. An appropriate solution of the equations of hydrodynamics is found analytically up to an arbitrary constant, which can be chosen so that the analytical solution describes with good accuracy the numerical one. The gain with respect to the energy of neutrons $G\\approx 200$ at $H\\rho_0 \\approx 1$ g/cm$^2$, and $G>2000$ at $H\\rho_0 \\approx 5$ g/cm$^2$. To evaluate the ignition energy $E_{\\mathrm{ig}}$ of cylindrical targets, the quasi-1D model, limiting trajectories of $\\alpha$-particles by a cylinder of a given radius, is suggested. The model reproduces the known theoretical dependence $E_{\\mathrm{ig}} \\sim \\rho_0^{-2}$ and gives $E_{\\mathrm{ig}} = 160$ kJ for $\\rho_0 = 100\\rho_s \\approx 22$ g/cm$^3$.

  19. Bidirectional slapper detonators in spherical explosion systems

    NASA Astrophysics Data System (ADS)

    Martinez, Ernest C.

    1990-11-01

    A bidirectional slapper detonator has been proven effective for producing a spherically expanding shock wave. Two bridge foils are used to propel flyers in opposite directions, thereby initiating two explosive pellets, each embedded in one hemisphere of a spherical system. This detonation system produces a nearly perfect spherically expanding detonation front.

  20. A summary of hydrogen-air detonation experiments

    SciTech Connect

    Guirao, C.M.; Knystautas, R.; Lee, J.H.

    1989-05-01

    Dynamic detonation parameters are reviewed for hydrogen-air-diluent detonations and deflagration-to-detonation transitions (DDT). These parameters include the characteristic chemical length scale, such as the detonation cell width, associated with the three-dimensional cellular structure of detonation waves, critical transmission conditions of confined detonations into unconfined environments, critical initiation energy for unconfined detonations, detonability limits, and critical conditions for DDT. The detonation cell width, which depends on hydrogen and diluent concentrations, pressure, and temperature, is an important parameter in the prediction of critical geometry-dependent conditions for the transmission of confined detonations into unconfined environments and the critical energies for the direct initiation of unconfined detonations. Detonability limits depend on both initial and boundary conditions and the limit has been defined as the onset of single head spin. Four flame propagation regimes have been identified and the criterion for DDT in a smooth tube is discussed. 108 refs., 28 figs., 5 tabs.

  1. Measurement of CO2-laser-induced shock pressures above and below LSD-wave thresholds

    Microsoft Academic Search

    R. E. Beverly III; C. T. Walters

    1976-01-01

    TEA-CO2-laser-induced shock pressures in aluminum, cellulose acetate, and polymethyl methacrylate (PMMA) targets were measured by both backsurface and in-material techniques as functions of peak laser power density and ambient air pressure. We report the first experimental observation of shock-pressure profiles in metallic and nonmetallic targets above and below the thresholds for laser-supported-detonation-wave (LSD-wave) initiation. For aluminum irradiations above threshold conditions,

  2. 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.

  3. Rotary detonation engine

    Microsoft Academic Search

    Eidelman

    1988-01-01

    In an engine of the type wherein the combustion of the fuel mixture is carried out by a detonation wave, the improvement is described comprising: (a) an elongated shaft having a central longitudinal chamber, the chamber being supplied with a detonatable fuel mixture; (b) axisymmetrical elements integral with the shaft and disposed along the length thereof; (c) means for selectively

  4. Dynamic aspects of detonations; International Colloquium on Dynamics of Explosions and Reactive Systems, 13th, Nagoya, Japan, July 28-Aug. 2, 1991, Technical Papers

    NASA Astrophysics Data System (ADS)

    Kuhl, A. L.; Leyer, J.-C.; Borisov, A. A.; Sirignano, W. A.

    Various papers on the dynamic aspects of detonations are presented. Individual subjects addressed include: high-resolution numerical simulations for 2D unstable detonations, simulation of cellular structure in a detonation wave, Mach reflection of detonation waves, mechanism of unstable detonation front origin, numerical modeling of galloping detonation, experimental study of the fine structure in spin detonation, influence of fluorocarbon on H2O2Ar detonation, digial signal processing analysis of soot foils, cylindrical detonations in methane-oxygen-nitrogen mixtures, structure of reaction waves behind oblique shocks, ignition in a complex Mach structure, simulations for detonation initiation behind reflected shock waves. Also discussed are: limiting tube diameter of gaseous detonation, mechanisms of detonation propagation in a porous medium propagation and extinction of detonation waves in tube bundles, structure and velocity deficit of gaseous detonation in rough tubes, possible method for quenching of a gaseous detonation, effect of hollow heterogeneities on nitromethane detonation.

  5. Burning and detonation

    SciTech Connect

    Forest, C.A.

    1981-01-01

    The effect of confined burning explosive abutting nonburning explosive in a variety of one-dimensional geometries has been studied by numerical simulation, demonstrating the effects of confinement, burning rate, and shock sensitivity. The model includes porous bed burning, compressible solids and gases, shock-induced decomposition with possible transition to detonation, and constant velocity ignition waves. Two-phase flow, gas relative to solid, is not allowed. Because the shock sensitivity of an explosive changes with explosive density and because such experimental data is rarely available over a range of densities, a method for the calculation of the density effect on the initial-shock-pressure, distance-to-detonation (wedge test) measure of shock sensitivity is given. The calculation uses the invariance with density of the shock particle velocity as a function of time to detonation, and the experimental data at some high density.

  6. Dynamic aspects of detonations; International Colloquium on Dynamics of Explosions and Reactive Systems, 13th, Nagoya, Japan, July 28Aug. 2, 1991, Technical Papers

    Microsoft Academic Search

    A. L. Kuhl; J.-C. Leyer; A. A. Borisov; W. A. Sirignano

    1993-01-01

    Various papers on the dynamic aspects of detonations are presented. Individual subjects addressed include: high-resolution numerical simulations for 2D unstable detonations, simulation of cellular structure in a detonation wave, Mach reflection of detonation waves, mechanism of unstable detonation front origin, numerical modeling of galloping detonation, experimental study of the fine structure in spin detonation, influence of fluorocarbon on H2O2Ar detonation,

  7. NEW DETONATION CONCEPTS FOR PROPULSION AND POWER GENERATION

    E-print Network

    Texas at Arlington, University of

    for an airbreathing, rotating detonation wave engine (RDE) is presented. The engine consists of a steady inlet system detonation wave engines, and his enthusiasm led to my own interest which has resulted in some of the work and assistance with using pulsed detonation engines for linear power generation. I would like to thank all

  8. PRELUDE TO A DOUBLE DEGENERATE MERGER: THE ONSET OF MASS TRANSFER AND ITS IMPACT ON GRAVITATIONAL WAVES AND SURFACE DETONATIONS

    SciTech Connect

    Dan, Marius; Rosswog, Stephan [School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen (Germany); Guillochon, James; Ramirez-Ruiz, Enrico, E-mail: m.dan@jacobs-university.de, E-mail: rosswog@jacobs-university.de, E-mail: jfg@ucolick.org, E-mail: enrico@ucolick.org [TASC, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2011-08-20

    We present the results of a systematic numerical study of the onset of mass transfer in double degenerate binary systems and its impact on the subsequent evolution. All investigated systems belong to the regime of direct impact, unstable mass transfer. In all of the investigated cases, even those considered unstable by conventional stability analysis, we find a long-lived mass transfer phase continuing for as many as several dozen orbital periods. This settles a recent debate sparked by a discrepancy between earlier smoothed particle hydrodynamics (SPH) calculations that showed disruptions after a few orbital periods and newer grid-based studies in which mass transfer continued for tens of orbits. The number of orbits a binary survives sensitively depends on the exact initial conditions. We find that the approximate initial conditions that have been used in most previous SPH calculations have a serious impact on all stages of the evolution from the onset of mass transfer up to the final structure of the remnant. We compare 'approximate' initial conditions where spherical stars are placed at an initial separation obtained from an estimate of the Roche lobe size with 'accurate' initial conditions that were constructed by carefully driving the binary system to equilibrium by a relaxation scheme. Simulations that use the approximate initial conditions underestimate the initial separation when mass transfer sets in, which yields a binary that only survives for only a few orbits and thus a rapidly fading gravitational wave signal. Conversely, the accurate initial conditions produce a binary system in which the mass transfer phase is extended by almost two orders of magnitude in time, resulting in a gravitational wave signal with amplitude and frequency that remain essentially constant up until merger. As we show that these binaries can survive at small separation for hundreds of orbital periods, their associated gravitational wave signal should be included when calculating the gravitational wave foreground (although expected to be below Laser Interferometer Space Antenna's sensitivity at these high frequencies). We also show that the inclusion of the entropy increase associated with shock heating of the accreted material reduces the number of orbits a binary survives given the same initial conditions, although the effect is not as pronounced when using the appropriate initial conditions. The use of accurate initial conditions and a correct treatment of shock heating allows for a reliable time evolution of the temperature, density, and angular momentum, which are important when considering thermonuclear events that may occur during the mass transfer phase and/or after merger. Our treatment allows us to accurately identify when surface detonations may occur in the lead-up to the merger, as well as the properties of final merger products.

  9. A multiphase model for compressible flows with interfaces, shocks, detonation waves and cavitation

    Microsoft Academic Search

    Richard Saurel; Olivier Lemetayer

    2001-01-01

    A compressible multiphase unconditionally hyperbolic model is proposed. It is able to deal with a wide range of applications: interfaces between compressible materials, shock waves in condensed multiphase mixtures, homogeneous two-phase flows (bubbly and droplet flows) and cavitation in liquids. Here we focus on the generalization of the formulation to an arbitrary number of fluids, and to mass and energy

  10. Analysis of Laser-Generated Impulse In An Airbreathing Pulsed Detonation Engine: Part 1

    NASA Astrophysics Data System (ADS)

    Richard, Jacques C.; Myrabo, Leik N.

    2005-04-01

    An investigation is performed on an airbreathing laser propulsion (LP) system designed to propel a 1.4 m diameter, 120-kg (dry mass) vehicle called the Lightcraft Technology Demonstrator (LTD) into low Earth orbit, along with its opto-electronics payload. The LTD concept led directly to the model ?200 lightcraft — recently demonstrated in laboratory and flight experiments at White Sands Missile Range, NM at the High Energy Laser Systems Test Facility (HELSTF), using the 10-kW PLVTS CO2 laser. The pulsed detonation wave engine (PDE) employs repetitively ignited, laser-supported detonation (LSD) waves to develop thrust by expanding high pressure blast waves over an annular, interior shroud surface. Numerical simulation of thruster impulse is accomplished with a 1-D cylindrical model of blast waves propagating radially outward from a laser-generated `line-source' of high temperature, high pressure air. External airflow over the LTD structure is also analyzed to predict basic engine/vehicle drag characteristics, including inlet total pressure recovery, and captured air mass flow rate — all projected vs. flight Mach number and altitude.

  11. CIT: Detonators

    Microsoft Academic Search

    Davis R. Thomsen; Loretta A. Weiss

    2012-01-01

    Detonators are: (1) exploding bridge wire (EBW) initiators, (2) exploding foil initiators (EFI), and (3) explosive surface initiators (covered under 'high explosives'). Controls are: (1) NSG DUL: 6.A.1., (2) WA: 1.A.7, (3) EU: 1A007, 3A232, and (4) HS: 3603.00. Nuclear uses are to initiate HE charge of an implosion-type nuclear weapon. Other uses are commercial mining operations (EBWs), and downhole

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

    Microsoft Academic Search

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

    2009-01-01

    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

  13. INITIATION OF THE DETONATION IN THE GRAVITATIONALLY CONFINED DETONATION MODEL OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Seitenzahl, Ivo R. [Department of Physics, University of Chicago, Chicago, IL 60637 (United States); Meakin, Casey A.; Truran, James W. [Joint Institute for Nuclear Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Lamb, Don Q. [Center for Astrophysical Thermonuclear Flashes, University of Chicago, Chicago, IL 60637 (United States)

    2009-07-20

    We study the initiation of the detonation in the gravitationally confined detonation (GCD) model of Type Ia supernovae (SNe Ia). In this model, ignition occurs at one or several off-center points, resulting in a burning bubble of hot ash that rises rapidly, breaks through the surface of the star, and collides at a point on the stellar surface opposite the breakout, producing a high-velocity inwardly directed flow. Initiation of the detonation occurs spontaneously in a region where the length scale of the temperature gradient extending from the flow (in which carbon burning is already occurring) into unburned fuel is commensurate to the range of critical length scales which have been derived from one-dimensional simulations that resolve the initiation of a detonation. By increasing the maximum resolution in a truncated cone that encompasses this region, beginning somewhat before initiation of the detonation occurs, we successfully simulate in situ the first gradient-initiated detonation in a whole-star simulation. The detonation emerges when a compression wave overruns a pocket of fuel situated in a Kelvin-Helmholtz cusp at the leading edge of the inwardly directed jet of burning carbon. The compression wave preconditions the temperature in the fuel in such a way that the Zel'dovich gradient mechanism can operate and a detonation ensues. We explore the dependence of the length scale of the temperature gradient on spatial resolution and discuss the implications for the robustness of this detonation mechanism. We find that the time and the location at which initiation of the detonation occurs varies with resolution. In particular, initiation of a detonation had not yet occurred in our highest resolution simulation by the time we ended the simulation because of the computational demand it required. However, it may detonate later. We suggest that the turbulent shear layer surrounding the inwardly directed jet provides the most favorable physical conditions, and therefore the most likely location, for initiation of a detonation in the GCD model.

  14. Detonation shock dynamics of Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Dunkley, Scott D.; Sharpe, Gary J.; Falle, Sam A. E. G.

    2013-06-01

    The wavefront propagation of curved detonation waves in carbon-oxygen cores and helium shells of Type Ia supernova (SNIa) progenitors is determined via a detonation shock dynamics approach. A level set implementation is used to track the front, which is evolved according to intrinsic quasi-steady, quasi-one-dimensional detonation speed-curvature relationships. The effects of curvature are analysed for a number of SNIa models from the literature by comparing the results to those obtained by wavefront propagation at the local planar detonation speed. The differences can be very profound in the low-density regions where detonation models are exploited to produce intermediate-mass elements. In detonable low-density regions, the speed tends to be much lower than the planar wave analysis predicts, while the subsonic driving zone controlling the dynamics is many orders of magnitude shorter. However, the lower shock temperatures ensure that the complete reaction lengths are orders of magnitude longer when curvature effects are properly accounted. Furthermore, the material cannot be detonated in sufficiently low-density regions due to a curvature-induced extinction limit. The implications for and need to reassess the nucleosynthesis and intermediate-mass element production of SNIa detonation models is discussed.

  15. Internal Detonation Velocity Measurements Inside High Explosives

    SciTech Connect

    Benterou, J; Bennett, C V; Cole, G; Hare, D E; May, C; Udd, E

    2009-01-16

    In order to fully calibrate hydrocodes and dynamic chemistry burn models, initiation models and detonation models of high explosives, the ability to continuously measure the detonation velocity within an explosive is required. Progress on an embedded velocity diagnostic using a 125 micron diameter optical fiber containing a chirped fiber Bragg grating is reported. As the chirped fiber Bragg grating is consumed by the moving detonation wave, the physical length of the unconsumed Bragg grating is monitored with a fast InGaAs photodiode. Experimental details of the associated equipment and data in the form of continuous detonation velocity records within PBX-9502 are presented. This small diameter fiber sensor has the potential to measure internal detonation velocities on the order of 10 mm/{micro}sec along path lengths tens of millimeters long.

  16. Modeling two-dimensional detonations with detonation shock dynamics

    SciTech Connect

    Bdzil, J.B.; Stewart, D.S.

    1988-01-01

    In any explosive device, the chemical reaction of the explosive takes place in a thin zone just behind the shock front. The finite size of the reaction zone is responsible for: the pressure generated by the explosive being less near the boundaries, for the detonation velocity being lower near a boundary than away from it, and for the detonation velocity being lower for a divergent wave than for a plane wave. In computer models that are used for engineering design calculations, the simplest treatment of the explosive reaction zone is to ignore it completely. Most explosive modeling is still done this way. The neglected effects are small when the reaction zone is very much smaller than the explosive's physical dimensions. When the ratio of the explosive's detonation reaction-zone length to a representative system dimension is of the order of 1/100, neglecting the reaction zone is not adequate. An obvious solution is to model the reaction zone in full detail. At present, there is not sufficient computer power to do so economically. Recently we have developed an alternative to this standard approach. By transforming the governing equations to the proper intrinsic-coordinate frame, we have simplified the analysis of the two-dimensional reaction-zone problem. When the radius of curvature of the detonation shock is large compared to the reaction-zone length, the calculation of the two-dimensional reaction zone can be reduced to a sequence of one-dimensional problems. 9 refs., 5 figs.

  17. Detonation Simulation with the AMROC Framework Ralf Deiterding

    E-print Network

    Barr, Al

    , shock and reaction zone propagate es- sentially with an identical speed dCJ that is approximated to good in instationary shock waves propagating perpendicular to the detonation front. A complex flow pattern is formed phenomena are not very well understood. One of these phenomena is the propagation of detonation waves

  18. 2011 International Workshop on Detonation for Propulsion November 14-15, 2011

    E-print Network

    Texas at Arlington, University of

    investigations of rotating detonation wave engines, and are currently involved in a DARPA-funded investigation, Korea Summary of Recent Research on Detonation Wave Engines at UTA Donald R. Wilson,* Frank K. Lu pulse detonation engine (PDE) research at UTA is provided to lay the background for the development

  19. Measurement of Detonation Velocity by Doppler Effect at Three-Centimeter Wavelength

    Microsoft Academic Search

    Melvin A. Cook; Ray L. Doran; Glen J. Morris

    1955-01-01

    This article describes the application of the Doppler principle to the measurement of detonation velocity with three-centimeter electromagnetic radiation. The method makes use of the ionized wave front in detonation as a moving reflecting surface for electromagnetic waves. Detonation velocities for four different solid explosives were calculated from the observed Doppler frequencies and the indices of refraction, which were measured

  20. Characterizing Detonator Output Using Dynamic Witness Plates

    Microsoft Academic Search

    Michael John Murphy; Ronald J. Adrian

    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

  1. CHARACTERIZING DETONATOR OUTPUT USING DYNAMIC WITNESS PLATES

    Microsoft Academic Search

    Michael J. Murphy; Ronald J. Adrian

    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

  2. Detonation properties of the insensitive explosive TATB

    Microsoft Academic Search

    R. K. Jackson; R. C. Weingart

    1976-01-01

    The detonation properties of various compositions of the insensitive explosive TATB were investigated using thin flyer plates. These flyer plates were accelerated by electrically exploding metal foils. The divergence of the detonation wave in TATB is improved for compositions of lower-density, lower-binder-percentage, and smaller HE particle size. Increasing the velocity or the diameter of the flyer plate or increasing the

  3. Detonation Phenomena of PBX Microsamples

    NASA Astrophysics Data System (ADS)

    Plaksin, Igor; Campos, Jose; Ribeiro, Jose; Mendes, Ricardo

    2001-06-01

    Detonation study of PBX micro-samples, based on HMX with an inert (HTPB, epoxy) or energetic (GAP) binder was developed on the mesoscale level, using the multifiber optical probes, of 50 ?m resolution, connected directly to a fast electronic streak camera with 0.5 ns of temporal resolution. This record system allows the 2D direct observation of particle-to-particle successive transition of ?-waves through the interparticle binder space. The obtained results show, when the individual coarse HMX particles are subjected to a strong shock wave (30 GPa), the pulsed, double phase, process of energy release (a fast initial phase followed by relatively slow second phase). Also it can be observed the cooperative formation of a multi-head detonation front (DF) in collections of particles surrounded by the binder and the synergetic effect, behind the DF, by the appearing of spatial-temporal dissipative structures, followed by the self-organization of DF oscillations.

  4. Methods for proving the equivalency of detonator performance

    SciTech Connect

    Munger, Alan C [Los Alamos National Laboratory; Akinci, Adrian A [Los Alamos National Laboratory; Thomas, Keith A [Los Alamos National Laboratory; Clarke, Steve A [Los Alamos National Laboratory; Martin, Eric S [Los Alamos National Laboratory; Murphy, Michael J [Los Alamos National Laboratory

    2009-01-01

    One of the challenges facing engineers is developing newer, safer detonators that are equivalent to devices currently in use. There is no clear consensus on an exact method for drawing equivalence of detonators. This paper summarizes our current efforts to develop diagnostics addressing various aspects of detonator design to better quantify and prove equivalency. We consider various optical techniques to quantify the output pressure and output wave shape. The development of a unique interpretation of streak camera breakouts, known as the apparent center of initiation, will be discussed as a metric for detonation wave shape. Specific examples apply these techniques to the comparison of a new laser-driven detonator with an existing exploding bridgewire (EBW) detonator. Successes and short-comings of the techniques will be discussed.

  5. Spin detonation in reactive particles-oxidizing gas flow

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Grönig, H.

    1991-08-01

    Development of detonation waves in corn starch particles-oxidizing gas mixtures was studied in a horizontal circular tube having an inside diameter of 141 mm and a test section length of 17.4 m. The results show that a stable self-sustained detonation can be achieved in such a heterogeneous system. The sequence of the transition process was essentially recognized as follows: (1) initial particle ignition, (2) pressure wave amplification by coherent energy release, (3) unsteady reaction shock, and (4) spin detonation. Thus transverse waves play a dominant role in stable detonation propagation in this two-phase system. The spin structure exists both on the circumference and in the inner region of the cross section. For a stable single spin detonation there are two constant velocities at the wave front: axial propagation velocity and angular velocity.

  6. 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.

  7. High-Resolution Numerical Simulation and Analysis of Mach Reflection Structures in Detonation Waves in Low-Pressure H2–O2–Ar Mixtures: A Summary of Results Obtained with the Adaptive Mesh Refinement Framework AMROC

    DOE PAGESBeta

    Deiterding, Ralf

    2011-01-01

    Numerical simulation can be key to the understanding of the multidimensional nature of transient detonation waves. However, the accurate approximation of realistic detonations is demanding as a wide range of scales needs to be resolved. This paper describes a successful solution strategy that utilizes logically rectangular dynamically adaptive meshes. The hydrodynamic transport scheme and the treatment of the nonequilibrium reaction terms are sketched. A ghost fluid approach is integrated into the method to allow for embedded geometrically complex boundaries. Large-scale parallel simulations of unstable detonation structures of Chapman-Jouguet detonations in low-pressure hydrogen-oxygen-argon mixtures demonstrate the efficiency of the described techniquesmore »in practice. In particular, computations of regular cellular structures in two and three space dimensions and their development under transient conditions, that is, under diffraction and for propagation through bends are presented. Some of the observed patterns are classified by shock polar analysis, and a diagram of the transition boundaries between possible Mach reflection structures is constructed.« less

  8. Doppler interferometry study of unstable detonations

    NASA Astrophysics Data System (ADS)

    Lee, J. J.; Dupré, G.; Knystautas, R.; Lee, J. H.

    1995-10-01

    Near-limit detonations are highly unstable and characterized by very large longitudinal velocity fluctuations that can range from 0.4 to 1.8 times the normal Chapman-Jouguet value. The period of the fluctuations also varies over a wide range from a few to a hundred tube diameters. In an attempt to establish a criterion for detonation limits, the velocity fluctuations of near-limit detonations are studied. A novel microwave Doppler technique based on a single coaxial mode has been developed for this purpose to give an unambiguous quasi-continuous velocity measurement of the detonation wave over the entire length of its travel. The near-limit unstable behavior in the detonable stoichiometric mixtures of hydrocarbons (C2H2, C2H4, C2H6, C3H8) with O2, air or N2O, tested in this work, have been characterized by four distinct modes of unstable behavior. This classification allows a qualitative description of the wide range of velocity fluctuations occurring near the detonation limit, including galloping waves.

  9. Demonstration of a multi-channel, low-profile wire gauge for tracing wave development and detonation turning in explosives

    SciTech Connect

    Skidmore, Bradley E [Los Alamos National Laboratory; Novak, Alan M [Los Alamos National Laboratory; Zucker, Jonathan M [Los Alamos National Laboratory; Parker, Jr, Gary R [Los Alamos National Laboratory; Dickson, Peter [Los Alamos National Laboratory; Foley, Timothy J [Los Alamos National Laboratory; Trebs, Adam A [Los Alamos National Laboratory

    2010-01-01

    The multi-channel low-profile wire gauge is a device which measures high pressure wave position via the continuous variation in length of a conductor in conjunction with a fiducial, allowing in situ measurement of wave front curvature during wave development. The gauge's low profile ({approx}250 {micro}m) and high resolution measurements (up to 0.5 nanoseconds) make it minimally intrusive and highly responsive, with a typically wave position accuracy of {+-}1 mm. Gauge construction and data analysis methods are described and waveforms are presented for Detasheet and N-9 explosives.

  10. Detonation and Transition to Detonation in Horizontal Water-Filled Pipes

    NASA Astrophysics Data System (ADS)

    Bitter, Neal P.; Shepherd, Joseph E.

    2012-11-01

    Detonations and deflagration-to-detonation transition (DDT) are experimentally studied in horizontal pipes which are partially filled with water. The gas layer above the water is stoichiometric hydrogen-oxygen at 1 bar. The detonation wave produces oblique shock waves in the water, which focus at the bottom of the pipe due to the curvature of the walls. This results in peak pressures at the bottom of the pipe that are 4-6 times greater than the peak detonation pressure. Such pressure amplification is measured for water depths of 0.25, 0.5, 0.75, 0.87, and 0.92 pipe diameters. Focusing of the oblique shock waves is studied further by measuring the circumferential variation of pressure when the water depth is 0.5 pipe diameters, and reasonable agreement with theoretical modeling is found. Failure of the detonation waves was not observed, even for water depths as high as 0.92 pipe diameters. Transition to detonation also occurred at every water height, and transition distance did not vary significantly with water height.

  11. Detonation Phenomena of PBX Microsamples

    NASA Astrophysics Data System (ADS)

    Plaksin, I.; Campos, J.; Ribeiro, J.; Mendes, R.

    2002-07-01

    Detonation study of PBX micro-samples, based in HMX with an inert (HTPB, epoxy) or energetic (GAP) binder was performed on the meso-scale level, using the multifiber optical probes of 50 mum of maximum resolution, connected directly to a fast electronic streak camera with 0.6 ns resolution. The direct 2D observation of particle to particle successive transition of transmitted shock wave, through the binder, allows to analyse and to discuss, not only the cooperative formation of a multihead detonation front (DF), in the collection of particles surrounded by binder, but also the synenergetic effect, behind the DF, by the appearing of dissipative structures drawing spatial and temporal DF oscillations.

  12. Ignition and Growth Modeling of Detonating TATB Cones and Arcs

    Microsoft Academic Search

    Craig Tarver; Steven Chidester

    2007-01-01

    . The Ignition and Growth reactive flow model for the detonating triaminotrinitrobenzene (TATB)-based explosives LX-17 and PBX 9502 is applied to recent experimental data on converging conical charges plus confined and unconfined arc charges. The conical charges are at first overdriven by the converging flow and then fail to detonate as the radial rarefaction wave slows the reaction rate. Unconfined

  13. Transition of combustion to detonation in gasoline-air mixtures

    Microsoft Academic Search

    N. N. Smirnov; A. P. Boichenko

    1986-01-01

    The goal of the present study is to determine the time and point at which detonation develops and study the dependence of these parameters on initial mixture temperature. The experiments were performed on a test stand provided with sensors and recording equipment to determine flow rate, temperature, pressure, and composition of the mixture supplied to the detonation wave generator, the

  14. Structural Response of Piping to Internal Gas Detonation

    Microsoft Academic Search

    Joseph E. Shepherd

    2009-01-01

    Detonation waves in gas-filled piping or tubing pose special challenges in analysis and prediction of structural response. The challenges arise due the nature of the detonation process and the role of fluid-structure interaction in determining the prop- agation and arrest of fractures. Over the past ten years, our laboratory has been engaged in studying this problem and devel- oping methodologies

  15. Computation of a diverging Comp-B detonation

    SciTech Connect

    Bukiet, B.G.

    1989-01-01

    The expansion which occurs in diverging detonations weakens the wave and yields pressures and densities below those occurring in planar geometry. We study the problem of a spherically expanding detonation of Comp-B. The effect of varying the order of reaction as well as the rate law parameters (using an Arrhenius burn model) is studied. 14 refs., 3 figs.

  16. A High-resolution Method for Realistic Detonation Structure Simulation

    E-print Network

    Deiterding, Ralf

    . Introduction Detonations are shock-induced combustion waves that internally consist of a dis- continuous hydrodynamic shock followed by a smooth region of decaying combus- tion. In a self-sustaining detonation, shock- tinction and reignition of combustion, and the propagation of triple points in good structural agreement

  17. Ignition and Growth Modeling of Detonating Tatb Cones and Arcs

    NASA Astrophysics Data System (ADS)

    Tarver, Craig M.; Chidester, Steven K.

    2007-12-01

    Previously established Ignition and Growth reactive flow models for the detonating triaminotrinitrobenzene (TATB) based plastic bonded explosives LX-17 and PBX 9502 are applied to recent experimental detonation propagation/failure experiments using unconfined cones, confined arcs, and unconfined arcs. The conical experiments are initially overdriven by the convergent geometry and then fail to detonate at smaller diameters than do unconfined cylindrical charges when the radial rarefaction wave lowers the shock pressure and temperature and thus decreases the chemical energy release rate. Unconfined TATB arcs detonate more slowly than cylindrical charges on the inner surface and exhibit large phase velocities on the outer surface. Confinement reduces but does not eliminate these effects. The Ignition and Growth model calculations based on parameters normalized to a great deal of one-, two- and three-dimensional detonation propagation data reproduce these features and agree closely with experimental detonation velocity and arrival time data.

  18. Detonation diffraction from an annular channel

    NASA Astrophysics Data System (ADS)

    Meredith, James; Ng, Hoi Dick; Lee, John H. S.

    2010-12-01

    In this study, gaseous detonation diffraction from an annular channel was investigated with a streak camera and the critical pressure for transmission of the detonation wave was obtained. The annular channel was used to approximate an infinite slot resulting in cylindrically expanding detonation waves. Two mixtures, stoichiometric acetylene-oxygen and stoichiometric acetylene-oxygen with 70% Ar dilution, were tested in a 4.3 and 14.3 mm channel width ( W). The undiluted and diluted mixtures were found to have values of the critical channel width over the cell size around 3 and 12 respectively. Comparing these results to values of the critical diameter ( d c ), in which a spherical detonation occurs, a value of critical d c / W c near 2 is observed for the highly diluted mixture. This value corresponds to the geometrical factor of the curvature term between a spherical and cylindrical diverging wave. Hence, the result is in support of Lee's proposed mechanism [Lee in Dynamics of Exothermicity, pp. 321, Gordon and Breach, Amsterdam, 1996] for failure due to diffraction based on curvature in stable mixtures such as those highly argon diluted with very regular detonation cellular patterns.

  19. Analysis of the influence of inert particles on the propagation of a cellular heterogeneous detonation

    NASA Astrophysics Data System (ADS)

    Fedorov, A. V.; Kratova, Y. V.

    2015-05-01

    The interaction of a cellular detonation wave with a cloud of inert particles is investigated numerically. The regimes of propagation of the heterogeneous cellular detonation and its suppression are identified. The influence of various parameters of the inert cloud is demonstrated. The critical length of the cloud for detonation suppression is determined. It is shown that the disperse composition and the non-uniform distribution of particles of the particle cloud are important parameters affecting the detonation propagation mode.

  20. Effect of chemically inert particles on parameters and suppression of detonation in gases

    Microsoft Academic Search

    P. A. Fomin; J.-R. Chen

    2009-01-01

    An algorithm for calculating the parameters of a steady one-dimensional detonation wave in mixtures of a gas with chemically\\u000a inert particles and estimating the detonation-cell size in such mixtures is proposed. The calculated detonation parameters\\u000a and cell size in stoichiometric hydrogen-oxygen mixtures with W, Al2O3, and SiO2 particles are used to analyze the method of suppression of multifront gas detonation

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

    SciTech Connect

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    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 wave with a speed that is on average correct. The EOS modification also adjusts the release isentrope to correct the energy release.

  2. Annihilation explosions in macroscopic polyelectrons. Photon detonation

    E-print Network

    Alexei M. Frolov

    2009-09-03

    Annihilation of the electron-positron pairs in macroscopic polyelectrons is considered. It is shown that very fast collapse of the spatial area occupied by macroscopic polyelectron (or dense electron-positron plasma) produces an instant annihilation of a very large number of electron-positron pairs. This phenomenon corresponds to the so-called annihilation explosion. Annihilation of each electron-positron pair is a highly exothermic process. Therefore, in dense electron-positron plasma one can observe a very interesting phenomenon of photon detonation, i.e. a self-organized formation and propagation of the detonation wave which coincides with the annihilation wave. The photon detonation can be used in many applications, including many military and astrophysical problems.

  3. Ignition and detonation initiation by shock focussing

    NASA Astrophysics Data System (ADS)

    Chan, C. K.; Lau, D.; Thibault, P. A.; Penrose, J. D.

    Ignition and detonation resulting from a collision of a shock wave with a 90 deg reentrant corner wave were investigated in stoichiometric H2-O2 mixtures. The results show that local hot spots capable of igniting and initiating detonation in the mixture are created by shock focusing caused by the collision. The focusing effect due to complex shock reflections is very sensitive to the orientation of the corner. The critical conditions for ignition and initiation of detonation increase rapidly as the angle between one corner face and the incident shock deviates from 45 deg. The pressure and temperature at the corner are the highest when this angle is 45 deg. Critical conditions also depend on the size of the corner as well as the initial pressure of the mixtures.

  4. Bidirectional slapper detonator

    DOEpatents

    McCormick, Robert N. (Los Alamos, NM); Boyd, Melissa D. (Los Alamos, NM)

    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.

  5. Detonation initiation techniques for pulse detonation propulsion

    NASA Astrophysics Data System (ADS)

    Frolov, S. M.

