Equation of state for detonation product gases

NASA Astrophysics Data System (ADS)

Nagayama, Kunihito; Kubota, Shiro

2003-03-01

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

Diameter Effect In Initiating Explosives, Numerical Simulations

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

Lefrancois, A.; Benterou, J.; Roeske, F.

2006-02-10

The ability to safely machine small pieces of HE with the femtosecond laser allows diameter effect experiments to be performed in initiating explosives in order to study the failure diameter, the reduction of the detonation velocity and curvature versus the diameter. The reduced diameter configuration needs to be optimized, so that the detonation products of the first cylinder will not affect the measurement of the detonation velocity of the second cylinder with a streak camera. Different 2D axi-symmetrical configurations have been calculated to identify the best solution using the Ignition and Growth reactive flow model for LX16 Pellet with Ls-Dyna.

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.

Optimum performance of explosives in a quasistatic detonation cycle

NASA Astrophysics Data System (ADS)

Baker, Ernest L.; Stiel, Leonard I.

2017-01-01

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

Chemical Energy Release in Several Recently Discovered Detonation and Deflagration Flows

NASA Astrophysics Data System (ADS)

Tarver, Craig M.

2010-10-01

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

Eigenvalue Detonation of Combined Effects Aluminized Explosives

NASA Astrophysics Data System (ADS)

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

2007-12-01

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

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.

Detonation velocity in poorly mixed gas mixtures

NASA Astrophysics Data System (ADS)

Prokhorov, E. S.

2017-10-01

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

Subnanosecond measurements of detonation fronts in solid high explosives

NASA Astrophysics Data System (ADS)

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

1984-04-01

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

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

Jackson, Scott I.

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

Theory and Modeling of Liquid Explosive Detonation

NASA Astrophysics Data System (ADS)

Tarver, Craig M.; Urtiew, Paul A.

2010-10-01

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

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

DOE PAGES

Jackson, Scott I.

2016-11-17

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

Helium in double-detonation models of type Ia supernovae

NASA Astrophysics Data System (ADS)

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

2017-03-01

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

Detonation Characteristics of Plastic Explosives Based on Attractive Nitramines with Polyisobutylene and Poly(methyl methacrylate) Binders

NASA Astrophysics Data System (ADS)

Elbeih, Ahmed; Pachman, Jiri; Zeman, Svatopluk; Vávra, Pavel; Trzciński, Waldemar A.; Akštein, zbyněk

2012-10-01

Four highly brisant nitramines, RDX (1,3,5-trinitro-1,3,5-triazinane), HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane), BCHMX (cis-1,3,4,6-tetranitro-octahydroimidazo-[4,5-d]imidazole), and ɛ-HNIW (ɛ-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), were studied as extruded plastic explosives bonded by two plastic matrices based on polyisobutylene (C4 matrix) and poly-methylmethacrylate (plasticized by dioctyl-adipate) binders. The detonation velocities, D, were measured experimentally. Detonation parameters were also calculated by means of the Kamlet and Jacobs method and CHEETAH and EXPLO5 codes. These detonation parameters showed that plastic-bonded explosives (PBXs) based on BCHMX are more powerful explosives than those based on RDX. The Urizar coefficient for poly(methyl methacrylate) binder was also calculated.

Molecular simulations of Crussard curves of detonation product mixtures at chemical equilibrium: Microscopic calculation of the Chapman-Jouguet state

NASA Astrophysics Data System (ADS)

Bourasseau, Emeric; Dubois, Vincent; Desbiens, Nicolas; Maillet, Jean-Bernard

2007-06-01

The simultaneous use of the Reaction Ensemble Monte Carlo (ReMC) method and the Adaptative Erpenbeck EOS (AE-EOS) method allows us to calculate direclty the thermodynamical and chemical equilibrium of a mixture on the hugoniot curve. The ReMC method allow to reach chemical equilibrium of detonation products and the AE-EOS method constraints ths system to satisfy the Hugoniot relation. Once the Crussard curve of detonation products has been established, CJ state properties may be calculated. An additional NPT simulation is performed at CJ conditions in order to compute derivative thermodynamic quantities like Cp, Cv, Gruneisen gama, sound velocity, and compressibility factor. Several explosives has been studied, of which PETN, nitromethane, tetranitromethane, and hexanitroethane. In these first simulations, solid carbon is eventually treated using an EOS.

Reaction of Shocked but Undetonated HMX-Based Explosive

NASA Astrophysics Data System (ADS)

Taylor, P.; Salisbury, D. A.; Markland, L. S.; Winter, R. E.; Andrew, M. I.

2002-07-01

Cylindrical samples of the pressed plastic bonded HMX based explosive EDC37, backed by metal discs, were shocked through a stainless steel attenuator by an explosive donor. Reaction of the EDC37 sample was diagnosed with embedded PVDF pressure gauges and a distance to detonation for the geometry was determined. Sample length was then reduced to less than the observed detonation distance and laser interferometry was used to record the free surface velocity of the metal backing disc. The results provide data on the metal driving energy liberated by explosive which is shocked and reacting but not detonated. The results are compared with 2-D Eulerian calculations incorporating a 3-term ignition and growth reactive burn model with desensitisation. It is found that a parameter set for the reaction model which replicates the PVDF pressure profiles before reflection also gives good agreement to the metal disc velocity history at early times. The results show that an appreciable fraction of the metal driving potential of an explosive can be released without detonation being established.

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

NASA Astrophysics Data System (ADS)

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

2017-07-01

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

Determination of the effects of water adsorption on the sensitivity and detonation performance of the explosive JOB-9003 by molecular dynamics simulation.

PubMed

Hang, GuiYun; Yu, WenLi; Wang, Tao; Li, Zhen

2016-11-01

In order to determine the adsorption mechanism of water on the crystal surfaces of the explosive JOB-9003 and the effect of this adsorption on the sensitivity and detonation performance of this explosive, a model of the crystal of JOB-9003 was created in the software package Materials Studio (MS). The adsorption process was simulated, and molecular dynamics simulation was performed with the COMPASS force field in the NPT ensemble to calculate the sensitivity and detonation performance of the explosive. The results show that the maximum trigger bond length decreases whereas the interaction energy of the trigger bond and the cohesive energy density increase after adsorption, indicating that the sensitivity of JOB-9003 decreases. The results for the detonation performance show that the detonation pressure, detonation velocity, and detonation heat decrease upon the adsorption of water, thus illustrating that the detonation performance of JOB-9003 is degraded. In summary, the adsorption of water has a positive effect on the sensitivity and safety of the explosive JOB-9003 but a negative effect on its detonation performance.

Ignition and growth modeling of detonation reaction zone experiments on single crystals of PETN and HMX

NASA Astrophysics Data System (ADS)

White, Bradley W.; Tarver, Craig M.

2017-01-01

It has long been known that detonating single crystals of solid explosives have much larger failure diameters than those of heterogeneous charges of the same explosive pressed or cast to 98 - 99% theoretical maximum density (TMD). In 1957, Holland et al. demonstrated that PETN single crystals have failure diameters of about 8 mm, whereas heterogeneous PETN charges have failure diameters of less than 0.5 mm. Recently, Fedorov et al. quantitatively determined nanosecond time resolved detonation reaction zone profiles of single crystals of PETN and HMX by measuring the interface particle velocity histories of the detonating crystals and LiF windows using a PDV system. The measured reaction zone time durations for PETN and HMX single crystal detonations were approximately 100 and 260 nanoseconds, respectively. These experiments provided the necessary data to develop Ignition and Growth (I&G) reactive flow model parameters for the single crystal detonation reaction zones. Using these parameters, the calculated unconfined failure diameter of a PETN single crystal was 7.5 +/- 0.5 mm, close to the 8 mm experimental value. The calculated failure diameter of an unconfined HMX single crystal was 15 +/- 1 mm. The unconfined failure diameter of an HMX single crystal has not yet been determined precisely, but Fedorov et al. detonated 14 mm diameter crystals confined by detonating a HMX-based plastic bonded explosive (PBX) without initially overdriving the HMX crystals.

The effect of detonation wave incidence angle on the acceleration of flyers by explosives heavily laden with inert additives

NASA Astrophysics Data System (ADS)

Loiseau, Jason; Georges, William; Frost, David L.; Higgins, Andrew J.

2017-01-01

The incidence angle of a detonation wave in a conventional high explosive influences the acceleration and terminal velocity of a metal flyer by increasing the magnitude of the material velocity imparted by the transmitted shock wave as the detonation is tilted towards normal loading. For non-ideal explosives heavily loaded with inert additives, the detonation velocity is typically subsonic relative to the flyer sound speed, leading to shockless accelerations when the detonation is grazing. Further, in a grazing detonation the particles are initially accelerated in the direction of the detonation and only gain velocity normal to the initial orientation of the flyer at later times due to aerodynamic drag as the detonation products expand. If the detonation wave in a non-ideal explosive instead strikes the flyer at normal incidence, a shock is transmitted into the flyer and the first interaction between the particle additives and the flyer occurs due to the imparted material velocity from the passage of the detonation wave. Consequently, the effect of incidence angle and additive properties may play a more prominent role in the flyer acceleration. In the present study we experimentally compared normal detonation loadings to grazing loadings using a 3-mm-thick aluminum slapper to impact-initiate a planar detonation wave in non-ideal explosive-particle admixtures, which subsequently accelerated a second 6.4-mm-thick flyer. Flyer acceleration was measured with heterodyne laser velocimetry (PDV). The explosive mixtures considered were packed beds of glass or steel particles of varying sizes saturated with sensitized nitromethane, and gelled nitromethane mixed with glass microballoons. Results showed that the primary parameter controlling changes in flyer velocity was the presence of a transmitted shock, with additive density and particle size playing only secondary roles. These results are similar to the grazing detonation experiments, however under normal loading the largest, higher density particles yielded the highest terminal flyer velocity, whereas in the grazing experiments the larger, low density particles yielded the highest terminal velocity.

Structure of the detonation wave front in a mixture of nitromethane with acetone

NASA Astrophysics Data System (ADS)

Buravova, S. N.

2012-09-01

It is shown that the leading front of an inhomogeneous detonation wave is a shock wave in which wave structures of the type of triple shock configurations are moving. It was experimentally found that the reaction in these inhomogeneities occurs in oblique shock waves. The reaction sites at the wave front are ring-shaped. In a 75: 25 mixture of nitromethane with acetone, up to 70% of the front surface is occupied by the reaction at the sites in the wave front. Measurements of the mass velocity profile indicate that afterburning takes place in the unloading area behind the Jouguet plane. Calculations of the heat release in the reaction mixture with a decrease in the mass velocity indicate that the material that have not reacted in the inhomogeneities can be ignited in the induction zone. It is suggested that the adiabatic flashes are a mechanism that generates inhomogeneities in the detonation wave front.

Features of the incorporation of single and double based powders within emulsion explosives

NASA Astrophysics Data System (ADS)

Ribeiro, J. B.; Mendes, R.; Tavares, B.; Louro, C.

2014-05-01

In this work, features of the thermal and detonation behaviour of compositions resulting from the mixture of single and double based powders within ammonium nitrate based emulsion explosives are shown. Those features are portrayed through results of thermodynamic-equilibrium calculations of the detonation velocity, the chemical compatibility assessment through differential thermal analysis [DTA] and thermo gravimetric analysis [TGA], the experimental determination of the detonation velocity and a comparative evaluation of the shock sensitivity using a modified version of the "gap-test". DTA/TGA results for the compositions and for the individual components overlap until the beginning of the thermal decomposition which is an indication of the absence of formation of any new chemical species and so of the compatibility of the components of the compositions. After the beginning of the thermal decomposition it can be seen that the rate of mass loss is much higher for the compositions with powder than for the one with sole emulsion explosive. Both, theoretical and experimental, values of the detonation velocity have been shown to be higher for the powdered compositions than for the sole emulsion explosive. Shock sensitivity assessments have ended-up with a slightly bigger sensitivity for the compositions with double based powder when compared to the single based compositions or to the sole emulsion.

Features of the Valorization of Single and Double Based Powders for Codetonation in Emulsion Explosives

NASA Astrophysics Data System (ADS)

Ribeiro, Jose; Mendes, Ricardo; Tavares, Bruno; Louro, Cristina

2013-06-01

In this work, features of the thermal and detonation behavior of compositions resulting from the mixture of single and double based gun powder within ammonium nitrate (AN) based emulsion explosives are shown. That includes results of thermodynamic-equilibrium calculations of the detonation velocity, the chemical compatibility assessment through differential scanning calorimetry [DSC] and thermo gravimetric analysis [TGA], the experimental determination of the detonation velocity and a comparative evaluation of the shock sensitivity using a modified version of the ``gap-test''. DSC/TGA results for the compositions and for the individual components overlap until the beginning of the thermal decomposition which is an indication of the absence of formation of any new chemical specimens and so of the capability of the composition components. After the beginning of the thermal decomposition it can be seen that the rate of mass loss is much higher for the compositions with gun powder than for the sole emulsion explosive. Both, theoretical and experimental, values of the detonation velocity have shown to be higher for the powdered compositions than for the pure emulsion explosive. Shock sensitivity assessment have ended-up with a slightly bigger sensitivity for the compositions with double based gun powder when compared to the single based compositions or to the pure emulsion.