    2009-09-01

    The paper outlines recent efforts of the research team directed by the author on the development of efficient means for reducing the deflagration-to-detonation transition (DDT) run-up distance and time for liquidfueled air-breathing pulse detonation engine (PDE) applications. The main objective of the studies was to ensure fast DDT in a PDE tube at the lowest possible ignition energy, at the shortest distance, with the lowest pressure loss, and using aviation kerosene TS-1 (Russian analogue of JetA) as fuel and air as oxidizer.

  6. Numerical Simulation of the Detonation Propagation in Silicon Carbide Shell

    NASA Astrophysics Data System (ADS)

    Balagansky, Igor; Terechov, Anton

    2013-06-01

    Last years it was experimentally shown that in condensed high explosive charges (HE) placed in silicon carbide shell with sound velocity greater than the detonation velocity in HE, there may be observed interesting phenomena. Depending on the conditions, as an increase or decrease of the detonation velocity and pressure on the detonation front can be observed. There is also the distortion of the detonation front until the formation of a concave front. For a detailed explanation of the physical nature of the phenomenon we have provided numerical simulation of detonation wave propagation in Composition B HE charge, which was placed in silicon carbide shell. Modeling was performed with Ansys Autodyn in 2D-axis symmetry posting on an Eulerian mesh. Special attention was paid to selection of the parameters values in Lee-Tarver kinetic equation for HE and choice of constants to describe behavior of the ceramics. For comparison, also we have carried out the modeling of propagation of detonation in a completely similar assembly with brass shell. The simulation results agree well with the experimental data. In particular, in silicon carbide shell distortion of the detonation front was observed. A characteristic feature of the process is the pressure waves propagating in the direction of the axis of symmetry on the back surface of the detonation front.

  7. Modeling Hemispheric Detonation Experiments in 2-Dimensions

    SciTech Connect

    Howard, W M; Fried, L E; Vitello, P A; Druce, R L; Phillips, D; Lee, R; Mudge, S; Roeske, F

    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, 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.

  8. Modelling detonation in ultrafine tatb hemispherical boosters using crest

    NASA Astrophysics Data System (ADS)

    Whitworth, Nicholas J.

    2012-03-01

    Hemispherical ultrafine TATB boosters can initiate detonation in the TATB-based explosive LX-17. For accurate hydrocode predictions of experiments using this combination of explosives, it is important to accurately model the detonation wave emerging from the booster material since this may influence the detonation behaviour in the main charge. Since ultrafine TATB exhibits non-ideal detonation behaviour, its response should be modelled using reactive flow. In this paper, the CREST reactive burn model, which uses entropy-dependent reaction rates to simulate explosive behaviour, is applied to LLNL experimental data obtained from ultrafine TATB hemispherical boosters initiated by slapper detonators at three initial temperatures (ambient, -20°C, and -54°C). The ambient temperature data is used to develop an initial CREST model for ultrafine TATB which is then subsequently applied to the cold data. A comparison of the experimental and modelling results is presented showing that the model gives good agreement to experiment at both ambient and cold temperatures

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

    SciTech Connect

    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 of 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.

  10. Phase detonated shock tube (PFST)

    SciTech Connect

    Zerwekh, W.D.; Marsh, S.P.; Tan, Tai-Ho.

    1993-01-01

    The simple, cylindrically imploding and axially driven fast shock tube (FST) has been a basic component in the high velocity penetrator (HVP) program. It is a powerful device capable of delivering a directed and very high pressure output that has been successfully employed to drive hypervelocity projectiles. The FST is configured from a hollow, high-explosive (HE) cylinder, a low-density Styrofoam core, and a one-point initiator at one end. A Mach stem is formed in the core as the forward-propagating, HE detonation wave intersects the reflected radial wave. This simple FST has been found to be a powerful pressure multiplier. Up to 1-Mbar output pressure can be obtained from this device. Further increase in the output pressure can be achieved by increasing the HE detonation velocity. The FST has been fine tuned to drive a thin plate to very high velocity under an impulse per unit area of about 1 Mbar[mu]s/cm[sup 2]. A 1.5-mm-thick stainless steel disk has been accelerated intact to 0.8 cm/[mu]s under a loading pressure rate of several Mbar/[mu]s. By making the plate curvature slightly convex at the loading side the authors have successfully accelerated it to almost 1.0 cm/[mu]s. The incorporation of a barrel at the end of the FST has been found to be important as confinement of the propellant gas by the barrel tends to accelerate the projectile to higher velocity. The desire to accelerate the plate above 1.0 cm/[mu]s provided the impetus to develop a more advanced fast shock tube to deliver a much higher output pressure. This report describes the investigation of a relatively simple air-lens phase-detonation system (PFST) with fifty percent higher phase-detonation velocity and a modest 2 Mbar output. Code calculations have shown that this PFST acceleration of a plate to about 1.2 cm/[mu]s can be achieved. The performance of these PFSTs has been evaluated and the details are discussed.

  11. Phase detonated shock tube (PFST)

    SciTech Connect

    Zerwekh, W.D.; Marsh, S.P.; Tan, Tai-Ho

    1993-07-01

    The simple, cylindrically imploding and axially driven fast shock tube (FST) has been a basic component in the high velocity penetrator (HVP) program. It is a powerful device capable of delivering a directed and very high pressure output that has been successfully employed to drive hypervelocity projectiles. The FST is configured from a hollow, high-explosive (HE) cylinder, a low-density Styrofoam core, and a one-point initiator at one end. A Mach stem is formed in the core as the forward-propagating, HE detonation wave intersects the reflected radial wave. This simple FST has been found to be a powerful pressure multiplier. Up to 1-Mbar output pressure can be obtained from this device. Further increase in the output pressure can be achieved by increasing the HE detonation velocity. The FST has been fine tuned to drive a thin plate to very high velocity under an impulse per unit area of about 1 Mbar{mu}s/cm{sup 2}. A 1.5-mm-thick stainless steel disk has been accelerated intact to 0.8 cm/{mu}s under a loading pressure rate of several Mbar/{mu}s. By making the plate curvature slightly convex at the loading side the authors have successfully accelerated it to almost 1.0 cm/{mu}s. The incorporation of a barrel at the end of the FST has been found to be important as confinement of the propellant gas by the barrel tends to accelerate the projectile to higher velocity. The desire to accelerate the plate above 1.0 cm/{mu}s provided the impetus to develop a more advanced fast shock tube to deliver a much higher output pressure. This report describes the investigation of a relatively simple air-lens phase-detonation system (PFST) with fifty percent higher phase-detonation velocity and a modest 2 Mbar output. Code calculations have shown that this PFST acceleration of a plate to about 1.2 cm/{mu}s can be achieved. The performance of these PFSTs has been evaluated and the details are discussed.

  12. Predictive model of onset of pipe failure due to a detonation of hydrogen–air and hydrocarbon–air mixtures

    Microsoft Academic Search

    Dae-hyun Kim; Jack J. Yoh

    2009-01-01

    A fuel specific detonation wave in a pipe propagates with a predictable wave velocity. This internal detonation wave speed determines the level of flexural wave excitation of pipes and the possibility of resonance response leading to a serious structural damage. In this paper, we study the elastic response of metallic tubes and establish the resonance conditions of pipe breakage for

  13. Application of the CE\\/SE Method to a Two-Phase Detonation Model in Porous Media

    Microsoft Academic Search

    He-Fei Dong; Tao Hong; De-Liang Zhang

    2011-01-01

    We extend the conservation-element and solution-element method to simulate a two-phase detonation model in porous media. The accuracy of the method is validated by calculating an inert compaction problem. The main characteristics of piston-driven detonation phenomena, including the compaction wave, the onset of combustion, and the transition to detonation, could be predicted successfully.

  14. High efficiency detonation internal combustion engine (DICE)

    NASA Astrophysics Data System (ADS)

    Loth, Eric; Loth, John; Loth, Frank

    1992-07-01

    Controlled detonation combustion could be used in future internal combustion engines to achieve high cycle efficiency and minimize NO(x) formation, if conventional design limitations are removed. An engine is proposed that uses a separate detonation combustion chamber which discharges tangentially into an expansion chamber formed by the piston and cylinder at top dead center. The expansion chamber is designed to efficiently store a portion of the detonation wave's kinetic energy in the form of a vortex, which is subsequently converted into static pressure. The rapid burning, followed by 'leaning' through mixing with air in the vortex chamber, may reduce the formation of NO(x) and unburned hydrocarbons as compared to conventional combustion. The thermodynamic aspects of detonation combustion compared to either constant volume or constant pressure combustion yield a significant increase in combustion compression ratio for fuels such as natural gas. The shock wave propagation through the vortex chamber is described with a shock-capturing finite element Euler flow code supporting the premise of vortex storage and rapid-mixing characteristics.

  15. Influence of and additives on acetylene detonation

    NASA Astrophysics Data System (ADS)

    Drakon, A.; Emelianov, A.; Eremin, A.

    2014-03-01

    The influence of and admixtures (known as detonation suppressors for combustible mixtures) on the development of acetylene detonation was experimentally investigated in a shock tube. The time-resolved images of detonation wave development and propagation were registered using a high-speed streak camera. Shock wave velocity and pressure profiles were measured by five calibrated piezoelectric gauges and the formation of condensed particles was detected by laser light extinction. The induction time of detonation development was determined as the moment of a pressure rise at the end plate of the shock tube. It was shown that additive had no influence on the induction time. For , a significant promoting effect was observed. A simplified kinetic model was suggested and characteristic rates of diacetylene formation were estimated as the limiting stage of acetylene polymerisation. An analysis of the obtained data indicated that the promoting species is atomic chlorine formed by pyrolysis, which interacts with acetylene and produces radical, initiating a chain mechanism of acetylene decomposition. The results of kinetic modelling agree well with the experimental data.

  16. Evaluating detonation possibilities in a Hanford radioactive waste tank

    SciTech Connect

    Travis, J.R.; Fujita, R.K.; Ross, M.C.; Edwards, J.N. [Los Alamos National Lab., NM (United States); Shepherd, J.E. [California Inst. of Tech., Pasadena, CA (United States)

    1994-07-01

    Since the early 1940s, radioactive wastes generated from the defense operations at the Hanford Site have been stored in underground waste storage tanks. During the intervening years, the waste products in some of these tanks have transformed into a potentially hazardous mixture of gases and solids as a result of radiolytic and thermal chemical reactions. One tank in particular, Tank 101-SY, has been periodically releasing high concentrations of a hydrogen/nitrous oxide/nitrogen/ ammonia gas mixture into the tank dome vapor space. There are concerns that under certain conditions a detonation of the flammable gas mixture may occur. There are two ways that a detonation can occur during a release of waste gases into the dome vapor splice: (1) direct initiation of detonation by a powerful ignition source, and (2) deflagration to detonation transition (DDT). The first case involves a strong ignition source of high energy, high power, or of large size (roughly 1 g of high explosive (4.6 kj) for a stoichiometric hydrogen-air mixture{sup 1}) to directly initiate a detonation by ``shock`` initiation. This strong ignition is thought to be incredible for in-tank ignition sources. The second process involves igniting the released waste gases, which results in a subsonic flame (deflagration) propagating into the unburned combustible gas. The flame accelerates to velocities that cause compression waves to form in front of the deflagration combustion wave. Shock waves may form, and the combustion process may transition to a detonation wave.

  17. CALTECH ASCI TECHNICAL REPORT 135 Analysis of Numerical Simulations of Detonation Diffraction

    E-print Network

    Barr, Al

    of these disturbances corresponds to the trajectories of acoustic waves propagating inside the reaction zone Abstract We investigate the problem of a self-sustaining detonation wave diffracting from a tube, and confining geometry dimensions. In the simplest concept of detonation failure, the decoupling of the reaction

  18. Multi-Dimensional Adaptive Simulation of Shock-Induced Detonation in a Shock Tube

    E-print Network

    Texas at Arlington, University of

    results, providing new insights in detonation wave propagation. Nomenclature Ar j , Af j Pre applications, primarily in propulsion.1 Detonations use a reacting flow mechanism wherein a strong shock wave, coupled with a chemical reacting zone, propagates at supersonic speed. The reaction zone helps

  19. Reverse slapper detonator

    DOEpatents

    Weingart, Richard C. (Livermore, CA)

    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.

  20. Detonation failure characterization of non-ideal explosives

    Microsoft Academic Search

    Robert S Janesheski

    2011-01-01

    Current methods of characterizing non-ideal explosives require large-scale testing to obtain steady detonation wave propagation for analysis due to the relatively thick reaction zones. A small scale experiment would be very useful in quickly characterizing many materials. Use of a microwave interferometer applied to small-scale confined transient experiments was implemented yielding time resolved characterization of a failing detonation that is

  1. Ignition and detonation initiation by shock focussing

    NASA Astrophysics Data System (ADS)

    Chan, C. K.; Lau, D.; Thibault, P. A.; Penrose, J. D.

    1990-07-01

    Ignition and detonation resulting from a collision of a shock wave with a 90° re-entrant corner were examined using a 9 cm×9 cm shock tube. Schlieren photographs revealed that the collision of shock wave with a re-entrant corner created a complicated shock structure in the vicinity of the corner, causing local strengthening (or focussing) of the shock wave. Depending on the incident shock strength, the compound reflections resulted in ignition of the gas mixture or direct initiation of detonation. The critical shock strength for ignition and detonation initiation, and thus the degree of focussing, were found to be very sensitive to the orientation of the re-entrant corner. To better understand the gasdynamic processes involved, the interaction between the shock wave with the re-entrant corner was simulated using a 2-dimensional computer code. The scale dependence of the phenomena was also examined by performing experiments with re-entrant corners of different sizes and with gas mixtures of different initial pressures.

  2. Optimization study of spray detonation initiation by electric discharges

    NASA Astrophysics Data System (ADS)

    Frolov, S. M.; Basevich, V. Ya.; Aksenov, V. S.; Polikhov, S. A.

    2005-11-01

    Development of air-breathing pulse detonation engines is faced with a challenging problem of detonation initiation in fuel sprays at distances feasible for propulsion applications. Extensive experimental study on initiation of a confined n-hexane spray detonation in air by electric discharges is reported. It is found that for direct initiation of spray detonation with minimal energy requirements (1) it is worth to use one discharger located near the closed end of a detonation tube and at least one additional discharger downstream from it to be triggered in-phase with primary shock wave arrival; (2) the discharge area should be properly insulated to avoid electric loss to metal tube walls; (3) discharge duration should be minimized to at least 50 ?s; (4) discharge channel should preferably occupy a large portion of a tube cross-section; (5) test tube should be preferably of a diameter close to the limiting tube diameter; (6) gradual transition between the volume with electric discharger and the tube should be used; and (7) a powerful electric discharger utilized for generating a primary shock wave can be replaced by a primary shock wave generator comprising a relatively low-energy electric discharger, Shchelkin spiral, and tube coil. With all these principles implemented, the rated electric energy of about 100 J was required to initiate n-hexane spray air detonation in a 28-mm tube at a distance of about 1 m from the atomizer.

  3. In-Situ Continuous Detonation Velocity Measurements Using Fiber-optic Bragg Grating Sensors

    SciTech Connect

    Benterou, J; Udd, E; Wilkins, P; Roeske, F; Roos, E; Jackson, D

    2007-07-25

    In order to fully calibrate hydrocodes and dynamic chemistry burn models, initiation and detonation research requires continuous measurement of low order detonation velocities as the detonation runs up to full order detonation for a given density and initiation pressure pulse. A novel detector of detonation velocity is presented using a 125 micron diameter optical fiber with an integral chirped fiber Bragg grating as an intrinsic sensor. This fiber is embedded in the explosive under study and interrogated during detonation as the fiber Bragg grating scatters light back along the fiber to a photodiode, producing a return signal dependant on the convolution integral of the grating reflection bandpass, the ASE intensity profile and the photodetector response curve. Detonation velocity is measured as the decrease in reflected light exiting the fiber as the grating is consumed when the detonation reaction zone proceeds along the fiber sensor axis. This small fiber probe causes minimal perturbation to the detonation wave and can measure detonation velocities along path lengths tens of millimeters long. Experimental details of the associated equipment and preliminary data in the form of continuous detonation velocity records within nitromethane and PBX-9502 are presented.

  4. Characterizing Detonator Output Using Dynamic Witness Plates

    NASA Astrophysics Data System (ADS)

    Murphy, Michael; Adrian, Ronald

    2009-06-01

    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 the 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. Successful application of the PIV system to full-up explosive detonator output is also demonstrated.

  5. RESPONSE OF ALUMINUM SPHERES IN SITU TO DETONATION

    SciTech Connect

    Molitoris, J D; Garza, R G; Tringe, J W; Batteux, J D; Wong, B M; Villafana, R J; Cracchiola, B A; Forbes, J W

    2010-03-26

    Time sequence x-ray imaging was utilized to determine the response of aluminum spheres embedded in a detonating high-explosive cylinder. The size of these spheres ranged from 3/8-inch to 1/32-inch in diameter. These experiments directly observed the response of the spheres as a function of time after interaction with the detonation wave. As the spheres are entrained in the post-detonation flow field, they are accelerating and their velocity profile is complicated, but can be determined from the radiography. Using the aluminum spheres as tracers, radial velocities of order 1.6 mm/us and horizontal velocities of order 0.08 mm/us were measured at early times post detonation. In terms of response, these data show that the largest sphere deforms and fractures post detonation. The intermediate size spheres suffer negligible deformation, but appear to ablate post detonation. Post detonation, the smallest spheres either react, mechanically disintegrate, atomize as a liquid or some combination of these.

  6. Printable sensors for explosive detonation

    NASA Astrophysics Data System (ADS)

    Griffith, Matthew J.; Cooling, Nathan A.; Elkington, Daniel C.; Muller, Elmar; Belcher, Warwick J.; Dastoor, Paul C.

    2014-10-01

    Here, we report the development of an organic thin film transistor (OTFT) based on printable solution processed polymers and employing a quantum tunnelling composite material as a sensor to convert the pressure wave output from detonation transmission tubing (shock tube) into an inherently amplified electronic signal for explosives initiation. The organic electronic detector allows detection of the signal in a low voltage operating range, an essential feature for sites employing live ordinances that is not provided by conventional electronic devices. We show that a 30-fold change in detector response is possible using the presented detector assembly. Degradation of the OTFT response with both time and repeated voltage scans was characterised, and device lifetime is shown to be consistent with the requirements for on-site printing and usage. The integration of a low cost organic electronic detector with inexpensive shock tube transmission fuse presents attractive avenues for the development of cheap and simple assemblies for precisely timed initiation of explosive chains.

  7. Printable sensors for explosive detonation

    SciTech Connect

    Griffith, Matthew J., E-mail: matthew.griffith@newcastle.edu.au; Cooling, Nathan A.; Elkington, Daniel C.; Belcher, Warwick J.; Dastoor, Paul C. [Priority Research Centre for Organic Electronics, University of Newcastle, University Drive, Callaghan, New South Wales 2308 (Australia); Muller, Elmar [AEL Mining Services Ltd., 1 Platinum Drive, Modderfontein, Johannesburg, 1645 (South Africa)

    2014-10-06

    Here, we report the development of an organic thin film transistor (OTFT) based on printable solution processed polymers and employing a quantum tunnelling composite material as a sensor to convert the pressure wave output from detonation transmission tubing (shock tube) into an inherently amplified electronic signal for explosives initiation. The organic electronic detector allows detection of the signal in a low voltage operating range, an essential feature for sites employing live ordinances that is not provided by conventional electronic devices. We show that a 30-fold change in detector response is possible using the presented detector assembly. Degradation of the OTFT response with both time and repeated voltage scans was characterised, and device lifetime is shown to be consistent with the requirements for on-site printing and usage. The integration of a low cost organic electronic detector with inexpensive shock tube transmission fuse presents attractive avenues for the development of cheap and simple assemblies for precisely timed initiation of explosive chains.

  8. Computer modeling of detonators

    Microsoft Academic Search

    C. M. Furnberg

    1994-01-01

    A mathematical model of detonators which describes the resistance of the exploding bridgewire or exploding foil initiator as a function of energy deposition will be described. This model includes many parameters that can be adjusted to obtain a close fit to experimental data. This has been demonstrated using recent experimental data taken within Sandia National Laboratories

  9. Environmentally Benign Stab Detonators

    SciTech Connect

    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 caused 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 flash metal multilayer and sol-gel to be generic technologies applicable to a wide range of devices, especially in small caliber ammunition and sub-munitions. We will replace the NOL-130 mixture with a nanocomposite that consists of a mechanically robust energetic multilayer foil that has been coated with a sol-gel energetic material. The exothermic reactions are activated in this nanocomposite are the transformation of the multilayer material to its respective intermetallic alloy and the thermite reaction, which is characterized by very high temperatures, a small pressure pulse, and hot particle ejection. The proposed materials and their reaction products consist of, but are not limited to aluminum, nickel, iron, aluminum oxide, titanium, iron oxide and boron. These materials have much more desirable environmental and health characteristics than the NOL-130 composition.

  10. Experimental Realization of H2\\/Air Continuous Rotating Detonation in a Cylindrical Combustor

    Microsoft Academic Search

    Liu Shi-jie; Lin Zhi-yong; Liu Wei-dong; Lin Wei; Zhuang Feng-chen

    2012-01-01

    Results of experimental studies on H2\\/air continuous rotating detonation in an annular combustor are presented. A tangentially injected H2\\/O2 hotshot jet is used to ignite the engine. H2\\/air continuous rotating detonations are realized at a wide range of total mass flow and equivalence ratio conditions. The detonation propagation modes of all the tests can be divided into four kinds: two-wave,

  11. Influence of discrete sources on detonation propagation in a Burgers equation analog system

    NASA Astrophysics Data System (ADS)

    Mi, XiaoCheng; Higgins, Andrew J.

    2015-05-01

    An analog to the equations of compressible flow that is based on the inviscid Burgers equation is utilized to investigate the effect of spatial discreteness of energy release on the propagation of a detonation wave. While the traditional Chapman-Jouguet (CJ) treatment of a detonation wave assumes that the energy release of the medium is homogeneous through space, the system examined here consists of sources represented by ? functions embedded in an otherwise inert medium. The sources are triggered by the passage of the leading shock wave following a delay that is either of fixed period or randomly generated. The solution for wave propagation through a large array (103-104) of sources in one dimension can be constructed without the use of a finite difference approximation by tracking the interaction of sawtooth-profiled waves for which an analytic solution is available. A detonation-like wave results from the interaction of the shock and rarefaction waves generated by the sources. The measurement of the average velocity of the leading shock front for systems of both regular, fixed-period and randomized sources is found to be in close agreement with the velocity of the equivalent CJ detonation in a uniform medium, wherein the sources have been spatially homogenized. This result may have implications for the applicability of the CJ criterion to detonations in highly heterogeneous media (e.g., polycrystalline, solid explosives) and unstable detonations with a transient and multidimensional structure (e.g., gaseous detonation waves).

  12. Ignition and Growth Modeling of Detonating TATB Cones and Arcs*

    NASA Astrophysics Data System (ADS)

    Tarver, Craig; Chidester, Steven

    2007-06-01

    . The Ignition and Growth reactive flow model for the detonating triaminotrinitrobenzene (TATB)-based explosives LX-17 and PBX 9502 is applied to recent experimental data on converging conical charges plus confined and unconfined arc charges. The conical charges are at first overdriven by the converging flow and then fail to detonate as the radial rarefaction wave slows the reaction rate. Unconfined TATB arcs detonate more slowly than cylindrical charges on the inner surface and exhibit large phase velocities on the outer surface. Confinement reduces but does not eliminate these effects. The model calculations reproduce these features and agree well with experimental detonation velocity and arrival time data. *This work was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

  13. 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, the orifice diameter, and the plenum cavity pressure. Results indicate that the detonation wave pressure temporarily interrupts the fluidic valve supply, but the wave products can be quickly expelled by the fresh fuel supply to allow for refueling. The interruption time of the valve scales with injection and detonation wave pressure ratios as well as a characteristic time. The feasibility of using a detonation wave as a source for producing power in conjunction with a linear generator is considered. Such a facility can be constructed by placing a piston--spring system at the end of a pulsed detonation engine (PDE). Once the detonation wave reflects off the piston, oscillations of the system drive the linear generator. An experimental facility was developed to explore the interaction of a gaseous detonation wave with the piston. Experimental results were then used to develop a model for the interaction. Governing equations for two engine designs are developed and trends are established to indicate a feasible design space for future development.

  14. Using Schlieren Visualization to Track Detonator Performance

    Microsoft Academic Search

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

    2007-01-01

    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

  15. USING SCHLIEREN VISUALIZATION TO TRACK DETONATOR PERFORMANCE

    Microsoft Academic Search

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

    2007-01-01

    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

  16. Using Schlieren Visualization to Track Detonator Performance

    Microsoft Academic Search

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

    2007-01-01

    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

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

    DOEpatents

    Bickes, Jr., Robert W. (Albuquerque, NM); Kopczewski, Michael R. (Albuquerque, NM); Schwarz, Alfred C. (Albuquerque, NM)

    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.

  18. 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.

  19. Detonation in TATB Hemispheres

    Microsoft Academic Search

    B Druce; P C Souers; C Chow; F Roeske; P Vitello; C Hrousis

    2004-01-01

    Streak camera breakout and Fabry-Perot interferometer data have been taken on the outer surface of 1.80 g\\/cm³ TATB hemispherical boosters initiated by slapper detonators at three temperatures. The slapper causes breakout to occur at 54{sup o} at ambient temperatures and 42{sup o} at -54 C, where the axis of rotation is 0{sup o}. The Fabry velocities may be associated with

  20. Hydrogen-air detonations

    Microsoft Academic Search

    C. M. Guirao; R. Knystautas; J. H. Lee; W. Benedick; M. Berman

    1982-01-01

    The Three Mile Island nuclear plant accident has triggered renewed interest in fundamental combustion studies in hydrogen-air mixtures. The present study is concerned with the problem of detonation of atmospheric, hydrogen-air mixtures and reports new experimental results on cell sizes lambda and critical tube diameters d\\/sub c\\/. The results confirm the empirical correlation d\\/sub c\\/ = 13lambda. Comparison of the

  1. On detonation initiation by a temperature gradient for a detailed chemical reaction models

    NASA Astrophysics Data System (ADS)

    Liberman, M. A.; Kiverin, A. D.; Ivanov, M. F.

    2011-04-01

    The evolution from a temperature gradient to a detonation is investigated for combustion mixture whose chemistry is governed by a detailed chemical kinetics. We show that a detailed chemical reaction model has a profound effect on the spontaneous wave concept for detonation initiation by a gradient of reactivity. The evolution to detonation due to a temperature gradient is considered for hydrogen-oxygen and hydrogen-air mixtures at different initial pressures. It is shown that the minimal length of the temperature gradient for which a detonation can be ignited is much larger than that predicted from a one-step chemical model.

  2. Numerical modeling of detonation in solid explosives

    SciTech Connect

    Tarver, C.M.

    1992-09-01

    Current experimental data on detonation waves in solid explosives can be calculated in one-, two-, and three-dimensional hydrodynamic computer codes using reactive flow models. The ignition and growth model was applied to available experimental data on heterogeneous solid explosives based on PETN, TNT, HMX, RDX, and TATB. After the reaction rates for an individual explosive have been calculated, these rates can be used to first order in mixtures; this has been done for several mixtures. For two- and three-dimensional applications, it is best to have at least ten zones in the reaction zone; enough zones should be used so that the the detonation propagates at CJ velocity and reaches CJ pressure. Possible future improvements are considered.

  3. Computational Analysis of Zel'dovich-von Neumann-Doering (ZND) Detonation 

    E-print Network

    Nakamura, Tetsu

    2010-07-14

    of the injectors shown in Figure 1.1. Figure 1.2 schematically describes the procedure of single detonation wave propagation. A detonation generator is an unsteady propulsive 3 device in which the combustion chamber is periodically filled with a reactive gas...

  4. Thrust Vectoring of a Continuous Rotating Detonation Engine by Changing the Local Injection Pressure

    Microsoft Academic Search

    Shi-Jie Liu; Zhi-Yong Lin; Ming-Bo Sun; Wei-Dong Liu

    2011-01-01

    The thrust vectoring ability of a continuous rotating detonation engine is numerically investigated, which is realized via increasing local injection stagnation pressure of half of the simulation domain compared to the other half. Under the homogeneous injection condition, both the flow-field structure and the detonation wave propagation process are analyzed. Due to the same injection condition along the inlet boundary,

  5. TRANSIENT NUMERICAL CODE WITH GRID ADAPTATION FOR GAS COMBUSTION AND DETONATION STUDIES

    Microsoft Academic Search

    Nicolas Gascoin; Sergey M. Frolov; Philippe Gillard

    Combustion, shock waves and detonations in enclosure are implicated in a wide range of applications: knock in internal combustion engines, flame propagation in kerosene tank, pulsed detonation engines. But they also may be related to explosion and hazard when uncontrolled. These phenomena are highly transient and they are managed by heat transfer, fluid mechanics and chemical processes, whose characteristic times

  6. Computational Analysis of Zel'dovich-von Neumann-Doering (ZND) Detonation

    E-print Network

    Nakamura, Tetsu

    2010-07-14

    of multiple detonation waves issuing from different ?stages? along a simple ducted engine, and aims to eliminate the need for compressors at low speeds. Currently, the Zel?dovichvon Neumann-Doering (ZND) steady, one-dimensional detonation is the simplest...

  7. The role of diffusion at shear layers in irregular detonations Marco Arienti1

    E-print Network

    Barr, Al

    propagation is intrin- sically three-dimensional with waves moving transversely to the main front cell. Both models are based on an idealized detonation cell cycle, with imposed detonation speed profile. Following the standard triple-point analysis at the shock front, time-accurate integration

  8. The Use of Steady and Pulsed Detonations for Propulsion Systems

    SciTech Connect

    Adelman, H.G.; Menees, G.P.; Cambier, J.L.; Bowles, J.V.

    1996-02-01

    Objectives of the ODWE concept studies are: demonstrate the feasibility of the oblique detonation wave engine (ODWE) for hypersonic propulsion; demonstrate the existance and stability of an oblique detonation wave in hypersonic wind tunnels; develop engineering codes which predict the performance characteristics of the ODWE including specific impulse and thrust coefficients for various operating conditions; develop multi-dimensional computer codes which can model all aspects of the ODWE including fuel injection, mixing, ignition, combustion and expansion with fully detailed chemical kinetics and turbulence models; and validate the codes with experimental data use the simulations to predict the ODWE performance for conditions not easily obtained in wind tunnels.

  9. Low voltage nonprimary explosive detonator

    DOEpatents

    Dinegar, Robert H. (Los Alamos, NM); Kirkham, John (Newbury, GB2)

    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.

  10. 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, and/or the need for a longer DDT section.

  11. 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.

  12. A study of unstable detonations using a microwave interferometer

    Microsoft Academic Search

    D H Edwards; G Hooper; J M Morgan

    1974-01-01

    Under certain narrow limits of initial pressure conditions, self-sustaining detonation waves in gaseous mixtures exhibit large periodic variations of velocity with distance, although the mean value is close to the calculated Chapman-Jouguet value; these waves are known as `galloping' waves.A microwave interferometer, employing the fundamental TE01 mode at a frequency of 9000 MHz, is used to study the propagation of

  13. Detonation diffraction in gases

    SciTech Connect

    Pintgen, F.; Shepherd, J.E. [California Institute of Technology, Mail stop 105-50, 1200 E California Blvd, Pasadena, CA 91125 (United States)

    2009-03-15

    We have experimentally investigated detonation diffraction out of a round tube into an unconfined half-space. The focus of our study is examining how the extent of detonation cellular instability influences the quantitative and qualitative features of diffraction. Detailed quantitative and qualitative measurements were obtained through simultaneous schlieren imaging, multiple-exposure chemiluminescence imaging, and planar laser-induced fluorescence imaging of OH molecules. Two types of stoichiometric mixtures, highly diluted H{sub 2}-O{sub 2}-Ar and H{sub 2}-N{sub 2}O, were studied in the sub-critical, critical and super-critical regime. These mixture types represent extreme cases in the classification of cellular instability with highly diluted H{sub 2}-O{sub 2}-Ar mixtures having very regular instability structures and H{sub 2}-N{sub 2}O having very irregular instability structures. The most striking differences between the mixtures occur in the sub-critical and critical regimes, for which the detonation fails to transition into the unconfined half-space. For the H{sub 2}-O{sub 2}-Ar mixture, the velocity on the center line was found to decay significantly slower than for the H{sub 2}-N{sub 2}O mixture. In case of the H{sub 2}-O{sub 2}-Ar mixture, it was evident from simultaneous schlieren-fluorescence images that the reaction front was coupled to the lead shock front up to 2.3 tube diameters from the exit plane. For the H{sub 2}-N{sub 2}O mixture, the reaction front velocity decreased to 60% of the corresponding Chapman-Jouguet value at 1.1 tube diameters from the tube exit plane. A geometric acoustic model showed that the observed differences in failure patterns are not caused by the differences in thermodynamic properties of the two mixtures but is linked to the larger effective activation energy and critical decay time in the H{sub 2}-N{sub 2}O mixture as compared to the H{sub 2}-O{sub 2}-Ar mixture. The re-initiation events appear similar for the two mixtures and are a consequence of local fluctuations at random locations within the region between the lead shock and decoupled reaction zone, resulting in strong transverse detonations sweeping through shocked but largely unreacted gas. (author)

  14. 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.

  15. Semiconductor bridge (SCB) detonator

    DOEpatents

    Bickes, Jr., Robert W. (Albuquerque, NM); Grubelich, Mark C. (Albuquerque, NM)

    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.

  16. Characterizing Detonator Output Using Dynamic Witness Plates

    NASA Astrophysics Data System (ADS)

    Murphy, Michael J.; Adrian, Ronald J.

    2009-12-01

    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 the 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.

  17. Characterizing detonator output using dynamic witness plates

    SciTech Connect

    Murphy, Michael John [Los Alamos National Laboratory; Adrian, Ronald J [Los Alamos National Laboratory

    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 the 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.

  18. Smooth blasting with the electronic delay detonator

    SciTech Connect

    Yamamoto, Masaaki [Asahi Chemical Industry Co., Ltd. (Japan); Ichijo, Toshiyuki; Tanaka, Yoshiharu

    1995-12-31

    The authors utilized electronic detonators (EDs) to investigate the effect of high detonator delay accuracy on overbreak, remaining rock damage, and surface smoothness, in comparison with that of long-period delay detonators (0.25 sec interval) PDs. The experiments were conducted in a deep mine, in a test site region composed of very hard granodiorite with a seismic wave velocity of about 6.0 km/sec and a uniaxial compressive strength, uniaxial tensile strength, and Young`s modulus of 300 MPa, 12 MPa, and 73 GPa, respectively. The blasting design was for a test tunnel excavation of 8 m{sup 2} in cross section, with an advance per round of 2.5 m. Five rounds were performed, each with a large-hole cut and perimeter holes in a 0.4-m spacing charged with 20-mm-diameter water gel explosive to obtain low charge concentration. EDs were used in the holes on the perimeter of the right half, and PDs were used in all other holes. Following each shot, the cross section was measured by laser to determine amount of overbreak and surface smoothness. In situ seismic prospecting was used to estimate the depth of damage in the remaining rock, and the damage was further investigated by boring into both side walls.

  19. 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).

  20. Detonation Failure Characterization of Non-Ideal Explosives

    NASA Astrophysics Data System (ADS)

    Janesheski, Robert; Son, Steven; Groven, Lori

    2011-06-01

    Non-ideal explosives are currently poorly characterized, which limits the modeling of them. Current characterization requires large-scale testing to obtain detonation wave characterization for analysis due to the relatively thick reaction zones. Use of a microwave interferometer applied to small-scale confined experiments is being implemented to allow for time resolved characterization of a failing detonation. The microwave interferometer measures the failing detonation wave in a tube, and this experiment only requires small amounts of non-ideal explosives. A non-ideal explosive is initiated with a booster charge and a measurement of the failure distance and a continuous position-time trace of the detonation front location can be obtained. Initial tests have been performed that show this method is feasible using an ammonium perchlorate (AP) composite propellant as a model non-ideal explosive. Future work will apply this approach to non-ideal explosives. Successful results of this method would allow for the calibration of detonation models for many different non-ideal explosives. This project was funded by the Department of Homeland Security through the Center of Excellence for Explosive Detection, Mitigation, and Response under award number 080409/0002251.

  1. 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.

  2. Diameter Effect Curve and Detonation Front Curvature Measurements for ANFO

    Microsoft Academic Search

    R. A. Catanach; L. G. Hill

    2001-01-01

    Diameter effect and front curvature measurements are reported for rate stick experiments on commercially available prilled ANFO (ammonium nitrate-fuel oil) at ambient temperature. The shots were fired in paper tubes so as to provide minimal confinement. Diameters ranged from 77 mm. (≈ failure diameter) to 200 mm., with the tube length being ten diameters in all cases. Each detonation wave

  3. Diameter Effect Curve and Detonation Front Curvature Measurements for ANFO

    Microsoft Academic Search

    R. A. Catanach; L. G. Hill

    2002-01-01

    Diameter effect and front curvature measurements are reported for rate stick experiments on commercially available prilled ANFO (ammonium-nitrate\\/fuel-oil) at ambient temperature. The shots were fired in paper tubes so as to provide minimal confinement. Diameters ranged from 77 mm (≈ failure diameter) to 205 mm, with the tube length being ten diameters in all cases. Each detonation wave shape was

  4. Diameter Effect Curve and Detonation Front Curvature Measurements for ANFO

    Microsoft Academic Search

    R. A. Catanach; L. G. Hill

    2002-01-01

    Diameter effect and front curvature measurements are reported for rate stick experiments on commercially available prilled ANFO (ammonium-nitrate\\/fuel-oil) at ambient temperature. The shots were fired in paper tubes so as to provide minimal confinement. Diameters ranged from 77 mm (approximately failure diameter) to 205 mm, with the tube length being ten diameters in all cases. Each detonation wave shape was

  5. Theoretical and computer models of detonation in solid explosives

    Microsoft Academic Search

    C. M. Tarver; P. A. Urtiew

    1997-01-01

    Recent experimental and theoretical advances in understanding energy transfer and chemical kinetics have led to improved models of detonation waves in solid explosives. The Nonequilibrium Zeldovich - von Neumann - Doring (NEZND) model is supported by picosecond laser experiments and molecular dynamics simulations of the multiphonon up-pumping and internal vibrational energy redistribution (IVR) processes by which the unreacted explosive molecules

  6. Detonation Reaction Zones in Condensed Explosives

    SciTech Connect

    Tarver, C M

    2005-07-14

    Experimental measurements using nanosecond time resolved embedded gauges and laser interferometric techniques, combined with Non-Equilibrium Zeldovich--von Neumann--Doring (NEZND) theory and Ignition and Growth reactive flow hydrodynamic modeling, have revealed the average pressure/particle velocity states attained in reaction zones of self-sustaining detonation waves in several solid and liquid explosives. The time durations of these reaction zone processes is discussed for explosives based on pentaerythritol tetranitrate (PETN), nitromethane, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), triaminitrinitrobenzene(TATB) and trinitrotoluene (TNT).

  7. The dynamics of unsteady detonation in ozone

    SciTech Connect

    Aslam, Tariq D [Los Alamos National Laboratory; Powers, Joseph M [Los Alamos National Laboratory

    2008-01-01

    An ultra-fine, sub-micron discrete grid is used to capture the unsteady dynamics of a one-dimensional detonation in an inviscid O - O{sub 2} - O{sub 3} mixture. The ultra-fine grid is necessary to capture the length scales revealed by a complementary analysis of the steady detonation wave structure. For the unsteady calculations, shock-fitting coupled with a high order spatio-temporal discretization scheme combine to render numerical corruption negligible. As a result, mathematically verified solutions for a mixture initially of all O{sub 3} at one atmosphere and 298.15 K have been obtained; the solutions are converging at a rate much faster than the sub-first order convergence rate of all shock-capturing schemes. Additionally, the model has been validated against limited experimental data. Transient calculations show that strongly overdriven waves are stable and moderately overdriven waves unstable. New limit cycle behavior is revealed, and the first high resolution bifurcation diagram for etonation with detailed kinetics is found.

  8. The role of cellular structure on increasing the detonability limits of three-step chain-branching detonations

    SciTech Connect

    Short, Mark [Los Alamos National Laboratory; Kiyanda, Charles B [Los Alamos National Laboratory; Quirk, James J [Los Alamos National Laboratory; Sharpe, Gary J [UNIV OF LEEDS, UK

    2011-01-27

    In [1], the dynamics of a pulsating three-step chain-branching detonation were studied. The reaction model consists of, sequentially, chain-initiation, chain-branching and chain-termination steps. The chain-initiation and chain-branching steps are taken to be thermally neutral, with chemical energy release occuring in the chain-termination stage. The purpose of the present study is to examine whether cellular detonation structure can increase the value of the chain-branching cross-over temperature T{sub b} at which fully coupled detonation solutions are observed over those in 1 D. The basic concept is straightforward and has been discussed in [1] and [3]; if T{sub s} drops below T{sub b} at the lead shock, the passage of a transverse shock can increase both the lead shock temperature and the temperature behind the transverse wave back above T{sub b}, thus sustaining an unstable cellular detonation for values of T{sub b} for which a one-dimensional pulsating detonation will fail. Experiments potentially supporting this hypothesis with irregular detonations have been shown in [3] in a shock tube with acoustically absorbing walls. Removal of the transverse waves results in detonation failure, giving way to a decoupled shock-flame complex. A number of questions remain to be addressed regarding the possibility of such a mechanism, and, if so, about the precise mechanisms driving the cellular structure for large T{sub b}. For instance, one might ask what sets the cell size in a chain-branching detonation, particularly could the characteristic cell size be set by the chain-branching cross-over temperature T{sub b}: after a transverse wave shock collision, the strength of the transverse wave weakens as it propagates along the front. If the spacing between shock collisions is too large (cell size), then the transverse shocks may weaken to the extent that the lead shock temperature or that behind the transverse waves is not raised above T{sub b}, losing chemical energy to drive the front in those regions. Failure may result if less than sufficient of the lead shock be driven above n to sustain reaction. Our starting point for generating cellular solutions is as in [I], consisting of an initial ZND wave in the channel, but perturbed here by a density non-uniformity to generate a cellular structure. Exactly how far the detonability limits (value of T{sub b}) can be extended is not addressed here, as such issues relate in part to the way the cellular structure is generated [6]. Our concern here is to investigate the mechanisms of self-sustained cellular detonation for values of T{sub b} above those that lead to 1D pulsating wave failure that can be generated from the initial ZND wave. Finally, we do not consider cellular propagation driven by a process of apparent thermal ignition of hot-spots downstream that tends to appear close to the 20 detonability limit. Such events are subject to the lack of correct thermal diffusive physics in the model and thus to the form of numerical dissipation in the underlying flow algorithm.

  9. Detonation spreading in fine TATBs

    SciTech Connect

    Kennedy, J.E.; Lee, K.Y.; Spontarelli, T.; Stine, J.R.

    1998-12-31

    A test has been devised that permits rapid evaluation of the detonation-spreading (or corner-turning) properties of detonations in insensitive high explosives. The test utilizes a copper witness plate as the medium to capture performance data. Dent depth and shape in the copper are used as quantitative measures of the detonation output and spreading behavior. The merits of the test are that it is easy to perform with no dynamic instrumentation, and the test requires only a few grams of experimental explosive materials.

  10. Vortex formation in a proposed detonation internal combustion engine

    NASA Astrophysics Data System (ADS)

    Loth, Eric

    1995-05-01

    A possible configuration for taking advantage of detonation combustion in an internal combustion engine is described, which uses a separate detonation combustion chamber that discharges tangentially into a vortex chamber formed by the piston and cylinder at top dead center. The vortex chamber is designed to efficiently store a portion of the kinetic energy produced by the detonation wave in the form of a vortex, which would subsequently be converted into static pressure. By placing this chamber above the piston surface, the detonation and primary shock waves are directed parallel to the piston surface, thus avoiding potentially destructive loads to the piston. The rapid burning followed by mixing with air in the vortex chamber may reduce the formation of NOx and unburned hydrocarbons as compared to conventional combustion. Such a configuration may efficiently take advantage of clean-burning slow-deflagrating fuels such as natural gas to yield constant volume-type efficiencies. Shock wave propagation through the vortex chamber was simulated to qualitatively observe the vortex storage and rapid mixing characteristics.

  11. Vortex formation in a proposed detonation internal combustion engine

    SciTech Connect

    Loth, E. [Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)

    1995-05-01

    A possible configuration for taking advantage of detonation combustion in an internal combustion engine is described, which uses a separate detonation combustion chamber that discharges tangentially into a vortex chamber formed by the piston and cylinder at top dead center. The vortex chamber is designed to efficiently store a portion of the kinetic energy produced by the detonation wave in the form of a vortex, which would subsequently be converted into static pressure. By placing this chamber above the piston surface, the detonation and primary shock waves are directed parallel to the piston surface, thus avoiding potentially destructive loads to the piston. The rapid burning followed by mixing with air in the vortex chamber may reduce the formation of NOx and unburned hydrocarbons as compared to conventional combustion. Such a configuration may efficiently take advantage of clean-burning slow-deflagrating fuels such as natural gas to yield constant volume-type efficiencies. Shock wave propagation through the vortex chamber was simulated to qualitatively observe the vortex storage and rapid mixing characteristics. 30 refs.

  12. Modeling Detonation in Ultrafine TATB Hemispherical Boosters Using CREST

    NASA Astrophysics Data System (ADS)

    Whitworth, Nicholas

    2011-06-01

    Hemispherical ultrafine TATB boosters are often used to initiate detonation in the TATB-based explosive LX-17. For accurate hydrocode predictions of experiments using this combination of explosives, it is important to accurately model the detonation wave emerging from the booster material since this may influence the detonation behaviour in the main charge. Since ultrafine TATB exhibits non-ideal detonation behaviour, it's response should be modeled using reactive flow. In this paper, the CREST reactive burn model, which uses entropy-dependent reaction rates to simulate explosive behaviour, is applied to experimental data obtained from ultrafine TATB hemispherical boosters initiated by slapper detonators at three initial temperatures (ambient, -20 degC and -54 degC). The ambient temperature data is used to develop an initial CREST model for ultrafine TATB which is then subsequently applied to the cold data. A comparison of the experimental and modeling results is presented showing that the model gives good agreement to experiment at both ambient and cold temperatures.

  13. Detonation tube impulse in sub-atmospheric environments.

    SciTech Connect

    Cooper, Marcia A.; Shepherd, Joseph E. (California Institute of Technology, Pasadena, CA)

    2005-04-01

    The thrust from a multi-cycle, pulse detonation engine operating at practical flight altitudes will vary with the surrounding environment pressure. We have carried out the first experimental study using a detonation tube hung in a ballistic pendulum arrangement within a large pressure vessel in order to determine the effect that the environment has on the single-cycle impulse. The air pressure inside the vessel surrounding the detonation tube varied between 100 and 1.4 kPa while the initial pressure of the stoichiometric ethylene-oxygen mixture inside the tube varied between 100 and 30 kPa. The original impulse model (Wintenberger et al., Journal of Propulsion and Power, Vol. 19, No. 1, 2002) was modified to predict the observed increase in impulse and blow down time as the environment pressure decreased below one atmosphere. Comparisons between the impulse from detonation tubes and ideal, steady flow rockets indicate incomplete expansion of the detonation tube exhaust, resulting in a 37% difference in impulse at a pressure ratio (ratio of pressure behind the Taylor wave to the environment pressure) of 100.

  14. An experimental study of laser supported hydrogen plasmas

    NASA Technical Reports Server (NTRS)

    Vanzandt, D. M.; Mccay, T. D.; Eskridge, R. H.

    1984-01-01

    The rudiments of a rocket thruster which receives its enthalpy from an energy source which is remotely beamed from a laser is described. An experimental study now partially complete is discussed which will eventually provide a detailed understanding of the physics for assessing the feasibility of using hydrogen plasmas for accepting and converting this energy to enthalpy. A plasma ignition scheme which uses a pulsed CO2 laser has been developed and the properties of the ignition spark documented, including breakdown intensities in hydrogen. A complete diagnostic system capable of determining plasma temperature and the plasma absorptivity for subsequent steady state absorption of a high power CO2 laser beam are developed and demonstrative use is discussed for the preliminary case study, a two atmosphere laser supported argon plasma.

  15. Characterization of shock and reaction fronts in detonations

    NASA Astrophysics Data System (ADS)

    Tulis, Allen J.; Selman, J. Robert

    1982-10-01

    An instrumental technique has been developed which allows the concomitant measurement of the arrival times of both shock and reaction (flame) fronts in propagating detonations. A combination of fiber-optic probes and light detectors is used to monitor the arrival of the reaction front, whereas piezoelectric pressure gauges monitor the arrival of the pressure pulse from the preceding shock wave. Both signals provide the measurement of the detonation velocity; variance between shock and reaction front velocities implies nonstable detonation (growing or dying detonation) which can be attributed to variation in density, concentration, or homogeneity of the detonating media. This technique is straightforward in the case of pressed or cast formulations but presents difficulties when gas-phase or two-phase detonations are involved. The detonation of near-stoichiometric ethylene-air mixtures in a detonation-tube facility was used to refine the technique and calibrate the instrumentation. The technique was then used to characterize the detonation of two-phase aluminum powder-air mixtures of various concentrations. Compared to the 3-?s induction time between the shock and reaction fronts in the case of ethylene-air mixtures, the induction times for aluminum powder-air mixtures varied from about 1 to over 100 ?s. The variation in induction time was attributed to several factors: extended heating time to ignition of the particles due to inhomogeneity of the two-phase mixtures; variation in particle size; and variable aluminum-oxide surface coating thickness. The concentration of aluminum powder in the air was monitored dynamically using instrumentation that related the concentration of aluminum to the attenuation of a laser beam through the mixture. A mean, or overall, value was also estimated by determining the mass flow rate and overall discharge time using photographic coverage. In the former case, in order to obtain meaningful signals for these high-concentration two-phase systems it was necessary to reduce the pathlength of the laser beam through the mixture to a small fraction of the total width of the tube. Hence, the observed concentration measurements did not necessarily reflect good homogeneity across the width of the tube. Nevertheless, with some modifications this technique can be exceptionally useful for this most difficult measurement.

  16. Low-frequency two-dimensional linear instability of plane detonation

    NASA Astrophysics Data System (ADS)

    Short, Mark; Stewart, D. Scott

    1997-06-01

    An analytical dispersion relation describing the linear stability of a plane detonation wave to low-frequency two-dimensional disturbances with arbitrary wavenumbers is derived using a normal mode approach and a combination of high activation energy and Newtonian limit asymptotics, where the ratio of specific heats [gamma][rightward arrow]1. The reaction chemistry is characterized by one-step Arrhenius kinetics. The analysis assumes a large activation energy in the plane steady-state detonation wave and a characteristic linear disturbance wavelength which is longer than the fire-zone thickness. Newtonian limit asymptotics are employed to obtain a complete analytical description of the disturbance behaviour in the induction zone of the detonation wave. The analytical dispersion relation that is derived depends on the activation energy and exhibits favourable agreement with numerical solutions of the full linear stability problem for low-frequency one- and two-dimensional disturbances, even when the activation energy is only moderate. Moreover, the dispersion relation retains vitally important characteristics of the full problem such as the one-dimensional stability of the detonation wave to low-frequency disturbances for decreasing activation energies or increasing overdrives. When two-dimensional oscillatory disturbances are considered, the analytical dispersion relation predicts a monotonic increase in the disturbance growth rate with increasing wavenumber, until a maximum growth rate is reached at a finite wavenumber. Subsequently the growth rate decays with further increases in wavenumber until the detonation becomes stable to the two-dimensional disturbance. In addition, through a new detailed analysis of the behaviour of the perturbations near the fire front, the present analysis is found to be equally valid for detonation waves travelling at the Chapman Jouguet velocity and for detonation waves which are overdriven. It is found that in contrast to the standard imposition of a radiation or piston condition on acoustic disturbances in the equilibrium zone for overdriven waves, a compatibility condition on the perturbation jump conditions across the fire zone must be satisfied for detonation waves propagating at the Chapman Jouguet detonation velocity. An insight into the physical mechanisms of the one- and two-dimensional linear instability is also gained, and is found to involve an intricate coupling of acoustic and entropy wave propagation within the detonation wave.

  17. High-speed photography for pressure generation using the underwater explosion of spiral detonating cord

    NASA Astrophysics Data System (ADS)

    Itoh, Shigeru; Nagano, Shirou; Hamada, Toru; Murata, Kenji; Kato, Yukio

    2001-04-01

    In recent years we have devoted our efforts to the studies on the various shock processing techniques using explosives for the objectives of gaining materials with the good properties. Those techniques include the punch of pipes, shock consolidation of metallic and ceramic powders, explosive welding of amorphous ribbon on the steel or copper substrate, explosive engraving for the art objects and explosive forming of shells and spheres, and the improvement of the permeability of wood by shock wave. However, to a specific processing technique, it needs to control the shock wave for meeting the demands of that processing purpose. One important control is how to increase the strength of underwater shock wave. Therefore, we propose the following method to converge the underwater shock wave by putting a piece of detonating cord in a spiral way. First, the assignment of the spiral shape of detonation was determined from the geometrical consideration and the basic features of the detonation cord itself. Second, the converging process of the underwater shock wave from the explosion of such designed shape of detonating cord was photographically observed by using the high speed camera in the framing form. The spiral shape with the 100 mm distance from detonating start point to the center of the spiral (indicated by r1) was selected. They were amounted together with the electric detonator and the detonating cord. The photographs confirm that the underwater shock wave moves toward the spiral center in a convergence way. Third, the pressure nearing the spiral center was measured experimentally by means of the pressure transducers. The distance, Dh, between the detonating cord and the transducer was set to be 272 mm. Compared to the case that the detonating cord was placed in straight way, the maximum pressure in the case with the spiral shape is verified to be unchanged, but the impulse, however, is much improved. This reason may be due to over- greatly set Dh. When the distance Dh was set to 50 mm, the pressure measurement was made again and as a result, the large pressure value was record. Compared to the straightly placed detonating cord, it is shown that 3 times higher peak pressure is available in the spiral detonation cord. The results demonstrate that in a small range the pressure of underwater shock wave is indeed converged and higher pressure value is obtained.

  18. Detonation in TATB Hemispheres

    SciTech Connect

    Druce, B; Souers, P C; Chow, C; Roeske, F; Vitello, P; Hrousis, C

    2004-03-17

    Streak camera breakout and Fabry-Perot interferometer data have been taken on the outer surface of 1.80 g/cm{sup 3} TATB hemispherical boosters initiated by slapper detonators at three temperatures. The slapper causes breakout to occur at 54{sup o} at ambient temperatures and 42{sup o} at -54 C, where the axis of rotation is 0{sup o}. The Fabry velocities may be associated with pressures, and these decrease for large timing delays in breakout seen at the colder temperatures. At room temperature, the Fabry pressures appear constant at all angles. Both fresh and decade-old explosive are tested and no difference is seen. The problem has been modeled with reactive flow. Adjustment of the JWL for temperature makes little difference, but cooling to -54 C decreases the rate constant by 1/6th. The problem was run both at constant density and with density differences using two different codes. The ambient code results show that a density difference is probably there but it cannot be quantified.

  19. Deflagration-to-Detonation Transition Induced by Hot Jets in a Supersonic Premixed Airstream

    NASA Astrophysics Data System (ADS)

    Han, Xu; Zhou, Jin; Lin, Zhi-Yong; Liu, Yu

    2013-05-01

    Detonation is initiated through a hot jet in a supersonic premixed mixture of H2 and air, which is produced by using a air heater. The results show that initiation fails in the low-equivalence-ratio premixed gas. With the increase of equivalence ratio, the hot jet can induce deflagration to detonation transition (DDT) in the premixed mixture, which an indirect initiation of detonation. Further studies show that the DDT process is due to the combined effect of a local hemispherical explosion shock wave, the bow shock, and the flame produced by the hot jet.

  20. Detonation of insensitive high explosives by a Q-switched ruby laser.

    NASA Technical Reports Server (NTRS)

    Yang, L. C.; Menichelli, V. J.

    1971-01-01

    Immediate longitudinal detonations have been observed in confined small-diameter columns of PETN, RDX, and tetryl by using a focused Q-switched ruby laser. The energy ranged from 0.8 to 4.0 J in a pulse width of 25 nsec. A 1000-A-thick aluminum film deposited on a glass window was used to generate a shock wave at the window-explosive interface when irradiated by the laser. In some cases, steady-state detonations were reached in less than .5 microsec with less than 10% variation in the detonation velocity.

  1. DSD front models : nonideal explosive detonation

    SciTech Connect

    Bdzil, J. B. (John Bohdan); Short, M. (Mark Short); Aslam, T. D. (Tariq D.); Catanach, R. A. (Richard A.); Hill, L. G. (Larry G.)

    2001-01-01

    The Detonation Shock Dynamics (DSD) method for propagating detonation in numerical simulation of detonation in high explosive (HE) is based on three elements: (1) a subscale theory of multi-dimensional detonation that treats the evolving detonation as a front with dynamics that depends only on metrics of the front (such as curvature, etc.), (2) high-resolution direct numerical sirnuliltion of detonation serving both to test existing subscale theories and suggest modifications, and (3) physical experiments to characterize multi-dimensional detonation propagation on real explosives and to calibrate the front models for use in engineering simulations. In this paper we describe our work on all three of these elements of the DSD method as it applies to detonation in nonideal explosives.

  2. 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 magnet assembly were then installed on Marshall Space Flight Center's (MSFC's) rectangular channel pulse detonation research engine. Magnetohydrodynamic (MHD) electrical power extraction experiments were carried out for a range of load impedances in which cesium hydroxide seed (dissolved in methanol) was sprayed into the gaseous oxygen/hydrogen propellants. Positive power extraction was obtained, but preliminary analysis of the data indicated that the plasma electrical conductivity is lower than anticipated and the near-electrode voltage drop is not negligible. It is believed that the electrical conductivity is reduced due to a large population of negative OH ions. This occurs because OH has a strong affinity for capturing free electrons. The effect of near-electrode voltage drop is associated with the high surface-to-volume ratio of the channel (1-inch by 1-inch cross-section) where surface effects play a dominant role. As usual for MHD devices, higher performance will require larger scale devices. Overall, the gathered data is extremely valuable from the standpoint of understanding plasma behavior and for developing empirical scaling laws.

  3. A VIRTUAL TEST FACILITY FOR SIMULATING DETONATION-INDUCED DEFORMATION AND FRACTURE OF THIN FLEXIBLE SHELLS

    Microsoft Academic Search

    Ralf Deiterding; Fehmi Cirak; Sean P. Mauch; Daniel I. Meiron

    2006-01-01

    The fluid-structure interaction simulation of detonation- and shock-wave- loaded fracturing thin-walled structures requires numerical methods that can cope with large deformations as well as topology changes. We present a robust level-set-based approach that integrates a Lagrangian thin shell finite element solver with fracture and fragmenta- tion capabilities with an Eulerian Cartesian detonation solver with optional dynamic mesh adaptation. As computational

  4. Continuous Detonation Engine and Effects of Different Types of Nozzle on Its Propulsion Performance

    Microsoft Academic Search

    Shao Yetao; Liu Meng; Wang Jianping

    2010-01-01

    The rotating propagation of a continuous detonation engine (CDE) with different types of nozzles is investigated in three-dimensional numerical simulation using a one-step chemical reaction model. Flux terms are solved by the so-called monotonicity-preserving weighted essentially non-oscillatory (MPWENO) scheme. The simulated flow field agrees well with the previous experimental results. Once the initial transient effects die down, the detonation wave

  5. A Virtual Test Facility for Simulating Detonation-Induced Fracture of Thin Flexible Shells

    Microsoft Academic Search

    Ralf Deiterding; Fehmi Cirak; Sean Mauch; Daniel I. Meiron

    2006-01-01

    The fluid-structure interaction simulation of detonation- and shock-wave-loaded fracturing thin-walled structures requires numerical methods that can cope with large deformations as well as topology changes. We present a robust level-set-based approach that integrates a Lagrangian thin shell finite element solver with fracture and fragmen- tation capabilities with an Eulerian Cartesian detonation solver with optional dynamic mesh adaptation. As an application

  6. 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 analytical solutions in order to quantify the numerical error in the simulations. Additionally, experimental data from laboratory scale combustors was used to validate 2D and 3D numerical simulations. The effects of different modeling parameters on RDC predictions was also studied. The validated simulation strategy was then used to assess the performance of RDC for different combustion chamber geometries and operating conditions relevant to GT applications. As a result, the limiting conditions for which continuous detonation and pressure gain combustion can be achieved were predicted and the effect of operating conditions on flow structures and RDC performance was assessed. The modeling strategy and the results from this study could be further used to design more efficient and more stable RDC systems.

  7. Development of a Detonation Profile Test for Studying Aging Effects in LX-17

    SciTech Connect

    Tran, T; Lewis, P; Tarver, C; Maienschein, J; Druce, R; Lee, R; Roeske, F

    2002-03-25

    A new small-scale Detonation Profile Test (DPT) is being developed to investigate aging effects on the detonation behavior of insensitive high explosives. The experiment involves initiating a small LX-17 cylindrical charge (12.7-19.1 mm diameter x 25.4-33 mm long) and measuring the velocity and curvature of the emerging detonation wave using a streak camera. Results for 12.7 mm diameter unconfined LX-17 charges show detonation velocity in the range between 6.79 and 7.06 km/s for parts up to 33 mm long. Since LX-17 can not sustain detonation at less than 7.3 km/s, these waves were definitely failing. Experiments with confined 12.7 mm diameter and unconfined 19.1 mm diameter samples showed wave velocities in the range of 7.4-7.6 km/s, values approaching steady state conditions at infinite diameter. Experiments with unconfined 19.1 mm diameter specimens are expected to provide reproducible and useful range of detonation parameters suitable for studying aging effects.

  8. 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 on a 25 mm i.d. PDE. The dual-stage PDE was run at both 1 Hz and 10 Hz using solenoid valves. The two types of valves have their drawbacks and advantages which are discussed, along with ways to enhance their functionality. Rotary valves with stepper motor drives are recommended to be used for air flow control, while an array of solenoid injectors may be used for liquid or gaseous fuel injection. Various DDT enhancing devices were tested, including Shchelkin spirals (with varying thicknesses, lengths and pitches), grooved sleeves and converging-diverging nozzles. The Shchelkin spirals are found to be the most effective of all, at blockage ratios in the region of 50 to 55%. To improve the durability of Shchelkin spirals, it is recommended that they be grooved into the inside of tubes or inserted as replaceable sleeves. Orifice plates with high blockage ratios, in the region of 50 to 80%, are also recommended due to their simple and rugged design. All these devices along with the PDE combustor will require a strong cooling system to prevent damage from the extreme detonation temperatures. High energy (HE) and low energy (LE) ignition systems were tested and compared along with various designs of igniters and automotive spark plugs. It is concluded that while HE ignition may help unsensitized fuel-air mixtures to achieve detonations faster than LE systems, the former have severe drawbacks. The HE igniters get damaged quickly, and require large and heavy power supplies. While the HE ignition is able to reduce ignition delay in a propane-oxygen pre-detonator, it did not show a significant improvement in bringing about DDT in the main combustor using propane-air mixtures. The compact pre-detonator design with a gradual area change transitioning to a larger combustor is found to be effective for detonation initiation, but the pre-detonator concept is recommended for high-speed applications only, since higher speeds requires more sensitive, easily detonable fuels that have short ignition delays and DDT run-up distances. Dynamic pressure transducers, ion detectors and p

  9. Shock initiation and detonation properties of bisfluorodinitroethyl formal (FEFO)

    NASA Astrophysics Data System (ADS)

    Gibson, L. L.; Sheffield, S. A.; Dattelbaum, Dana M.; Stahl, David B.

    2012-03-01

    FEFO is a liquid explosive with a density of 1.60 g/cm3 and an energy output similar to that of trinitrotoluene (TNT), making it one of the more energetic liquid explosives. Here we describe shock initiation experiments that were conducted using a two-stage gas gun using magnetic gauges to measure the wave profiles during a shock-to-detonation transition. Unreacted Hugoniot data, time-to detonation (overtake) measurements, and reactive wave profiles were obtained from each experiment. FEFO was found to initiate by the homogeneous initiation model, similar to all other liquid explosives we have studied (nitromethane, isopropyl nitrate, hydrogen peroxide). The new unreacted Hugoniot points agree well with other published data. A universal liquid Hugoniot estimation slightly under predicts the measured Hugoniot data. FEFO is very insensitive, with about the same shock sensitivity as the triamino-trinitro-benzene (TATB)-based explosive PBX9502 and cast TNT.

  10. Reaction zone structure for strong, weak overdriven, and weak underdriven oblique detonations

    NASA Technical Reports Server (NTRS)

    Powers, Joseph M.; Gonthier, Keith A.

    1992-01-01

    A simple dynamic systems analysis is used to give examples of strong, weak overdriven, and weak underdriven oblique detonations. Steady oblique detonations consisting of a straight lead shock attached to a solid wedge followed by a resolved reaction zone structure are admitted as solutions to the reactive Euler equations. This is demonstrated for a fluid that is taken to be an inviscid, calorically perfect ideal gas that undergoes a two-step irreversible reaction with the first step exothermic and the second step endothermic. This model admits solutions for a continuum of shock wave angles for two classes of solutions identified by a Rankine-Hugoniot analysis: strong and weak overdriven waves. The other class, weak underdriven, is admitted for eigenvalue shock-wave angles. Chapman-Jouguet waves, however, are not admitted. These results contrast those for a corresponding onestep model that, for detonations with a straight lead shock, only admits strong, weak overdriven, and Chapman-Jouguet solutions.

  11. FRONT CURVATURE RATE STICK MEASUREMENTS AND DETONATION SHOCK DYNAMICS CALIBRATION

    E-print Network

    Aslam, Tariq

    87545 Detonation velocities and wave shapes were measured for PBX 9502 95 wt. TATB, 5 wt. Kel-F 800 rate computationally e cient because it does not re- quire calculation of the reaction zone structure.1 TATB composition 95.00 wt. TATB 5.00 wt. Kel-F 800. Sieve analysis showed 74.8 wt. 45 m and 31.2 wt. 20 m. The BET

  12. FRONT CURVATURE RATE STICK MEASUREMENTS AND DETONATION SHOCK DYNAMICS CALIBRATION

    E-print Network

    Aslam, Tariq

    87545 Detonation velocities and wave shapes were measured for PBX 9502 (95 wt.% TATB, 5 wt.% Kel­F 800 computationally efficient because it does not re­ quire calculation of the reaction zone structure. 1 TATB composition 95.00 wt.% TATB / 5.00 wt.% Kel­F 800. Sieve analysis showed 74.8 wt.% ! 45 ¯m and 31.2 wt.% ! 20

  13. An excitonic mechanism of detonation initiation in explosives

    Microsoft Academic Search

    Maija M. Kuklja; Eugene V. Stefanovich; A. Barry Kunz

    2000-01-01

    A novel mechanism for detonation initiation in solid explosives is proposed. This is based on electronic excitations induced by an impact wave propagating through the crystal. We illustrate the model by using the RDX (C3H6N6O6) crystal as an example. In our model, a key role belongs to lattice defects, in particular edge dislocations, which promote dramatic changes in the electronic

  14. ASYMMETRY AND THE NUCLEOSYNTHETIC SIGNATURE OF NEARLY EDGE-LIT DETONATION IN WHITE DWARF CORES

    SciTech Connect

    Chamulak, David A.; Truran, James W. [Argonne National Laboratory, Argonne, IL (United States); Meakin, Casey A. [Steward Observatory, University of Arizona, Tucson, AZ (United States); Seitenzahl, Ivo R., E-mail: dchamulak@anl.gov [Max Planck Institute for Astrophysics, Garching (Germany)

    2012-01-01

    Most of the leading explosion scenarios for Type Ia supernovae involve the nuclear incineration of a white dwarf star through a detonation wave. Several scenarios have been proposed as to how this detonation may actually occur, but the exact mechanism and environment in which it takes place remain unknown. We explore the effects of an off-center initiated detonation on the spatial distribution of the nucleosynthetic yield products in a toy model-a pre-expanded near Chandrasekhar-mass white dwarf. We find that a single-point near edge-lit detonation results in asymmetries in the density and thermal profiles, notably the expansion timescale, throughout the supernova ejecta. We demonstrate that this asymmetry of the thermodynamic trajectories should be common to off-center detonations where a small amount of the star is burned prior to detonation. The sensitivity of the yields on the expansion timescale results in an asymmetric distribution of the elements synthesized as reaction products. We tabulate the shift in the center of mass of the various elements produced in our model supernova and find an odd-even pattern for elements past silicon. Our calculations show that off-center single-point detonations in carbon-oxygen white dwarfs are marked by significant composition asymmetries in their remnants which bear potentially observable signatures in both velocity and coordinate space, including an elemental nickel mass fraction that varies by a factor of 2-3 from one side of the remnant to the other.