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

NASA Astrophysics Data System (ADS)

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

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

Formic Acid Investigation for the Prediction of High Explosive Detonation Properties and Performance

DTIC Science & Technology

2010-07-01

determine constants of the Jones-Wilkins-Lee ( JWL ) and Jones-Wilkins-Lee- Baker (JWLB) thermodynamic equations of state for hydrocode calculations by the...empirical JWL relationships for a number of explosives. Similarly, calculated cylinder velocities at 7 area expansions were within 1% of

Age Life Evaluation of Space Shuttle Crew Escape System Pyrotechnic Components Loaded with Hexanitrostilbene (HNS)

NASA Technical Reports Server (NTRS)

Hoffman, William C., III

1996-01-01

Determining deterioration characteristics of the Space Shuttle crew escape system pyrotechnic components loaded with hexanitrostilbene would enable us to establish a hardware life-limit for these items, so we could better plan our equipment use and, possibly, extend the useful life of the hardware. We subjected components to accelerated-age environments to determine degradation characteristics and established a hardware life-limit based upon observed and calculated trends. We extracted samples using manufacturing lots currently installed in the Space Shuttle crew escape system and from other NASA programs. Hardware included in the study consisted of various forms and ages of mild detonating fuse, linear shaped charge, and flexible confined detonating cord. The hardware types were segregated into 5 groups. One was subjected to detonation velocity testing for a baseline. Two were first subjected to prolonged 155 F heat exposure, and the other two were first subjected to 255 F, before undergoing detonation velocity testing and/or chromatography analysis. Test results showed no measurable changes in performance to allow a prediction of an end of life given the storage and elevated temperature environments the hardware experiences. Given the lack of a definitive performance trend, coupled with previous tests on post-flight Space Shuttle hardware showing no significant changes in chemical purity or detonation velocity, we recommend a safe increase in the useful life of the hardware to 20 years, from the current maximum limits of 10 and 15 years, depending on the hardware.

Phase velocity enhancement of linear explosive shock tubes

NASA Astrophysics Data System (ADS)

Loiseau, Jason; Serge, Matthew; Szirti, Daniel; Higgins, Andrew; Tanguay, Vincent

2011-06-01

Strong, high density shocks can be generated by sequentially detonating a hollow cylinder of explosives surrounding a thin-walled, pressurized tube. Implosion of the tube results in a pinch that travels at the detonation velocity of the explosive and acts like a piston to drive a shock into the gas ahead of it. In order to increase the maximum shock velocities that can be obtained, a phase velocity generator can be used to drag an oblique detonation wave along the gas tube at a velocity much higher than the base detonation velocity of the explosive. Since yielding and failure of the gas tube is the primary limitation of these devices, it is desirable to retain the dynamic confinement effects of a heavy-walled tamper without interfering with operation of the phase velocity generator. This was accomplished by cutting a slit into the tamper and introducing a phased detonation wave such that it asymmetrically wraps around the gas tube. This type of configuration has been previously experimentally verified to produce very strong shocks but the post-shock pressure and shock velocity limits have not been investigated. This study measured the shock trajectory for various fill pressures and phase velocities to ascertain the limiting effects of tube yield, detonation obliquity and pinch aspect ratio.

Measuring In-Situ Mdf Velocity Of Detonation

DOEpatents

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

2005-10-25

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

Near-limit propagation of gaseous detonations in narrow annular channels

NASA Astrophysics Data System (ADS)

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

2017-03-01

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

3-nitro-1,2,4-triazol-5-one: A less sensitive explosive

DOEpatents

Lee, Kien-Yin; Coburn, M.D.

1987-01-30

A less sensitive explosive, 3-nitro-1,2,4-triazol-5-one. The compound 3-nitro--1,2,4-triazol-5-one (NTO) has a crystal density of 1.93 g/cm/sup 3/ and calculated detonation velocity and pressure equivalent to those of RDX. It can be prepared in high yield from inexpensive starting materials in a safe synthesis. Results from initial small-scale sensitivity tests indicate that NTO is less sensitive than RDX and HMX in all respects. A 4.13 cm diameter, unconfined plate-dent test at 92% of crystal density gave the detonation pressure predicted for NTO by the BKW calculation. 3 tabs.

3-nitro-1,2,4-triazol-5-one, a less sensitive explosive

DOEpatents

Lee, Kien-Yin; Coburn, Michael D.

1988-01-01

A less sensitive explosive, 3-nitro-1,2,4-triazol-5-one. The compound 3-nitro-1,2,4-triazol-5-one (NTO) has a crystal density of 1.93 g/cm.sup.3 and calculated detonation velocity and pressure equivalent to those of RDX. It can be prepared in high yield from inexpensive starting materials in a safe synthesis. Results from initial small-scale sensitivity tests indicate that NTO is less sensitive than RDX and HMX in all respects. A 4.13 cm diameter, unconfined plate-dent test at 92% of crystal density gave the detonation pressure predicted for NTO by the BKW calculation.

Shock and Static Compression of Nitrobenzene

NASA Astrophysics Data System (ADS)

Kozu, Naoshi; Arai, Mitsuru; Tamura, Masamitsu; Fujihisa, Hiroshi; Aoki, Katsutoshi; Yoshida, Masatake

2000-08-01

The Hugoniot and static compression curve (isotherm) were investigated using explosive plane wave generators and diamond anvil cells, respectively. The obtained Hugoniot from the shock experiments is represented by two linear lines: Us=2.52+1.23 up (0.8

Equation of State for Detonation Product Gases

NASA Astrophysics Data System (ADS)

Nagayama, Kunihito; Kubota, Shiro

2013-06-01

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

Investigation of detonation velocity in heterogeneous explosive system using the reactive Burgers' analog

NASA Astrophysics Data System (ADS)

Di Labbio, G.; Kiyanda, C. B.; Mi, X.; Higgins, A. J.; Nikiforakis, N.; Ng, H. D.

2016-06-01

In this study, the applicability of the Chapman-Jouguet (CJ) criterion is tested numerically for heterogeneous explosive media using a simple detonation analog. The analog system consists of a reactive Burgers' equation coupled with an Arrhenius type reaction wave, and the heterogeneity of the explosive media is mimicked using a discrete energy source approach. The governing equation is solved using a second order, finite-volume approach and the average propagation velocity of the discrete detonation is determined by tracking the leading shock front. Consistent with previous studies, the averaged velocity of the leading shock front from the unsteady numerical simulations is also found to be in good agreement with the velocity of a CJ detonation in a uniform medium wherein the energy source is spatially homogenized. These simulations have thus implications for whether the CJ criterion is valid to predict the detonation velocity in heterogeneous explosive media.

Theoretical Study on Vibrational Spectra, Detonation Properties and Pyrolysis Mechanism for Cyclic 2-Diazo-4,6-dinitrophenol

NASA Astrophysics Data System (ADS)

Li, Xiao-hong; Yin, Geng-xin; Zhang, Xian-zhou

2012-10-01

Based on the full optimized molecular geometrical structures at the DFT-B3LYP/6-311+G** level, there exists intramolecular hydrogen bond interaction for cyclic 2-diazo-4,6-dinitrophenol. The assigned infrared spectrum is obtained and used to compute the thermodynamic properties. The results show that there are four main characteristic regions in the calculated IR spectra of the title compound. The detonation velocities and pressures are also evaluated by using Kamlet-Jacobs equations based on the calculated density and condensed phase heat of formation. Thermal stability and the pyrolysis mechanism of 2-diazo-4,6-dinitrophenol are investigated by calculating the bond dissociation energies at the B3LYP/6-311+G** level.

Prediction of the explosion effect of aluminized explosives

NASA Astrophysics Data System (ADS)

Zhang, Qi; Xiang, Cong; Liang, HuiMin

2013-05-01

We present an approach to predict the explosion load for aluminized explosives using a numerical calculation. A code to calculate the species of detonation products of high energy ingredients and those of the secondary reaction of aluminum and the detonation products, velocity of detonation, pressure, temperature and JWL parameters of aluminized explosives has been developed in this study. Through numerical calculations carried out with this code, the predicted JWL parameters for aluminized explosives have been compared with those measured by the cylinder test. The predicted JWL parameters with this code agree with those measured by the cylinder test. Furthermore, the load of explosion for the aluminized explosive was calculated using the numerical simulation by using the JWL equation of state. The loads of explosion for the aluminized explosive obtained using the predicted JWL parameters have been compared with those using the measured JWL parameters. Both of them are almost the same. The numerical results using the predicted JWL parameters show that the explosion air shock wave is the strongest when the mass fraction of aluminum powder in the explosive mixtures is 30%. This result agrees with the empirical data.

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

NASA Astrophysics Data System (ADS)

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

2009-06-01

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

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

NASA Astrophysics Data System (ADS)

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

2009-12-01

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

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.

Modeling a Material's Instantaneous Velocity during Acceleration Driven by a Detonation's Gas-Push Process

NASA Astrophysics Data System (ADS)

Backofen, Joseph E.

2005-07-01

This paper will describe both the scientific findings and the model developed in order to quantfy a material's instantaneous velocity versus position, time, or the expansion ratio of an explosive's gaseous products while its gas pressure is accelerating the material. The formula derived to represent this gas-push process for the 2nd stage of the BRIGS Two-Step Detonation Propulsion Model was found to fit very well the published experimental data available for twenty explosives. When the formula's two key parameters (the ratio Vinitial / Vfinal and ExpansionRatioFinal) were adjusted slightly from the average values describing closely many explosives to values representing measured data for a particular explosive, the formula's representation of that explosive's gas-push process was improved. The time derivative of the velocity formula representing acceleration and/or pressure compares favorably to Jones-Wilkins-Lee equation-of-state model calculations performed using published JWL parameters.

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

PubMed

Gottfried, Jennifer L; Bukowski, Eric J

2017-01-20

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

Precursor detonation wave development in ANFO due to aluminum confinement

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

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

2010-01-01

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

An Experimental study of Corner Turning in a Granular Ammonium Nitrate Based Explosive

NASA Astrophysics Data System (ADS)

Sorber, Susan; Taylor, Peter

2007-06-01

A novel experimental geometry has been designed to perform controlled studies of corner turning in a ``tap density'' granular explosive. It enables the study of corner turning and detonation properties with high speed framing camera, piezo probes and ionization probes. The basic geometry consists of a large diameter PMMA cylinder filled with the granular explosive which is initiated on axis from below by a smaller diameter cylinder of the same explosive or a booster charge. Four experiments have been performed on a granular Ammonium Nitrate based non ideal explosive (NIE). Two experiments were initiated directly from a PE4 booster charge and two were initiated from a train including a booster charge and a 1'' diameter Copper cylinder containing the same NIE. Data from the four experiments was reproducible and observed detonation and shock waves showed good 2-D symmetry. Detonation phase velocity on the vertical side of the main container was observed and both shock and detonation velocities were observed in the corner turning region along the base of the main container. Analysis of the data shows that the booster initiated geometries with a higher input shock pressure into the NIE gave earlier detonation arrival at the lowest probes on the container side. The corner turning data is compared to a hydrocode calculation using a simple JWL++ reactive burn model.

An Experimental Study of Corner Turning in a Granular Ammonium Nitrate Based Explosive

NASA Astrophysics Data System (ADS)

Sorber, S.; Taylor, P.; Burns, M.

2007-12-01

A novel experimental geometry has been designed to perform controlled studies of corner turning in a "tap density" granular explosive. It enables the study of corner turning and detonation properties with high speed framing camera, piezo probes and ionisation probes. The basic geometry consists of a large diameter PMMA cylinder filled with the granular explosive and is initiated on axis from below by a smaller diameter cylinder of granular explosive or a booster charge. Four experiments were performed on a granular Ammonium Nitrate based non-ideal explosive (NIE). Two experiments were initiated directly with the PE4 booster and two were initiated from a train including a booster charge and a 1″ diameter copper cylinder containing the same NIE. Experimental data from the four experiments was reproducible and the observed detonation and shock waves showed good 2-D symmetry. Detonation phase velocity on the vertical side of the main container was observed and both shock and detonation velocities were observed in the corner turning region along the base of the main container. Analysis of the data shows that the booster-initiated geometries with a higher input shock pressure into the granular explosive gave earlier detonation arrival at the lowest probes on the container side. The corner turning data is compared to a hydrocode calculation using a simple JWL++ reactive burn model.