  15. A Study of Moving Mesh Methods Applied to a Thin Flame Propagating in a Detonator Delay Element

    E-print Network

    Higham, Nicholas J.

    of the delay element. A de agration wave is thus initiated at the fuse end which propagates along the delay agration wave is then converted to a detonation wave which travels with a speed of several hundred metres partial di#11;erential equations (PDEs) having large solution gradients, such as shock waves, boundary

  16. Instability threshold of gaseous detonations

    Microsoft Academic Search

    EMI D AOU; PAUL C LAVIN

    pments in nonlinear analyses for describing the cellular structure of weakly unstable detonation fronts, particular attention is paid to the neighbourhood of the instability threshold. A first objective is to check the validity domain of the analytical results and to investigate to what extent they are useful when approaching the self-sustained regime (Chapman-Jouguet conditions). A second objective is to study

  17. 33 CFR Appendix A to Part 154 - Guidelines for Detonation Flame Arresters

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...7. 4.2Deflagration—A combustion wave that propagates subsonically (as measured...3Detonation—A reaction in a combustion wave propagating at sonic or supersonic...allow for ease of inspection and removal of internal elements for replacement, cleaning...

  18. 33 CFR Appendix A to Part 154 - Guidelines for Detonation Flame Arresters

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...7. 4.2Deflagration—A combustion wave that propagates subsonically (as measured...3Detonation—A reaction in a combustion wave propagating at sonic or supersonic...allow for ease of inspection and removal of internal elements for replacement, cleaning...

  19. 33 CFR Appendix A to Part 154 - Guidelines for Detonation Flame Arresters

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...7. 4.2Deflagration—A combustion wave that propagates subsonically (as measured...3Detonation—A reaction in a combustion wave propagating at sonic or supersonic...allow for ease of inspection and removal of internal elements for replacement, cleaning...

  20. 33 CFR Appendix A to Part 154 - Guidelines for Detonation Flame Arresters

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...7. 4.2Deflagration—A combustion wave that propagates subsonically (as measured...3Detonation—A reaction in a combustion wave propagating at sonic or supersonic...allow for ease of inspection and removal of internal elements for replacement, cleaning...

  1. 33 CFR Appendix A to Part 154 - Guidelines for Detonation Flame Arresters

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...7. 4.2Deflagration—A combustion wave that propagates subsonically (as measured...3Detonation—A reaction in a combustion wave propagating at sonic or supersonic...allow for ease of inspection and removal of internal elements for replacement, cleaning...

  2. Under consideration for publication in J. Fluid Mech. 1 Condensed-phase detonation stability for a

    E-print Network

    Anguelova, Iana

    is a destructive form of propagating wave front, consisting of a lead shock sustained by chemical reaction (Fickett & Davis 1979), which in most cases propagates at a minimum speed defined by the presence of a sonic flow point (relative to the detonation wave speed) within the reaction zone, known as the Chapman

  3. MULTI-DIMENSIONAL MODELS FOR DOUBLE DETONATION IN SUB-CHANDRASEKHAR MASS WHITE DWARFS

    SciTech Connect

    Moll, R.; Woosley, S. E. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2013-09-10

    Using two-dimensional and three-dimensional simulations, we study the ''robustness'' of the double detonation scenario for Type Ia supernovae, in which a detonation in the helium shell of a carbon-oxygen white dwarf induces a secondary detonation in the underlying core. We find that a helium detonation cannot easily descend into the core unless it commences (artificially) well above the hottest layer calculated for the helium shell in current presupernova models. Compressional waves induced by the sliding helium detonation, however, robustly generate hot spots which trigger a detonation in the core. Our simulations show that this is true even for non-axisymmetric initial conditions. If the helium is ignited at multiple points, then the internal waves can pass through one another or be reflected, but this added complexity does not defeat the generation of the hot spot. The ignition of very low-mass helium shells depends on whether a thermonuclear runaway can simultaneously commence in a sufficiently large region.

  4. Fluid dynamics in a Rotating-Detonation-Engine with micro-injectors

    NASA Astrophysics Data System (ADS)

    Schwer, Douglas

    2011-11-01

    Rotating detonation engines (RDE's) represent a natural extension of the extensively studied pulse detonation engines (PDE's) for obtaining propulsion from the high efficiency detonation cycle. RDE's require fuel and oxidizer under high pressure to be injected through micro-nozzles from one or two plenums (for premixed and non-premixed). This injection process is critically important to the stability and performance of the RDE. This paper studies the effect of this injection process on the detonation wave within the combustion chamber, with an emphasis on how the fluid dynamics are affected. Both two-dimensional and three-dimensional simulations are done using well proven numerical methods for both the combustion chamber and mixture plenums of an idealized RDE. This work is supported through NRL 6.1 Computational Physics Task Area

  5. THE EFFECT OF THE PRE-DETONATION STELLAR INTERNAL VELOCITY PROFILE ON THE NUCLEOSYNTHETIC YIELDS IN TYPE Ia SUPERNOVA

    SciTech Connect

    Kim, Yeunjin; Jordan, G. C. IV; Graziani, Carlo; Lamb, D. Q.; Truran, J. W. [Astronomy Department, University of Chicago, Chicago, IL 60637 (United States); Meyer, B. S. [Physics and Astronomy Department, Clemson University, Clemson, SC 29634 (United States)

    2013-07-01

    A common model of the explosion mechanism of Type Ia supernovae is based on a delayed detonation of a white dwarf. A variety of models differ primarily in the method by which the deflagration leads to a detonation. A common feature of the models, however, is that all of them involve the propagation of the detonation through a white dwarf that is either expanding or contracting, where the stellar internal velocity profile depends on both time and space. In this work, we investigate the effects of the pre-detonation stellar internal velocity profile and the post-detonation velocity of expansion on the production of {alpha}-particle nuclei, including {sup 56}Ni, which are the primary nuclei produced by the detonation wave. We perform one-dimensional hydrodynamic simulations of the explosion phase of the white dwarf for center and off-center detonations with five different stellar velocity profiles at the onset of the detonation. In order to follow the complex flows and to calculate the nucleosynthetic yields, approximately 10,000 tracer particles were added to every simulation. We observe two distinct post-detonation expansion phases: rarefaction and bulk expansion. Almost all the burning to {sup 56}Ni occurs only in the rarefaction phase, and its expansion timescale is influenced by pre-existing flow structure in the star, in particular by the pre-detonation stellar velocity profile. We find that the mass fractions of the {alpha}-particle nuclei, including {sup 56}Ni, are tight functions of the empirical physical parameter {rho}{sub up}/v{sub down}, where {rho}{sub up} is the mass density immediately upstream of the detonation wave front and v{sub down} is the velocity of the flow immediately downstream of the detonation wave front. We also find that v{sub down} depends on the pre-detonation flow velocity. We conclude that the properties of the pre-existing flow, in particular the internal stellar velocity profile, influence the final isotopic composition of burned matter produced by the detonation.

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

    Microsoft Academic Search

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

    2009-01-01

    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

  7. DETONATOR PERFORMANCE CHARACTERIZATION USING MULTI-FRAME LASER SCHLIEREN IMAGING

    Microsoft Academic Search

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

    2009-01-01

    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

  8. Numerical simulation of detonation reignition in H 2-O 2 mixtures in area expansions

    NASA Astrophysics Data System (ADS)

    Jones, D. A.; Kemister, G.; Tonello, N. A.; Oran, E. S.; Sichel, M.

    Time-dependent, two-dimensional, numerical simulations of a transmitted detonation show reignition occuring by one of two mechanisms. The first mechanism involves the collision of triple points as they expand along a decaying shock front. In the second mechanism ignition results from the coalescence of a number of small, relatively high pressure regions left over from the decay of weakened transverse waves. The simulations were performed using an improved chemical kinetic model for stoichiometric H 2-O 2 mixtures. The initial conditions were a propagating, two-dimensional detonation resolved enough to show transverse wave structure. The calculations provide clarification of the reignition mechanism seen in previous H 2-O 2-Ar simulations, and again demonstrate that the transverse wave structure of the detonation front is critical to the reignition process.

  9. Effect of Velocity of Detonation of Explosives on Seismic Radiation

    NASA Astrophysics Data System (ADS)

    Stroujkova, A. F.; Leidig, M.; Bonner, J. L.

    2014-12-01

    We studied seismic body wave generation from four fully contained explosions of approximately the same yields (68 kg of TNT equivalent) conducted in anisotropic granite in Barre, VT. The explosions were detonated using three types of explosives with different velocities of detonation (VOD): Black Powder (BP), Ammonium Nitrate Fuel Oil/Emulsion (ANFO), and Composition B (COMP B). The main objective of the experiment was to study differences in seismic wave generation among different types of explosives, and to determine the mechanism responsible for these differences. The explosives with slow burn rate (BP) produced lower P-wave amplitude and lower corner frequency, which resulted in lower seismic efficiency (0.35%) in comparison with high burn rate explosives (2.2% for ANFO and 3% for COMP B). The seismic efficiency estimates for ANFO and COMP B agree with previous studies for nuclear explosions in granite. The body wave radiation pattern is consistent with an isotropic explosion with an added azimuthal component caused by vertical tensile fractures oriented along pre-existing micro-fracturing in the granite, although the complexities in the P- and S-wave radiation patterns suggest that more than one fracture orientation could be responsible for their generation. High S/P amplitude ratios and low P-wave amplitudes suggest that a significant fraction of the BP source mechanism can be explained by opening of the tensile fractures as a result of the slow energy release.

  10. Non-detonable explosive simulators

    DOEpatents

    Simpson, Randall L. (Livermore, CA); Pruneda, Cesar O. (Livermore, CA)

    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.

  11. 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.

  12. Phase detonated shock tube (PFST)

    SciTech Connect

    Zerwekh, W.D.; Marsh, S.P.; Tan, T. (Group M-6, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States))

    1994-07-10

    Mesa2D hydrocode has been used to model the collapse of 304SS cylinder onto the 6061Al phasing lens, shock in the lines, phase detonation of the PBX 9501 explosive, and Mach disk position. The phase velocity in the system was meausred in microwave-interferometry experiments, and favorably compared with the calculations. The technique allows to accelerate a thin plate intact to above 1 cm/micro-s. (AIP) [copyright]American Institute of Physics

  13. Phase detonated shock tube (PFST)

    NASA Astrophysics Data System (ADS)

    Zerwekh, W. D.; Marsh, S. P.; Tan, T.-H.

    1994-07-01

    Mesa2D hydrocode has been used to model the collapse of 304SS cylinder onto the 6061Al phasing lens, shock in the lines, phase detonation of the PBX 9501 explosive, and Mach disk position. The phase velocity in the system was meausred in microwave-interferometry experiments, and favorably compared with the calculations. The technique allows to accelerate a thin plate intact to above 1 cm/micro-s. (AIP)

  14. Application of fast infrared detectors to detonation science

    SciTech Connect

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

    1982-07-28

    Infrared radiometers have been used to make time-resolved emission measurements of shocked explosives. Instruments of moderate time resolution were used to estimate temperatures in shocked but not detonated explosives. The heterogeneity of the shock-induced heating was discovered in pressed explosives by two-band techniques, and the time-resolved emittance or extent of hot spot coverage indicated a great dependence on shock pressures. Temperatures in moderately shocked organic liquids were also measured. Faster response radiometers with 5 ns rise times based on InSb and HgCdTe photovoltaic detectors were constructed and tested. Preliminary data on reactive shocks and detonations reveal a resolution of the heating in the shock wave and the following reaction.

  15. Detonation characteristics of prilled ammonium nitrate

    Microsoft Academic Search

    C. H. Winning

    1965-01-01

    Detonation characteristics of prilled ammonium nitrate vary greatly with physical factors. Minimum primer requirements and\\u000a minimum propagating diameters of industrial and fertilizer grade prills are compared as well as the detonation velocities\\u000a and blast effects of prill “shots” of various sizes and degrees of confinement. The sensitizing effect of elevated temperature\\u000a on AN detonations also is demonstrated.

  16. Quantic Industries Inc. slapper detonator performance

    Microsoft Academic Search

    J. L. Cutting; R. S. Lee; R. L. Hodgin

    1994-01-01

    Under the Lawrence Livermore National Laboratories (LLNL) Small Business Technology Transfer Program, assistance was given to Quantic Industries Inc. to use the High Explosive Applications Facility (HEAF), its apparatus, and LLNL expertise to characterize the performance of Quantic`s micro-clad copper\\/kapton slapper detonator assemblies and establish their threshold to detonate HNS-IV. The project involved measuring the performance of these slapper detonators,

  17. Curved detonation fronts in solid explosives 1 Curved detonation fronts in solid explosives

    E-print Network

    Aslam, Tariq

    Curved detonation fronts in solid explosives 1 Curved detonation fronts in solid explosives(). At the edges of the explosive, Dn() is supplemented with boundary conditons. By direct numerical simulation for simulating complex explosive-containing systems. Key words: Detonation, Curvature eect, Edge interactions

  18. Curved detonation fronts in solid explosives 1 Curved detonation fronts in solid explosives#

    E-print Network

    Aslam, Tariq

    Curved detonation fronts in solid explosives 1 Curved detonation fronts in solid explosives ###. At the edges of the explosive# D n ### is supplemented with boundary conditons. By direct numerical simulation for simulating complex explosive#containing systems. Key words# Detonation# Curvature e#ect# Edge interactions

  19. Detonation Limit Thresholds in H2\\/O2 Rotating Detonation Engine

    Microsoft Academic Search

    Takayuki Yamada; A. Koichi Hayashi; Eisuke Yamada; Nobuyuki Tsuboi; Venkat E. Tangirala; Toshi Fujiwara

    2010-01-01

    The rotating detonation engine (RDE) is a new engine system using detonation, which may provide a higher performance and smaller and simpler design in comparison with the pulse detonation engine (PDE) and other traditional engines. However the research on RDE stands just at the first step now. The authors perform a numerical analysis to understand about RDE in terms of

  20. Detonation failure diameters and detonation velocities of nitric acid, acetic acid and water mixtures

    Microsoft Academic Search

    P. Vidal; H. N. Presles; J. L. Gustin; J. Calzia

    1993-01-01

    Detonation failure experiments and detonation velocity measurements were carried out with homogeneous liquid compositions of nitric acid, acetic acid and water contained in steel tubes with different diameters. The criterion for failure or propagation of detonation was based upon the type of damage exhibited by the tubes after the experiments. Mixtures with the same critical diameter were determined by varying

  1. Understanding Detonation Corner Turning within Ultra-Fine TATB: Measurements and Modeling

    NASA Astrophysics Data System (ADS)

    Sinibaldi, Jose; Vitello, Peter; May, Chadd

    2013-06-01

    Detonation corner turning within insensitive high explosives has demonstrated difficulties as the insensitivity of the high explosive increases. Experiments tend to report breakout profiles, which show times of arrival of the detonation wave at the surface of the IHE charge. Although, various reactive flow models are able to predict these breakout profiles, none of these models agree perfectly with each other. Models predict major differences in pressure profiles and in the internal detonation wave propagation characteristics. Thus, the objective of this study was to provide detailed accounts of the wave propagation within an ultra-fine TATB charge, through the use embedded fiber-optic diagnostics that allowed measuring the detonation wave propagation within the ultra-fine TATB charges. In addition, these experiments were also instrumented at multiple points with Photonic Doppler Velocimetry to provide dynamic pressure profiles at the hemispherical surface; and orthogonal streak cameras to provide the conventional breakout profiles. Comparisons between experimental data and simulation results using a high resolution reactive flow model for ultra-fine TATB will be presented. Detonation corner turning within insensitive high explosives has demonstrated difficulties as the insensitivity of the high explosive increases. Experiments tend to report breakout profiles, which show times of arrival of the detonation wave at the surface of the IHE charge. Although, various reactive flow models are able to predict these breakout profiles, none of these models agree perfectly with each other. Models predict major differences in pressure profiles and in the internal detonation wave propagation characteristics. Thus, the objective of this study was to provide detailed accounts of the wave propagation within an ultra-fine TATB charge, through the use embedded fiber-optic diagnostics that allowed measuring the detonation wave propagation within the ultra-fine TATB charges. In addition, these experiments were also instrumented at multiple points with Photonic Doppler Velocimetry to provide dynamic pressure profiles at the hemispherical surface; and orthogonal streak cameras to provide the conventional breakout profiles. Comparisons between experimental data and simulation results using a high resolution reactive flow model for ultra-fine TATB will be presented. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  2. 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.

  3. Detonation phenomena observed with a CCD camera

    NASA Astrophysics Data System (ADS)

    Held, Manfred

    1995-05-01

    With an appropriate test set up, the Hadland Photonics Ballistic Range Camera (SVR), designed primarily for exterior and terminal ballistics, can also be used very well for studying initiation events and analyzing a variety of detonation phenomena. This paper explains in detail the test set up of one interesting detonic experiment, observed with the Ballistic Range Camera, and the analysis of the results. The ability of the camera to superimpose up to 16 exposures on a single image allowed particularly detailed examination of the detonation propagation, the detonation velocities, the corner turning distance and the nonreacting radial zones.

  4. Investigation on detonation in 2H2/O2 mixture initiated by AgN3

    NASA Astrophysics Data System (ADS)

    Xu, S. L.; Takayama, K.; Sun, M. Y.

    Gas detonation in 2H2/O2 mixture initiated by high explosive AgN3 is numerically studied in this paper. Fully 3D Navier-Stokes equations are solved by upper wind TVD scheme. Self-similar solution is used to simulate ignition of AgN3 by neglecting its detailed chemistry. The flow field near explosion center must be simplified because of the high temperature. Chemical source term is treated by point-implicit method to avoid the stiffness. 12species/23steps model is used to describe the chemistry of 2H2/O2 mixture. Contours of pressure, temperature, and species mass fraction are obtained. The results indicate that the self-sustained propagating spherical detonation wave can be generated, and DDT process is shortened for large shock Mach number Ms. The detonation wave reflects as shock waves on side and end walls. For different Ms (2.0˜3.5), the parameters of steady detonation are the same but flow field near the explosion center is different. The computed detonation parameters are less than those got from C-J theory.

  5. Non-Equilibrium Zeldovich-Von Neumann-Doring Theory and Reactive Flow Modeling of Detonation

    SciTech Connect

    Tarver, C M; Forbes, J W; Urtiew, P A

    2002-05-02

    This paper discusses the Non-Equilibrium Zeldovich - von Neumann - Doring (NEZND) theory of self-sustaining detonation waves and the Ignition and Growth reactive flow model of shock initiation and detonation wave propagation in solid explosives. The NEZND theory identified the non-equilibrium excitation processes that precede and follow the exothermic decomposition of a large high explosive molecule into several small reaction product molecules. The thermal energy deposited by the leading shock wave must be distributed to the vibrational modes of the explosive molecule before chemical reactions can occur. The induction time for the onset of the initial endothermic reactions can be calculated using high pressure, high temperature transition state theory. Since the chemical energy is released well behind the leading shock front of a detonation wave, a physical mechanism is required for this chemical energy to reinforce the leading shock front and maintain its overall constant velocity. This mechanism is the amplification of pressure wavelets in the reaction zone by the process of de-excitation of the initially highly vibrationally excited reaction product molecules. This process leads to the development of the three-dimensional structure of detonation waves observed for all explosives. For practical predictions of shock initiation and detonation in hydrodynamic codes, phenomenological reactive flow models have been developed. The Ignition and Growth reactive flow model of shock initiation and detonation in solid explosives has been very successful in describing the overall flow measured by embedded gauges and laser interferometry. This reactive flow model uses pressure and compression dependent reaction rates, because time resolved experimental temperature data is not yet available. Since all chemical reaction rates are ultimately controlled by temperature, the next generation of reactive flow models will use temperature dependent reaction rates. Progress on a statistical hot spot ignition and growth reactive flow model with multistep Arrhenius chemical reaction pathways is discussed.

  6. Detonation Initiation by a Temperature Gradient for a Detailed Chemical Reaction Models

    NASA Astrophysics Data System (ADS)

    Liberman, Michael; Kiverin, Alexey; Chukalovsky, Alexander; Ivanov, Mikhail

    2011-04-01

    The evolution from a temperature gradient to a detonation is investigated using high resolution numerical simulations for combustion mixture whose chemistry is governed by a detailed chemical kinetics. We employ a model representing an initial linear temperature gradient in the fuel. Emphasis is on comparing the results with previous studies that used simple one-step kinetics. It is shown that the evolution to detonation from temperature nonuniformities is considerably different for one-step kinetics models than for chain-branching kinetic models and it is different in different fuels for the same initial conditions. A detailed chemical model has a profound effect on the validity of Zel'dovich's spontaneous wave concept for detonation initiation by a gradient of reactivity. The evolution to detonation from a temperature gradient is considered for hydrogen-air and methane-air mixtures at different initial pressures. The analysis shows that for a detailed chemical kinetics the temperature gradients, which was thought to appear in the form of hot spots and the like, are not satisfy the criteria to initiate detonation, and the gradient mechanism can not be origin of the deflagration-to-detonation transition.

  7. Laterally Propagating Detonations in Thin Helium Layers on Accreting White Dwarfs

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

    Theoretical work has shown that intermediate mass (0.01 M ? < M He < 0.1 M ?) helium shells will unstably ignite on the accreting white dwarf (WD) in an AM CVn binary. For more massive (M > 0.8 M ?) WDs, these helium shells can be dense enough (>5 × 105 g cm-3) that the convectively burning region runs away on a timescale comparable to the sound travel time across the shell, raising the possibility for an explosive outcome rather than an Eddington limited helium novae. The nature of the explosion (i.e., deflagration or detonation) remains ambiguous, is certainly density dependent, and likely breaks spherical symmetry. In the case of detonation, this causes a laterally propagating front whose properties in these geometrically thin and low-density shells we begin to study here. Our calculations show that the radial expansion time of <0.1 s leads to incomplete helium burning, in agreement with recent work by Sim and collaborators, but that the nuclear energy released is still adequate to realize a self-sustaining laterally propagating detonation. These detonations are slower than the Chapman-Jouguet speed of 1.5 × 109 cm s-1, but still fast enough at 0.9 × 109 cm s-1 to go around the star prior to the transit through the star of the inwardly propagating weak shock. Our simulations resolve the subsonic region behind the reaction front in the detonation wave. The two-dimensional nucleosynthesis is shown to be consistent with a truncated one-dimensional Zeldovich-von Neumann-Döring calculation at the slower detonation speed. The ashes from the lateral detonation are typically He rich, and consist of predominantly 44Ti, 48Cr, along with a small amount of 52Fe, with very little 56Ni and with significant 40Ca in carbon-enriched layers. If this helium detonation results in a Type Ia supernova, its spectral signatures would appear for the first few days after explosion.

  8. 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.

  9. Detonation in tungsten-loaded HMX

    SciTech Connect

    Goldstein, S.; Mader, C.L.

    1985-01-01

    The detonation behavior of X-0233, a heavily tungsten-loaded HMX explosive, has been studied using failure diameter measurements, plate dents, and aquarium tests. A model with features resembling those of a weak detonation describe the experimental results. 7 refs., 10 figs.

  10. Detonation Diffraction into a Confined Volume 

    E-print Network

    Polley, Nolan Lee

    2012-02-14

    facility was constructed to study this problem, and experiments were conducted to determine under what conditions a planar detonation could be successfully transformed into a cylindrical detonation. Four different fuel-oxidizer mixtures, C?H?+ 2.5 O?, C?H?...

  11. FLOW TEST FOR PULSE DETONATION ENGINE

    Microsoft Academic Search

    Eric J. Gamble; Jose Gutierrez; Evan Riordan

    A test was conducted to measure the time-averaged flow rate of a pulse detonation engine. The objective of this flow test was to determine the flow effectiveness of a pulse detonation engine utilizing a rotating spool of tubes. Since thrust is directly proportional to flow, the ability of the device to pass flow at operating rotational speeds is critical to

  12. Formation of detonation in rotating channels

    Microsoft Academic Search

    V. A. Levin; I. S. Manu?lovich; V. V. Markov

    2010-01-01

    308 For estimating the possibility of detonation initia? tion during rotation, we considered the gasmixture flow inside and outside the rotating elliptic cylinder included in the circular cylinder. The values of critical parameters at which the detonation is formed were determined. We presented the analogy to the detona? tion initiation in the gasmixture flow in the channel of a special

  13. 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.

  14. 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

  15. On detonation behavior of mixed fuels

    NASA Astrophysics Data System (ADS)

    Takita, K.; Niioka, T.

    1996-07-01

    An experimental study of detonation was carried out for mixed fuels (H2/CH4, H2/C3H8 and CH4/C4H_{10}). The results obtained demonstrate that detonation velocities of mixed fuels agree very well with normal C-J velocity and that detonation limits were not extended by the addition of a small amount of C4H_{10}. As for CH4/C4H_{10} mixed fuel, detonation velocities and detonation limits as a function of the equivalence ratio of the whole mixture of mixed fuel coincided with those of CH4 single fuel. However, the detonation induction time of a mixture of CH4/O2/N2 with a lower sensitivity to detonation decreased considerably with the addition of a small amount of C4H_{10}. In addition, the influence of mixed fuels on the quasi-detonation and the fast deflagration in the process of DDT was investigated, showing interesting and complicated features in mixed fuel.

  16. Detonation phenomena observed with a CCD camera

    Microsoft Academic Search

    Manfred Held

    1995-01-01

    With an appropriate test set up, the Hadland Photonics Ballistic Range Camera (SVR), designed primarily for exterior and terminal ballistics, can also be used very well for studying initiation events and analyzing a variety of detonation phenomena. This paper explains in detail the test set up of one interesting detonic experiment, observed with the Ballistic Range Camera, and the analysis

  17. Tritium labeling of detonation nanodiamonds.

    PubMed

    Girard, Hugues A; El-Kharbachi, Abdelouahab; Garcia-Argote, Sébastien; Petit, Tristan; Bergonzo, Philippe; Rousseau, Bernard; Arnault, Jean-Charles

    2014-03-18

    For the first time, the radioactive labeling of detonation nanodiamonds was efficiently achieved using a tritium microwave plasma. According to our measurements, the total radioactivity reaches 9120 ± 120 ?Ci mg(-1), with 93% of (3)H atoms tightly bonded to the surface and up to 7% embedded into the diamond core. Such (3)H doping will ensure highly stable radiolabeled nanodiamonds, on which surface functionalization is still allowed. This breakthrough opens the way to biodistribution and pharmacokinetics studies of nanodiamonds, while this approach can be scalable to easily treat bulk quantities of nanodiamonds at low cost. PMID:24492594

  18. Performance characterization of the NASA standard detonator

    SciTech Connect

    Tarbell, W.W. [Sandia National Labs., Albuquerque, NM (United States); Burke, T.L.; Solomon, S.E. [Component Engineering, USBI, Huntsville, AL (United States)

    1995-05-01

    The NASA Standard Detonator (NSD) is employed in support of a number of current applications, including the Space Shuttle. This effort was directed towards providing test results to characterize the output of this device for its use in a safe and arm device. As part of the investigation, flash X-ray was used to provide stop-motion photographs of the flying metal plate that is created by initiation of the detonator. This provided researchers with a better understanding of the shape and character of the high-velocity disk as it propagated across the gap between the detonator and next assembly. The second portion of the study used a velocity interferometer to evaluate the acceleration and velocity histories of the flying plate, providing a quantified assessment of the detonator`s ability to initiate the explosive in the next explosive.

  19. On the Exit Boundary Condition for One-Dimensional Calculations of Pulsed Detonation Engine Performance

    NASA Technical Reports Server (NTRS)

    Wilson, Jack; Paxson, Daniel E.

    2002-01-01

    In one-dimensional calculations of pulsed detonation engine (PDE) performance, the exit boundary condition is frequently taken to be a constant static pressure. In reality, for an isolated detonation tube, after the detonation wave arrives at the exit plane, there will be a region of high pressure, which will gradually return to ambient pressure as an almost spherical shock wave expands away from the exit, and weakens. Initially, the flow is supersonic, unaffected by external pressure, but later becomes subsonic. Previous authors have accounted for this situation either by assuming the subsonic pressure decay to be a relaxation phenomenon, or by running a two-dimensional calculation first, including a domain external to the detonation tube, and using the resulting exit pressure temporal distribution as the boundary condition for one-dimensional calculations. These calculations show that the increased pressure does affect the PDE performance. In the present work, a simple model of the exit process is used to estimate the pressure decay time. The planar shock wave emerging from the tube is assumed to transform into a spherical shock wave. The initial strength of the spherical shock wave is determined from comparison with experimental results. Its subsequent propagation, and resulting pressure at the tube exit, is given by a numerical blast wave calculation. The model agrees reasonably well with other, limited, results. Finally, the model was used as the exit boundary condition for a one-dimensional calculation of PDE performance to obtain the thrust wall pressure for a hydrogen-air detonation in tubes of length to diameter ratio (L/D) of 4, and 10, as well as for the original, constant pressure boundary condition. The modified boundary condition had no performance impact for values of L/D > 10, and moderate impact for L/D = 4.

  20. Modeling and analysis of hydrogen detonation events in the advanced neutron source reactor containment

    Microsoft Academic Search

    R. P. Taleyarkhan; V. Georgevich; S. H. Kim; S. Valenti; D. B. Simpson; W. Sawruk

    1996-01-01

    This paper describes salient aspects of the modeling, analyses and evaluations for hydrogen detonation in selected regions of the Advanced Neutron Source (ANS) containment during hypothetical severe accident conditions. Shock wave generation and transport modeling and analyses were conducted for two stratified configurations in the dome region of the high bay. Principal tools utilized for these purposes were the CTH

  1. Theory of Oblique Detonations and Application to Propulsion Joseph M. Powers

    E-print Network

    solutions, what is the dependency of the steady propagation speed on the ambient condition, what by an oblique shock, arises in most supersonic combustion applications including, most notably, the oblique detonation wave engine and the ram accelerator. Additionally, it is the generic two-dimensional compressible

  2. Improved estimates of separation distances to prevent unacceptable damage to nuclear power plant structures from hydrogen detonation for gaseous hydrogen storage. Technical report

    SciTech Connect

    Not Available

    1994-05-01

    This report provides new estimates of separation distances for nuclear power plant gaseous hydrogen storage facilities. Unacceptable damage to plant structures from hydrogen detonations will be prevented by having hydrogen storage facilities meet separation distance criteria recommended in this report. The revised standoff distances are based on improved calculations on hydrogen gas cloud detonations and structural analysis of reinforced concrete structures. Also, the results presented in this study do not depend upon equivalencing a hydrogen detonation to an equivalent TNT detonation. The static and stagnation pressures, wave velocity, and the shock wave impulse delivered to wall surfaces were computed for several different size hydrogen explosions. Separation distance equations were developed and were used to compute the minimum separation distance for six different wall cases and for seven detonating volumes (from 1.59 to 79.67 lbm of hydrogen). These improved calculation results were compared to previous calculations. The ratio between the separation distance predicted in this report versus that predicted for hydrogen detonation in previous calculations varies from 0 to approximately 4. Thus, the separation distances results from the previous calculations can be either overconservative or unconservative depending upon the set of hydrogen detonation parameters that are used. Consequently, it is concluded that the hydrogen-to-TNT detonation equivalency utilized in previous calculations should no longer be used.

  3. Explosion and detonation characteristics of dimethyl ether.

    PubMed

    Mogi, Toshio; Horiguchi, Sadashige

    2009-05-15

    In this study, the explosion and detonation characteristics of dimethyl ether (DME) were experimentally investigated. A spherical pressure vessel with an internal volume of 180L was used as the explosion vessel. Therefore, tubes 10m in length with internal diameters of 25mm and 50mm were used as detonation tubes. In addition, we compared the characteristics of DME with those of propane since DME is considered as a substitute fuel for liquid petroleum gas (LPG). At room temperature and atmospheric pressure, the maximum explosive pressure increased tenfold. The explosion index (K(G) values), an indicator of the intensity of an explosion, was larger than that of propane, indicating that the explosion was intense. No experimental study has been conducted on the detonation behavior of DME so far, but this research confirmed a transition to detonation. The detonation characteristics were similar to the characteristics of the Chapman-Jouguet detonation, and the concentration range for detonation was from 5.5% to 9.0%. PMID:18774641

  4. Synergetic phenomena in detonation of solid heterogeneous explosives. Control of oscillations and dissipative structures in detonation flow

    Microsoft Academic Search

    I. Plaksin; J. Campos; J. Direito; R. Mendes; J. Ribeiro; J. Gois; P. Simoes; L. Pedroso; A. Portugal; J. Kennedy; S. Coffey

    2005-01-01

    We present experimental evidences for existence of synergetic effects in detonations of PBX -most advanced class of the modern high explosives. Both phenomena, oscillating regimes of detonation propagation and origination of dissipative structures in detonation flow are detected at wide variation of global geometry of detonation flow and PBX macro-structure.

  5. Shockwave and detonation studies at ITEP-TWAC proton radiography facility

    NASA Astrophysics Data System (ADS)

    Kolesnikov, Sergey; Dudin, Sergey; Lavrov, Vladimir; Nikolaev, Dmitry; Mintsev, Victor; Shilkin, Nikolay; Ternovoi, Vladimir; Utkin, Alexander; Yakushev, Vladislav; Yuriev, Denis; Fortov, Vladimir; Golubev, Alexander; Kantsyrev, Alexey; Shestov, Lev; Smirnov, Gennady; Turtikov, Vladimir; Sharkov, Boris; Burtsev, Vasily; Zavialov, Nikolay; Kartanov, Sergey; Mikhailov, Anatoly; Rudnev, Alexey; Tatsenko, Mikhail; Zhernokletov, Mikhail

    2012-03-01

    In recent years studies of shock and detonation wave phenomena at extreme dynamic conditions were performed at proton radiography facility developed at the 800 MeV proton beam line of ITEP Terawatt Accelerator (ITEP-TWAC). The facility provides a multi-frame imaging capability at 50 ?m spatial and 70 ns temporal resolution. The results of latest studies conducted there are presented, including explosion and detonation of pressed and emulsion high explosives, shock-induced dense non-ideal plasma of argon and xenon and shock loading of non-uniform metal surfaces. New compact explosive generators developed specifically for a use at proton radiography facilities are also presented.

  6. Experimental study and kinetic modeling of the thermal decomposition of gaseous monomethylhydrazine. Application to detonation sensitivity

    NASA Astrophysics Data System (ADS)

    Catoire, L.; Bassin, X.; Dupre, G.; Paillard, C.

    1996-09-01

    The thermal decomposition of gaseous monomethylhydrazine has been studied in a 38.4 mm i.d. shock tube behind a reflected shock wave at 1040-1370 K, 140-455 kPa and in mixtures containing 97 to 99 mol% argon, by using MMH absorption at 220 nm. A chemical kinetic model based on MMH decomposition profiles has been developed. This model has been used, with some assumptions, to evaluate the detonation sensitivity of pure gaseous MMH. This compound is found to be much less sensitive to detonation than hydrazine.

  7. Detonator comprising a nonlinear transmission line

    DOEpatents

    Elizondo-Decanini, Juan M

    2014-12-30

    Detonators are described herein. In a general embodiment, the detonator includes a nonlinear transmission line that has a variable capacitance. Capacitance of the nonlinear transmission line is a function of voltage on the nonlinear transmission line. The nonlinear transmission line receives a voltage pulse from a voltage source and compresses the voltage pulse to generate a trigger signal. Compressing the voltage pulse includes increasing amplitude of the voltage pulse and decreasing length of the voltage pulse in time. An igniter receives the trigger signal and detonates an explosive responsive to receipt of the trigger signal.

  8. Condensation of carbon during high explosive detonation

    NASA Astrophysics Data System (ADS)

    Fried, Laurence; Bastea, Sorin; Garza, Raul

    2012-02-01

    The formation of nano-carbon clusters is believed to be responsible for the non-ideal detonation behavior of carbon-rich explosives, such as triamino-trinitrobenzene (TATB). We have developed a new model of carbon formation during detonation. The model is based on the assumption that carbon cluster growth has features of both activated Arrhenius kinetics and diffusion controlled kinetics. In our model the variation of temperature, density, and viscosity throughout the high explosive reaction zone and expansion is calculated using a thermochemical model linked to a hydrodynamic code. We compare our model to new experimental results on the size scaling of detonations in TATB-based explosives.

  9. Influence of Discrete Sources on Detonation Propagation in a Burgers Equation Analog System

    E-print Network

    Mi, XiaoCheng

    2015-01-01

    An analog to the equations of compressible flow that is based on the inviscid Burgers equation is utilized to investigate the effect of spatial discreteness of energy release on the propagation of a detonation wave. While the traditional Chapman-Jouguet (CJ) treatment of a detonation wave assumes that the energy release of the medium is homogeneous through space, the system examined here consists of sources represented by $\\delta$-functions embedded in an otherwise inert medium. The sources are triggered by the passage of the leading shock wave following a delay that is either of fixed period or randomly generated. The solution for wave propagation through a large array ($10^3$-$10^4$) of sources in one dimension can be constructed without the use of a finite difference approximation by tracking the interaction of sawtooth-profiled waves for which an analytic solution is available. A detonation-like wave results from the interaction of the shock and rarefaction waves generated by the sources. The measurement ...

  10. Free-field microwave interferometry for detonation front tracking and run-to-detonation measurements

    NASA Astrophysics Data System (ADS)

    Rae, Philip; Glover, Brian; Gunderson, Jake; Perry, Lee

    2012-03-01

    A quadrature interferometer used in a free-field measurement mode has, with the aid of a high directivity horn antenna, been successfully used to measure the detonation front of PBX-9501 within a dielectric can. Using the known length of explosive, a relative dielectric permittivity of 3.84 has been calculated for the 34 GHz frequency used. Using this value, the displacement vs. time of the detonation front can be found and hence the velocity of detonation may be calculated. This technique shows good promise as a method of measuring the run-to-detonation distance in explosives using a totally non-contacting technique.

  11. Characterizing Detonating LX-17 Charges Crossing a Transverse Air Gap with Experiments and Modeling

    NASA Astrophysics Data System (ADS)

    Lauderbach, Lisa M.; Souers, P. Clark; Garcia, Frank; Vitello, Peter; Vandersall, Kevin S.

    2009-12-01

    Experiments were performed using detonating LX-17 (92.5% TATB, 7.5% Kel-F by weight) charges with various width transverse air gaps with manganin peizoresistive in-situ gauges present. The experiments, performed with 25 mm diameter by 25 mm long LX-17 pellets with the transverse air gap in between, showed that transverse gaps up to about 3 mm could be present without causing the detonation wave to fail to continue as a detonation. The Tarantula/JWL++ code was utilized to model the results and compare with the in-situ gauge records with some agreement to the experimental data with additional work needed for a better match to the data. This work will present the experimental details as well as comparison to the model results.

  12. CHARACTERIZING DETONATING LX-17 CHARGES CROSSING A TRANSVERSE AIR GAP WITH EXPERIMENTS AND MODELING

    SciTech Connect

    Lauderbach, L M; Souers, P C; Garcia, F; Vitello, P; Vandersall, K S

    2009-06-26

    Experiments were performed using detonating LX-17 (92.5% TATB, 7.5% Kel-F by weight) charges with various width transverse air gaps with manganin peizoresistive in-situ gauges present. The experiments, performed with 25 mm diameter by 25 mm long LX-17 pellets with the transverse air gap in between, showed that transverse gaps up to about 3 mm could be present without causing the detonation wave to fail to continue as a detonation. The Tarantula/JWL{sup ++} code was utilized to model the results and compare with the in-situ gauge records with some agreement to the experimental data with additional work needed for a better match to the data. This work will present the experimental details as well as comparison to the model results.

  13. 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.

  14. Study of detonation initiation in kerosene-oxidizer mixtures in short tubes

    NASA Astrophysics Data System (ADS)

    Kindracki, J.

    2014-11-01

    The paper describes experimental studies of detonation initiation in a kerosene-oxidizer mixture in a short test tube. The aim of the study is to determine the minimum diameter of the tube and the minimum level of energy that enables direct initiation of the detonation. Knowledge about these values will inform the design of a jet engine combustion chamber in which thermal energy will be generated by a rotating detonation process. The test tube and the oxidizer inside the tube were heated using specially designed heaters installed outside of the tube. The heated oxidizer provided thermal conditions similar to the conditions for a compressor with small to medium static pressure. The study was conducted for four different tube diameters and for various energies of initiation. As a result, measurements of pressure waveforms were obtained for various cases of fuel injection, which were then compared against the results of the shock wave generated by the initiator. This study provides a value for the energy (the pressure of the mixture in the initiator), which provided direct initiation of detonation for a kerosene-oxidizer mixture. Different tube diameters led to the initiation of detonation for various oxygen-nitrogen compositions as an oxidizer.

  15. Parametric study of double cellular detonation structure

    NASA Astrophysics Data System (ADS)

    Khasainov, B.; Virot, F.; Presles, H.-N.; Desbordes, D.

    2013-05-01

    A parametric numerical study is performed of a detonation cellular structure in a model gaseous explosive mixture whose decomposition occurs in two successive exothermic reaction steps with markedly different characteristic times. Kinetic and energetic parameters of both reactions are varied in a wide range in the case of one-dimensional steady and two-dimensional (2D) quasi-steady self-supported detonations. The range of governing parameters of both exothermic steps is defined where a "marked" double cellular structure exists. It is shown that the two-level cellular structure is completely governed by the kinetic parameters and the local overdrive ratio of the detonation front propagating inside large cells. Furthermore, since it is quite cumbersome to use detailed chemical kinetics in unsteady 2D case, the proposed work should help to identify the mixtures and the domain of their equivalence ratio where double detonation structure could be observed.

  16. Microwave interferometer techniques for detonation study

    SciTech Connect

    Stanton, P.L.; Venturini, E.L.; Dietzel, R.W.

    1985-01-01

    Techniques have been developed to improve resolution in microwave interferometry of detonating explosives. Unwanted reflections in the measurement arm of the interferometer result in phase distortion of the recorded signal. By using tuning techniques, unwanted reflections can be virtually eliminated, and phase distortion is minimized, for some experimental conditions. The use of a quadrature detector and an intensity monitor also improve the resolution of the interferometer. Data obtained in several detonation experiments are presented and interpreted. 13 refs., 7 figs.

  17. Stability of idealized condensed phase detonations

    Microsoft Academic Search

    Mark Short; Iana I. Anguelova; Tariq D. Aslam; John B. Bdzil; Andrew K. Henrick; Gary J. Sharpe

    The linear and nonlinear stability of Chapman-Jouguet (CJ) and overdriven detonations of Zeldovich-von Neumann-Doring (ZND) type are examined in the context of the idealized condensed phase (liquid or solid) detonation model. This model includes a two-component mixture (fuel and product), with a one-step irre- versible reaction possessing a rate that is pressure-sensitive (p n ) and has a variable reaction

  18. Initiation and Detonation Physics on Millimeter Scales

    SciTech Connect

    Philllips, D F; Benterou, J J; May, C A

    2012-03-20

    The LLNL Detonation Science Project has a major interest in understanding the physics of detonation on a millimeter scale. This report summarizes the rate stick experiment results of two high explosives. The GO/NO-GO threshold between varying diameters of ultra-fine TATB (ufTATB) and LX-16 were recorded on an electronic streak camera and analyzed. This report summarizes the failure diameters of rate sticks for ufTATB and LX-16. Failure diameter for the ufTATB explosive, with densities at 1.80 g/cc, begin at 2.34 mm (not maintaining detonation velocity over the entire length of the rate stick). ufTATB rate sticks at the larger 3.18 mm diameter maintain a constant detonation velocity over the complete length. The PETN based and LLNL developed explosive, LX-16, with densities at 1.7 g/cc, shows detonation failure between 0.318 mm and 0.365 mm. Additional tests would be required to narrow this failure diameter further. Many of the tested rate sticks were machined using a femtosecond laser focused into a firing tank - in case of accidental detonation.

  19. Influence of ambient air pressure on the energy conversion of laser-breakdown induced blast waves

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Komurasaki, Kimiya; Arakawa, Yoshihiro

    2013-09-01

    Influence of ambient pressure on energy conversion efficiency from a Nd?:?glass laser pulse (? = 1.053 µm) to a laser-induced blast wave was investigated at reduced pressure. Temporal incident and transmission power histories were measured using sets of energy meters and photodetectors. A half-shadowgraph half-self-emission method was applied to visualize laser absorption waves. Results show that the blast energy conversion efficiency ?bw decreased monotonically with the decrease in ambient pressure. The decrease was small, from 40% to 38%, for the pressure change from 101 kPa to 50 kPa, but the decrease was considerable, to 24%, when the pressure was reduced to 30 kPa. Compared with a TEA-CO2-laser-induced blast wave (? = 10.6 µm), higher fraction absorption in the laser supported detonation regime ?LSD of 90% was observed, which is influenced slightly by the reduction of ambient pressure. The conversion fraction ?bw/?LSD?90% was achieved at pressure >50 kPa, which is significantly higher than that in a CO2 laser case.

  20. SLAG CHARACTERIZATION AND REMOVAL USING PULSE DETONATION TECHNOLOGY DURING COAL GASIFICATION

    SciTech Connect

    DR. DANIEL MEI; DR. JIANREN ZHOU; DR. PAUL O. BINEY; DR. ZIAUL HUQUE

    1998-07-30

    Pulse detonation technology for the purpose of removing slag and fouling deposits in coal-fired utility power plant boilers offers great potential. Conventional slag removal methods including soot blowers and water lances have great difficulties in removing slags especially from the down stream areas of utility power plant boilers. The detonation wave technique, based on high impact velocity with sufficient energy and thermal shock on the slag deposited on gas contact surfaces offers a convenient, inexpensive, yet efficient and effective way to supplement existing slag removal methods. A slight increase in the boiler efficiency, due to more effective ash/deposit removal and corresponding reduction in plant maintenance downtime and increased heat transfer efficiency, will save millions of dollars in operational costs. Reductions in toxic emissions will also be accomplished due to reduction in coal usage. Detonation waves have been demonstrated experimentally to have exceptionally high shearing capability, important to the task of removing slag and fouling deposits. The experimental results describe the parametric study of the input parameters in removing the different types of slag and operating condition. The experimental results show that both the single and multi shot detonation waves have high potential in effectively removing slag deposit from boiler heat transfer surfaces. The results obtained are encouraging and satisfactory. A good indication has also been obtained from the agreement with the preliminary computational fluid dynamics analysis that the wave impacts are more effective in removing slag deposits from tube bundles rather than single tube. This report presents results obtained in effectively removing three different types of slag (economizer, reheater, and air-heater) t a distance of up to 20 cm from the exit of the detonation tube. The experimental results show that the softer slags can be removed more easily. Also closer the slag to the exit of the detonation tube, the better are their removals. Side facing slags are found to shear off without breaking. Wave strength and slag orientation also has different effects on the chipping off of the slag. One of the most important results from this study is the observation that the pressure of the waves plays a vital role in removing slag. The wave frequency is also important after a threshold pressure level is attained.

  1. Detonation nanodiamonds for doping Kevlar.

    PubMed

    Comet, Marc; Pichot, Vincent; Siegert, Benny; Britz, Fabienne; Spitzer, Denis

    2010-07-01

    This paper reports on the first attempt to enclose diamond nanoparticles--produced by detonation--into a Kevlar matrix. A nanocomposite material (40 wt% diamond) was prepared by precipitation from an acidic solution of Kevlar containing dispersed nanodiamonds. In this material, the diamond nanoparticles (Ø = 4 nm) are entirely wrapped in a Kevlar layer about 1 nm thick. In order to understand the interactions between the nanodiamond surface and the polymer, the oxygenated surface functional groups of nanodiamond were identified and titrated by Boehm's method which revealed the exclusive presence of carboxyl groups (0.85 sites per nm2). The hydrogen interactions between these groups and the amide groups of Kevlar destroy the "rod-like" structure and the classical three-dimensional organization of this polymer. The distortion of Kevlar macromolecules allows the wrapping of nanodiamonds and leads to submicrometric assemblies, giving a cauliflower structure reminding a fractal object. Due to this structure, the macroscopic hardness of Kevlar doped by nanodiamonds (1.03 GPa) is smaller than the one of pure Kevlar (2.31 GPa). To our knowledge, this result is the first illustration of the change of the mechanical properties induced by doping the Kevlar with nanoparticles. PMID:21128413

  2. Hydrodynamic modeling of detonations for structural design of containment vessels.

    SciTech Connect

    Rodriguez, E. A. (Edward A.); Romero, C. (Christopher)

    2005-01-01

    Los Alamos National Laboratory (LANL), under the auspices of the U.S. Department of Energy (DOE) and the National Nuclear Security Administration (NNSA), has been conducting confined high explosion experiments utilizing large, spherical, steel pressure vessels to contain the reaction products and hazardous materials from high-explosive (HE) events. Structural design of these spherical vessels was originally accomplished by maintaining that the vessel's kinetic energy, developed from the detonation impulse loading, be equilibrated by the elastic strain energy inherent in the vessel. In some cases, the vessel is designed for one-time use only, efficiently utilizing the significant plastic energy absorption capability of ductile vessel materials. Alternatively, the vessel can be designed for multiple use, in which case the material response is restricted to the elastic range. Within the last decade, designs have been accomplished utilizing sophisticated and advanced 3D computer codes that address both the detonation hydrodynamics and the vessel's highly nonlinear structural dynamic response. This paper describes the hydrodynamic modeling of HE reaction products phase, which produces transient pressures resulting in an impulsive load on the vessel shell. Modeling is accomplished through either (a) empirical/analytical methods utilizing a vast experimental database developed primarily for the Department of Defense (DoD) or (b) through application of numerical hydrodynamics codes, such as the Sandia National Laboratories (SNL) shock-wave physics code, CTH, which accurately model the thermochemistry and thermophysics of a detonation. It should be noted that this paper only addresses blast load prediction using the methods stated and does not include an assessment of structural response methods.

  3. Plasma-assisted ignition and deflagration-to-detonation transition.

    PubMed

    Starikovskiy, Andrey; Aleksandrov, Nickolay; Rakitin, Aleksandr

    2012-02-13

    Non-equilibrium plasma demonstrates great potential to control ultra-lean, ultra-fast, low-temperature flames and to become an extremely promising technology for a wide range of applications, including aviation gas turbine engines, piston engines, RAMjets, SCRAMjets and detonation initiation for pulsed detonation engines. The analysis of discharge processes shows that the discharge energy can be deposited into the desired internal degrees of freedom of molecules when varying the reduced electric field, E/n, at which the discharge is maintained. The amount of deposited energy is controlled by other discharge and gas parameters, including electric pulse duration, discharge current, gas number density, gas temperature, etc. As a rule, the dominant mechanism of the effect of non-equilibrium plasma on ignition and combustion is associated with the generation of active particles in the discharge plasma. For plasma-assisted ignition and combustion in mixtures containing air, the most promising active species are O atoms and, to a smaller extent, some other neutral atoms and radicals. These active particles are efficiently produced in high-voltage, nanosecond, pulse discharges owing to electron-impact dissociation of molecules and electron-impact excitation of N(2) electronic states, followed by collisional quenching of these states to dissociate the molecules. Mechanisms of deflagration-to-detonation transition (DDT) initiation by non-equilibrium plasma were analysed. For longitudinal discharges with a high power density in a plasma channel, two fast DDT mechanisms have been observed. When initiated by a spark or a transient discharge, the mixture ignited simultaneously over the volume of the discharge channel, producing a shock wave with a Mach number greater than 2 and a flame. A gradient mechanism of DDT similar to that proposed by Zeldovich has been observed experimentally under streamer initiation. PMID:22213667

  4. APPLICATION OF THE EMBEDDED FIBER OPTIC PROBE IN HIGH EXPLOSIVE DETONATION STUDIES: PBX-9502 AND LX-17

    SciTech Connect

    Hare, D; Goosman, D; Lorenz, K; Lee, E

    2006-09-26

    The Embedded Fiber Optic probe directly measures detonation speed continuously in time, without the need to numerically differentiate data, and is a new tool for measuring time-dependent as well as steady detonation speed to high accuracy. It consists of a custom-design optical fiber probe embedded in high explosive. The explosive is detonated and a refractive index discontinuity is produced in the probe at the location of the detonation front by the compression of the detonation. Because this index-jump tracks the detonation front a measurement of the Doppler shift of laser light reflected from the jump makes it possible to continuously measure detonation velocity with high spatial and temporal resolution. We have employed this probe with a Fabry-Perot-type laser Doppler velocimetry system additionally equipped with a special filter for reducing the level of non-Doppler shifted light relative to the signal. This is necessary because the index-jump signal is relatively weak compared to the return expected from a well-prepared surface in the more traditional and familiar example of material interface velocimetry. Our observations were carried out on a number of explosives but this work is focused on our results on PBX-9502 (95% TATB, 5% Kel-F) and LX-17 (92.5% TATB, 7.5% Kel-F) at varying initial charge density. Our measurements reveal a density dependence significantly lower than previous quoted values and lower than theoretical calculations. Our limited data on detonation speed dependence on wave curvature is in reasonable agreement with previous work using more standard methods and confirms deviation from the Wood-Kirkwood theoretical formula.

  5. Pulsed Detonation Operation of an Axial Turbine

    NASA Astrophysics Data System (ADS)

    Munday, David; St. George, Andrew; Driscoll, Robert; Gutmark, Ephraim; Gas Dynamics and Propulsion Lab Team

    2013-11-01

    A detonation is by its nature a more thermodynamically efficient combustion mode than deflagration. Several attempts are underway to integrate detonating combustion into turbomachines in order to realize the increased efficiency available, save resources and reduce emissions. One approach to this challenge is to employ pulsed detonations as from pulsed detonation engines (PDEs) and use the pulsed outflow to drive a turbine. The difficulty with this approach is that turbines, especially the more efficient axial turbines suffer in efficiency when their inflow is pulsed. At present there is not even a commonly acknowledged turbine efficiency measure which works reasonably for a pulsed input. The present work investigates the efficiency of an axial turbine with pulsed flow. Initial tests are performed with non-combusting flow in order to study the influence of pulsation on the turbine performance. This cold flow will admit a broader range of instrumentation which can be inserted within the turbine. This allows time-resolved measure of the flow angles which have a pronounced effect on the turbine performance. Later tests with detonating inflow yield global measures and these are compared to the non-combusting results. Work sponsored by Innovative Scientific Solutions, Inc.

  6. 33 CFR 154.2106 - Detonation arresters installation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Detonation arresters installation. 154.2106 Section 154.2106...Transfer Facilities-Vcs Design and Installation § 154.2106 Detonation arresters installation. This section applies only to...

  7. Detonator cable initiation system safety investigation: Consequences of energizing the detonator and actuator cables

    SciTech Connect

    Osher, J.; Chau, H.; Von Holle, W.

    1994-03-01

    This study was performed to explore and assess the worst-case response of a W89-type weapons system, damaged so as to expose detonator and/or detonator safing strong link (DSSL) cables to the most extreme, credible lightning-discharge, environment. The test program used extremely high-current-level, fast-rise-time (1- to 2-{mu}s) discharges to simulate lightning strikes to either the exposed detonator or DSSL cables. Discharges with peak currents above 700 kA were required to explode test sections of detonator cable and launch a flyer fast enough potentially to detonate weapon high explosive (HE). Detonator-safing-strong-link (DSSL) cables were exploded in direct contact with hot LX-17 and Ultrafine TATB (UFTATB). At maximum charging voltage, the discharge system associated with the HE firing chamber exploded the cables at more than 600-kA peak current; however, neither LX-17 nor UFTATB detonated at 250{degree}C. Tests showed that intense surface arc discharges of more than 700 kA/cm in width across the surface of hot UFTATB [generally the more sensitive of the two insensitive high explosives (IHE)] could not initiate this hot IHE. As an extension to this study, we applied the same technique to test sections of the much-narrower but thicker-cover-layer W87 detonator cable. These tests were performed at the same initial stored electrical energy as that used for the W89 study. Because of the narrower cable conductor in the W87 cables, discharges greater than 550-kA peak current were sufficient to explode the cable and launch a fast flyer. In summary, we found that lightning strikes to exposed DSSL cables cannot directly detonate LX-17 or UFTATB even at high temperatures, and they pose no HE safety threat.

  8. Theoretical and computer models of detonation in solid explosives

    SciTech Connect

    Tarver, C.M.; Urtiew, P.A.

    1997-10-01

    Recent experimental and theoretical advances in understanding energy transfer and chemical kinetics have led to improved models of detonation waves in solid explosives. The Nonequilibrium Zeldovich - von Neumann - Doring (NEZND) model is supported by picosecond laser experiments and molecular dynamics simulations of the multiphonon up-pumping and internal vibrational energy redistribution (IVR) processes by which the unreacted explosive molecules are excited to the transition state(s) preceding reaction behind the leading shock front(s). High temperature, high density transition state theory calculates the induction times measured by laser interferometric techniques. Exothermic chain reactions form product gases in highly excited vibrational states, which have been demonstrated to rapidly equilibrate via supercollisions. Embedded gauge and Fabry-Perot techniques measure the rates of reaction product expansion as thermal and chemical equilibrium is approached. Detonation reaction zone lengths in carbon-rich condensed phase explosives depend on the relatively slow formation of solid graphite or diamond. The Ignition and Growth reactive flow model based on pressure dependent reaction rates and Jones-Wilkins-Lee (JWL) equations of state has reproduced this nanosecond time resolved experimental data and thus has yielded accurate average reaction zone descriptions in one-, two- and three- dimensional hydrodynamic code calculations. The next generation reactive flow model requires improved equations of state and temperature dependent chemical kinetics. Such a model is being developed for the ALE3D hydrodynamic code, in which heat transfer and Arrhenius kinetics are intimately linked to the hydrodynamics.

  9. Diamonds in the chemical products of detonation

    SciTech Connect

    Greiner, N.R. (Los Alamos National Lab., NM (USA))

    1989-01-01

    Diamonds have been found among the solid carbonaceous chemical products of high-explosive detonations. Explosives are fuel-oxidizer systems premixed on a molecular scale. This talk discusses some aspects of the chemical and hydrodynamic environment in which these diamonds form and some characteristics of the diamonds recovered. Diamonds have been recovered from detonations of composite explosives composed of trinitrotoluene (TNT) mixed with other powdered solid explosives, such as cyclo-trimethylenetrinitramine (RDX), triaminotrinitrobenzene (TATB), ammonium nitrate (AN), and nitroguanidine (NQ). The detonations were carried out in a 1.5-m{sup 3} tank, usually filled with 1 atm of Ar gas. Other explosive composites and one-component explosives have also been investigated. The diamonds have been characterized by transmission electron microscopy, x-ray diffraction, and various chemical means.

  10. Diamonds in the chemical products of detonation

    SciTech Connect

    Greiner, N.R.

    1988-01-01

    Diamonds have been found among the solid carbonaceous chemical products of high-explosive detonations. Explosives are fuel-oxidizer systems premixed on a molecular scale. This talk discusses some aspects of the chemical and hydrodynamic environment in which these diamonds form and some characteristics of the diamonds recovered. Diamonds have been recovered from detonations of composite explosives composed of trinitrotoluene (TNT) mixed with other powdered solid explosives, such as cyclo-trimethylenetrinitramine (RDX), triaminotrinitrobenzene (TATB), ammonium nitrate (AN), and nitroguanidine (NQ). The detonations were carried out in a 1.5-m/sup 3/ tank, usually filled with 1 atm of Ar gas. Other explosive composites and one-component explosives have also been investigated. The diamonds have been characterized by transmission electron microscopy, x-ray diffraction, and various chemical means. 8 refs., 3 figs.

  11. Quantic Industries Inc. slapper detonator performance

    SciTech Connect

    Cutting, J.L.; Lee, R.S.; Hodgin, R.L.

    1994-05-01

    Under the Lawrence Livermore National Laboratories (LLNL) Small Business Technology Transfer Program, assistance was given to Quantic Industries Inc. to use the High Explosive Applications Facility (HEAF), its apparatus, and LLNL expertise to characterize the performance of Quantic`s micro-clad copper/kapton slapper detonator assemblies and establish their threshold to detonate HNS-IV. The project involved measuring the performance of these slapper detonators, otherwise known as Exploding Foil Initiators (EFI`s), manufactured by Quantic Industries Inc. Slapper performance was measured by using a laser velocimeter, which is an expensive and specialized facility which Quantic does not own. The authors measured slapper velocity vs. time as a function of charging voltage. Quantic supplied slappers which were coated with {approximately}100 nm of Al to provide a reflective surface for the laser velocimeter measurements. LLNL provided to a capacitor discharge unit (CDU) to fire the slappers and matched the Quantic CDU waveforms as close as possible.

  12. Detonation characteristics of ammonium nitrate and activated carbon mixtures

    Microsoft Academic Search

    Atsumi Miyake; Hidefumi Kobayashi; Hiroshi Echigoya; Shiro Kubota; Yuji Wada; Yuji Ogata; Hiroyuki Arai; Terushige Ogawa

    2007-01-01

    To better understand the detonation characteristics of ammonium nitrate (AN) and activated carbon (AC) mixtures, steel tube tests were carried out for AN\\/AC mixtures of various compositions and different forms of AN (powdered, prilled, phase stabilized and granular), and the detonation velocity was measured. The powdered AN\\/AC mixtures gave higher detonation velocities than the other AN forms. For all the

  13. Use of detonation in gases for coating application

    Microsoft Academic Search

    Yu. A. Kharlamov; M. Kh. Shorshorov; V. V. Kudinov; O. V. Gusev; B. L. Ryaboshapko

    1975-01-01

    At the present time, together with other methods of pulverized coating application -plasma, gas plasma, electric arc - the detonation method is receiving ever-wider use. The high particle velocity in detonation coating application, 5-10 times higher than in other processes, produces favorable conditions for creating coatings for various purposes. Detonation coatings have been used successfully to increase wear and heat

  14. Observations of Detonation in Solid Explosives by Microwave Interferometry

    Microsoft Academic Search

    G. F. Cawsey; J. L. Farrands; S. Thomas

    1958-01-01

    Detonation processes have been observed in narrow, heavily confined, columns of solid explosive by a new microwave interferometric technique. The technique is described and a multiple-beam theory of fringe shape is given. The location, with respect to the detonation front, of the surface reflecting the microwaves is discussed. Detonation velocity as a function of distance along the column is derived

  15. Pressure Feedback in Rotating Detonation Engines

    NASA Astrophysics Data System (ADS)

    Schwer, Douglas; Kailasanath, K.

    2012-11-01

    Rotating detonation engines (RDEs) represent a unique method for obtaining propulsion from the high efficiency detonation cycle. In order for the RDE to be a practical propulsive device, engines must be capable of running efficiently at low pressure ratios, however, this type of injection typically results in a large amount of pressure feedback into the injection system. This paper examines different aspects of the pressure feedback phenomena, and investigates approaches to injecting fresh mixture that reduce the amount of feedback. This work is supported by the Office of Naval Research through NRL 6.1 Computational Physics Task Area.

  16. Ignition-and-Growth Modeling of NASA Standard Detonator and a Linear Shaped Charge

    NASA Technical Reports Server (NTRS)

    Oguz, Sirri

    2010-01-01

    The main objective of this study is to quantitatively investigate the ignition and shock sensitivity of NASA Standard Detonator (NSD) and the shock wave propagation of a linear shaped charge (LSC) after being shocked by NSD flyer plate. This combined explosive train was modeled as a coupled Arbitrary Lagrangian-Eulerian (ALE) model with LS-DYNA hydro code. An ignition-and-growth (I&G) reactive model based on unreacted and reacted Jones-Wilkins-Lee (JWL) equations of state was used to simulate the shock initiation. Various NSD-to-LSC stand-off distances were analyzed to calculate the shock initiation (or failure to initiate) and detonation wave propagation along the shaped charge. Simulation results were verified by experimental data which included VISAR tests for NSD flyer plate velocity measurement and an aluminum target severance test for LSC performance verification. Parameters used for the analysis were obtained from various published data or by using CHEETAH thermo-chemical code.

  17. Supporting Structure of the LSD Wave in an Energy Absorption Perspective

    SciTech Connect

    Fukui, Akihiro; Hatai, Keigo; Cho, Shinatora; Arakawa, Yoshihiro [Department of Aeronautics and Astronautics, School of Engineering, University of Tokyo (Japan); Komurasaki, Kimiya [Department of Advanced Energy, School of Frontier Sciences, University of Tokyo (Japan)

    2008-04-28

    In Repetitively Pulsed (RP) Laser Propulsion, laser energy irradiated to a vehicle is converted to blast wave enthalpy during the Laser Supported Detonation (LSD) regime. Based on the measured post-LSD electron number density profiles by two-wavelength Mach Zehnder interferometer in a line-focusing optics, electron temperature and absorption coefficient were estimated assuming Local Thermal Equilibrium. A 10J/pulse CO{sub 2} laser was used. As a result, laser absorption was found completed in the layer between the shock wave and the electron density peak. Although the LSD-termination timing was not clear from the shock-front/ionization-front separation in the shadowgraph images, there observed drastic changes in the absorption layer thickness from 0.2 mm to 0.5 mm and in the peak heating rate from 12-17x10{sup 13} kW/m{sup 3} to 5x10{sup 13} kW/m{sup 3} at the termination.

  18. Performance Evaluation of Hybrid Gas Turbine Engine Embedded with Pulse Detonation Combustor

    NASA Astrophysics Data System (ADS)

    Deng, Jun-Xiang; Yan, Chuan-Jun; Zheng, Long-Xi; Huang, Xi-Qiao

    2011-09-01

    The numerical investigations of performance evaluation of a hybrid gas turbine engine embedded with a pulse detonation combustor (PDC) were performed to examine the improvement of the performance of the hybrid propulsion system. The calculation model and method were described. The architecture, configuration and size of detonation tubes were investigated in the calculation. Two models of detonation tube exit temperature were utilized. Eight configuration choices for the PDC based on the calculation model were designed. Specific fuel consumption of a hybrid gas turbine engine was compared with that of the baseline engine at the condition of the same engine net thrust. The experimental research of a PDC interacted with a radial flow turbine of a turbocharger was conducted. The numerical results show that if the net thrust of hybrid PDC engine is matched to that of baseline engine, specific fuel consumption of hybrid PDC engine is 20-25% less than that of baseline engine. The total volume of the hybrid engine combustor is reduced. The incorporation of PDC into gas turbine engine can improve the performance of hybrid PDC engine, decrease the combustor weight, and increase the thrust-weight ratio. The experimental results show that the fully developed detonation waves are achieved in the experimental apparatus.