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

NASA Astrophysics Data System (ADS)

Gottfried, Jennifer; Bukowski, Eric

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

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

PubMed

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

2014-03-01

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

Eigenvalue Detonation of Combined Effects Aluminized Explosives

NASA Astrophysics Data System (ADS)

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

2007-06-01

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

Detonation properties of the nitromethane/ diethylenetriamine solution

NASA Astrophysics Data System (ADS)

Mochalova, Valentina; Utkin, Alexander; Lapin, Sergey

2015-06-01

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

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

NASA Astrophysics Data System (ADS)

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

2007-12-01

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

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

NASA Astrophysics Data System (ADS)

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

2007-06-01

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

Critical velocities for deflagration and detonation triggered by voids in a REBO high explosive

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

Herring, Stuart Davis; Germann, Timothy C; Jensen, Niels G

2010-01-01

The effects of circular voids on the shock sensitivity of a two-dimensional model high explosive crystal are considered. We simulate a piston impact using molecular dynamics simulations with a Reactive Empirical Bond Order (REBO) model potential for a sub-micron, sub-ns exothermic reaction in a diatomic molecular solid. The probability of initiating chemical reactions is found to rise more suddenly with increasing piston velocity for larger voids that collapse more deterministically. A void with radius as small as 10 nm reduces the minimum initiating velocity by a factor of 4. The transition at larger velocities to detonation is studied in amore » micron-long sample with a single void (and its periodic images). The reaction yield during the shock traversal increases rapidly with velocity, then becomes a prompt, reliable detonation. A void of radius 2.5 nm reduces the critical velocity by 10% from the perfect crystal. A Pop plot of the time-to-detonation at higher velocities shows a characteristic pressure dependence.« less

A velocity probe-based method for continuous detonation and shock measurement in near-field underwater explosion.

PubMed

Li, Kebin; Li, Xiaojie; Yan, Honghao; Wang, Xiaohong; Miao, Yusong

2017-12-01

A new velocity probe which permits recording the time history of detonation and shock waves has been developed by improving the commercial on principle and structure. A method based on the probe is then designed to measure the detonation velocity and near-field shock parameters in a single underwater explosion, by which the oblique shock wave front of cylindrical charges and the peak pressure attenuation curve of spherical explosive are obtained. A further derivation of detonation pressure, adiabatic exponent, and other shock parameters is conducted. The present method offers a novel and reliable parameter determination for near-field underwater explosion.

A velocity probe-based method for continuous detonation and shock measurement in near-field underwater explosion

NASA Astrophysics Data System (ADS)

Li, Kebin; Li, Xiaojie; Yan, Honghao; Wang, Xiaohong; Miao, Yusong

2017-12-01

A new velocity probe which permits recording the time history of detonation and shock waves has been developed by improving the commercial on principle and structure. A method based on the probe is then designed to measure the detonation velocity and near-field shock parameters in a single underwater explosion, by which the oblique shock wave front of cylindrical charges and the peak pressure attenuation curve of spherical explosive are obtained. A further derivation of detonation pressure, adiabatic exponent, and other shock parameters is conducted. The present method offers a novel and reliable parameter determination for near-field underwater explosion.

Detonation properties of nitromethane/diethylenetriamine solution

NASA Astrophysics Data System (ADS)

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

2017-01-01

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

Detonation mode and frequency analysis under high loss conditions for stoichiometric propane-oxygen

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

Jackson, Scott I.; Lee, Bok Jik; Shepherd, Joseph E.

In this paper, the propagation characteristics of galloping detonations were quantified with a high-time-resolution velocity diagnostic. Combustion waves were initiated in 30-m lengths of 4.1-mm inner diameter transparent tubing filled with stoichiometric propane–oxygen mixtures. Chemiluminescence from the resulting waves was imaged to determine the luminous wave front position and velocity every 83.3 μ. As the mixture initial pressure was decreased from 20 to 7 kPa, the wave was observed to become increasingly unsteady and transition from steady detonation to a galloping detonation. While wave velocities averaged over the full tube length smoothly decreased with initial pressure down to half ofmore » the Chapman–Jouguet detonation velocity (D CJ) at the quenching limit, the actual propagation mechanism was seen to be a galloping wave with a cycle period of approximately 1.0 ms, corresponding to a cycle length of 1.3–2.0 m or 317–488 tube diameters depending on the average wave speed. The long test section length of 7300 tube diameters allowed observation of up to 20 galloping cycles, allowing for statistical analysis of the wave dynamics. In the galloping regime, a bimodal velocity distribution was observed with peaks centered near 0.4 D CJ and 0.95 D CJ. Decreasing initial pressure increasingly favored the low velocity mode. Galloping frequencies ranged from 0.8 to 1.0 kHz and were insensitive to initial mixture pressure. Wave deflagration-to-detonation transition and detonation failure trajectories were found to be repeatable in a given test and also across different initial mixture pressures. The temporal duration of wave dwell at the low and high velocity modes during galloping was also quantified. It was found that the mean wave dwell duration in the low velocity mode was a weak function of initial mixture pressure, while the mean dwell time in the high velocity mode depended exponentially on initial mixture pressure. Analysis of the velocity histories using dynamical systems ideas demonstrated trajectories that varied from stable to limit cycles to aperiodic motion with decreasing initial pressure. Finally, the results indicate that galloping detonation is a persistent phenomenon at long tube lengths.« less

Detonation mode and frequency analysis under high loss conditions for stoichiometric propane-oxygen

DOE PAGES

Jackson, Scott I.; Lee, Bok Jik; Shepherd, Joseph E.

2016-03-24

In this paper, the propagation characteristics of galloping detonations were quantified with a high-time-resolution velocity diagnostic. Combustion waves were initiated in 30-m lengths of 4.1-mm inner diameter transparent tubing filled with stoichiometric propane–oxygen mixtures. Chemiluminescence from the resulting waves was imaged to determine the luminous wave front position and velocity every 83.3 μ. As the mixture initial pressure was decreased from 20 to 7 kPa, the wave was observed to become increasingly unsteady and transition from steady detonation to a galloping detonation. While wave velocities averaged over the full tube length smoothly decreased with initial pressure down to half ofmore » the Chapman–Jouguet detonation velocity (D CJ) at the quenching limit, the actual propagation mechanism was seen to be a galloping wave with a cycle period of approximately 1.0 ms, corresponding to a cycle length of 1.3–2.0 m or 317–488 tube diameters depending on the average wave speed. The long test section length of 7300 tube diameters allowed observation of up to 20 galloping cycles, allowing for statistical analysis of the wave dynamics. In the galloping regime, a bimodal velocity distribution was observed with peaks centered near 0.4 D CJ and 0.95 D CJ. Decreasing initial pressure increasingly favored the low velocity mode. Galloping frequencies ranged from 0.8 to 1.0 kHz and were insensitive to initial mixture pressure. Wave deflagration-to-detonation transition and detonation failure trajectories were found to be repeatable in a given test and also across different initial mixture pressures. The temporal duration of wave dwell at the low and high velocity modes during galloping was also quantified. It was found that the mean wave dwell duration in the low velocity mode was a weak function of initial mixture pressure, while the mean dwell time in the high velocity mode depended exponentially on initial mixture pressure. Analysis of the velocity histories using dynamical systems ideas demonstrated trajectories that varied from stable to limit cycles to aperiodic motion with decreasing initial pressure. Finally, the results indicate that galloping detonation is a persistent phenomenon at long tube lengths.« less

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

DOE PAGES

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

2017-12-04

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

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

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

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

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

On the theory of the propagation of detonation in gaseous systems

NASA Technical Reports Server (NTRS)

Zeldovich, Y B

1950-01-01

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

Computational assessment of several hydrogen-free high energy compounds.

PubMed

Tan, Bisheng; Huang, Ming; Long, Xinping; Li, Jinshan; Fan, Guijuan

2016-01-01

Tetrazino-tetrazine-tetraoxide (TTTO) is an attractive high energy compound, but unfortunately, it is not yet experimentally synthesized so far. Isomerization of TTTO leads to its five isomers, bond-separation energies were empolyed to compare the global stability of six compounds, it is found that isomer 1 has the highest bond-separation energy (1204.6kJ/mol), compared with TTTO (1151.2kJ/mol); thermodynamic properties of six compounds were theoretically calculated, including standard formation enthalpies (solid and gaseous), standard fusion enthalpies, standard vaporation enthalpies, standard sublimation enthalpies, lattice energies and normal melting points, normal boiling points; their detonation performances were also computed, including detonation heat (Q, cal/g), detonation velocity (D, km/s), detonation pressure (P, GPa) and impact sensitivity (h50, cm), compared with TTTO (Q=1311.01J/g, D=9.228km/s, P=40.556GPa, h50=12.7cm), isomer 5 exhibites better detonation performances (Q=1523.74J/g, D=9.389km/s, P=41.329GPa, h50= 28.4cm). Copyright © 2015 Elsevier Inc. All rights reserved.

Theoretical studies on the crystal structure, thermodynamic properties, detonation performance and thermal stability of cage-tetranitrotetraazabicyclooctane as a novel high energy density compound.

PubMed

Zhao, Guo-zheng; Lu, Ming

2013-01-01

The B3LYP/6-31G (d) method of density functional theory (DFT) was used to study molecular geometry, electronic structure, infrared spectrum (IR) and thermodynamic properties. The heat of formation (HOF) and calculated density were estimated to evaluate the detonation properties using Kamlet-Jacobs equations. Thermal stability of 3,5,7,10,12,14,15,16-octanitro- 3,5,7,10,12,14,15,16-octaaza-heptacyclo[7.5.1.1(2,8).0(1,11).0(2,6).0(4,13).0(6,11)]hexadecane (cage-tetranitrotetraazabicyclooctane) was investigated by calculating the bond dissociation energy (BDE) at unrestricted B3LYP/6-31G (d) level. The calculated results show that the N-NO2 bond is a trigger bond during thermolysis initiation process. The crystal structure obtained by molecular mechanics (MM) methods belongs to Pna2(1) space group, with cell parameters a=12.840 Å, b=9.129 Å, c=14.346 Å, Z=6 and ρ=2.292 g·cm(-3). Both the detonation velocity of 9.96 km·s(-1) and the detonation pressure of 47.47 GPa are better than those of CL-20. According to the quantitative standard of energetics and stability, as a high energy density compound (HEDC), cage-tetranitrotetraazabicyclooctane essentially satisfies this requirement.

Theoretical insights into the stabilities, detonation performance, and electrostatic potentials of cocrystals containing α- or β-HMX and TATB, FOX-7, NTO, or DMF in various molar ratios.

PubMed

Song, Ken-Peng; Ren, Fu-de; Zhang, Shu-Hai; Shi, Wen-Jing

2016-10-01

A molecular dynamics method was employed to study the binding energies associated with the cocrystallization (at selected crystal planes) of either 1,3,5-triamino-2,4,6-trinitro-benzene (TATB), 1,1-diamino-2,2-dinitroethylene, 3-nitro-1,2,4-triazol-5-one (TATB, FOX-7, and NTO, respectively, all of which are explosives), or N,N-dimethylformamide (DMF, a nonenergetic solvent) in various molar ratios with 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane in its α and β conformations (α-HMX and β-HMX, respectively). The results showed that the cocrystals with low molar ratios (2:1, 1:1, 1:2, and 1:3) were the most stable. The binding energies of HMX/NTO and HMX/DMF were larger than those of HMX/TATB and HMX/FOX-7. According to the calculated stabilities, HMX prefers to adopt its α form in HMX/TATB and its β form in HMX/NTO, whereas the two forms coexist in HMX/FOX-7. For HMX/TATB, HMX/NTO, and α-HMX/FOX-7, increasing the proportion of the cocrystal component with the highest detonation heat (HMX in the first two cases, FOX-7 in the latter) increases the detonation heat, velocity, and pressure of the cocrystal. However, increasing the proportion of the component with the highest detonation heat in β-HMX/FOX-7 and γ-CL-20/FOX-7 increases the detonation heat of the cocrystal but decreases its detonation velocity. An investigation of the surface electrostatic potential revealed how the sensitivity changes upon cocrystal formation. Graphical Abstract Surface electrostatic potential of HMX/TATB.

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

NASA Astrophysics Data System (ADS)

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

2017-06-01

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

A technique for generating shear waves in cylindrical shells under radial impact

NASA Technical Reports Server (NTRS)

Blum, A.; Mortimer, R. W.; Rose, J. L.