  19. Mechanisms of deflagration-to-detonation transition under initiation by high-voltage nanosecond discharges

    SciTech Connect

    Rakitin, Aleksandr E.; Starikovskii, Andrei Yu. [Physics of Nonequilibrium Systems Lab, Moscow Institute of Physics and Technology, 9 Institutski Lane, Dolgoprudny 141700 (Russian Federation)

    2008-10-15

    An experimental study of detonation initiation in a stoichiometric propane-oxygen mixture by a high-voltage nanosecond gas discharge was performed in a detonation tube with a single-cell discharge chamber. The discharge study performed in this geometry showed that three modes of discharge development were realized under the experimental conditions: a spark mode with high-temperature channel formation, a streamer mode with nonuniform gas excitation, and a transient mode. Under spark and transient initiation, simultaneous ignition inside the discharge channel occurred, forming a shock wave and leading to a conventional deflagration-to-detonation transition (DDT) via an adiabatic explosion. The DDT length and time at 1 bar of initial pressure in the square smooth tube with a 20-mm transverse size amounted to 50 mm and 50{mu}s, respectively. The streamer mode of discharge development at an initial pressure of 1 bar resulted in nonuniform mixture excitation and a successful DDT via a gradient mechanism, which was confirmed by high-speed time resolved ICCD imaging. The gradient mechanism implied a longer DDT time of 150{mu}s, a DDT run-up distance of 50 mm, and an initiation energy of 1 J, which is two orders of magnitude less than the direct initiation energy for a planar detonation under these conditions. (author)

  20. Fracture response of externally flawed aluminum cylindrical shells under internal gaseous detonation loading

    Microsoft Academic Search

    Tong Wa Chao; Joseph E. Shepherd

    2005-01-01

    Experiments were performed to observe the fracture behavior of thin-wall and initially-flawed aluminum tubes to internal gaseous detonation loading. The load can be characterized as a propagating pressure jump with speed of 2.4 km\\/s and magnitude ranging from 2 MPa to 6 MPa, followed by an expansion wave. Flaws were machined as external axial surface notches. Cracks ran both in the upstream and

  1. Low-frequency two-dimensional linear instability of plane detonation

    Microsoft Academic Search

    Mark Short; D. Scott Stewart

    1997-01-01

    An analytical dispersion relation describing the linear stability of a plane detonation wave to low-frequency two-dimensional disturbances with arbitrary wavenumbers is derived using a normal mode approach and a combination of high activation energy and Newtonian limit asymptotics, where the ratio of specific heats [gamma][rightward arrow]1. The reaction chemistry is characterized by one-step Arrhenius kinetics. The analysis assumes a large

  2. Spontaneous transition of turbulent flames to detonations in unconfined media.

    PubMed

    Poludnenko, Alexei Y; Gardiner, Thomas A; Oran, Elaine S

    2011-07-29

    A deflagration-to-detonation transition (DDT) can occur in environments ranging from experimental and industrial systems to astrophysical thermonuclear (type Ia) supernovae explosions. Substantial progress has been made in explaining the nature of DDT in confined systems with walls, internal obstacles, or preexisting shocks. It remains unclear, however, whether DDT can occur in unconfined media. Here we use direct numerical simulations (DNS) to show that for high enough turbulent intensities unconfined, subsonic, premixed, turbulent flames are inherently unstable to DDT. The associated mechanism, based on the nonsteady evolution of flames faster than the Chapman-Jouguet deflagrations, is qualitatively different from the traditionally suggested spontaneous reaction-wave model. Critical turbulent flame speeds, predicted by this mechanism for the onset of DDT, are in agreement with DNS results. PMID:21867073

  3. Spontaneous Transition of Turbulent Flames to Detonations in Unconfined Media

    NASA Astrophysics Data System (ADS)

    Poludnenko, Alexei Y.; Gardiner, Thomas A.; Oran, Elaine S.

    2011-07-01

    A deflagration-to-detonation transition (DDT) can occur in environments ranging from experimental and industrial systems to astrophysical thermonuclear (type Ia) supernovae explosions. Substantial progress has been made in explaining the nature of DDT in confined systems with walls, internal obstacles, or preexisting shocks. It remains unclear, however, whether DDT can occur in unconfined media. Here we use direct numerical simulations (DNS) to show that for high enough turbulent intensities unconfined, subsonic, premixed, turbulent flames are inherently unstable to DDT. The associated mechanism, based on the nonsteady evolution of flames faster than the Chapman-Jouguet deflagrations, is qualitatively different from the traditionally suggested spontaneous reaction-wave model. Critical turbulent flame speeds, predicted by this mechanism for the onset of DDT, are in agreement with DNS results.

  4. Hydrogen detonation and detonation transition data from the High-Temperature Combustion Facility

    SciTech Connect

    Ciccarelli, G.; Boccio, J.L.; Ginsberg, T.; Finfrock, C.; Gerlach, L. [Brookhaven National Lab., Upton, NY (United States). Dept. of Advanced Technology; Tagawa, H. [Nuclear Power Engineering Corp., Tokyo (Japan); Malliakos, A. [Nuclear Regulatory Commission, Washington, DC (United States)

    1995-12-31

    The BNL High-Temperature Combustion Facility (HTCF) is an experimental research tool capable of investigating the effects of initial thermodynamic state on the high-speed combustion characteristic of reactive gas mixtures. The overall experimental program has been designed to provide data to help characterize the influence of elevated gas-mixture temperature (and pressure) on the inherent sensitivity of hydrogen-air-steam mixtures to undergo detonation, on the potential for flames accelerating in these mixtures to transition into detonations, on the effects of gas venting on the flame-accelerating process, on the phenomena of initiation of detonations in these mixtures by jets of hot reactant product,s and on the capability of detonations within a confined space to transmit into another, larger confined space. This paper presents results obtained from the completion of two of the overall test series that was designed to characterize high-speed combustion phenomena in initially high-temperature gas mixtures. These two test series are the intrinsic detonability test series and the deflagration-to-detonation (DDT) test series. A brief description of the facility is provided below.

  5. Screen Secures Detonator to Explosive Charge

    NASA Technical Reports Server (NTRS)

    Moshenrose, H. D.; Kindsfather, R. A.

    1983-01-01

    Brass screen sleeve attaches blasting cap to fuse, shaped charge, detonating cord, or other formed explosive. Screen makes it easy to control distance between cap and charge, because user can see both parts, and to cool cap by convection, making use of low-cost blasting caps possible for some hot environments.

  6. HEAT TRANSFER ANALYSIS OF A PULSE DETONATION

    E-print Network

    Texas at Arlington, University of

    analysis of the effect of sensible heat release on the walls of the detonation chamber for stoichiometric to operate at 20 Hz and cooled by a water jacket to dissipate the heat from the walls which ensures thermal conductivity. The study showed a slow temperature rise along the walls of the combustion chamber

  7. Supra-Pressure Detonation of Aluminized Explosive

    Microsoft Academic Search

    Ronald Brown; B. Karosich; J. Gamble; J. Stork; A. Biesterveld; T. Moore; J. Sinibaldi; M. Walpole; A. Lindfors; K. Jackson; R. Koontz; D. Thompson

    2007-01-01

    Results suggest that there is a continuum of reactions induced behind a supra-pressure convergent shock front in explosive cores of coaxial charges. The pressures in convergent fronts continually increase at an increasing rate from the circumference to the charge axis. Furthermore the unreacted explosive enveloped within the front is pre-pressurized at Von Neumann states much greater than from divergent detonation.

  8. SHIP STRUCTURES SUBJECT TO HIGH EXPLOSIVE DETONATION

    Microsoft Academic Search

    Mark Z. Vulitsky; John J. McMullen; H. Karni

    Predicting the structural response of a naval vessel to a high explosive detonation is an important requirement in naval shipbuilding. Unfortunately, current analysis methods do not provide high level of confidence leading to the utilization of large structural design safety factors. As a result, ships are heavier and more expensive to construct and maintain than may actually be required. Moreover,

  9. Microwave interferometer techniques for detonation study

    Microsoft Academic Search

    P. L. Stanton; E. L. Venturini; R. W. Dietzel

    1985-01-01

    Techniques have been developed to improve resolution in microwave interferometry of detonating explosives. Unwanted reflections in the measurement arm of the interferometer result in phase distortion of the recorded signal. By using tuning techniques, unwanted reflections can be virtually eliminated, and phase distortion is minimized, for some experimental conditions. The use of a quadrature detector and an intensity monitor also

  10. Size effect and detonation front curvature

    Microsoft Academic Search

    P. Clark Souers

    1997-01-01

    Heat flow in a cylinder with internal heating is used as a basis for deriving a simple theory of detonation front curvature, leading to the prediction of quadratic curve shapes. A thermal conductivity of 50 MW\\/mm² is found for TATB samples.

  11. Detonation characteristics of powerful insensitive explosives

    Microsoft Academic Search

    Yu. A. Bogdanova; S. A. Gubin; B. L. Korsunskii; V. I. Pepekin

    2009-01-01

    Experimental and calculated detonation characteristics of powerful insensitive explosives are given. Features of explosives\\u000a with a high hydrogen content are discussed. The relationship between the power and sensitivity characteristics of explosives\\u000a and the structure of their molecules are considered. Prospects for the development of powerful explosives are discussed.

  12. Size effect and detonation front curvature

    SciTech Connect

    Souers, P. C., LLNL

    1997-07-01

    Heat flow in a cylinder with internal heating is used as a basis for deriving a simple theory of detonation front curvature, leading to the prediction of quadratic curve shapes. A thermal conductivity of 50 MW/mm{sup 2} is found for TATB samples.

  13. EBW's and EFI's: The other electric detonators

    NASA Technical Reports Server (NTRS)

    Varosh, Ron

    1994-01-01

    Exploding Bridgewire Detonators (EBW) and Exploding Foil Initiators (EFI) which were originally developed for military applications, have found numerous uses in the non-military commercial market while still retaining their military uses. While not as common as the more familiar hot wire initiators, EBW's and EFI's have definite advantages in certain applications. These advantages, and disadvantages, are discussed for typical designs.

  14. Initiation and detonation characteristics of TATB

    Microsoft Academic Search

    R. K. Jackson; L. G. Green; R. H. Barlett; W. W. Hofer; P. E. Kramer; R. S. Lee; E. J. Jr. Nidick; L. L. Shaw; R. C. Weingart

    1976-01-01

    The initiation and detonation characteristics of TATB were investigated using several different experimental techniques. In the crushing impact environment of the Susan Test, TATB formulations were among the least sensitive explosives ever tested. Thin flyer plates accelerated by electrically exploded metal foils or by gas guns were used to study shock sensitivity. In high density TATB the minimum flyer kinetic

  15. Computer modeling of electrical performance of detonators

    Microsoft Academic Search

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

    1995-01-01

    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

  16. Jet-initiated hydrogen detonation phenomena

    NASA Astrophysics Data System (ADS)

    Medvedev, S. P.; Khomik, S. V.; Olivier, H.; Polenov, A. N.; Bartenev, A. M.; Gelfand, B. E.

    Extensive studies of detonation initiation by a turbulent jet of combustion products over the past three decades are aimed at to clarify the mechanism of transition from deflagration to detonation (DDT). Numerous experiments [1-8] under different conditions give decisive evidence that detonation by jet mixing can be initiated both in confined and unconfined geometry. The inconsistency in the experimental data of different authors can be due to the different jet formation techniques used. The disadvantage of the flame jet drivers [1,5,8] is given by the continuous outflow of the unburned mixture in front of the flame front. This outflow can lead to a significant turbulization of the mixture downstream of the jet and in this case detonation starts under uncontrolled conditions. This difficulty can be overcome by the use of the bursting membrane technique [2-4,6,7]. In this case, the jet upstream stagnation conditions immediately in front of the jet orifice are maintained. However, the fragments of the bursting membrane can significantly influence the flow properties of the jet.

  17. Detonation and Shock Reactivity Properties of Explosives Containing RDX and Reduced Sensitivity RDX

    NASA Astrophysics Data System (ADS)

    Sutherland, Gerrit

    2005-07-01

    The detonation and shock reactivity properties of two monomodal research explosives were measured to assess how these properties change when different quality RDX is used. One explosive contained class 1 (coarse) RDX and HTPB binder; the other explosive contained reduced sensitivity (high quality) class 1 RDX (I-RDX) and HTPB binder. Experiments preformed included wave curvature, rate stick and flyer plate experiments. Wave curvature and rate stick experiments indicate that the reaction zone length is shorter for the explosive containing RDX. Our results show that decrement and wave curvature results are bounded by the results of Moulard and coworkers^1,2 for similar explosives containing fine and very coarse RDX particles. We will also present work of ongoing shock reactivity experiments. In these experiments, a flyer impacts an explosive sample containing multiple embedded pressure gauges. Analyses of the pressure gauge records allow us to determine shock reactivity trends for each explosive. ^1Moulard, H., Kury, J.W., Delclos, A., Proceedings of Eighth Symposium (International) on Detonation, Albuquerque, NM, 1985, pg. 902-913. ^2 Moulard, H., Proceedings of the Ninth Symposium (International) on Detonation, Portland, Oregon, 1989, pg. 18-24.

  18. Self-sustained nonlinear waves in traffic flow

    E-print Network

    Flynn, M. R.

    In analogy to gas-dynamical detonation waves, which consist of a shock with an attached exothermic reaction zone, we consider herein nonlinear traveling wave solutions to the hyperbolic (“inviscid”) continuum traffic ...

  19. 39th AIAA Fluid Dynamics Conference & Exhibit, 2225 June 2009, San Antonio, Texas Detection of Wave Propagation by Nonstationary

    E-print Network

    Texas at Arlington, University of

    of the propagation time of sharp disconti- nuities such as steps or spikes that model shock or detonation waves of shocks and other discontinuities.1 In particular, the propagation of a detonation wave is of importance common method for determining the wave propagation speed is by the time-of-flight (TOF) method in which

  20. 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.

  1. Bactericidal effect of the Nd:YAG lasers in laser-supported curettage

    NASA Astrophysics Data System (ADS)

    Gutknecht, Norbert; Fischer, Julia; Conrads, Georg; Lampert, Friedrich

    1997-05-01

    In this study, the efficacy of laser-supported curettage was examined with relation to the periodontitis-reference germs. Initially, a manual subgingival curettage followed by irradiation using the Nd:YAG-laser was carried out on 18 diseased periodontia. At two further appointments with weekly intervals, only laser irradiation was performed. Prior to and upon completion of therapy, subgingival plaque samples were taken at each appointment from all the treated periodontia. These were then examined microbiologically to establish the number of prevotella intermedia. A distinct bacterial reduction as well as a decrease in recolonization was shown. In conclusion the application of the Nd:YAG laser with a 400 micron fiber and an energy setting of 2 watts, 20 pps is beneficial when used in conjunction with manual periodontal treatment because of its disinfecting effect.

  2. 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.

  3. DSD front models: nonideal explosive detonation in ANFO

    SciTech Connect

    Bdzil, J. B. (John Bohdan); Aslam, T. D. (Tariq D.); Catanach, R. A. (Richard A.); Hill, L. G. (Larry G.); Short, M. (Mark Short)

    2002-01-01

    The DSD method for modeling propagating detonation is based on three elements: (1) a subscale theory of multi-dimensional detonation that treats the detonation as a front whose dynamics depends only on metrics of the front (such as curvature, etc.), (2) high-resolution, direct numerical simulation of detonation using Euler equation models, and (3) physical experiments to characterize multi-dimensional detonation propagation in real explosives and to provide data to calibrate DSD front models. In this paper, we describe our work on elements (1) and (3), develop a DSD calibration for the nonideal explosive ANFO and then demonstrate the utility of the ANFO calibration, with an example 3D detonation propagation calculation.

  4. Significance of blast wave studies to propulsion.

    NASA Technical Reports Server (NTRS)

    Oppenheim, A. K.

    1971-01-01

    Brief survey of experimental methods currently used for the study of blast wave phenomena with emphasis on high rate exothermic processes. The experimental techniques have used such devices as divergent test sections in shock or detonation tubes, employment of proper test gases, as in marginal detonations, and a variety of explosion systems from finite source explosion apparatus to devices where virtually point explosions are obtained by local breakdown initiated by means of focused laser irradiation. Other methods used are detonation tubes where pressure waves are generated by accelerating flames or by exothermic reactions developed behind reflected shocks, as well as a variety of converging shock and implosion vessels.

  5. Numerical predictions of oblique detonation stability boundaries

    Microsoft Academic Search

    M. J. Grismer; J. M. Powers

    1996-01-01

    Oblique detonation stability was studied by numerically integrating the two-dimensional, one-step reactive Euler equations\\u000a in a generalized, curvilinear coordinate system. The integration was accomplished using the Roe scheme combined with fractional\\u000a stepping; nonlinear flux limiting was used to prevent unphysical solution oscillations near discontinuities. The method was\\u000a verified on one-and two-dimensional flows with exact solutions, and its ability to correctly

  6. TEMPERATURES FROM UNDERGROUND DETONATION, SHOT RAINIER

    Microsoft Academic Search

    T. C. Goodale; B. Ragent; A. H. Samuel; A. L. Anderson; D. E. Nielsen; J. L. Olsen

    1958-01-01

    The results of temaperature measuring experiments conducted for Rainier ;\\u000a shot, Operation Plumbbob are described, The temperature distribution in the ;\\u000a surrounding tuff resulting from the detonation of an underground nuclear device ;\\u000a yielding 1.7 kilotons of energy has been measured, Data indicate peak ;\\u000a temperatures in the vicinity or 90 deg existing in the central regions which ;\\u000a drop

  7. Deflagration to detonation experiments in granular HMX

    Microsoft Academic Search

    N. J. Burnside; S. F. Son; B. W. Asay; P. M. Dickson

    1998-01-01

    In this paper the authors report on continuing work involving a series of deflagration-to-detonation transition (DDT) experiments in which they study the piston-initiated DDT of heavily confined granular cyclotetramethylenetetranitramine (HMX). These experiments were designed to he useful in model development and evaluation. A main focus of these experiments is the effect of density on the DDT event. Particle size distribution

  8. Large-scale hydrogen deflagrations and detonations

    Microsoft Academic Search

    M. Groethe; E. Merilo; J. Colton; S. Chiba; Y. Sato; H. Iwabuchi

    2007-01-01

    Large-scale deflagration and detonation experiments of hydrogen and air mixtures provide fundamental data needed to address accident scenarios and to help in the evaluation and validation of numerical models such as the AutoReaGas code (used by Mitsubishi Heavy Industries, Ltd). Several different experiments of this type were performed. Measurements included flame-front time of arrival (TOA) using ionization probes, blast pressure,

  9. Liquid Explosives with Transparent Detonation Products

    Microsoft Academic Search

    H. Dean Mallory; R. A. Plauson

    1963-01-01

    IN an attempt to observe events behind the shock front of detonating explosives we have investigated the possibility of finding materials having transparent reaction products. Explosives of this sort might then simplify the problems since visible light photography could be used instead of X-ray techniques. Preliminary results obtained using a high-speed framing camera have been reported1 for 18 molal hydrazine

  10. 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 diverging ejector pressure distribution shows that the diverging section acts as a subsonic diffuser. To provide a better explanation of the observed performance trends, shadowgraph images of the detonation wave and starting vortex interacting with the ejector inlet were obtained. The acoustic signature of a pulse detonation engine was characterized in both the near-field and far-field regimes. Experimental measurements were performed in an anechoic test facility designed for jet noise testing. Both shock strength and speed were mapped as a function of radial distance and direction from the PDE exhaust plane. It was found that the PDE generated pressure field can be reasonably modeled by a theoretical point-source explosion. The effect of several exit nozzle configurations on the PDE acoustic signature was studies. These included various chevron nozzles, a perforated nozzle, and a set of proprietary noise attenuation mufflers. Experimental studies were carried out to investigate the performance of a hybrid propulsion system integrating an axial flow turbine with multiple pulse detonation combustors. The integrated system consisted of a circular array of six pulse detonation combustor (PDC) tubes exhausting through an axial flow turbine. Turbine component performance was quantified by measuring the amount of power generated by the turbine section. Direct comparisons of specific power output and turbine efficiency between a PDC-driven turbine and a turbine driven by steady-flow combustors were made. It was found that the PDC-driven turbine had comparable performance to that of a steady-burner-driven turbine across the operating map of the turbine.

  11. Developing Subgrid Models for Shock-to-Detonation Mesoscale Simulations

    NASA Astrophysics Data System (ADS)

    Jackson, Thomas

    2012-11-01

    Determining the thermal and mechanical sensitivity of new and existing energetic materials is important for transportation, safety and storage concerns. Initiation of an energetic material can occur when an impulse delivered to the material evolves into a self-sustaining detonation wave. The microstructure can lead to local regions of high temperature, so-called ``hot spots.'' Temperatures in these hot spots can exceed the bulk temperature expected from shock heating, which in turn can trigger ignition even when a homogenized model might fail to predict it. If the chemical and mechanical energy release within hot spots exceeds cooling by diffusion and join up, a localized ignition can occur. Ignition spread due to evolution and growth of high-temperature regions, potentially with reinforcement from neighboring regions or preconditioning of the material, can then lead to detonation. Hot spots are thought to be formed due to shock interaction with microscale and molecular-scale material inhomogeneities through processes such as void collapse, shear banding, debonding, and grain sliding. The most important question at the device scale is whether or not the individual hot spots will coalesce to create a local ignition front, and whether the ignition front or fronts are in turn sufficient to initiate the entire device. Our approach has two principal steps. We first develop sub-grid models based on hot-spot dynamics, and then use the sub-grid model in our mesoscale simulations using our shock dynamics code. In this talk we present recent efforts into developing subgrid models that can be incorporated into mesoscale simulation codes.

  12. Thrust Vectoring of a Continuous Rotating Detonation Engine by Changing the Local Injection Pressure

    NASA Astrophysics Data System (ADS)

    Liu, Shi-Jie; Lin, Zhi-Yong; Sun, Ming-Bo; Liu, Wei-Dong

    2011-09-01

    The thrust vectoring ability of a continuous rotating detonation engine is numerically investigated, which is realized via increasing local injection stagnation pressure of half of the simulation domain compared to the other half. Under the homogeneous injection condition, both the flow-field structure and the detonation wave propagation process are analyzed. Due to the same injection condition along the inlet boundary, the outlines of fresh gas zones at different moments are similar to each other. The main flow-field features under thrust vectoring cases are similar to that under the baseline condition. However, due to the heterogeneous injection system, both the height of the fresh gas zone and the pressure value of the fresh gas in the high injection pressure zone are larger than that in the low injection pressure zone. Thus the average pressure in half of the engine is larger than that in the other half and the thrust vectoring adjustment is realized.

  13. On presupernova dynamical mass ejection by non-detonated stellar cores

    NASA Technical Reports Server (NTRS)

    Buchler, J.-R.; Mazurek, T. J.

    1975-01-01

    Stars in the range of 4 to 8 solar masses are known to develop degenerate carbon-oxygen cores of about 1.4 solar masses. Arguments are presented why, contrary to past assumption, carbon ignition may not lead to the formation of a detonation wave. Rather, an initially subsonic burning front results which subsequently may be brought under control by adiabatic expansion. This dynamic phase leads to a centrally incinerated and expanded core. The loosely bound red-giant envelope is ejected to form an extended nebula. Neutrino cooling of the core finally induces collapse. Provided that sufficient energy is liberated in the dynamic formation of a neutron star, a supernova event will result. The distended nebula is ideally suited for the production of the visible supernova light curves. Thus, carbon nondetonation may give a viable alternative evolution to supernovae that avoids the impasse encountered by the detonation-disrupted models.

  14. Dissolution of composition B detonation residuals.

    PubMed

    Lever, J H; Taylor, S; Perovich, L; Bjella, K; Packer, B

    2005-11-15

    Composition B (Comp B) detonation residuals pose environmental concern to the U.S. Army because hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a constituent, has contaminated groundwater near training ranges. To mimic their dissolution on surface soils, we dripped water at 0.51 ml/h onto individual Comp B particles (0.1-2.0 mg) collected from the detonation of 81-mm mortars. Analyses of the effluent indicate thatthe RDX and 2,4,6-trinitrotoluene (TNT) in Comp B do not dissolve independently. Rather, the relatively slow dissolution of RDX controls dissolution of the particle as a whole by limiting the exposed area of TNT. Two dissolution models, a published steady-flow model and a drop-impingement model developed here, provide good agreementwith the data using RDX parameters for time scaling. They predict dissolution times of 6-600 rainfall days for 0.01-100 mg Comp B particles exposed to 0.55 cm/h rainfall rate. These models should bracket the flow regimes for dissolution of detonation residuals on soils, but they require additional data to validate them across the range of particle sizes and rainfall rates of interest. PMID:16323780

  15. Detonation of Meta-stable Clusters

    SciTech Connect

    Kuhl, Allen; Kuhl, Allen L.; Fried, Laurence E.; Howard, W. Michael; Seizew, Michael R.; Bell, John B.; Beckner, Vincent; Grcar, Joseph F.

    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 Cheetah 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.

  16. Future Modeling Needs in Pulse Detonation Rocket Engine Design

    NASA Technical Reports Server (NTRS)

    Meade, Brian; Talley, Doug; Mueller, Donn; Tew, Dave; Guidos, Mike; Seymour, Dave

    2001-01-01

    This paper presents a performance model rocket engine design that takes advantage of pulse detonation to generate thrust. The contents include: 1) Introduction to the Pulse Detonation Rocket Engine (PDRE); 2) PDRE modeling issues and options; 3) Discussion of the PDRE Performance Workshop held at Marshall Space Flight Center; and 4) Identify needs involving an open performance model for Pulse Detonation Rocket Engines. This paper is in viewgraph form.

  17. The Propagation of Detonation in Thin Layers of Nitroglycerine

    Microsoft Academic Search

    M. F. R. Mulcahy; R. G. Vines

    1947-01-01

    An investigation has been made on the propagation of the low-velocity detonation through layers of nitroglycerine 0\\\\cdot 01 to 0\\\\cdot 75 mm. thick. By the rotating drum photographic method the detonation velocity was found to be 1800 ± 200 m.\\/sec. The forward and backward movement of the decomposition products behind the detonation front has been recorded and the velocities measured

  18. Numerical investigation of the physics of rotating-detonation-engines

    Microsoft Academic Search

    Douglas Schwer; Kailas Kailasanath

    2011-01-01

    Rotating-detonation-engines (RDE’s) represent an alternative to the extensively studied pulse-detonation-engines (PDE’s) for obtaining propulsion from the high efficiency detonation cycle. Since it has received considerably less attention, the general flow-field and effect of parameters such as stagnation conditions and back pressure on performance are less well understood than for PDE’s. In this article we describe results from time-accurate calculations of

  19. BNCP prototype detonator studies using a semiconductor bridge initiator

    SciTech Connect

    Fyfe, D.W.; Fronabarger, J.W. [Pacific Scientific Co., Avondale-Goodyear, AZ (United States). Energy Dynamics Div.; Bickes, R.W. Jr. [Sandia National Labs., Albuquerque, NM (United States)

    1994-06-01

    We report on experiments with prototype BNCP detonators incorporating a semiconductor bridge, SCB. We tested two device designs; one for DoD and one for DOE applications. We report tests with the DoD detonator using different firing conditions and two different grain sizes of BNCP. The DOE detonator utilized a 50 {mu}F CDU firing set with a 24 V all-fire condition.

  20. THE DETONATION MECHANISM OF THE PULSATIONALLY ASSISTED GRAVITATIONALLY CONFINED DETONATION MODEL OF Type Ia SUPERNOVAE

    SciTech Connect

    Jordan, G. C. IV; Graziani, C.; Weide, K.; Norris, J.; Hudson, R.; Lamb, D. Q. [Flash Center for Computational Science, University of Chicago, Chicago, IL 60637 (United States); Fisher, R. T. [Department of Physics, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02740 (United States); Townsley, D. M. [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Meakin, C. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Reid, L. B. [NTEC Environmental Technology, Subiaco WA 6008 (Australia)

    2012-11-01

    We describe the detonation mechanism composing the 'pulsationally assisted' gravitationally confined detonation (GCD) model of Type Ia supernovae. This model is analogous to the previous GCD model reported in Jordan et al.; however, the chosen initial conditions produce a substantively different detonation mechanism, resulting from a larger energy release during the deflagration phase. The resulting final kinetic energy and {sup 56}Ni yields conform better to observational values than is the case for the 'classical' GCD models. In the present class of models, the ignition of a deflagration phase leads to a rising, burning plume of ash. The ash breaks out of the surface of the white dwarf, flows laterally around the star, and converges on the collision region at the antipodal point from where it broke out. The amount of energy released during the deflagration phase is enough to cause the star to rapidly expand, so that when the ash reaches the antipodal point, the surface density is too low to initiate a detonation. Instead, as the ash flows into the collision region (while mixing with surface fuel), the star reaches its maximally expanded state and then contracts. The stellar contraction acts to increase the density of the star, including the density in the collision region. This both raises the temperature and density of the fuel-ash mixture in the collision region and ultimately leads to thermodynamic conditions that are necessary for the Zel'dovich gradient mechanism to produce a detonation. We demonstrate feasibility of this scenario with three three-dimensional (3D), full star simulations of this model using the FLASH code. We characterized the simulations by the energy released during the deflagration phase, which ranged from 38% to 78% of the white dwarf's binding energy. We show that the necessary conditions for detonation are achieved in all three of the models.

  1. A library of prompt detonation reaction zone data

    SciTech Connect

    Souers, P. C., LLNL

    1998-06-01

    Tables are given listing literature data that allows calculation of sonic reaction zones at or near steady-state for promptly detonating explosive cylinders. The data covers homogeneous, heterogeneous, composite, inorganic and binary explosives and allows comparison across the entire explosive field. Table 1 lists detonation front curvatures. Table 2 lists Size Effect data, i.e. the change of detonation velocity with cylinder radius. Table 3 lists failure radii and detonation velocities. Table 4 lists explosive compositions. A total of 51 references dating back into the 1950`s are given. Calculated reaction zones, radii of curvature and growth rate coefficients are listed.

  2. Unique electrical detonator enhances safety in explosive operations: Case histories

    SciTech Connect

    Motley, J.; Barker, J.

    1996-12-31

    The electroexplosive devices most commonly used in today`s oilfield operations include hot-wire detonators, resistorized detonators, exploding bridgewire devices, and exploding foil initiators. Each of these detonators functions differently and is subject to inherent operational, safety, and/or economic drawbacks. To overcome limitations of the present devices, a new type of electrical detonator has been designed. The new device, designated the rig-type environment detonator, utilizes semiconductor bridge technology and deflagration-to-detonation techniques with secondary explosives and does not require primary explosives, special surface firing panels, or downhole firing units in order to function. The new detonating device is insensitive to common wellsite hazards from radio transmissions, electrostatic discharge, cathodic protection, and welding, which have caused problems with other detonators, and thus, can significantly enhance operational safety. In addition, the new device is cost efficient and versatile as the different embodiments of the device allow it to be easily adapted for use with other common downhole explosive hardware and surface firing panels. A description of the qualification tests to which the new detonator has been subjected will be presented and will compare its safety and operational capabilities to that of other traditionally used devices. Case histories of its usage to date and evaluations from independent testing authorities in both the US and UK attest to its safety and reliability for oilfield explosive operations.

  3. Numerical simulation of transient detonation structures in H2-O2 mixtures in smooth pipe bends

    SciTech Connect

    Deiterding, Ralf [ORNL

    2007-01-01

    While the detailed structure of detonations in low-pressure hydrogen-oxygen mixtures with high argon dilution has been fairly well analyzed by means of numerical simulation for two-dimensional rectangular channels, open questions remain for three space dimensions and non-rectangular geometries. In the present paper, we simulate the transient structural evolution as Chapman-Jouguet detonation waves in a perfectly stirred 2 H2+O2+7 Ar mixture at initial pressure 10kPa and room temperature propagate through smooth two-dimensional pipeline bends. The pipes have the constant width 8cm and encompass initially five regular detonation cells. For an unchanged inner radius of 15cm, we consider the bending angles 15, 30, 45, and 60 degree. The computations employ detailed chemical kinetics with 9 thermally perfect species and have been carried out with a massively parallel high-resolution finite volume code with temporal and spatial dynamic mesh adaptation. While we observe only changes in the detonation cell size for 15 degree, a partial decoupling of shock and reaction front occurs in the expansion region for larger bend angles. For 45 and 60 degree, a violent transverse detonation wave reignites the failure region. It is found that the reignition wave itself exhibits an instationary triple point around which the maximal pressure and temperature levels of the entire configuration do occur.

  4. Application_Of_Holographic_Interferometry To Problems In Geophysics And Detonics

    NASA Astrophysics Data System (ADS)

    Holloway, D. C.; Wilson, W. H.

    1985-02-01

    Holographic interferometry, with a Q-switched Ruby laser, has been used for laboratory study of dynamic problems in geophysics and detonics. The holograms provided not only the images of transient phenomena not visible in ordinary high speed photography, but also the data needed to analyze wave speeds and particle motions in solids, or density and pressure in gasses. Explosively driven cracks in rock plates have been studied dynamically by a modification to the usual timing sequence, in which both laser pulses occur after the explosive loading, and within less than a microsecond of each other. Changes in surface displacements, due to the stress wave motion in the model between exposures, cause interferometric fringes which are discontinuous along crack boundaries in the material. This method has successfully located cracks which would not be visible by normal optical methods. Surface and near-surface disturbances propagating in the earth from blasting sites were studied. Three-dimensional models were explosively loaded at points on the model surfaces. Holograms made at various delay times after loading showed the model's surface motions due to waves propagating from the source. Interactions of waves from two neighboring sources and wave interactions with steps and trenches in the model surface have been analyzed. Rayleigh waves crossing trenches were shown to undergo significant reductions in total particle displacement, particle velocity, and frequency content. It was also shown that as the diltational wave crosses steps or trenches, a substantial new Rayleigh wave is generated and propagates ahead of the source Rayleigh wave. Air shock due to explosive detonations has also been studied. Transmission holograms were made of the shock wave at the open end of a fine tube internally lined with an explosive coating.

  5. 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.

  6. Stability of the detonation front in liquid explosives

    Microsoft Academic Search

    A. N. Dremin; S. D. Savrov

    1966-01-01

    1.An experimental study has been made of the stability of the detonation front of series of liquid explosives: nitromethane, glycidol nitrate, a mixture of nitric acid and dichloroethane, tetranitromethane, and glycerol dinitrate and trinitrate.2.In tetranitromethane, glycerol dinitrate and trinitrate we observe stability of the normal detonation front. By direct experimental measurement of the mass velocity profile in the reaction zone

  7. Direct Observations of Reaction Zone Structure in Propagating Detonations

    E-print Network

    Barr, Al

    Direct Observations of Reaction Zone Structure in Propagating Detonations F. Pintgen, C.A. Eckett 1 of self-sustaining, cellular detonations propagating near the Chapman-Jouguet state in hydrogen- oxygen propagating transversely to the main front. As a consequence, the reaction zone region is spatially nonuniform

  8. 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

  9. Gaseous Detonation-Driven Fracture of Tubes Tong Wa Chao

    E-print Network

    -scale modeling. Axial surface flaws were introduced to control the crack initiation site. Fracture thresholdGaseous Detonation-Driven Fracture of Tubes Thesis by Tong Wa Chao In Partial Fulfillment An experimental investigation of fracture response of aluminum 6061-T6 tubes under internal gaseous detonation

  10. On the mechanism of the deflagration-to-detonation transition in a hydrogen-oxygen mixture

    SciTech Connect

    Liberman, M. A., E-mail: misha.liberman@gmail.co [Uppsala University, Department of Physics (Sweden); Ivanov, M. F.; Kiverin, A. D. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Kuznetsov, M. S., E-mail: mike.kuznetsov@kit.ed [Forschungszentrum Karlsruhe (Germany); Rakhimova, T. V.; Chukalovskii, A. A. [Moscow State University, Institute of Nuclear Physics (Russian Federation)

    2010-10-15

    The flame acceleration and the physical mechanism underlying the deflagration-to-detonation transition (DDT) have been studied experimentally, theoretically, and using a two-dimensional gasdynamic model for a hydrogen-oxygen gas mixture by taking into account the chain chemical reaction kinetics for eight components. A flame accelerating in a tube is shown to generate shock waves that are formed directly at the flame front just before DDT occurred, producing a layer of compressed gas adjacent to the flame front. A mixture with a density higher than that of the initial gas enters the flame front, is heated, and enters into reaction. As a result, a high-amplitude pressure peak is formed at the flame front. An increase in pressure and density at the leading edge of the flame front accelerates the chemical reaction, causing amplification of the compression wave and an exponentially rapid growth of the pressure peak, which 'drags' the flame behind. A high-amplitude compression wave produces a strong shock immediately ahead of the reaction zone, generating a detonation wave. The theory and numerical simulations of the flame acceleration and the new physical mechanism of DDT are in complete agreement with the experimentally observed flame acceleration, shock formation, and DDT in a hydrogen-oxygen gas mixture.

  11. Microscopic approaches to liquid nitromethane detonation properties.

    PubMed

    Hervouët, Anaïs; Desbiens, Nicolas; Bourasseau, Emeric; Maillet, Jean-Bernard

    2008-04-24

    In this paper, thermodynamic and chemical properties of nitromethane are investigated using microscopic simulations. The Hugoniot curve of the inert explosive is computed using Monte Carlo simulations with a modified version of the adaptative Erpenbeck equation of state and a recently developed intermolecular potential. Molecular dynamic simulations of nitromethane decomposition have been performed using a reactive potential, allowing the calculation of kinetic rate constants and activation energies. Finally, the Crussard curve of detonation products as well as thermodynamic properties at the Chapman-Jouguet (CJ) point are computed using reactive ensemble Monte Carlo simulations. Results are in good agreement with both thermochemical calculations and experimental measurements. PMID:18376884

  12. Analyses of the cellular structure of detonations

    NASA Astrophysics Data System (ADS)

    Shepherd, J. E.; Moen, I. O.; Murray, S. B.; Thibault, P. A.

    1986-07-01

    We have investigated the effects of chemical composition and dilution on the regularity of gaseous detonation cellular structure at a fixed critical tube diameter of 52 mm. Three fuel-oxygen mixtures were studied as a function of argon dilution (0% to 80% by volume); the fuels were acetylene, hydrogen and ethane. Smoked foil records were analyzed by digital image processing to obtain a quantitative spectrum of the spatial wavelengths present in the cellular structures. Chemical kinetic and thermodynamic analyses have been used to identify parameters that could control the observed variations in regularity of the cellular structures.

  13. Flow Characterization of a Detonation Gun Facility and First Coating Experiments

    NASA Astrophysics Data System (ADS)

    Henkes, C.; Olivier, H.

    2014-06-01

    A computer-controlled detonation gun based spraying device has been designed and tested to obtain particle velocities over 1200 m/s. The device is able to be operated in two modes based on different flow-physical principles. In one mode, the device functions like a conventional detonation gun in which the powder is accelerated in a blast wave. In the other mode, an extension of the facility with a nozzle uses the detonated gas for an intermittently operated shock tunnel process in which the particles are injected into and accelerated by a quasi-steady high enthalpy nozzle flow with high reservoir conditions. Presented are experimental results of the operation without nozzle in which the device generates moderate to high particle velocities in an intermittent process with a frequency of 5 Hz. A hydrogen/oxygen mixture and Cu and WC-Co (88/12) powders are used in the experiments. Operation performance and tube outflow are characterized by time-resolved Schlieren images and pressure measurements. The particle velocities in the outflow are obtained by laser Doppler anemometry. Different substrate/powder combinations (Al/Cu, Steel/Cu, Al/WC-Co, and Steel/WC-Co) have been investigated by light microscopy and measurements of microhardness.

  14. The hypervelocity hot subdwarf US 708 - remnant of a double-detonation SN Ia?

    NASA Astrophysics Data System (ADS)

    Geier, Stephan

    2013-10-01

    Type Ia supernovae {SN Ia} are the most important standard candles for measuring the expansion history of the universe. The thermonuclear explosion of a white dwarf can explain their observed properties, but neither the progenitor systems nor any stellar remnants have been conclusively identified. Underluminous SN Ia have been proposed to originate from a so-called double-detonation of a white dwarf. After a critical amount of helium is deposited on the surface through accretion from a close companion, the helium is ignited causing a detonation wave that triggers the explosion of the white dwarf itself. The helium star will then be ejected at so large a velocity that it will escape the Galaxy. The predicted properties of this remnant are an excellent match to the so-called hypervelocity star US 708, a hot, helium-rich star moving at more than 750 km/s, sufficient to leave the Galaxy.Here we propose medium-resolution COS spectroscopy to measure the vsini of the hypervelocity He-sdO US 708 for the first time and to search for abundance anomalies caused by pollution through an SN Ia event. This will allow us to test the double-detonation scenario with sdB donor empirically.

  15. 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.

  16. Jaguar Procedures for Detonation Behavior of Explosives Containing Boron

    NASA Astrophysics Data System (ADS)

    Stiel, L. I.; Baker, E. L.; Capellos, C.

    2009-12-01

    The Jaguar product library was expanded to include boron and boron containing products by analysis of Available Hugoniot and static volumetric data to obtain constants of the Murnaghan relationships for the components. Experimental melting points were also utilized 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 the boron does not react near the detonation front or that boron mixtures exhibit eigenvalue detonation behavior (as shown by some aluminized explosives), with higher detonation velocities at the initial points. 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 detonation properties of the formulation.

  17. Surface Detonations in Double Degenerate Binary Systems Triggered by Accretion Stream Instabilities

    NASA Astrophysics Data System (ADS)

    Guillochon, James; Dan, Marius; Ramirez-Ruiz, Enrico; Rosswog, Stephan

    2010-01-01

    We present three-dimensional simulations on a new mechanism for the detonation of a sub-Chandrasekhar CO white dwarf in a dynamically unstable system where the secondary is either a pure He white dwarf or an He/CO hybrid. For dynamically unstable systems where the accretion stream directly impacts the surface of the primary, the final tens of orbits can have mass accretion rates that range from 10-5 to 10-3 M sun s-1, leading to the rapid accumulation of helium on the surface of the primary. After ~10-2 M sun of helium has been accreted, the ram pressure of the hot helium torus can deflect the accretion stream such that the stream no longer directly impacts the surface. The velocity difference between the stream and the torus produces shearing which seeds large-scale Kelvin-Helmholtz instabilities along the interface between the two regions. These instabilities eventually grow into dense knots of material that periodically strike the surface of the primary, adiabatically compressing the underlying helium torus. If the temperature of the compressed material is raised above a critical temperature, the timescale for triple-? reactions becomes comparable to the dynamical timescale, leading to the detonation of the primary's helium envelope. This detonation drives shock waves into the primary which tend to concentrate at one or more focal points within the primary's CO core. If a relatively small amount of mass is raised above a critical temperature and density at these focal points, the CO core may itself be detonated.

  18. Lattice Boltzmann model for combustion and detonation

    E-print Network

    Yan, Bo; Zhang, Guang-Cai; Ying, Yang-Jun; Li, Hua; 10.1007/s11467-013-0286-z

    2013-01-01

    In this paper we present a lattice Boltzmann model for combustion and detonation. In this model the fluid behavior is described by a finite-difference lattice Boltzmann model by Gan et al. [Physica A, 2008, 387: 1721]. The chemical reaction is described by the Lee-Tarver model [Phys. Fluids, 1980, 23: 2362]. The reaction heat is naturally coupled with the flow behavior. Due to the separation of time scales in the chemical and thermodynamic processes, a key technique for a successful simulation is to use the operator-splitting scheme. The new model is verified and validated by well-known benchmark tests. As a specific application of the new model, we studied the simple steady detonation phenomenon. To show the merit of LB model over the traditional ones, we focus on the reaction zone to study the non-equilibrium effects. It is interesting to find that, at the von Neumann peak, the system is nearly in its thermodynamic equilibrium. At the two sides of the von Neumann peak, the system deviates from its equilibri...

  19. Spark-safe low-voltage detonator

    DOEpatents

    Lieberman, Morton L. (Albuquerque, NM)

    1989-01-01

    A column of explosive in a low-voltage detonator which makes it spark-safe ncludes an organic secondary explosive charge of HMX in the form of a thin pad disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to an electrical ignition device at one end of the bore. The pad of secondary charge has an axial thickness within the range of twenty to thirty percent of its diameter. The explosive column also includes a first explosive charge of CP disposed in the housing bore in the ignition region of the explosive column next to the secondary charge pad on a side opposite from the ignition device. The first CP charge is loaded under sufficient pressure, 25 to 40 kpsi, to provide mechanical confinement of the pad of secondary charge and physical coupling thereof with the ignition device. The explosive column further includes a second explosive charge of CP disposed in the housing bore in a transition region of the explosive column next to the first CP charge on a side opposite from the pad of secondary charge. The second CP charge is loaded under sufficient pressure, about 10 kpsi, to allow occurrence of DDT. The first explosive CP charge has an axial thickness within the range of twenty to thirty percent of its diameter, whereas the second explosive CP charge contains a series of increments (nominally 4) each of which has an axial thickness-to-diameter ratio of one to two.

  20. Bonfire-safe low-voltage detonator

    DOEpatents

    Lieberman, Morton L. (Albuquerque, NM)

    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.

  1. 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.

  2. Waves

    NSDL National Science Digital Library

    Mr. Hansen

    2010-11-12

    The following websites are useful tools in understanding how energy is transferred from place to place through waves. Start by downloading the assignment and then begin with website number 1 and continue until you have visited all three websites. Begin by downloading the IA Waves Internet Assignment: IA Waves Internet Assignment You will answer the questions in Microsoft Word and then e-mail the assignment to me. Website #1: Read about basic information on waves and answer the questions from part 1 of the IA Waves Guide: Basic Wave Information Website #2: Follow the instructions for the following ...

  3. The effect of minimum detonation diameter on the mechanism of jet initiation of bare explosives

    NASA Astrophysics Data System (ADS)

    Chick, M. C.; Bussell, T. J.

    1988-05-01

    Metal jets generated from 15- and 38-mm-diam-shaped explosive charges were fired into bare samples of the explosives, composition B and H-6. The results showed that a reduction in the jet diameter caused a transition in the mode of initiation from that produced at the sample surface by the impact shock to that produced in the bulk of the explosive by the bow wave from the penetrating jet. The transition is accompanied by a significant change in the explosive's sensitivity to jets. A simple criterion is proposed for predicting the transition in terms of the minimum diameter of the explosive to support detonation and the diameter of the jet.

  4. First-Principles Investigation of Reactive Molecular Dynamics in Detonating Rdx and Tatb

    NASA Astrophysics Data System (ADS)

    Oleynik, I. I.; Landerville, A. C.; White, C. T.

    2009-12-01

    Possible initial chemical reactions in detonating RDX and TATB that result from intermolecular collisions behind the shock wave front have been investigated using first-principles reactive molecular dynamics. The reaction dynamics was studied as a function of collision velocities and crystallographic orientations. Threshold collision velocities of chemical initiation and products of decomposition were obtained for each orientation, and compared to calculated bond dissociation energies to rationalize the outcome chemical events. Reaction timescales were also determined and used to understand whether these initial chemical events are largely driven by reaction dynamics or temperature.

  5. Impurity-doped optical shock, detonation and damage location sensor

    DOEpatents

    Weiss, J.D.

    1995-02-07

    A shock, detonation, and damage location sensor providing continuous fiber-optic means of measuring shock speed and damage location, and could be designed through proper cabling to have virtually any desired crush pressure. The sensor has one or a plurality of parallel multimode optical fibers, or a singlemode fiber core, surrounded by an elongated cladding, doped along their entire length with impurities to fluoresce in response to light at a different wavelength entering one end of the fiber(s). The length of a fiber would be continuously shorted as it is progressively destroyed by a shock wave traveling parallel to its axis. The resulting backscattered and shifted light would eventually enter a detector and be converted into a proportional electrical signals which would be evaluated to determine shock velocity and damage location. The corresponding reduction in output, because of the shortening of the optical fibers, is used as it is received to determine the velocity and position of the shock front as a function of time. As a damage location sensor the sensor fiber cracks along with the structure to which it is mounted. The size of the resulting drop in detector output is indicative of the location of the crack. 8 figs.

  6. Impurity-doped optical shock, detonation and damage location sensor

    DOEpatents

    Weiss, Jonathan D. (Albuquerque, NM)

    1995-01-01

    A shock, detonation, and damage location sensor providing continuous fiber-optic means of measuring shock speed and damage location, and could be designed through proper cabling to have virtually any desired crush pressure. The sensor has one or a plurality of parallel multimode optical fibers, or a singlemode fiber core, surrounded by an elongated cladding, doped along their entire length with impurities to fluoresce in response to light at a different wavelength entering one end of the fiber(s). The length of a fiber would be continuously shorted as it is progressively destroyed by a shock wave traveling parallel to its axis. The resulting backscattered and shifted light would eventually enter a detector and be converted into a proportional electrical signals which would be evaluated to determine shock velocity and damage location. The corresponding reduction in output, because of the shortening of the optical fibers, is used as it is received to determine the velocity and position of the shock front as a function of time. As a damage location sensor the sensor fiber cracks along with the structure to which it is mounted. The size of the resulting drop in detector output is indicative of the location of the crack.

  7. Approximate solutions for oblique detonations in the hypersonic limit

    NASA Astrophysics Data System (ADS)

    Powers, Joseph M.; Stewart, D. S.

    1992-03-01

    This article describes analytic solutions for hypersonic flow of a premixed reactive ideal gas over a wedge. The flow is characterized by a shock followed by a spatially resolved reaction zone. Explicit solutions are given for the irrotational flowfield behind a straight shock attached to a curved wedge and for the rotational flowfield behind a curved shock attached to a straight wedge. Continuous solution trajectories exist that connect the state just past the shock to the equilibrium end states found from a Rankine-Hugoniot theory for changes across oblique discontinuities with energy release. The analytic results are made possible by the hypersonic approximation, which implies that a fluid particle's kinetic energy is much larger than its thermal and chemical energy. The leading order solution is an inert oblique shock. The effects of heat release are corrected for at the next order. These results can be used to verify numerical results and are necessary for more advanced analytic studies. In addition, the theory has application to devices such as the oblique detonation wave engine, the ram accelerator, hypersonic airframes, or re-entry vehicles.

  8. 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)

  9. Numerical calculation of shock-induced initiation of detonations. [PBX 9501

    SciTech Connect

    Cort, G.E.; Fu, J.H.

    1980-01-01

    The results of some numerical calculations of the impact of steel cylinders and spheres on the plastic-bonded high explosive PBX 9501 are described. The calculations were carried out by a reactive, multicomponent, two-dimensional, Eulerian hydrodynamic computer code, 2DE. The 2DE computer code is a finite difference code that uses the donor-acceptor-cell method to compute mixed cell fluxes. The mechanism of shock initiation to detonation in heterogeneous explosives is best described as local decomposition at hot spots that are formed by shock interactions with density discontinuities. The liberated energy strengthens the shock so that as it interacts with additional inhomogeneities, hotter hot spots are formed, and more of the explosive is decomposed. The shock wave grows stronger until a detonation begins. This mechanism of initiation has been described numerically by the Forest Fire burn model, which gives the rate of explosive decomposition as a function of local pressure. The parameters in the Forest Fire burn model have been developed from experiments where the induced shock approximates a plane wave and are applied, in this case, to a situation where the induced shock is a divergent wave with curvature that depends on the size and shape of the projectile. The calculated results have been compared with results from experiments involving instrumented mock and live high explosives, with projectiles of varying sizes, shapes, and velocities. We find that there is good agreement between the calculated and experimental data.

  10. A laser-supported lowerable surface setup to study the role of ground contact during stepping.

    PubMed

    Berendes, Volker; Dübbert, Michael; Bockemühl, Till; Schmitz, Joscha; Büschges, Ansgar; Gruhn, Matthias

    2013-05-15

    We introduce a laser-supported setup to study the influence of afferent input on muscle activation during walking, using a movable ground platform. This approach allows investigating if and how the activity of stance phase muscles of an insect (e.g. stick insect) responds to a missing ground contact signal. The walking surface consists of a fixed and a lowerable part, which can be lowered to defined levels below the previous ground level at any time point during a walking sequence. As a consequence, the leg under investigation finds either a lower ground level or no ground support at all. The lowerable walking surface consists of a 49 mm × 34 mm stainless steel surface, made slippery and equipped for tarsal contact monitoring, similar to the system that was described by Gruhn and colleagues (Gruhn et al., 2006). The setup controller allows pneumatic lowering of the surface and subsequent detection of tarsal entry into the previous ground level with the help of a thin sheet of laser light and a corresponding detector. Here, we describe basic properties of the new setup and show the results of first experiments to demonstrate its use for the study of sensory and central influences in stepping of a small animal. In the experiments, we compare the effect of ground-support ("control") with either steps into the hole (SiH), ground support at a lower surface level, or the amputation of the tarsus on the onset of EMG activity in the flexor tibiae muscle of the stick insect. PMID:23562598

  11. Analysis of simulation technique for steady shock waves in materials with analytical equations of state.

    PubMed

    Reed, Evan J; Fried, Laurence E; Henshaw, William D; Tarver, Craig M

    2006-11-01

    We calculate and analyze a thermodynamic limit of a multiscale molecular dynamics based scheme that we have developed previously for simulating shock waves. We validate and characterize the performance of the former scheme for several simple cases. Using model equations of state for chemical reactions and kinetics in a gas and a condensed phase explosive, we show that detonation wave profiles computed using the computational scheme are in good agreement with the steady state wave profiles of hydrodynamic direct numerical simulations. We also characterize the stability of the technique when applied to detonation waves and describe a technique for determining the detonation shock speed. PMID:17280020

  12. A Mechanistic Study of Delayed Detonation in Impact Damaged Solid Rocket Propellant

    Microsoft Academic Search

    E. R. Matheson; J. T. Rosenberg

    2002-01-01

    One method of hazard assessment for mass detonable solid rocket propellants consists of impacting right circular cylinders of propellant end-on into thick steel witness plates at varying impact velocities. A detonation that occurs within one shock traversal of the cylinder length is termed a prompt detonation or a shock-to-detonation transition (SDT). At lower velocities, some propellants detonate at times later

  13. A Mechanistic Study of Delayed Detonation in Impact Damaged Solid Rocket Propellant

    Microsoft Academic Search

    Erik R. Matheson; J. Thomas Rosenberg

    2001-01-01

    One method of hazard assessment for mass detonable solid rocket propellants consists of impacting right circular cylinders of propellant end-on into thick steel witness plates at varying impact velocities. A detonation that occurs within one shock traversal of the cylinder length is termed a prompt detonation or a shock-to-detonation transition (SDT). At lower velocities, some propellants detonate at times later

  14. High-speed photographic study on overdriven detonation of high explosive

    Microsoft Academic Search

    Zhi-Yue Liu; Shiro Kubota; Shirou Nagano; Shigeru Itoh

    2001-01-01

    On the common circumstances the detonation of explosives has a steady propagation rate and can be satisfactorily explained by Chapman-Jouguet's theory on this phenomenon. Hence, this type of detonation is more frequently called the Chapman- Jouguet (C-J) detonation. The detonation properties such as pressure, density, and temperature, of the detonation products are often characterized as the C-J values of the

  15. Initiation and detonation of heterogeneous high explosives: a unified model

    SciTech Connect

    Tang, P.K.

    1988-09-01

    Reaction processes in initiation and detonation of heterogeneous high explosives can be characterized by three dominant rates that represent the special chemical and physical features found in various stages of the reaction: hot spot, propagation, and slow process. The first two stages control mainly the initiation; the last manifests itself in what is known as the nonsteady detonation. Three principal rate equations are thus constructed using the process time concept. Examples with triaminotrinitrobenzene-based explosives are presented to illustrate the model capability in the simulations of initiation and detonation. 11 refs., 9 figs.

  16. POINTWISE GREEN FUNCTION BOUNDS AND STABILITY OF COMBUSTION WAVES

    E-print Network

    Texier, Benjamin - Institut de Mathématiques de Jussieu, Université Paris 7

    POINTWISE GREEN FUNCTION BOUNDS AND STABILITY OF COMBUSTION WAVES GREGORY LYNG, MOHAMMADREZA ROOFI for traveling wave solutions of an abstract viscous combustion model including both Majda's model and the full-wave) approximation. Notably, our results apply to combustion waves of any type: weak or strong, detonations or defla

  17. Analysis of pulse detonation turbojet engines

    NASA Astrophysics Data System (ADS)

    Vutthivithayarak, Ronnachai

    2011-12-01

    Research over the last two decades has shown the potential advantages of pulse detonation engines (PDEs) over existing aero-engines in terms of improved thermodynamics efficiency, improved thrust performance, simplicity of design, and flexibility to operate over a wide speed range. The inherently unsteady characteristic of PDEs makes it difficulty to analyze and evaluate their performance. The conventional method that relies on steady-state assumptions cannot be directly applied. PDE studies have to employ unsteady gasdynamics behavior. In this study, the thermodynamic cycle of a PDE, which can be called the ZND cycle, is theoretically analyzed. A parametric analysis of turbojet PDEs is considered for both ideal and non-ideal cases. The conventional turbojet with a Brayton cycle is brought in the comparison to verify that PDEs can provide better performance.

  18. Lattice Boltzmann model for combustion and detonation

    E-print Network

    Bo Yan; Aiguo Xu; Guangcai Zhang; Yangjun Ying; Hua Li

    2013-05-10

    In this paper we present a lattice Boltzmann model for combustion and detonation. In this model the fluid behavior is described by a finite-difference lattice Boltzmann model by Gan et al. [Physica A, 2008, 387: 1721]. The chemical reaction is described by the Lee-Tarver model [Phys. Fluids, 1980, 23: 2362]. The reaction heat is naturally coupled with the flow behavior. Due to the separation of time scales in the chemical and thermodynamic processes, a key technique for a successful simulation is to use the operator-splitting scheme. The new model is verified and validated by well-known benchmark tests. As a specific application of the new model, we studied the simple steady detonation phenomenon. To show the merit of LB model over the traditional ones, we focus on the reaction zone to study the non-equilibrium effects. It is interesting to find that, at the von Neumann peak, the system is nearly in its thermodynamic equilibrium. At the two sides of the von Neumann peak, the system deviates from its equilibrium in opposite directions. In the front of von Neumann peak, due to the strong compression from the reaction product behind the von Neumann peak, the system experiences a sudden deviation from thermodynamic equilibrium. Behind the von Neumann peak, the release of chemical energy results in thermal expansion of the matter within the reaction zone, which drives the system to deviate the thermodynamic equilibrium in the opposite direction. From the deviation from thermodynamic equilibrium, defined in this paper, one can understand more on the macroscopic effects of the system due to the deviation from its thermodynamic equilibrium.

  19. Lattice Boltzmann model for combustion and detonation

    NASA Astrophysics Data System (ADS)

    Yan, Bo; Xu, Ai-Guo; Zhang, Guang-Cai; Ying, Yang-Jun; Li, Hua

    2013-02-01

    In this paper we present a lattice Boltzmann model for combustion and detonation. In this model the fluid behavior is described by a finite-difference lattice Boltzmann model by Gan et al. [Physica A, 2008, 387: 1721]. The chemical reaction is described by the Lee-Tarver model [Phys. Fluids, 1980, 23: 2362]. The reaction heat is naturally coupled with the flow behavior. Due to the separation of time scales in the chemical and thermodynamic processes, a key technique for a successful simulation is to use the operator-splitting scheme. The new model is verified and validated by well-known benchmark tests. As a specific application of the new model, we studied the simple steady detonation phenomenon. To show the merit of LB model over the traditional ones, we focus on the reaction zone to study the non-equilibrium effects. It is interesting to find that, at the von Neumann peak, the system is nearly in its thermodynamic equilibrium. At the two sides of the von Neumann peak, the system deviates from its equilibrium in opposite directions. In the front of von Neumann peak, due to the strong compression from the reaction product behind the von Neumann peak, the system experiences a sudden deviation from thermodynamic equilibrium. Behind the von Neumann peak, the release of chemical energy results in thermal expansion of the matter within the reaction zone, which drives the system to deviate the thermodynamic equilibrium in the opposite direction. From the deviation from thermodynamic equilibrium, ? m *, defined in this paper, one can understand more on the macroscopic effects of the system due to the deviation from its thermodynamic equilibrium.

  20. Spark-safe low-voltage detonator

    DOEpatents

    Lieberman, M.L.

    1988-07-01

    A column of explosive in a low-voltage detonator which makes it spark-safe includes an organic secondary explosive charge of HMX in the form of a thin pad disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to an electrical ignition device at one end of the bore. The pad of secondary charge has an axial thickness within the range of twenty to thirty percent of its diameter. The explosive column also includes a first explosive charge of CP disposed in the housing bore in the ignition region of the explosive column next to the secondary charge pad on a side opposite from the ignition device. The first CP charge is loaded under sufficient pressure, 25 to 40 kpsi, to provide mechanical confinement of the pad of secondary charge and physical coupling thereof with the ignition device. The explosive column further includes a second explosive charge of CP disposed in the housing bore in a transition region of the explosive column next to the first CP charge on a side opposite from the pad of secondary charge. The second CP charge is loaded under sufficient pressure, about 10 kpsi, to allow occurrence of DDT. The first explosive CP charge has an axial thickness within the range of twenty to thirty percent of its diameter, whereas the second explosive CP charge contains a series of increments (nominally 4), each of which has an axial thickness-to-diameter ratio of one to two. 2 figs.

  1. Shock-wave initiation of heated plastified TATB detonation

    Microsoft Academic Search

    Igor Kuzmitsky; Vladimir Rudenko; Leonid Gatilov; Alexandr Koshelev

    1999-01-01

    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

  2. AIAA 95-2197 Experimental Investigation of Pulse Detonation Wave

    E-print Network

    Texas at Arlington, University of

    , Texas 26th AIAA Fluid Dynamm Conference , -. June I9=22,1995/SanDiego, CA For permissionto copy chamber where several parameters could bc varied. These parameters were the length to diameter ratio conventional rocket motors.' This technology may also be used to clean slag offof coal furnaces which would

  3. Detonation Shock Dynamics Calibration for Non-Ideal He: Anfo

    Microsoft Academic Search

    Mark Short; Terry R. Salyer; Tariq D. Aslam; Charles B. Kiyanda; John S. Morris; Tony Zimmerley

    2009-01-01

    Linear Dn-kappa 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.

  4. DETONATION SHOCK DYNAMICS CALIBRATION FOR NON-IDEAL HE: ANFO

    Microsoft Academic Search

    Mark Short; Terry R. Salyer; Tariq D. Aslam; Charles B. Kiyanda; John S. Morris; Tony Zimmerly

    2009-01-01

    Linear Dn?? 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.

  5. Time-Resolved Optical Measurements of Detonation and Combustion Products

    NASA Astrophysics Data System (ADS)

    Carney, Joel R.; Wilkinson, John; Lightstone, James M.

    2007-12-01

    A first attempt at measuring the species evolution in the opaque post-detonation combustion product environment of a fuel-rich explosive using time-resolved absorption spectroscopy is presented. The time-resolved concentration of these species is helpful in identifying the rate and location of the extra energy released in the post-detonation phase due to the aluminum combustion, thus shedding light on the factors affecting the overall efficiency of air and internal-blast explosions. The methodology and results of time-resolved absorption spectroscopy are compared to previous emission spectroscopy investigations. The experimental arrangement and preliminary results of time-resolved absorption spectroscopy based on atomic aluminum in the post detonation environment of aluminized pressed PETN charges are presented. An assessment of the experimental approach and its usefulness in future detonation experiments is discussed.

  6. Jaguar Analyses of Experimental Detonation Values for Aluminized Explosives

    NASA Astrophysics Data System (ADS)

    Stiel, Leonard I.; Baker, Ernest L.; Capellos, Christos

    2004-07-01

    Comparisons of JAGUAR C-J velocities with experimental detonation values for a number of explosives indicate that only slight, if any, aluminum reaction occurs at the detonation front even if small or sub-micron particles are utilized. For sub-micron particles, it is important to account for the presence of aluminum oxide in the explosive formulation. The agreement with the calculated JAGUAR values for zero aluminum reaction is within 2% for most experimental detonation velocities considered. Comparisons of experimental cylinder velocities by JAGUAR analytical procedures indicate that with small aluminum particles substantial aluminum reaction occurs at low values of the radial expansion, even though little reaction is observed at the detonation front.

  7. Experimental investigation of detonation of nitric acid solutions

    Microsoft Academic Search

    V. M. Raikova; B. N. Kondrikov; G. D. Kozak

    1998-01-01

    Detonation of mixtures of concentrated (94–100%) nitric acid with nitromethane, diethylene glycol dinitrate, nitroglycol,\\u000a trinitrotoluene, dinitrotoluene, acetic anhydride, and dichlorethane was studied experimentally. The detonation failure diameter\\u000a was measured in glass tubes. For mixtures of nitric acid with nitromethane, dinitrotoluene, and trinitrotoluene, its minimum\\u000a values are smaller than 1 mm and correspond to zero oxygen balance of the mixtures (A=0).

  8. Dynamics of the detonation products of lead azide. I - Hydrodynamics

    Microsoft Academic Search

    Y. Tzuk; I. Bar; T. Ben-Porat; S. Rosenwaks

    1992-01-01

    The hydrodynamics of the transient species formed following the detonation of lead azide (LA) is investigated using results of extensive measurements of the spatial and temporal behaviors of the detonation products by high-speed framing photography, transmission of a HeNe laser beam through the products, and time-resolved chemiluminescence (CL). The CL had two components. The first, appearing 1-2 microsec after initiation,

  9. A study of detonation propagation and diffraction with compliant confinement

    Microsoft Academic Search

    J. W. Banks; W. D. Henshaw; D. W. Schwendeman; A. K. Kapila

    2008-01-01

    Previous computational studies of diffracting detonations with the ignition-and-growth (IG) model demonstrated that, contrary to experimental observations, the computed solution did not exhibit dead zones. For a rigidly confined explosive it was found that while diffraction past a sharp corner did lead to a temporary separation of the lead shock from the reaction zone, the detonation re-established itself in due

  10. 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.

  11. The Physics of Deflagration-to-Detonation Transition in Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Poludnenko, Alexei

    BACKGROUND: The scenario currently best capable of explaining the observational properties of normal bright type Ia supernovae (SNIa), which are of primary importance for cosmology, is the delayed detonation model of the explosion of a white dwarf star with the mass near the Chandrasekhar limit in a single-degenerate binary system. In this model, the explosion starts as a subsonic deflagration that later transitions to a supersonic detonation (deflagration-to-detonation transition, or DDT). Significant progress has been made over the years both experimentally and numerically in elucidating the physics of DDT in terrestrial confined systems. It remains unclear, however, whether and how a detonation can be formed in an unpressurized, unconfined system such as the interior of a WD. Modern large-scale multidimensional models of SNIa cannot capture the DDT process and, thus, are forced to make two crucial assumptions, namely (a) that DDT does occur at some point, and (b) when and where it occurs. As a result, delayed detonation is a parameterized model that must be "tuned" in order to obtain the proper match with the observations. This substantially hinders the possibility of investigating potential sources of systematic errors in the calibration of normal bright SNIa as standard candles. Recently we have carried out a systematic study of the high-speed turbulence-flame interaction through first-principles direct numerical simulations (DNS) using reaction models similar to those describing terrestrial chemical flames. Our analysis has shown that at sufficiently high turbulent intensities, subsonic turbulent flames in unconfined environments, such as the WD interior, are indeed inherently susceptible to DDT. The associated mechanism is based on the unsteady evolution of turbulent flames faster than the Chapman-Jouguet deflagrations. This process is qualitatively different from the traditional spontaneous reaction wave model and does not require the formation of distributed flames. These results provide the first direct ab initio demonstration of DDT in turbulent reactive flows. They show that DDT is indeed possible in unconfined media and provide a detailed physical description of this process. OBJECTIVES: Here we propose to perform the detailed and systematic analysis of the new spontaneous DDT mechanism to demonstrate its applicability in SNIa explosions and to determine precise conditions required for the onset of DDT. Culmination of this effort will be the first DNS-validated subgrid-scale DDT model capable of accurately predicting the time and location of detonation initiation and suitable for use in large-scale SNIa simulations. METHODS: All key stages of the new DDT mechanism will be studied using high-resolution direct numerical simulations of turbulence interaction with both chemical and thermonuclear flames. These will be carried out with fixed grid and adaptive mesh refinement numerical codes that have previously been extensively used in studies of both terrestrial and astrophysical combustion. The results will be incorporated as a subgrid model in large-scale 3D fluid dynamics calculations of SNIa. SIGNIFICANCE: Analysis performed in the course of this work will remove the parameterization of the single-degenerate delayed detonation model on DDT conditions. This, in turn, will open the possibility for meaningful comparison of the observational signatures of this explosion scenario with the photometric, spectroscopic, and polarimetric signatures of SNIa and, thus, for identifying and describing potential sources of systematic errors in SNIa calibration as cosmological standard candles. Substantial improvement of the accuracy of such calibration will be crucial for the success of current and future NASA missions aimed at studying the nature of dark energy.