1974-01-01

Experimental techniques are developed to study and measure the shear-wave velocity in an aluminum cylindrical shell subjected to a radial impact. The radial impact is obtained by exploding an electrical detonator inserted in plastic plugs mounted on the end of the shell. Strain gages, mounted on the outside surface of the shell at various axial locations, are used to obtain oscilloscope traces from which the shear-wave velocity can be calculated.

Influence of propane additives on the detonation characteristics of H2-air mixtures

NASA Astrophysics Data System (ADS)

Cheng, Guanbing; Bauer, Pascal; Zitoun, Ratiba

2014-03-01

Hydrogen is more and more considered as a potential fuel for propulsion applications. However, due to its low ignition energy and wide flammability limits, H2-air mixtures raise a concern in terms of safety. This aspect can be partly solved by adding an alkane to these mixtures, which plays the role of an inhibitor. The present paper provides data on such binary fuel-air mixtures where various amounts of propane are added to hydrogen. The behavior of the corresponding mixtures, in terms of detonation characteristics and other fundamental properties, such as the cell size of the detonation front and induction delay, are presented and discussed for a series of equivalence ratios and propane addition. The experimental detonation velocity is in good agreement with calculated theoretical Chapman-Jouguet values. Based on soot tracks records, the cell size λ is measured, whereas the induction length L i is derived from data using a GRI-Mech kinetic mechanism. These data allow providing a value of the coefficient K = λ/L i .

Conjugation in multi-tetrazole derivatives: a new design direction for energetic materials.

PubMed

Sun, Shuyang; Lu, Ming

2018-06-23

Multi-tetrazole derivatives with conjugated structures were designed and investigated in this study. Using quantum chemistry methods, the crystal structures, electrostatic potentials (ESPs), multicenter bond orders, HOMO-LUMO energy gaps, and detonation properties of the derivatives were calculated. As expected, these molecules with conjugated structures showed low energies of their crystal structures, molecular layering in their crystals, high average ESPs, high multicenter bond order values, and enhanced detonation properties. The derivative 1,2-di(1H-tetrazol-5-yl)diazene (N2) was predicted to have the best density (1.87 g/cm 3 ), detonation velocity (9006 m/s), and detonation pressure (36.8 GPa) of the designed molecules, while its total crystal energy was low, suggesting that it is relatively stable. Its sensitivity was also low, as the molecular stacking that occurs in its crystal allows external forces to be dissipated into movements of crystal layers. Finally, its multicenter bond order was high, indicating a highly conjugated structure.

Characterizing detonator output using dynamic witness plates

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

Murphy, Michael John; Adrian, Ronald J

2009-01-01

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

Molecular simulations of Hugoniots of detonation product mixtures at chemical equilibrium: Microscopic calculation of the Chapman-Jouguet state

NASA Astrophysics Data System (ADS)

Bourasseau, Emeric; Dubois, Vincent; Desbiens, Nicolas; Maillet, Jean-Bernard

2007-08-01

In this work, we used simultaneously the reaction ensemble Monte Carlo (ReMC) method and the adaptive Erpenbeck equation of state (AE-EOS) method to directly calculate the thermodynamic and chemical equilibria of mixtures of detonation products on the Hugoniot curve. The ReMC method [W. R. Smith and B. Triska, J. Chem. Phys. 100, 3019 (1994)] allows us to reach the chemical equilibrium of a reacting mixture, and the AE-EOS method [J. J. Erpenbeck, Phys. Rev. A 46, 6406 (1992)] constrains the system to satisfy the Hugoniot relation. Once the Hugoniot curve of the detonation product mixture is established, the Chapman-Jouguet (CJ) state of the explosive can be determined. A NPT simulation at PCJ and TCJ is then performed in order to calculate direct thermodynamic properties and the following derivative properties of the system using a fluctuation method: calorific capacities, sound velocity, and Grüneisen coefficient. As the chemical composition fluctuates, and the number of particles is not necessarily constant in this ensemble, a fluctuation formula has been developed to take into account the fluctuations of mole number and composition. This type of calculation has been applied to several usual energetic materials: nitromethane, tetranitromethane, hexanitroethane, PETN, and RDX.

Molecular simulations of Hugoniots of detonation product mixtures at chemical equilibrium: microscopic calculation of the Chapman-Jouguet state.

PubMed

Bourasseau, Emeric; Dubois, Vincent; Desbiens, Nicolas; Maillet, Jean-Bernard

2007-08-28

In this work, we used simultaneously the reaction ensemble Monte Carlo (ReMC) method and the adaptive Erpenbeck equation of state (AE-EOS) method to directly calculate the thermodynamic and chemical equilibria of mixtures of detonation products on the Hugoniot curve. The ReMC method [W. R. Smith and B. Triska, J. Chem. Phys. 100, 3019 (1994)] allows us to reach the chemical equilibrium of a reacting mixture, and the AE-EOS method [J. J. Erpenbeck, Phys. Rev. A 46, 6406 (1992)] constrains the system to satisfy the Hugoniot relation. Once the Hugoniot curve of the detonation product mixture is established, the Chapman-Jouguet (CJ) state of the explosive can be determined. A NPT simulation at P(CJ) and T(CJ) is then performed in order to calculate direct thermodynamic properties and the following derivative properties of the system using a fluctuation method: calorific capacities, sound velocity, and Gruneisen coefficient. As the chemical composition fluctuates, and the number of particles is not necessarily constant in this ensemble, a fluctuation formula has been developed to take into account the fluctuations of mole number and composition. This type of calculation has been applied to several usual energetic materials: nitromethane, tetranitromethane, hexanitroethane, PETN, and RDX.

Synthesis, characterization, and properties of peroxo-based oxygen-rich compounds for potential use as greener high energy density materials

NASA Astrophysics Data System (ADS)

Gamage, Nipuni-Dhanesha Horadugoda

One main aspect of high energy density material (HEDM) design is to obtain greener alternatives for HEDMs that produce toxic byproducts. Primary explosives lead azide, lead styphnate, and mercury fulminate contain heavy metals that cause heavy metal poisoning. Leaching of the widely used tertiary explosive NH4ClO4 into groundwater has resulted in human exposure to ClO4-- ions, which cause disruptions of thyroid related metabolic pathways and even thyroid cancer. Many research efforts to find replacements have gained little success. Thus, there is a need for greener HEDMs. Peroxo-based oxygen-rich compounds are proposed as a potential new class of greener HEDMs due to the evolution of CO2 and/or CO, H2O, and O 2 as the main decomposition products. Currently, triacetone triperoxide (TATP), diacetone diperoxide (DADP), hexamethylene triperoxide diamine (HMTD), and methyl ethyl ketone peroxide (MEKP) are the only well-studied highly energetic peroxides. However, due to their high impact and friction sensitivities, low thermal stabilities, and low detonation velocities they have not found any civil or military HEDM applications. In this dissertation research, we have synthesized and fully characterized four categories of peroxo-based compounds: tert-butyl peroxides, tert-butyl peroxy esters, hydroperoxides, and peroxy acids to perform a systematic study of their sensitivities and the energetic properties for potential use as greener HEDMs. tert-Butyl peroxides were not sensitive to impact, friction, or electrostatic spark. Hence, tert-butyl peroxides can be described as fairly safe peroxo-based compounds to handle. tert-Butyl peroxy esters were all surprisingly energetic (4896--6003 m/s), despite the low oxygen and nitrogen contents. Aromatic tert -butyl peroxy esters were much lower in impact and friction sensitivities with respect to the known peroxo-based explosives. These are among the first low sensitivity peroxo-based compounds that can be categorized as secondary HEDMs. Oxygen-rich (0.80--1.00) geminal hydroperoxides have detonation velocities in the range of 6150--7130 m/s. These impressive detonation velocities are greater than the detonation velocities of the known peroxo-based explosives. The highest detonation velocity (7130 m/s) was obtained for 1,4-bis(dihydroperoxymethyl)benzene, which has the highest crystalline density (1.648 g/cm3). This detonation velocity is greater than the secondary explosive 2,4,6-trinitrotoluene (TNT). The sensitivities of these oxygen-rich geminal hydroperoxides are lower than the known peroxo-based explosives due to the O--H•••O hydrogen bonds and O•••O contacts, which stabilize the weak O--O bonds in the crystalline lattice. They could be useful as primary HEDMs. Dihydroperoxy dioxane and dioxolanes have impressive detonation velocities in the range of 6350--6694 m/s. However, their extremely high sensitivities render them unsafe for HEDM applications. Interestingly, hydroperoxy dioxanol and dioxolanols also have high detonation velocities in the range of 6100--6461 m/s even with the lower oxygen contents. The hydroperoxy compounds with one less O--O bond were much less sensitive than the dihydroperoxy compounds. These hydroperoxy compounds could be useful as primary HEDMs. We observed that the ring strain was useful in increasing the detonation velocities, since it led to compounds with higher crystalline densities. However, increasing the steric strain using bulky groups led to lower crystalline densities and lower detonation velocities. Higher steric strain not only resulted in higher sensitivities but also lower thermal stabilities. Peroxy acids have high detonation velocities in the range of 5262--7885 m/s. The detonation velocity of 3,5-dinitrobenzoperoxoic acid (7217 m/s) was the highest detonation velocity obtained for the peroxo-based compounds synthesized in our study, which is greater than the detonation velocity of TNT. The detonation velocity of 2,4,6-trinitrobenzoperoxoic acid (7885 m/s) is close to the detonation velocity of the secondary high explosive 1,3,5-trinitroperhydro-1,3,5-triazine (RDX). Peroxy acids have surprisingly low impact and friction sensitivities that are well below the known peroxo-based explosives TATP, DADP, HMTD, and MEKP. Based on the crystal structure of 3,5-dinitrobenzoperoxoic acid, the low sensitivities can be attributed to the stabilization of the weak O--O bonds in the crystalline lattice by O--H•••O hydrogen bonds and O•••O short contacts. These are the first peroxo-based oxygen-rich compounds that can be useful as secondary HEDMs. The ease of synthesis in high yields with minimum synthetic manipulations, storability, and high thermal stabilities are all advantageous properties of peroxy acids for their use as HEDMs. Through this work, we have gained a wealth of fundamental information about the structures and energetic materials properties of a large family of peroxo-based compounds. Solid state intermolecular interactions were useful to understand the impact and friction sensitivities. The safe peroxy O:C ratio was found to be approximately 1.00. However, the oxygen contents could be further increased with more stable nitro and hydroxy groups. Highly attractive low sensitivity peroxo-based compounds were obtained with impressive detonation performances for potential use as greener primary and secondary HEDMs.

Dynamics of explosively imploded pressurized tubes

NASA Astrophysics Data System (ADS)

Szirti, Daniel; Loiseau, Jason; Higgins, Andrew; Tanguay, Vincent

2011-04-01

The detonation of an explosive layer surrounding a pressurized thin-walled tube causes the formation of a virtual piston that drives a precursor shock wave ahead of the detonation, generating very high temperatures and pressures in the gas contained within the tube. Such a device can be used as the driver for a high energy density shock tube or hypervelocity gas gun. The dynamics of the precursor shock wave were investigated for different tube sizes and initial fill pressures. Shock velocity and standoff distance were found to decrease with increasing fill pressure, mainly due to radial expansion of the tube. Adding a tamper can reduce this effect, but may increase jetting. A simple analytical model based on acoustic wave interactions was developed to calculate pump tube expansion and the resulting effect on the shock velocity and standoff distance. Results from this model agree quite well with experimental data.

Generalized Pseudo-Reaction Zone Model for Non-Ideal Explosives

NASA Astrophysics Data System (ADS)

Wescott, Bradley

2007-06-01

The pseudo-reaction zone model was proposed to improve engineering scale simulations when using Detonation Shock Dynamics with high explosives that have a slow reaction component. In this work an extension of the pseudo-reaction zone model is developed for non-ideal explosives that propagate well below their steady-planar Chapman-Jouguet velocity. A programmed burn method utilizing Detonation Shock Dynamics and a detonation velocity dependent pseudo-reaction rate has been developed for non-ideal explosives and applied to the explosive mixture of ammonium nitrate and fuel oil (ANFO). The pseudo-reaction rate is calibrated to the experimentally obtained normal detonation velocity---shock curvature relation. The generalized pseudo-reaction zone model proposed here predicts the cylinder expansion to within 1% by accounting for the slow reaction in ANFO.

Effect of Aluminium Confinement on ANFO Detonation

NASA Astrophysics Data System (ADS)

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

2013-06-01

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

Detonation propagation in a high loss configuration

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

Jackson, Scott I; Shepherd, Joseph E

2009-01-01

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

Using embedded fibers to measure explosive detonation velocities

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

Podsednik, Jason W.; Parks, Shawn Michael; Navarro, Rudolfo J.