  12. Nature of the buildup to detonation in solid high explosives during plane shock initiation. [PBX-9404 and PBX-9502

    SciTech Connect

    Dick, J.J.

    1980-01-01

    Two models for the initiation process are compared to results of experimental studies of initiation of detonation in two high explosives, PBX-9404 (HMX-based) and PBX-9502 (TATB-based), by sustained shock waves. A critical examination of the model known as single-curve buildup is made. Several comparisons are made with experimental results for the two explosives. The model describes the observed shock trajectories moderately well although it has some limitations. These are manifested by an examination of the relation between input pressure and distance of run to detonation. The data are also compared with model solutions for the initiation process which assume self-similar flow. The model can fit the experimental shock trajectory reasonably well but difficulties are encountered in attempting to complete the solution for the entire flow field. For PBX-9404, published pressure-time profiles are examined for self-similar character. The measured profiles show substantial disagreement with the similarity model.

  13. Waves

    E-print Network

    LaCure, Mari Mae

    2010-04-29

    travel as waves through space and time. Waves can also manifest visibly through other mediums, water for example, as they travel outward from where an object disturbs the surface. As the title of my thesis exhibit, Waves refers to my aim to imbue.... As a viewer approaches a drawing from different angles the light reflected by the image subtly changes intensity. 4 Sewing by hand further adds dimension where it is seen in the front, and creates a shadow where it can be seen through the back...

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

    SciTech Connect

    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 response 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 reliable performance, whether as a result of accident, hazard, or a fault in the detonation train. These models describe the build-up of detonation from a shock stimulus. They are generally consistent with the mesoscale picture of ignition at many small defects in the plane of the shock front and the growth of the resulting hot-spots, leading to detonation in heterogeneous explosives such as plastic-bonded explosives (PBX). The models included terms for ignition, and also for the growth of reaction as tracked by the local mass fraction of product gas, {lambda}. The growth of reaction in such models incorporates a form factor that describes the change of surface area per unit volume (specific surface area) as the reaction progresses. For unimolecular crystalline-based explosives, the form factor is consistent with the mesoscale picture of a galaxy of hot spots burning outward and eventually interacting with each other. For composite explosives and propellants, where the fuel and oxidizer are segregated, the diffusion flame at the fuel-oxidizer interface can be interpreted with a different form factor that corresponds to grains burning inward from their surfaces. The form factor influences the energy release rate, and the amount of energy released in the reaction zone. Since the 19th century, gun and cannon propellants have used perforated geometric shapes that produce an increasing surface area as the propellant burns. This helps maintain the pressure as burning continues while the projectile travels down the barrel, which thereby increases the volume of the hot gas. Interior ballistics calculations use a geometric form factor to describe the changing surface area precisely. As a result, with a suitably modified form factor, detonation models can represent burning and explosion in damaged and broken reactant. The disadvantage of such models in application to accidents is that the ignition term does not distinguish between a value of pressure that results from a shock, and the same pressure that results from a more gradual increase. This disagrees with experiments, where

  15. TNT particle size distributions from detonated 155-mm howitzer rounds.

    PubMed

    Taylor, Susan; Hewitt, Alan; Lever, James; Hayes, Charlotte; Perovich, Laura; Thorne, Phil; Daghlian, Chuck

    2004-04-01

    To achieve sustainable range management and avoid or minimize environmental contamination, the Army needs to know the amount of explosives deposited on ranges from different munitions and how these are degraded and transported under different geological and climatic conditions. The physical form of the deposited explosives has a bearing on this problem, yet the shapes and size distributions of the explosive particles remaining after detonations are not known. We collected residues from 8 high-order and 6 low-order non-tactical detonations of TNT-filled 155-mm rounds. We found significant variation in the amount of TNT scattered from the high-order detonations, ranging from 0.00001 to 2% of the TNT in the original shell. All low-order detonations scattered percent-level amounts of TNT. We imaged thousands of TNT particles and determined the size, mass and surface-area distributions of particles collected from one high-order and one low-order detonation. For the high-order detonation, particles smaller than 1 mm contribute most of the mass and surface area of the TNT scattered. For the low-order detonation, most of the scattered TNT mass was in the form of un-heated, centimeter-sized pieces whereas most of the surface area was again from particles smaller than 1 mm. We also observed that the large pieces of TNT disintegrate readily, giving rise to many smaller particles that can quickly dissolve. We suggest picking up the large pieces of TNT before they disintegrate to become point sources of contamination. PMID:14987934

  16. Deflagration to detonation experiments in granular HMX

    SciTech Connect

    Burnside, N.J.; Son, S.F.; Asay, B.W.; Dickson, P.M.

    1998-03-01

    In this paper the authors report on continuing work involving a series of deflagration-to-detonation transition (DDT) experiments in which they study the piston-initiated DDT of heavily confined granular cyclotetramethylenetetranitramine (HMX). These experiments were designed to he useful in model development and evaluation. A main focus of these experiments is the effect of density on the DDT event. Particle size distribution and morphology are carefully characterized. In this paper they present recent surface area analysis. Earlier studies demonstrated extensive fracturing and agglomeration in samples at densities as low as 75% TMD as evidenced by dramatic decreases in particle size distribution due to mild stimulus. This is qualitatively confirmed with SEM images and quantitatively studied with gas absorption surface area analysis. Also, in this paper they present initial results using a microwave interferometer technique. Dynamic calibration of the technique was performed, a 35 GHz signal is used to increase resolution, and the system has been designed to be inexpensive for repeated experiments. The distance to where deformation of the inner wall begins for various densities is reported. This result is compared with the microwave interferometer measurements.

  17. Particle Acceleration in a High Enthalpy Nozzle Flow with a Modified Detonation Gun

    NASA Astrophysics Data System (ADS)

    Henkes, C.; Olivier, H.

    2014-04-01

    The quality of thermal sprayed coatings depends on many factors which have been investigated and are still in scientific focus. Mostly, the coating material is inserted into the spray device as solid powder. The particle condition during the spray process has a strong effect on coating quality. In some cases, higher particle impact energy leads to improved coating quality. Therefore, a computer-controlled detonation gun based spraying device has been designed and tested to obtain particle velocities over 1200 m/s. The device is able to be operated in two modes based on different flow-physical principles. In one mode, the device functions like a conventional detonation gun in which the powder is accelerated in a blast wave. In the other mode, an extension with a nozzle transforms the detonation gun process into an intermittent shock tunnel process in which the particles are accelerated in a high enthalpy nozzle flow with high reservoir conditions. Presented are experimental results of the operation with nozzle in which the device generates very high particle velocities up to a frequency of 5 Hz. A variable particle injection system allows injection of the powder at any point along the nozzle axis to control particle temperature and velocity. A hydrogen/oxygen mixture is used in the experiments. Operation performance and nozzle outflow are characterized by time resolved pressure measurements. The particle conditions inside the nozzle and in the nozzle exit plane are calculated with a quasi-one-dimensional WENO-code of high order. For the experiments, particle velocity is obtained by particle image velocimetry, and particle concentration is qualitatively determined by a laser extinction method. The powders used are WC-Co(88/12), NiCr(80/20), Al2O3, and Cu. Different substrate/powder combinations for varying particle injection positions have been investigated by light microscopy and measurements of microhardness.

  18. The development of laser ignited deflagration-to-detonation transition (DDT) detonators and pyrotechnic actuators

    SciTech Connect

    Merson, J.A.; Salas, F.J.; Harlan, J.G.

    1993-11-01

    The use of laser ignited explosive components has been recognized as a safety enhancement over existing electrical explosive devices (EEDs). Sandia has been pursuing the development of optical ordnance for many years with recent emphasis on developing optical deflagration-to-detonation (DDT) detonators and pyrotechnic actuators. These low energy optical ordnance devices can be ignited with either a semiconductor diode laser, laser diode arrays or a solid state rod laser. By using a semiconductor laser diode, the safety improvement can be made without sacrificing performance since the input energy required for the laser diode and the explosive output are similar to existing electrical systems. The use of higher powered laser diode arrays or rod lasers may have advantages in fast DDT applications or lossy optical environments such as long fiber applications and applications with numerous optical connectors. Recent results from our continued study of optical ignition of explosive and pyrotechnic materials are presented. These areas of investigation can be separated into three different margin categories: (1) the margin relative to intended inputs (i.e. powder performance as a function of laser input variation), (2) the margin relative to anticipated environments (i.e. powder performance as a function of thermal environment variation), and (3) the margin relative to unintended environments (i.e. responses to abnormal environments or safety).

  19. CONDITIONS FOR SUCCESSFUL HELIUM DETONATIONS IN ASTROPHYSICAL ENVIRONMENTS

    SciTech Connect

    Holcomb, Cole; Guillochon, James; De Colle, Fabio; Ramirez-Ruiz, Enrico [TASC, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    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 between 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.

  20. 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.

  1. Laser detonator development for test-firing applications

    SciTech Connect

    Munger, A. C. (Alan C.); Thomas, K. A. (Keith A.); Kennedy, J. E. (James E.); Akinci, A. A. (Adrian A.); Mallett, H. L. (Heather L.)

    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 design 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.

  2. American Institute of Aeronautics and Astronautics Numerical Simulation of Detonation Processes in a

    E-print Network

    Texas at Arlington, University of

    , such as in propulsion1 and in high-enthalpy ground test facilities. 2 The primary advantage of detonation combustion The detonation processes occurring in a combustion chamber with variable cross-sections are numerically simulated

  3. 30 CFR 75.1312 - Explosives and detonators in underground magazines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Explosives and detonators in underground magazines. 75.1312 Section 75.1312 Mineral...Explosives and detonators in underground magazines. (a) The quantity of explosives...kept in— (1) Separate, closed magazines at least 5 feet apart; or (2)...

  4. 30 CFR 75.1313 - Explosives and detonators outside of magazines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Explosives and detonators outside of magazines. 75.1313 Section 75.1313 Mineral... Explosives and detonators outside of magazines. (a) The quantity of explosives outside a magazine for use in a working section or other...

  5. 30 CFR 75.1312 - Explosives and detonators in underground magazines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Explosives and detonators in underground magazines. 75.1312 Section 75.1312 Mineral...Explosives and detonators in underground magazines. (a) The quantity of explosives...kept in— (1) Separate, closed magazines at least 5 feet apart; or (2)...

  6. 30 CFR 75.1313 - Explosives and detonators outside of magazines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Explosives and detonators outside of magazines. 75.1313 Section 75.1313 Mineral... Explosives and detonators outside of magazines. (a) The quantity of explosives outside a magazine for use in a working section or other...

  7. 30 CFR 75.1312 - Explosives and detonators in underground magazines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Explosives and detonators in underground magazines. 75.1312 Section 75.1312 Mineral...Explosives and detonators in underground magazines. (a) The quantity of explosives...kept in— (1) Separate, closed magazines at least 5 feet apart; or (2)...

  8. 30 CFR 75.1313 - Explosives and detonators outside of magazines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Explosives and detonators outside of magazines. 75.1313 Section 75.1313 Mineral... Explosives and detonators outside of magazines. (a) The quantity of explosives outside a magazine for use in a working section or other...

  9. 30 CFR 75.1313 - Explosives and detonators outside of magazines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Explosives and detonators outside of magazines. 75.1313 Section 75.1313 Mineral... Explosives and detonators outside of magazines. (a) The quantity of explosives outside a magazine for use in a working section or other...

  10. 30 CFR 75.1312 - Explosives and detonators in underground magazines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Explosives and detonators in underground magazines. 75.1312 Section 75.1312 Mineral...Explosives and detonators in underground magazines. (a) The quantity of explosives...kept in— (1) Separate, closed magazines at least 5 feet apart; or (2)...

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Explosives and detonators in underground magazines. 75.1312 Section 75.1312 Mineral...Explosives and detonators in underground magazines. (a) The quantity of explosives...kept in— (1) Separate, closed magazines at least 5 feet apart; or (2)...

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Explosives and detonators outside of magazines. 75.1313 Section 75.1313 Mineral... Explosives and detonators outside of magazines. (a) The quantity of explosives outside a magazine for use in a working section or other...

  13. 30 CFR 75.1328 - Damaged or deteriorated explosives and detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Damaged or deteriorated explosives and detonators. 75.1328 Section...STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1328 Damaged or deteriorated explosives and detonators. (a) Damaged...

  14. 30 CFR 75.1328 - Damaged or deteriorated explosives and detonators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Damaged or deteriorated explosives and detonators. 75.1328 Section...STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1328 Damaged or deteriorated explosives and detonators. (a) Damaged...

  15. 30 CFR 75.1328 - Damaged or deteriorated explosives and detonators.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Damaged or deteriorated explosives and detonators. 75.1328 Section...STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1328 Damaged or deteriorated explosives and detonators. (a) Damaged...

  16. 49 CFR 178.318 - Specification MC 201; container for detonators and percussion caps.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...false Specification MC 201; container for detonators and percussion caps. 178.318 Section 178.318 Transportation Other Regulations...318 Specification MC 201; container for detonators and percussion...

  17. 49 CFR 178.318 - Specification MC 201; container for detonators and percussion caps.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...false Specification MC 201; container for detonators and percussion caps. 178.318 Section 178.318 Transportation Other Regulations...318 Specification MC 201; container for detonators and percussion...

  18. Introduction: Perspectives on Detonation-Based Propulsion DOI: 10.2514/1.26953

    E-print Network

    . These rapid speeds are attained because the major mechanism of energy transport in a detonation is acoustic detonations has been expended in the allied field of reactive solids, with application mainly to weapons

  19. Phenomenon of Gamma-Ray Bursts as Relativistic Detonation of Scalar Fields

    E-print Network

    V. Folomeev; V. Gurovich; R. Usupov

    2000-08-22

    In the modern Universe the existence of various forms of scalar fields is supposed. On the one hand these fields can explain recently discovered positive $\\Lambda$-term(see e.g. Ref. \\cite{ref:Sahni}), on the other hand its form cluster systems creating gravitational wells for galaxies and their clusters. At that a natural hypothesis is the existence of compact configurations ("stars") from scalar fields with a large enough energy density and total mass. The hypothesis is that the energy of these fields can be converted in relativistic plasma by an explosive way. Such process can be initiated by collision of relativistic particles which form a relativistic microscopic fireball. Thus effective temperature can amount to value sufficient for change of phase for scalar fields. Then the wave of relativistic "detonation" similar to the same process in classical physics will be spread from this source. In this paper the parameters of such field star and process of detonation are estimated. If the effect of the indicated change of phase (or something similar to one) exists, it is possible to get the parameters of relativistic plasma (macroscopic fireball) which could generate gamma - bursts. If in the modern Universe there is such unique form of a matter as fields of high density it would be strange for Nature not to take advantage of the possibility to convert their energy to radiation by an explosive way.

  20. 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.

  1. 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.

  2. 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.

  3. Nonideal detonation and initiation behavior of a composite solid rocket propellant. [HMX/AP/Al

    SciTech Connect

    Dick, J.J.

    1981-01-01

    Shock initiation and detonation behavior of an HMX/AP/Al rocket propellant were studied for nonideal character. Low detonation velocities and unusual shock initiation behavior were observed. Failure to propagate steady detonation in cylinders of the propellant was also noted.

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

    DOEpatents

    Stroud, John R. (Livermore, CA); Ornellas, Donald L. (Livermore, CA)

    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).

  5. Space-time correlations and the Taylor hypothesis behind forced detonations

    E-print Network

    Texas at Arlington, University of

    and manifests itself with a shift of the ellipsis towards the shock front. I. Introduction Rotating detonationSpace-time correlations and the Taylor hypothesis behind forced detonations Luca Massa and Monika between the intrinsic motion of detonation and convected disturbance is analyzed computationally by both

  6. American Institute of Aeronautics and Astronautics Development of a Compact Liquid Fueled Pulsed Detonation

    E-print Network

    Texas at Arlington, University of

    Detonation Engine with Predetonator Philip K. Panicker* Aerodynamic Research Center (ARC), University engine rpm = rotations per minute * Graduate Research Associate, Department of Mechanical and Aerospace) = cell width CJ = cell width of CJ detonation I. Introduction ulsed detonation engines can offer better

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

    Microsoft Academic Search

    Aaron J. Glaser

    2007-01-01

    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

  8. Calcium-rich gap transients: tidal detonations of white dwarfs?

    NASA Astrophysics Data System (ADS)

    Sell, P. H.; Maccarone, T. J.; Kotak, R.; Knigge, C.; Sand, D. J.

    2015-07-01

    We hypothesize that at least some of the recently discovered class of calcium-rich gap transients are tidal detonation events of white dwarfs (WDs) by black holes (BHs) or possibly neutron stars. We show that the properties of the calcium-rich gap transients agree well with the predictions of the tidal detonation model. Under the predictions of this model, we use a follow-up X-ray observation of one of these transients, SN 2012hn, to place weak upper limits on the detonator mass of this system that include all intermediate-mass BHs (IMBHs). As these transients are preferentially in the stellar haloes of galaxies, we discuss the possibility that these transients are tidal detonations of WDs caused by random flyby encounters with IMBHs in dwarf galaxies or globular clusters. This possibility has been already suggested in the literature but without connection to the calcium-rich gap transients. In order for the random flyby cross-section to be high enough, these events would have to be occurring inside these dense stellar associations. However, there is a lack of evidence for IMBHs in these systems, and recent observations have ruled out all but the very faintest dwarf galaxies and globular clusters for a few of these transients. Another possibility is that these are tidal detonations caused by three-body interactions, where a WD is perturbed towards the detonator in isolated multiple star systems. We highlight a number of ways this could occur, even in lower mass systems with stellar-mass BHs or neutron stars. Finally, we outline several new observational tests of this scenario, which are feasible with current instrumentation.

  9. Structure cellulaire de la détonation des mélanges H2 NO2/N2O4Cellular structure of the detonation of gaseous mixtures H2 NO2/N2O4

    NASA Astrophysics Data System (ADS)

    Joubert, Franckie; Desbordes, Daniel; Presles, Henri-Noël

    2003-05-01

    Calculations of the detonation reaction zone of gaseous reactive mixtures of NO 2/N 2O 4 as oxidizer and H 2, CH 4 or C 2H 6 as fuel, in the range of equivalence ratio ? between 0.5 and 2, show that, for ??1, the chemical energy is released in two distinct and successive exothermic steps with different chemical induction times. The first exothermic stage is mainly due to the reaction NO 2+H?NO+OH, NO being the main oxidizer of the second one. The experimental study conducted on the same range of equivalence ratio (0.5? ??2) shows that, for ??1, the detonation wave of these mixtures contains a double set of cellular structures. A similar result had already been obtained with the detonation of gaseous Nitromethane, the NO 2 group being here included in the molecule. Consequently, the oxidizer NO 2 being either initially separated from the fuel or included inside the molecule of a monopropellant (Nitromethane) is responsible, because of its specific chemical kinetics, of a chemical energy release in two main steps and of the existence of a double cellular structure in the detonation wave for the same range of equivalence ratio. These results reinforce the assumption that the cellular structure of the detonation finds its origin in the strong rates of chemical energy release inside the reaction zone. To cite this article: F. Joubert et al., C. R. Mecanique 331 (2003).

  10. Strategies for understanding the deflagration-to-detonation transition

    SciTech Connect

    Asay, B.W.

    1992-01-01

    The deflagration-to-detonation (DDT) phenomenon has been studied for many years. However, no comprehensive model of the DDT process is available. It is important to understand the mechanism by which an explosive will detonate when the source of ignition is a weak shock or flame, and to able to predict this response. We have identified several key areas of the DDT problem which need to be understood before any such prediction can be made, and have established a modest program to obtain a more fundamental understanding of the behavior of explosive under the conditions that can lead to DDT.

  11. Strategies for understanding the deflagration-to-detonation transition

    SciTech Connect

    Asay, B.W.

    1992-05-01

    The deflagration-to-detonation (DDT) phenomenon has been studied for many years. However, no comprehensive model of the DDT process is available. It is important to understand the mechanism by which an explosive will detonate when the source of ignition is a weak shock or flame, and to able to predict this response. We have identified several key areas of the DDT problem which need to be understood before any such prediction can be made, and have established a modest program to obtain a more fundamental understanding of the behavior of explosive under the conditions that can lead to DDT.

  12. 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.

  13. 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

  14. Indirect detonation initiation using acoustic timescale thermal power deposition

    NASA Astrophysics Data System (ADS)

    Regele, J. D.; Kassoy, D. R.; Vezolainen, A.; Vasilyev, O. V.

    2013-09-01

    A fluid dynamics video is presented that demonstrates an indirect detonation initiation process. In this process, a transient power deposition adds heat to a spatially resolved volume of fluid in an amount of time that is similar to the acoustic timescale of the fluid volume. A highly resolved two-dimensional simulation shows the events that unfold after the heat is added.

  15. A study of detonation processes in heterogeneous high explosives

    Microsoft Academic Search

    Pier K. Tang

    1988-01-01

    A model of multiple processes is used to simulate the behavior of reaction in detonation of heterogeneous high explosives. The features of the model are (1) the partition of the explosive medium into hot spots and the region exclusive of hot spots and (2) the separation of the mechanical-thermal process and chemical process. For each process, a characteristic time is

  16. Shock-Fitted Numerical Solutions for Two-Dimensional Detonations

    E-print Network

    Shock-Fitted Numerical Solutions for Two-Dimensional Detonations with Periodic Boundary Conditions Combustion Granada, Spain Los Alamos National Laboratory University of Notre Dame April 23, 2006 Shock Motivation & Background General Formulation Shock-Fitted Transformation Numerical Method 1-D Limiting Case

  17. Dimensional analysis of impulse loading resulting from detonation

    E-print Network

    Grujicic, Mica

    . Design/methodology/approach ­ In the present work, a critical assessment is carried out of some for the problem of impulse loading experienced by target structures (e.g. vehicle hull) due to detonation products takes place). Once the dimensional analysis is reformulated, a variety of experimental results

  18. Temperature-based model for condensed-phase explosive detonation

    NASA Astrophysics Data System (ADS)

    Desbiens, Nicolas; Matignon, Christophe; Sorin, Remy; Dubois, Vincent

    2013-06-01

    Simple reactive flow models for condensed explosives have four requirements: two equations of state (EOS), one for the unreacted condensed-phase explosive, and one for its detonation products, a reaction rate law that converts the explosive in products and a mixture rule to compute the biphasic partially reacted states. Generally, the chemical reaction rates are governed by local temperature. Nonetheless, temperature fields are scarcely known, especially in detonating condensed-phase explosives. Hence this quantity is not provided by the usual unreacted explosive EOS with the required accuracy. As a consequence, for shock initiation and detonation phenomena, rate laws are based on easily measurable properties such as pressure, compression or particle velocity. In this work, we build an EOS for a TATB-based explosive that provides a better estimate of the shocked explosive temperature. This EOS is derived from ab initio simulation results of monocristalline TATB. Then the well-known pressure-based WSD reaction rate law is rewritten to be temperature-dependent. This model is expected to give interesting results as regards shock desensitization and initial conditions variations while remaining very accurate for detonation propagation. Preliminary results will be shown.

  19. Modified detonation macrokinetics model of a tatb-based explosive

    Microsoft Academic Search

    Yu. A. Aminov; A. V. Vershinin; N. S. Es’kov; O. V. Kostitsyn; G. N. Rykovanov; V. A. Sibilev; M. A. Strizhenok

    1997-01-01

    A one-stage detonation macrokinetics model of a low-sensitivity heterogeneous explosive is considered. Within the framework\\u000a of the model, we have managed to describe uniformly a wide class of experiments on initiation of aTATB-based plasticized explosive, including the initiation from the impact by a metallic plate and compact metallic fragments.

  20. The Nuclear Detonation Detection System on the GPS satellites

    SciTech Connect

    Higbie, P.R. [Los Alamos National Lab., NM (United States); Blocker, N.K. [Sandia National Labs., Albuquerque, NM (United States)

    1993-07-27

    This article begins with a historical perspective of satellite usage in monitoring nuclear detonations. Current capabilities of the 24 GPS satellites in detecting the light, gamma rays, x-rays and neutrons from a nuclear explosion are described. In particular, an optical radiometer developed at Sandia National Laboratories is characterized. Operational information and calibration procedures are emphasized.

  1. 6. BUILDING NO. 232, ORDNANCE FACILITY (DETONATOR LOADING), LOOKING SOUTHEAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. BUILDING NO. 232, ORDNANCE FACILITY (DETONATOR LOADING), LOOKING SOUTHEAST AT STRUCTURE AND BLAST BARRICADES. BUILDING NO. 232-C VISIBLE BEHIND BARRICADE AT LEFT. - Picatinny Arsenal, 200 Area, Shell Component Loading, State Route 15 near I-80, Dover, Morris County, NJ

  2. Numerical Investigation of Rotating Detonation Engine Propulsive Performance

    Microsoft Academic Search

    Ye-Tao Shao; Meng Liu; Jian-Ping Wang

    2010-01-01

    A series of 3- and 2-dimensional numerical simulations of a rotating detonation engine (RDE) are carried out with a 1-step chemical reaction model to investigate the RDE's propulsive performance. First, the performance is computed by a 3-dimensional simulation. After the initial instability dies down, the specific impulse and mass flux of RDE converge to constant values. Then, some simplified 2-dimensional

  3. HIGH EXPLOSIVE EQUIVALENCE FOR UNDERGROUND DETONATION OF OPERATION PLUMBBOB

    Microsoft Academic Search

    O. K. Ehlers; F. A. Pieper; A. C. Tiemann

    1960-01-01

    Results are reported from a test to determine the percent of high ; explosive (HE) energy equivalence of the RANIER shot of Operation PLUMBBOB. ; Determination was made by duplicating strong motion measurements of RANIER for a ; relatively small-scale HE detonation under carefully controlled conditions. The ; principal strong motion measurements made included acceleration, pressure, and ; strain. All

  4. Detonation Engine Performance Comparison Using First and Second Law Analyses

    E-print Network

    Texas at Arlington, University of

    Entrance blockage factor CJ Chapman-Jouguet property d Diameter cp Constant pressure heat capacity f Fuel/air ratio hP R Fuel heating value Isp Specific impulse L Detonation tube length M Mach number mp Fuel mass S Entropy Sa Stream thrust function T Temperature V Velocity Graduate Research Associate, Aerodynamics

  5. Calcium-Rich Gap Transients: Tidal Detonations of White Dwarfs?

    E-print Network

    Sell, P H; Kotak, R; Knigge, C; Sand, D J

    2015-01-01

    We hypothesize that at least some of the recently discovered class of calcium-rich gap transients are tidal detonation events of white dwarfs (WDs) by black holes (BHs) or possibly neutron stars. We show that the properties of the calcium-rich gap transients agree well with the predictions of the tidal detonation model. Under the predictions of this model, we use a follow-up X-ray observation of one of these transients, SN 2012hn, to place weak upper limits on the detonator mass of this system that include all intermediate-mass BHs (IMBHs). As these transients are preferentially in the stellar haloes of galaxies, we discuss the possibility that these transients are tidal detonations of WDs caused by random flyby encounters with IMBHs in dwarf galaxies or globular clusters. This possibility has been already suggested in the literature but without connection to the calcium-rich gap transients. In order for the random flyby cross-section to be high enough, these events would have to be occurring inside these den...

  6. On the development of Hydrogen-air detonations

    NASA Astrophysics Data System (ADS)

    Romick, Christopher; Aslam, Tariq; Powers, Joseph

    2013-11-01

    The development and propagation of Hydrogen-air detonations is examined. An initially quiescent stoichiometric mixture at 298 . 15 K and 1 atm is initialized using a hot spot similar in character to a spark. Several two-dimensional channel widths are examined to obtain greater insight into the effect that no-slip walls have on the formation process of the detonation. To model the phenomena, the compressive, reactive Navier-Stokes equations using detailed kinetics are used with multicomponent diffusion including Soret and DuFour effects. A chemical mechanism composed of 19 reversible reactions, containing 9 species and 3 elements is used for the kinetics model. The use of detailed kinetics gives rise to multiple length scales; to predict the full richness of the unsteady behavior of a detonation, all these scales must be resolved. Resolving the finest and larger scales is accomplished using the Wavelet Adaptive Multiresolution Representation (WAMR) technique. This adaptive mesh refinement technique has a high compression ratio of the number of points needed to accurately represent the flow versus an uniform grid. The time to the initial thermal explosion is examined for the various channel widths. Additionally, the long time sustainability of the detonation is studied.

  7. High-speed photomicrographic setup for slapper detonator flyer

    Microsoft Academic Search

    Congliang Tao

    1995-01-01

    A high speed photomicrography setup is described and some basic problems related are discussed, including visual field, distinguishability, time resolving power, working distance and two of most difficult ones, i.e. depth of field and luminary. An experimental optic glass acceleration bore is made, which can be used to determine the flyer velocity of slapper detonators, the shape of the exploding

  8. 30 CFR 57.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current tests, conducted as frequently as necessary, indicate a maximum stray current of less than 0.05 ampere through a 1-ohm resistor as measured at...

  9. 30 CFR 56.6402 - Deenergized circuits near detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...circuits need not be deenergized between 25 to 50 feet of the electric detonators if stray current tests, conducted as frequently as necessary, indicate a maximum stray current of less than 0.05 amperes through a 1-ohm resistor as measured at...

  10. Steady detonation problem for slow and fast chemical reactions

    E-print Network

    Ceragioli, Francesca

    Steady detonation problem for slow and fast chemical reactions F. Conforto1 , M. Groppi2 , R chemical reaction are discussed. The former consists in a system of balance laws for the case of a chemical is a system of conser- vation laws for the case of short chemical relaxation time (fast reaction). After

  11. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting...are transported using trolley locomotives— (i) Trips carrying explosives...shall be separated from the locomotives by at least one car that is...container of detonators and the mine roof or other...

  12. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting...are transported using trolley locomotives— (i) Trips carrying explosives...shall be separated from the locomotives by at least one car that is...container of detonators and the mine roof or other...

  13. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting...are transported using trolley locomotives— (i) Trips carrying explosives...shall be separated from the locomotives by at least one car that is...container of detonators and the mine roof or other...

  14. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting...are transported using trolley locomotives— (i) Trips carrying explosives...shall be separated from the locomotives by at least one car that is...container of detonators and the mine roof or other...

  15. 30 CFR 75.1311 - Transporting explosives and detonators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting...are transported using trolley locomotives— (i) Trips carrying explosives...shall be separated from the locomotives by at least one car that is...container of detonators and the mine roof or other...

  16. Explosive plane-wave lens

    DOEpatents

    Marsh, Stanley P. (Los Alamos, NM)

    1988-01-01

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive.

  17. A Mechanistic Study of Delayed Detonation in Impact Damaged Solid Rocket Propellant

    NASA Astrophysics Data System (ADS)

    Matheson, Erik R.; Rosenberg, J. Thomas

    2001-06-01

    One method of hazard assessment for mass detonable solid rocket propellants consists of impacting right circular cylinders of propellant end-on into thick steel witness plates at varying impact velocities. A detonation that occurs within one shock traversal of the cylinder length is termed a prompt detonation or a shock-to-detonation transition (SDT). At lower velocities, some propellants detonate at times later than one shock transit, typically 1-5 shock transits. Because no mechanism for delayed detonation has been fully confirmed and accepted by the detonation physics community, these lower velocity detonations are referred to as unknown-to-detonation transitions (XDTs). A leading theory, however, is that prior to detonation mechanically induced damage sensitizes the material through the formation of internal porosity which provides new mechanical reaction initiation sites (hot spots) and enhanced internal burn surface. To study this phenomenology, we have developed the Coupled Damage and Reaction (CDAR) model, implemented it in the CTH shock physics code, and simulated propellant impact experiments. The CDAR model fully couples viscoelastic-viscoplastic deformation, tensile damage, porosity evolution, compaction and associated reaction initiation, and grain burning to model the increased reactivity of the propellant. In this paper, CDAR predictions of the effect of impact velocity on XDT delay time are presented. Implications regarding mechanisms for XDT are discussed.

  18. A Mechanistic Study of Delayed Detonation in Impact Damaged Solid Rocket Propellant

    NASA Astrophysics Data System (ADS)

    Matheson, E. R.; Rosenberg, J. T.

    2002-07-01

    One method of hazard assessment for mass detonable solid rocket propellants consists of impacting right circular cylinders of propellant end-on into thick steel witness plates at varying impact velocities. A detonation that occurs within one shock traversal of the cylinder length is termed a prompt detonation or a shock-to-detonation transition (SDT). At lower velocities, some propellants detonate at times later than one shock transit, typically 1-5 shock transits. Because no mechanism for delayed detonation has been fully confirmed and accepted by the detonation physics community, these low-velocity detonations are referred to as unknown-to-detonation transitions (XDTs). A leading theory, however, is that prior to detonation mechanically induced damage sensitizes the material through the formation of internal porosity which provides new mechanical reaction initiation sites (hot spots) and enhanced internal burn surface. To study this phenomenology, we have developed the Coupled Damage and Reaction (CDAR) model, implemented it in the CTH shock physics code, and simulated propellant impact experiments. The CDAR model fully couples viscoelastic-viscoplastic deformation, tensile damage, porosity evolution, reaction initiation, and grain burning to model the increased reactivity of the propellant. In this paper, CDAR simulations of propellant damage in spall and Taylor impact tests are presented and compared to experiment. An XDT experiment is also simulated, and implications regarding damage mechanisms and hydrodynamic processes leading to XDT are discussed.

  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. PMID:16674994

  20. 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.