2012-07-01

Single-mode fibers were cleverly embedded into fixtures holding nitromethane, and used in conjunction with a photonic Doppler velocimeter (PDV) to measure the associated detonation velocity. These measurements have aided us in our understanding of energetic materials and enhanced our diagnostic capabilities.

Superior Thermostability, Good Detonation Properties, Insensitivity, and the Effect on the Thermal Decomposition of Ammonium Perchlorate for a New Solvent-Free 3D Energetic PbII -MOF.

PubMed

Yang, Qi; Yang, Guoli; Zhang, Wendou; Zhang, Sheng; Yang, Zhaohui; Xie, Gang; Wei, Qing; Chen, Sanping; Gao, Shengli

2017-07-06

A new solvent-free energetic MOF, [Pb(HBTI)] n (1) (H 3 BTI=4,5-bis(1H-tetrazole)-1H-imidazole), has been synthesized under hydrothermal and acidic conditions. It was characterized by elemental analysis, IR, thermogravimetric, differential scanning calorimetry (DSC) and SEM. Single crystal X-ray diffraction analysis revealed that 1 features a rigid 3D framework architecture free of solvent molecules. Thermal analysis demonstrated that the thermostability of 1 was up to 325 °C. Non-isothermal kinetic and apparent thermodynamic parameters of exothermic decomposition process of 1 were determined by Kissinger's and Ozawa's methods. Through oxygen-bomb combustion calorimetry, the standard molar enthalpy of formation of 1 was determined. The calculated detonation properties (heat of detonation, detonation velocity and detonation pressure) and sensitivity tests of 1 were carried out. In addition, 1 was explored as combustion promoter to accelerate the thermal decompositions of ammonium perchlorate (AP) by differential scanning calorimetry. Experimental results indicated that 1 possesses potential application prospects in the field of explosives and propellants. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Shock Initiation of Secondary Explosives by MicroSlapper

NASA Astrophysics Data System (ADS)

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

2001-06-01

Using the well known Exploding Foil Initiator (EFI) also called slapper detonator the shock to Detonation Wave (DW) transition in a low dense secondary explosive like PETN and RDX is presented in this study. The EFI formed by a capacitor with capacity up to 0.2μF charged until 3kV was used to burst copper bridges with 0.3x0.3mm and 0.4x0.3mm with 5μm of thickness, and to accelerate Kapton flyer plates with 25μm of thickness until 5mm/μs. The process of Shock to Detonation Transition (SDT) in explosive samples with 5mm of diameter by 10mm of height was characterized by an optical method based on 64 optical fibbers ribbon (250mm of diameter each fibber) connected to a fast electronic streak camera. The obtained results, (x,t) diagrams, with 1ns resolution, show continuously the shock to detonation transition regime and allowed the evaluation of the detonation velocity and the detonation wave front curvature. In that regime DW propagation presents the oscillations in detonation velocity. The results also show the influence of the flyer plate velocity and the initial density of the explosive sample in the process of SDT and front oscillations.

Experimental Measurements of the Chemical Reaction Zone of Detonating Liquid Explosives

NASA Astrophysics Data System (ADS)

Bouyer, Viviane; Sheffield, Stephen A.; Dattelbaum, Dana M.; Gustavsen, Richard L.; Stahl, David B.; Doucet, Michel; Decaris, Lionel

2009-12-01

We have a joint project between CEA-DAM Le Ripault and Los Alamos National Laboratory (LANL) to study the chemical reaction zone in detonating high explosives using several different laser velocimetry techniques. The short temporal duration of the von Neumann spike and early part of the reaction zone make these measurements difficult. Here, we report results obtained from detonation experiments using VISAR (velocity interferometer system for any reflector) and PDV (photon Doppler velocimetry) methods to measure the particle velocity history at a detonating nitromethane/PMMA interface. Experiments done at CEA were high-explosive-plane-wave initiated and those at LANL were gas-gun-projectile initiated with a detonation run of about 6 charge diameters in all experiments. The experiments had either glass or brass confinement. Excellent agreement of the interface particle velocity measurements at both Laboratories were obtained even though the initiation methods and the velocimetry systems were somewhat different. Some differences were observed in the peak particle velocity because of the ˜2 ns time resolution of the techniques—in all cases the peak was lower than the expected von Neumann spike. This is thought to be because the measurements were not high enough time resolution to resolve the spike.

Predicting High Explosive Detonation Velocities from Their Composition and Structure

DTIC Science & Technology

1978-09-01

for a gamut of ideal explosives. The explosives ranged from nitroaromatics, cyclic and linear nitramines, nitrate esters and nitro-nitrato...structure is postulated for a gamut of explosives. Since detonation velocity, DQ, is density dependent, the linear regression plot. Figure 1, of the

Detonation initiation of heterogeneous melt-cast high explosives

NASA Astrophysics Data System (ADS)

Chuzeville, V.; Baudin, G.; Lefrançois, A.; Genetier, M.; Barbarin, Y.; Jacquet, L.; Lhopitault, J.-L.; Peix, J.; Boulanger, R.; Catoire, L.

2017-01-01

2,4,6-trinitrotoluene (TNT) is widely used in conventional and insensitive munitions as a fusible binder, commonly melt-cast with other explosives such as 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) or 3-nitro-1,2,4-triazol-one (NTO). In this paper, we study the shock-to-detonation transition phenomenon in two melt-cast high explosives (HE). We have performed plate impact tests on wedge samples to measure run-distance and time-to-detonation in order to establish the Pop-plot relation for several melt-cast HE. Highlighting the existence of the single curve buildup, we propose a two phase model based on a Zeldovich, Von-Neumann, Döring (ZND) approach where the deflagration fronts grow from the explosive grain boundaries. Knowing the grain size distribution, we calculate the deflagration velocities of the explosive charges as a function of shock pressure and explore the possible grain fragmentation.

Theoretical analysis of rotating two phase detonation in a rocket motor

NASA Technical Reports Server (NTRS)

Shen, I.; Adamson, T. C., Jr.

1973-01-01

Tangential mode, non-linear wave motion in a liquid propellant rocket engine is studied, using a two phase detonation wave as the reaction model. Because the detonation wave is followed immediately by expansion waves, due to the side relief in the axial direction, it is a Chapman-Jouguet wave. The strength of this wave, which may be characterized by the pressure ratio across the wave, as well as the wave speed and the local wave Mach number, are related to design parameters such as the contraction ratio, chamber speed of sound, chamber diameter, propellant injection density and velocity, and the specific heat ratio of the burned gases. In addition, the distribution of flow properties along the injector face can be computed. Numerical calculations show favorable comparison with experimental findings. Finally, the effects of drop size are discussed and a simple criterion is found to set the lower limit of validity of this strong wave analysis.

Systematic study of the reaction kinetics for HMX.

PubMed

Long, Yao; Chen, Jun

2015-05-07

The reaction process of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) in wide temperature and pressure ranges is simulated by molecular dynamics. A set of postprocessing programs is written to evaluate the intermediate molecules and chemical reactions. On the basis of these evaluations, the reaction rates, reactive Hugoniot curves, and detonation wave profile are calculated. The detonation velocity and detonation pressure are determined as 9984 m/s and 38.3349 GPa, in agreement with the experimental results, 9110 m/s and 39.5 GPa. The width of the reaction zone is 10 μm, and the main products are N2, H2O, and CO2. We find some molecules play an important role in intermediate reactions but are not exhibited in final products, such as N2O2, N2O5, and C3H3N3.

Measurement of Front Curvature and Detonation Velocity for a Nonideal Heterogeneous Explosive in Axisymmetric and Two-Dimensional Geometries

NASA Astrophysics Data System (ADS)

Higgins, Andrew

2009-06-01

Detonation in a heterogeneous explosive with a relatively sparse concentration of reaction centers (``hot spots'') is investigated experimentally. The explosive system considered is nitromethane gelled with PMMA and with glass microballoons (GMB's) in suspension. The detonation velocity is measured as a function of the characteristic charge dimension (diameter or thickness) in both axisymmetric and two-dimensional planar geometries. The use of a unique, annular charge geometry (with the diameter of the annulus much greater than the annular gap thickness) permits quasi-two-dimensional detonations to be observed without undesirable lateral rarefactions that result from a finite aspect ratio. The detonation front curvature is also measured directly using an electronic streak camera. The results confirm the prior findings of Gois et al. (1996) which showed that, for a low concentration of GMB's, detonation propagation does not exhibit the expected 2:1 scaling from axisymmetric to planar geometries. This reinforces the idea that detonation in highly nonideal explosives is not governed exclusively by front curvature.

Measurement of Detonation Velocity for a Nonideal Heterogeneous Explosive in Axisymmetric and Two-Dimensional Geometries

NASA Astrophysics Data System (ADS)

Higgins, Andrew

2009-12-01

Detonation in a heterogeneous explosive with a relatively sparse concentration of reaction centers ("hot spots") is investigated experimentally. The explosive system considered is nitromethane gelled with PMMA and with glass microballoons (GMB's) in suspension. The detonation velocity is measured as a function of the characteristic charge dimension (diameter or thickness) in both axisymmetric and two-dimensional geometries. The use of a unique, annular charge geometry (with the diameter of the annulus much greater than the annular gap thickness) permits quasi-two-dimensional detonations to be observed without undesirable lateral rarefactions that result from a finite aspect ratio. The results confirm the prior findings of Gois et al. (1996) which show that, for a low concentration of GMB's, detonation propagation does not exhibit the expected 2:1 scaling from axisymmetric to planar geometries. This reinforces the idea that detonation in highly nonideal explosives is not governed exclusively by global front curvature.

Magnetic Flux Compression Concept for Nuclear Pulse Propulsion and Power

NASA Technical Reports Server (NTRS)

Litchford, Ronald J.

2000-01-01

The desire for fast, efficient interplanetary transport requires propulsion systems having short acceleration times and very high specific impulse attributes. Unfortunately, most highly efficient propulsion systems which are within the capabilities of present day technologies are either very heavy or yield very low impulse such that the acceleration time to final velocity is too long to be of lasting interest, One exception, the nuclear thermal thruster, could achieve the desired acceleration but it would require inordinately large mass ratios to reach the range of desired final velocities. An alternative approach, among several competing concepts that are beyond our modern technical capabilities, is a pulsed thermonuclear device utilizing microfusion detonations. In this paper, we examine the feasibility of an innovative magnetic flux compression concept for utilizing microfusion detonations, assuming that such low yield nuclear bursts can be realized in practice. In this concept, a magnetic field is compressed between an expanding detonation driven diamagnetic plasma and a stationary structure formed from a high temperature superconductor (HTSC). In general, we are interested in accomplishing two important functions: (1) collimation of a hot diamagnetic plasma for direct thrust production; and (2) pulse power generation for dense plasma ignition. For the purposes of this research, it is assumed that rnicrofusion detonation technology may become available within a few decades, and that this approach could capitalize on recent advances in inertial confinement fusion ICF) technologies including magnetized target concepts and antimatter initiated nuclear detonations. The charged particle expansion velocity in these detonations can be on the order of 10 (exp 6)- 10 (exp 7) meters per second, and, if effectively collimated by a magnetic nozzle, can yield the Isp and the acceleration levels needed for practical interplanetary spaceflight. The ability to ignite pure fusion micro-bursts with reasonable levels of input energy is an equally challenging scientific problem. It remains to be seen, however, whether an effective ignition driver can be developed which meets the requirements for practical spaceflight application (namely high power density, compactness, low weight, and low cost). In this paper, system level performance and design issues are examined including generator performance, magnetic flux compression processes, magnetic diffusion processes, high temperature superconductor (HTSC) material properties, plasmadynamic processes, detonation plasma expansion processes, magnetohydrodynamic instabilities, magnetic nozzle performance, and thrust production performance. Representative generator performance calculations based on a simplified skin layer formulation are presented as well as the results of exploratory small-scale laboratory experiments on magnetic flux diffusion in HTSC materials. In addition, planned follow-on scientific feasibility experiments are described which utilize high explosive detonations and high energy gas discharges to simulate the plasma conditions associated with thermonuclear micro-detonations.

Synchro-ballistic recording of detonation phenomena

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

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

1997-09-01

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

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

PubMed

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

2008-09-15

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

Detonation of Meta-stable Clusters

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

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

2008-05-31

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

Synthesis, Characterization, Detonation Performance, and DFT Calculation of HMX/PNO Cocrystal Explosive

NASA Astrophysics Data System (ADS)

Lin, He; Chen, Jian-Fu; Zhu, Shun-Guan; Li, Hong-Zhen; Huang, Yong

2017-01-01

A novel 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX)/pyridine-N-oxide (PNO) cocrystal at 1:1 molar ratio was synthesized by a solvent evaporation method, and its crystal structure was determined using X-ray diffraction (XRD). It crystallizes in the orthorhombic system with the Pbcn space group and cell parameters a = 12.712(3)Å, b = 9.315(3)Å, c = 12.909(3)Å. In addition, detonation performance of this cocrystal was estimated. The predicted detonation velocity and detonation pressure of this cocrystal are 7.47 km/s and 23.20 GPa, respectively, suggesting that it is less powerful than β-HMX. Finally, density functional theory, involving binding energy, atoms in molecule (AIM) theory, natural bond orbital (NBO) analysis, band structure, and density of states, was adopted to characterize the driving forces for the formation of this cocrystal. The results show that driving forces are dominated by the interactions between O atoms of PNO and methylene groups of HMX. It is expected that this research provides some bases for further HMX cocrystal design and preparation.

Short pulse duration shock initiation experiments plus ignition and growth modeling on Composition B

NASA Astrophysics Data System (ADS)

May, Chadd M.; Tarver, Craig M.

2014-05-01

Composition B (63% RDX, 36% TNT, 1% wax) is still a widely used energetic material whose shock initiation characteristics are necessary to understand. It is now possible to shock initiate Composition B and other secondary explosives at diameters well below their characteristic failure diameters for unconfined self-sustaining detonation. This is done using very high velocity, very thin, small diameter flyer plates accelerated by electric or laser power sources. Recently experimental detonation versus failure to detonate threshold flyer velocity curves for Composition B using several KaptonTM flyer thicknesses and diameters were measured. Flyer plates with diameters of 2 mm successfully detonated Composition B, which has a nominal failure diameter of 4.3 mm. The shock pressures required for these initiations are greater than the Chapman-Jouguet (C-J) pressure in self-sustaining Composition B detonation waves. The initiation process is two-dimensional, because both rear and side rarefactions can affect the shocked Composition B reaction rates. The Ignition and Growth reactive flow model for Composition B is extended to yield accurate simulations of this new threshold velocity data for various flyer thicknesses.

Detonation suppression in hydrogen-air mixtures using porous coatings on the walls

NASA Astrophysics Data System (ADS)

Bivol, G. Yu.; Golovastov, S. V.; Golub, V. V.

2018-05-01

We considered the problem of detonation suppression and weakening of blast wave effects occurring during the combustion of hydrogen-air mixtures in confined spaces. The gasdynamic processes during combustion of hydrogen, an alternative environmentally friendly fuel, were also considered. Detonation decay and flame propagation in hydrogen-air mixtures were experimentally investigated in rectangular cross-section channels with solid walls and two types of porous coatings: steel wool and polyurethane foam. Shock wave pressure dynamics inside the section with porous coating were studied using pressure sensors; flame front propagation was studied using photodiodes and high-speed camera visualization. For all mixtures, the detonation wave formed before entering the section with porous coating. For both porous materials, the steady detonation wave decoupled in the porous section of the channel into a shock wave and flame front propagating with a velocity around the Chapman-Jouguet acoustic velocity. By the end of the porous section, shock wave pressure reductions of 70 and 85% were achieved for the polyurethane foam and steel wool, respectively. The dependence of the flame velocity on the mixture composition (equivalence ratio) is presented.

Using time-frequency analysis to determine time-resolved detonation velocity with microwave interferometry.

PubMed

Kittell, David E; Mares, Jesus O; Son, Steven F

2015-04-01

Two time-frequency analysis methods based on the short-time Fourier transform (STFT) and continuous wavelet transform (CWT) were used to determine time-resolved detonation velocities with microwave interferometry (MI). The results were directly compared to well-established analysis techniques consisting of a peak-picking routine as well as a phase unwrapping method (i.e., quadrature analysis). The comparison is conducted on experimental data consisting of transient detonation phenomena observed in triaminotrinitrobenzene and ammonium nitrate-urea explosives, representing high and low quality MI signals, respectively. Time-frequency analysis proved much more capable of extracting useful and highly resolved velocity information from low quality signals than the phase unwrapping and peak-picking methods. Additionally, control of the time-frequency methods is mainly constrained to a single parameter which allows for a highly unbiased analysis method to extract velocity information. In contrast, the phase unwrapping technique introduces user based variability while the peak-picking technique does not achieve a highly resolved velocity result. Both STFT and CWT methods are proposed as improved additions to the analysis methods applied to MI detonation experiments, and may be useful in similar applications.

Dynamics of an Overdriven Nitromethane Initiation System

NASA Astrophysics Data System (ADS)

Hároz, E. H.; Rae, P. J.; Armstrong, C. L.; Baca, E. V.; Campbell, C.; Gunderson, J. A.; Holmes, M.; Lopez-Pulliam, I.; Vaughan, L. D.; Dickson, P. M.

2017-06-01

For upcoming large-scale HE experiments, an initiation system is needed to ensure uniform and simultaneous burn. To that end, we developed an initiation system based on nitromethane. Initial, small-scale tests characterized the response of the nitromethane in the proposed cylindrical initiator geometry, indicating robust detonation under a variety of conditions such as a plane wave lenses & cylinders of PBX 9501 into a flyer plate or direct-drive. Detonation velocity, as measured by piezoelectric pin time-of-arrival measurements along the length and at bottom of vessel, shows an overdriven response. All cases show a detonation velocity faster than the literature value of 7.3 km s-1 for nitromethane, with the fastest velocity occurring for the 8-detonator, 8'' cylinder case with a velocity = 7.7 km s-1. Streak camera imaging characterized the curvature of the shock front as it arrived at the bottom of the vessel via spark gap. A final test of the initiator system looked at the expansion of the initiator vessel walls via PDV, showing velocities up to 3.5 km s-1. Finally, our initiator was placed inside a secondary vessel containing 1000 lbs of nitromethane. High-speed photography & pin data indicate complete symmetrical burn of the secondary nitromethane.

Detonation re-initiation in a concentric tube arrangement for C_2H_2/O_2/Ar mixtures

NASA Astrophysics Data System (ADS)

Wu, Y.; Lee, J. H. S.; Weng, C.

2017-05-01

Re-initiation of detonation in a concentric tube arrangement where a detonation exiting from a small diameter inner tube to a large diameter outer tube has been investigated. The outer tube diameter D is 50.8 mm and inner tube diameters d are 38, 25.4, and 12.7 mm giving diameter ratios D/d=1.34, 2, and 4. Stoichiometric C_2H_2-O_2 mixtures with argon dilution of 0, 25, 50, and 70% are used in the present study. Velocity measurements are made using photodiodes, and smoked foils downstream of the exit of the inner tube are also used to record the re-initiation process. Upon exit from the inner tube, the detonation suffers an abrupt decrease in velocity and at critical conditions, the velocity downstream of the exit is of the order of 50% of the Chapman-Jouguet velocity. It is found that re-initiation generally occurs within 10 tube diameters downstream of the exit. If re-initiation is not successful, the detonation continues to propagate at a low velocity for distances of the order of 30 tube diameters without any indication of flame acceleration of deflagration-to-detonation transition (DDT). Thus, the re-initiation process is clearly defined and distinct from the usual DDT in a smooth tube. The critical d/λ value ratio in the concentric tube is significantly lower than the usual unconfined case of d/λ =13 where λ is the detonation cell size. Thus, it is a result of re-initiation at the Mach stem of the reflected shock from the wall of the outer concentric tube. If re-initiation is not successful upon the first reflection, then subsequent multiple reflections at the tube axis and wall of the outer tube can also result in re-initiation. However, this is only observed for undiluted mixtures. For high-argon-diluted mixtures, re-initiation only occurs at the Mach stem of the first reflection.

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

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

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

2010-01-01

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

Properties of Deflagration Fronts and Models for Type IA Supernovae

NASA Astrophysics Data System (ADS)

Domínguez, I.; Höflich, P.

2000-01-01

Detailed models of the explosion of a white dwarf that include self-consistent calculations of the light curve and spectra provide a link between observational quantities and the underlying explosion model. These calculations assume spherical geometry and are based on parameterized descriptions of the burning front. Recently, the first multidimensional calculations for nuclear burning fronts have been performed. Although a fully consistent treatment of the burning fronts is beyond the current state of the art, these calculations provide a new and better understanding of the physics. Several new descriptions for flame propagation have been proposed by Khokhlov et al. and Niemeyer et al. Using various descriptions for the propagation of a nuclear deflagration front, we have studied the influence on the results of previous analyses of Type Ia supernovae, namely, the nucleosynthesis and structure of the expanding envelope. Our calculations are based on a set of delayed detonation models with parameters that give a good account of the optical and infrared light curves and of the spectral evolution. In this scenario, the burning front first propagates in a deflagration mode and subsequently turns into a detonation. The explosions and light curves are calculated using a one-dimensional Lagrangian radiation-hydro code including a detailed nuclear network. We find that the results of the explosion are rather insensitive to details of the description of the deflagration front, even if its speed and the time from the transition to detonation differ almost by a factor of 2. For a given white dwarf (WD) and a fixed transition density, the total production of elements changes by less than 10%, and the distribution in the velocity space changes by less than 7%. Qualitatively, this insensitivity of the final outcome of the explosion to the details of the flame propagation during the (slow) deflagration phase can be understood as follows: for plausible variations in the speed of the turbulent deflagration, the duration of this phase is several times longer than the sound crossing time in the initial WD. Therefore, the energy produced during the early nuclear burning can be redistributed over the entire WD, causing a slow preexpansion. In this intermediate state, the WD is still bound but its binding energy is reduced by the amount of nuclear energy. The expansion ratio depends mainly on the total amount of burning during the deflagration phase. Consequently, the conditions are very similar under which nuclear burning takes place during the subsequent detonation phase. In our example, the density and temperature at the burning front changes by less than 3%, and the expansion velocity changes by less than 10%. The burning conditions are very close to previous calculations which used a constant deflagration velocity. Based on a comparison with observations, those required low deflagration speeds (~2%-3% of the speed of sound). Exceptions to the similarity are the innermost layers of ~0.03-0.05 Msolar. Still, nuclear burning is in nuclear statistical equilibrium, but the rate of electron capture is larger for the new descriptions of the flame propagation. Consequently, the production of very neutron-rich isotopes is increased. In our example, close to the center Ye is about 0.44, compared to 0.46 in the model with constant deflagration speed. This increases the 48Ca production by more than a factor of 100 to 3.E-6 Msolar. Conclusions from previous analyses of light curves and spectra on the properties of the WD and the explosions will not change, and even with the new descriptions, the delayed detonation scenario is consistent with the observations. Namely, the central density results with respect to the chemical structure of the progenitor and the transition density from deflagration to detonation do not change. The reason for this similarity is the fact that the total amount of burning during the long deflagration phase determines the restructuring of the WD prior to the detonation. Therefore, we do not expect that the precise, microphysical prescription for the speed of a subsonic burning front has a significant effect on the outcome. However, at the current level of uncertainties for the burning front, the relation between properties of the burning front and of the initial white dwarf cannot be obtained from a comparison between observation and theoretical predictions by one-dimensional models. Multidimensional calculations are needed (1) to get inside the relations between model parameters such as central density and properties of the deflagration front and its relation to the transition density between deflagration and detonation and (2) to make use of information on asphericity that is provided by polarization measurements. These questions are essential to test, estimate, and predict some of the evolutionary effects of SNe Ia and their use as cosmological yardsticks.

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

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

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

1987-06-01

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

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.

Propagation of gaseous detonation waves in a spatially inhomogeneous reactive medium

NASA Astrophysics Data System (ADS)

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

2017-05-01

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

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

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

Tong Huifeng; Yuan Hong; Tang Zhiping

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 whichmore » 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.« less

Formation mechanisms and characteristics of transition patterns in oblique detonations

NASA Astrophysics Data System (ADS)

Miao, Shikun; Zhou, Jin; Liu, Shijie; Cai, Xiaodong

2018-01-01

The transition structures of wedge-induced oblique detonation waves (ODWs) in high-enthalpy supersonic combustible mixtures are studied with two-dimensional reactive Euler simulations based on the open-source program AMROC (Adaptive Mesh Refinement in Object-oriented C++). The formation mechanisms of different transition patterns are investigated through theoretical analysis and numerical simulations. Results show that transition patterns of ODWs depend on the pressure ratio Pd/Ps, (Pd, Ps are the pressure behind the ODW and the pressure behind the induced shock, respectively). When Pd/Ps > 1.3, an abrupt transition occurs, while when Pd/Ps < 1.3, a smooth transition appears. A parameter ε is introduced to describe the transition patterns quantitatively. Besides, a criterion based on the velocity ratio Φ=U0/UCJ is proposed to predict the transition patterns based on the inflow conditions. It is concluded that an abrupt transition appears when Φ < 0.98Φ*, while a smooth transition occurs when Φ > 1.02Φ∗ (Φ∗ is the critical velocity ratio calculated with an empirical formula).

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

NASA Astrophysics Data System (ADS)

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

2007-12-01

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

Detonation Shock Dynamics Calibration for Non-Ideal HE: ANFO

NASA Astrophysics Data System (ADS)

Short, Mark; Salyer, Terry

2009-06-01

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

Dynamics of High Sound-Speed Metal Confiners Driven By Non-Ideal High-Explosive Detonation

DOE PAGES

Short, Mark; Jackson, Scott I.

2015-01-23

Here, the results of 14 tests examining the behavior of aluminum (Al) conifners driven by non-ideal ANFO detonation in a cylinder test configuration are presented. In each test, the measured detonation phase velocity is slower than the aluminum sound speed. Thus, in the detonation reference frame, the ow in the Al is both shockless and subsonic. The tests involve: 3-inch inner diameter (ID) cylinders with Al wall thicknesses of 1/4, 3/8, 1/2, 1 and 2 inches; a 4-inch ID cylinder with a 1/2-inch Al wall thickness; and 6-inch ID cylinders with Al wall thicknesses of 1/2, 1 and 2 inches.more » The ANFO detonation velocity is seen to increase with increasing wall thickness for both the 3- and 6-inch ID tests, with no limiting velocity reached for the wall thicknesses used. The motion of the outer Al wall due to precursor elastic waves in the Al running ahead of the detonation is also measured at various axial locations along the cylinders. It is found that the magnitude of the outer wall motion due to the precursor elastic waves is small, while the associated wall motion is unsteady and decays in amplitude as the elastic disturbances move further ahead of the detonation front. The variations in the expansion history of the main outer wall motion of the cylinders are presented for increasing wall thickness at fixed ID, and for increasing cylinder inner diameter at a fixed wall thickness. Finally, we also explore the existence of a geometric similarity scaling of the wall expansion history for three geometrically scaled tests (3- and 6-inch ID cylinders with 1/4- and 1/2-inch walls respectively, 3- and 6-inch ID cylinders with 1/2- and 1-inch walls and 3- and 6-inch ID cylinders with 1- and 2-inch walls respectively). We find that the wall velocity histories for each of the three scaled tests, when plotted directly against time relative to start of main motion of the wall, are similar over a certain range of wall velocities without any geometric based rescaling in time. The range of wall velocities where the overlap occurs increases as the ratio of the wall thickness to inner diameter decreases. In conclusion, this is in contrast to ideal high explosives, where the outer wall velocity histories are only similar when the geometric scale factor (in this case a factor of 2) is applied to the wall velocity motion.« less

Dynamics of High Sound-Speed Metal Confiners Driven By Non-Ideal High-Explosive Detonation

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

Short, Mark; Jackson, Scott I.

Here, the results of 14 tests examining the behavior of aluminum (Al) conifners driven by non-ideal ANFO detonation in a cylinder test configuration are presented. In each test, the measured detonation phase velocity is slower than the aluminum sound speed. Thus, in the detonation reference frame, the ow in the Al is both shockless and subsonic. The tests involve: 3-inch inner diameter (ID) cylinders with Al wall thicknesses of 1/4, 3/8, 1/2, 1 and 2 inches; a 4-inch ID cylinder with a 1/2-inch Al wall thickness; and 6-inch ID cylinders with Al wall thicknesses of 1/2, 1 and 2 inches.more » The ANFO detonation velocity is seen to increase with increasing wall thickness for both the 3- and 6-inch ID tests, with no limiting velocity reached for the wall thicknesses used. The motion of the outer Al wall due to precursor elastic waves in the Al running ahead of the detonation is also measured at various axial locations along the cylinders. It is found that the magnitude of the outer wall motion due to the precursor elastic waves is small, while the associated wall motion is unsteady and decays in amplitude as the elastic disturbances move further ahead of the detonation front. The variations in the expansion history of the main outer wall motion of the cylinders are presented for increasing wall thickness at fixed ID, and for increasing cylinder inner diameter at a fixed wall thickness. Finally, we also explore the existence of a geometric similarity scaling of the wall expansion history for three geometrically scaled tests (3- and 6-inch ID cylinders with 1/4- and 1/2-inch walls respectively, 3- and 6-inch ID cylinders with 1/2- and 1-inch walls and 3- and 6-inch ID cylinders with 1- and 2-inch walls respectively). We find that the wall velocity histories for each of the three scaled tests, when plotted directly against time relative to start of main motion of the wall, are similar over a certain range of wall velocities without any geometric based rescaling in time. The range of wall velocities where the overlap occurs increases as the ratio of the wall thickness to inner diameter decreases. In conclusion, this is in contrast to ideal high explosives, where the outer wall velocity histories are only similar when the geometric scale factor (in this case a factor of 2) is applied to the wall velocity motion.« less

Portable fiber optic coupled Doppler interferometer system for detonation and shock wave diagnostics

NASA Technical Reports Server (NTRS)

Fleming, Kevin J.

1993-01-01

Testing and analysis of shock wave characteristics such as detonators and ground shock propagation frequently require a method of measuring velocity and displacement of the surface of interest. One method of measurement is Doppler interferometry. The VISAR (Velocity Interferometer System for Any Reflector) uses Doppler interferometry and has gained wide acceptance as the preferred tool for shock measurement. An important asset of VISAR is that it measures velocity and displacement nonintrusively.

Simple Model for Detonation Energy and Rate

NASA Astrophysics Data System (ADS)

Lauderbach, Lisa M.; Souers, P. Clark

2017-06-01

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

The Effect of Detonation Wave Incidence Angle on the Acceleration of Flyers by Explosives Heavily Laden with Inert Additives

NASA Astrophysics Data System (ADS)

Loiseau, Jason; Georges, William; Frost, David; Higgins, Andrew

2015-06-01

The incidence angle of a detonation wave is often assumed to weakly influence the terminal velocity of an explosively driven flyer. For explosives heavily loaded with dense additives, this may not be true due to differences in momentum and energy transfer between detonation products, additive particles, and the flyer. For tangential incidence the particles are first accelerated against the flyer via an expansion fan, whereas they are first accelerated by the detonation wave in the normal case. In the current study we evaluate the effect of normal versus tangential incidence on the acceleration of flyers by nitromethane heavily loaded with a variety of additives. Normal detonation was initiated via an explosively driven slapper. Flyer acceleration was measured with heterodyne laser interferometry (PDV). The influence of wave angle is evaluated by comparing the terminal velocity in the two cases (i.e., normal and grazing) for the heavily loaded mixtures. The decrement in flyer velocity correlated primarily with additive volume fraction and had a weak dependence on additive density or particle size. The Gurney energy of the heterogeneous explosive was observed to increase with flyer mass, presumably due to the timescale over which impinging particles could transfer momentum.

Explosive acceleration of plates using nonconventional explosives heavily loaded with inert and reactive materials

NASA Astrophysics Data System (ADS)

Loiseau, Jason; Petel, Oren; Huneault, Justin; Serge, Matthew; Frost, David; Higgins, Andrew

2013-06-01

The detonation behavior of high explosives containing dispersed quantities or packed beds of dense additives has been previously investigated with the observation that such systems depart from the ``gamma law'' behavior typical of homogeneous explosives due to momentum transfer and thermalization between particles and detonation products. However, the influence of this non-ideal detonation behavior on the divergence speed of plates has been far less rigorously studied and existing literature suggests that the effect of dense additives cannot be explained solely through the straightforward application of the Gurney method with energy and density averaging of the explosive. In the current study, the acceleration history and terminal velocity of aluminum flyers launched by packed beds of granular material saturated by amine-sensitized nitromethane is reported. Two experimental configurations are used to study acceleration either by a purely grazing detonation in a finite thickness slab of explosive or by a normal detonation from an effectively infinite thickness of explosive. Flyer acceleration and velocity is measured via Photonic Doppler Velocimetry. Packed beds of plastic, aluminum, glass, iron, and bismuth are considered and the data is compared to Gurney velocity predictions.

Nitromethane ignition observed with embedded PDV optical fibers

NASA Astrophysics Data System (ADS)

Mercier, P.; Bénier, J.; Frugier, P. A.; Debruyne, M.; Crouzet, B.

For a long time, the nitromethane (NM) ignition has been observed with different means such as high-speed cameras, VISAR or optical pyrometry diagnostics. By 2000, David Goosmann (LLNL) studied solid high-explosive detonation and shock loaded metal plates by measuring velocity (Fabry-Pérot interferometry) in embedded optical fibers. For six years Photonic Doppler Velocimetry (PDV) has become a major tool to better understand the phenomena occurring in shock physics experiments. In 2006, we began to use in turn this technique and studied shock-to-detonation transition in NM. Different kinds of bare optical fibers were set in the liquid; they provided two types of velocity information; those coming from phenomena located in front of the fibers (interface velocity, shock waves, overdriven detonation wave) and those due to phenomena environing the fibers (shock or detonation waves). We achieved several shots; devices were composed of a high explosive plane wave generator ended by a metal barrier followed by a cylindrical vessel containing NM. We present results.

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.

Novel Energetic Compounds Based on 3-Methyl-1,2,5-Oxadiazole 2-Oxide

NASA Astrophysics Data System (ADS)

Xu, Zhen; Yang, Hongwei; Cheng, Guangbin

2018-01-01

Two derivatives of 3-methyl-1,2,5-oxadiazole 2-oxide, (E) 4-methyl-1,2,5-oxadiazole-3-carboxaldehyde 5-oxide (2,4,6-trinitrophenyl)hydrazone (1) and 2,2,2-trinitroethyl 4-methyl-1,2,5-oxadiazole-3-carboxylate 5-oxide (2), were designed, synthesized, and fully characterized. The structures of the new compounds were confirmed by single-crystal X-ray analysis. Physicochemical and energetic properties including density, thermal stability, and sensitivity were investigated, and energetic properties (e.g., detonation velocities and detonation pressures) were calculated using EXPLO5 code. The results indicated that compound 1 exhibits positive heat of formation of 448.0 kJ mol-1 and acceptable sensitivities (IS: 20 J, FS: 280 N). In addition, compound 2 possesses low melting point (99.92°C), moderate decomposition temperature (183.67°C), good detonation performances (D: 8430 m s-1; P: 31.5 GPa), and lower sensitivities (IS: 18 J; FS: 220 N), which suggest 2 has the potential to be melt-cast explosive.

The shock sensitivity of nitromethane/methanol mixtures

NASA Astrophysics Data System (ADS)

Bartram, Brian; Dattelbaum, Dana; Sheffield, Steve; Gibson, Lee

2013-06-01

The dilution of liquid explosives has multiple effects on detonation properties including an increase in critical diameter, spatiotemporal lengthening of the chemical reaction zone, and the development of propagating wave instabilities. Earlier detonation studies of NM/methanol mixtures have shown several effects of increasing dilution, including: 1) a continual increase in the critical diameter, 2) lowering of the Chapman-Jouguet detonation pressure, and 3) slowing of the steady detonation velocity (Koldunov et al., Comb. Expl. Shock Waves). Here, we present the results of a series of gas gun-driven plate-impact experiments to study the shock-to-detonation transition in NM/methanol mixtures. Embedded electromagnetic gauges were used to obtain in situ particle velocity wave profiles at multiple Lagrangian positions in the initiating explosive mixture. From the wave profiles obtained in each experiment, an unreacted Hugoniot locus, the initiation mechanism, and the overtake-time-to-detonation were obtained as a function of shock input condition for mixture concentrations from 100% NM to 50 wt%/50 wt% NM/methanol. Desensitization with dilution is less than expected. For example, little change in overtake time occurs in 80 wt%/20 wt% NM/methanol when compared with neat NM. Furthermore, the shock wave profiles from the gauges indicate that wave instabilities grow in as the overdriven detonation wave settles down following the shock-to-detonation transition.

Some properties of explosive mixtures containing peroxides Part II. Relationships between detonation parameters and thermal reactivity of the mixtures with triacetone triperoxide.

PubMed

Zeman, Svatopluk; Bartei, Cécile

2008-06-15

This study concerns mixtures of triacetone triperoxide (3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexoxonane, TATP) and ammonium nitrate (AN) with added water (W), as the case may be, and two dry mixtures of TATP with urea nitrate (UN). Relative performances (RP) of the mixtures and their individual components, relative to TNT, were determined by means of ballistic mortar. Thermal reactivity of these mixtures was examined by means of differential thermal analysis and the data were analyzed according to the modified Kissinger method (the peak temperature was replaced by the temperature of decomposition onset in this case). The reactivity, expressed as the EaR(-1) slopes of the Kissinger relationship, correlates with the squares of the calculated detonation velocities for the charge density of 1000 kg m(-3) of the studied energetic materials. Similarly, the relationships between the EaR(-1) values and RP have been found. While the first mentioned correlation (modified Evans-Polanyi-Semenov equation) is connected with the primary chemical micro-mechanism of the mixtures detonation, the relationships in the second case should be connected with the thermochemical aspects of this detonation.

The Experimental Study about the Effect of Operating Conditions on Multi-tube Pulse Detonation Engine Performance

NASA Astrophysics Data System (ADS)

Kim, Jung-Min; Han, Hyung-Seok; Choi, Jeong-Yeol

2018-04-01

This study examines a multi-tube pulse detonation engine (PDE) which has a type of constant volume combustion. We designed and made the multi-tube PDE and then conducted an experiment in various operating frequencies and equivalence ratios. First, experiments with operating frequencies of 40, 80, 120, 160, and 200 Hz resulted in an average thrust and specific impulse 23.14 N and 42.34 s. The next experiment resulted in the equivalence ratio varying from 0.81 to 1.38, which resulted in an average thrust and specific impulse 22.36 N and 40.11 s. The average detonation velocity was 8% lower than that calculated according to C-J theory. The incidence ratios of the detonation wave were stable with the exception of the operating frequency of 200 Hz. However, at 200 Hz, the incidence ratio was less than 50%. We assumed that a low fill fraction occurred for this problem. The thrust of the PDE increased with the operating frequency. However, the thrust increase was at a lower rate than in previous studies, because of a lost thrust output result from the slow response time of the load cell amplifier.

Molecular design and property prediction of high density polynitro[3.3.3]-propellane-derivatized frameworks as potential high explosives.

PubMed

Zhang, Qinghua; Zhang, Jiaheng; Qi, Xiujuan; Shreeve, Jean'ne M

2014-11-13

Research in energetic materials is now heavily focused on the design and synthesis of novel insensitive high explosives (IHEs) for specialized applications. As an effective and time-saving tool for screening potential explosive structures, computer simulation has been widely used for the prediction of detonation properties of energetic molecules with relatively high precision. In this work, a series of new polynitrotetraoxopentaaza[3.3.3]-propellane molecules with tricyclic structures were designed. Their properties as potential high explosives including density, heats of formation, detonation properties, impact sensitivity, etc., have been extensively evaluated using volume-based thermodynamic calculations and density functional theory (DFT).These new energetic molecules exhibit high densities of >1.82 g cm(-3), in which 1 gives the highest density of 2.04 g cm(-3). Moreover, most new materials show good detonation properties and acceptable impact sensitivities, in which 5 displays much higher detonation velocity (9482 m s(-1)) and pressure (43.9 GPa) than HMX and has a h50 value of 11 cm. These results are expected to facilitate the experimental synthesis of new-generation nitramine-based high explosives.

Kinetic modeling of non-ideal explosives with CHEETAH

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

Fried, L E; Howard, W M; Souers, P C

1998-08-06

We report an implementation of the Wood-Kirkwood kinetic detonation model based on multi-species equations of state and multiple reaction rate laws. Finite rate laws are used for the slowest chemical reactions. Other reactions are given infinite rates and are kept in constant thermodynamic equilibrium. We model a wide range of ideal and non-ideal composite energetic materials. We find that we can replicate experimental detonation velocities to within a few per cent, while obtaining good agreement with estimated reaction zone lengths. The detonation velocity as a function of charge radius is also correctly reproduced.

Synchro-ballistic recording of detonation phenomena

NASA Astrophysics Data System (ADS)

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

1997-12-01

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

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

NASA Astrophysics Data System (ADS)

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

2007-06-01

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

Development of an Actuator for Flow Control Utilizing Detonation

NASA Technical Reports Server (NTRS)

Lonneman, Patrick J.; Cutler, Andrew D.

2004-01-01

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

Propagation velocities of laser-produced plasmas from copper wire targets and water droplets

NASA Technical Reports Server (NTRS)

Song, Kyo-Dong; Alexander, Dennis R.

1994-01-01

Experiments were performed to determine the plasma propagation velocities resulting from KrF laser irradiation of copper wire target (75 microns diameter) and water droplets (75 microns diameter) at irradiance levels ranging from 25 to 150 GW/sq cm. Plasma propagation velocities were measured using a streak camera system oriented orthogonally to the high-energy laser propagation axis. Plasma velocities were studied as a function of position in the focused beam. Results show that both the shape of the plasma formation and material removal from the copper wire are different and depend on whether the targets are focused or slightly defocused (approximately = 0.5 mm movement in the beam axis). Plasma formation and its position relative to the target is an important factor in determining the practical focal point during high-energy laser interaction with materials. At irradiance of 100 GW/sq cm, the air plasma has two weak-velocity components which propagate toward and away from the incident laser while a strong-velocity component propagates away from the laser beam as a detonation wave. Comparison of the measured breakdown velocities (in the range of 2.22-2.27 x 10(exp 5) m/s) for air and the value calculated by the nonlinear breakdown wave theory at irradiance of 100 GW/sq cm showed a quantitative agreement within approximately 50% while the linear theory and Gaussian pulse theory failed. The detonation wave velocities of plasma generated from water droplets and copper wire targets for different focused cases were measured and analyzed theoretically. The propagation velocities of laser-induced plasma liquid droplets obtained by previous research are compared with current work.

Evaluation of the Detonation Performance of Insensitive Explosive Formulations Based on 3,3 Diamino-4,4-Azoxyfurazan (DAAF) and 3-Nitro-1,2,4-Triazol-5-One (NTO)

NASA Astrophysics Data System (ADS)

Tappan, Bryce C.; Bowden, Patrick R.; Lichthardt, Joseph P.; Schmitt, Matthew M.; Hill, Larry G.

2018-04-01

Two energetic materials identified for relatively high energy, but little to no response to impact, spark or friction stimuli are 3-nitro-1,2,4-triazole-5-one (NTO), and 3,3' diamino-4,4'-azoxyfurazan (DAAF). More of an outlier in performance versus sensitivity, DAAF illustrates insensitivity by small-scale sensitivity tests, yet has a failure diameter estimated to be 1.25 mm and a short run length to detonation. Because of this unusual behavior, DAAF is an ideal material to formulate with NTO to obtain tailored shock sensitivity and critical diameter, with detonation velocities and pressures higher than PBX 9502. Here, we present detonation properties of Kel-F® bonded formulations with ratios of 20-70 wt.-% DAAF added to NTO. All formulations were evaluated for detonation velocity, aluminum flyer acceleration at jump-off, and via the cylinder expansion test.

The propulsive capability of explosives heavily loaded with inert materials

NASA Astrophysics Data System (ADS)

Loiseau, J.; Georges, W.; Frost, D. L.; Higgins, A. J.

2018-01-01

The effect of inert dilution on the accelerating ability of high explosives for both grazing and normal detonations was studied. The explosives considered were: (1) neat, amine-sensitized nitromethane (NM), (2) packed beds of glass, steel, or tungsten particles saturated with amine-sensitized NM, (3) NM gelled with PMMA containing dispersed glass microballoons, (4) NM gelled with PMMA containing glass microballoons and steel particles, and (5) C-4 containing varying mass fractions of glass or steel particles. Flyer velocity was measured via photonic Doppler velocimetry, and the results were analysed using a Gurney model augmented to include the influence of the diluent. Reduction in accelerating ability with increasing dilution for the amine-sensitized NM, gelled NM, and C-4 was measured experimentally. Variation of flyer terminal velocity with the ratio of flyer mass to charge mass (M/C) was measured for both grazing and normally incident detonations in gelled NM containing 10% microballoons by mass and for steel beads saturated with amine-sensitized NM. Finally, flyer velocity was measured in grazing versus normal loading for a number of explosive admixtures. The augmented Gurney model predicted the effect of dilution on accelerating ability and the scaling of flyer velocity with M/C for mixtures containing low-density diluents. The augmented Gurney model failed to predict the scaling of flyer velocity with M/C for mixtures heavily loaded with dense diluents. In all cases, normally incident detonations propelled flyers to higher velocity than the equivalent grazing detonations because of material velocity imparted by the incident shock wave and momentum/energy transfer from the slapper used to uniformly initiate the charge.

The propulsive capability of explosives heavily loaded with inert materials

NASA Astrophysics Data System (ADS)

Loiseau, J.; Georges, W.; Frost, D. L.; Higgins, A. J.

2018-07-01

The effect of inert dilution on the accelerating ability of high explosives for both grazing and normal detonations was studied. The explosives considered were: (1) neat, amine-sensitized nitromethane (NM), (2) packed beds of glass, steel, or tungsten particles saturated with amine-sensitized NM, (3) NM gelled with PMMA containing dispersed glass microballoons, (4) NM gelled with PMMA containing glass microballoons and steel particles, and (5) C-4 containing varying mass fractions of glass or steel particles. Flyer velocity was measured via photonic Doppler velocimetry, and the results were analysed using a Gurney model augmented to include the influence of the diluent. Reduction in accelerating ability with increasing dilution for the amine-sensitized NM, gelled NM, and C-4 was measured experimentally. Variation of flyer terminal velocity with the ratio of flyer mass to charge mass ( M/ C) was measured for both grazing and normally incident detonations in gelled NM containing 10% microballoons by mass and for steel beads saturated with amine-sensitized NM. Finally, flyer velocity was measured in grazing versus normal loading for a number of explosive admixtures. The augmented Gurney model predicted the effect of dilution on accelerating ability and the scaling of flyer velocity with M/ C for mixtures containing low-density diluents. The augmented Gurney model failed to predict the scaling of flyer velocity with M/ C for mixtures heavily loaded with dense diluents. In all cases, normally incident detonations propelled flyers to higher velocity than the equivalent grazing detonations because of material velocity imparted by the incident shock wave and momentum/energy transfer from the slapper used to uniformly initiate the charge.

Initiation of Gaseous Detonation by Conical Projectiles

NASA Astrophysics Data System (ADS)

Verreault, Jimmy

Initiation and stabilization of detonation by hypersonic conical projectiles launched into combustible gas mixtures is investigated. This phenomenon must be understood for the design and optimization of specific hypersonic propulsion devices, such as the oblique detonation wave engine and the ram accelerator. The criteria for detonation initiation by a projectile is also related to fundamental aspects of detonation research, such as the requirement for direct initiation of a detonation by a blast wave. Experimental results of this problem also offer useful references for validation of numerical and theoretical modeling. Projectiles with cone half angles varying from 15° to 60° were launched into stoichiometric mixtures of hydrogen/oxygen with 70% argon dilution at initial pressures between 10 and 200 kPa. The projectiles were launched from a combustion-driven gas gun at velocities up to 2.2 km/s (corresponding to 133% of the Chapman Jouguet velocity). Pictures of the flowfields generated by the projectiles were taken via Schlieren photography. Five combustion regimes were observed about the projectile ranging from prompt and delayed oblique detonation wave formation, combustion instabilities, a wave splitting, and an inert shock wave. Two types of transition from the prompt oblique detonation wave regime to the inert shock regime were observed. The first (the delayed oblique detonation wave regime) showed an inert shock attached to the tip of the projectile followed by a sharp kink at the onset of an oblique detonation wave; this regime occurred by decreasing the cone angle at high mixture pressures. The second (the combustion instabilities regime) exhibited large density gradients due to combustion ignition and quenching phenomena; this regime occurred by decreasing the mixture pressure at large cone angles. A number of theoretical models were considered to predict critical conditions for the initiation of oblique detonations. The Lee-Vasiljev model agreed qualitatively well with the experimental results for relatively blunt projectiles (cone half-angle larger than 35°) and low mixture pressures (lower than 100 kPa). The trend of the critical Damköhler number calculated along the projectile cone surface was similar to that of the experimental results for slender cones (cone half-angles lower 35°) and high mixture pressures (higher than 100 kPa). Steady 2D simulations of reacting flows over finite wedges using the method of characteristics with a one-step Arrhenius chemical reaction model reproduced the three regimes observed for direct initiation of a detonation: the subcritical, critical and supercritical regimes. It is shown that in order for a 2D wedge to be equivalent to the problem of blast initiation of a detonation (which is the essence of the Lee-Vasiljev model), the Mach number normal to the oblique shock needs to be greater than 50 and the wedge angle has to be smaller than 30°. Simulations of reacting flows over semi-infinite wedges and cones were validated with CFD results. Excellent agreement was reached between the angle of overdriven oblique detonations obtained from the simulations and those from a polar analysis. For wedge or cone angles equal or lower than the minimum angle for which an oblique detonation is attached (according to the polar analysis), a Chapman-Jouguet oblique detonation was initiated. In the conical configuration, the curvature around the cone axis allowed an oblique detonation to be self-sustained at an angle less than without the curvature effect. At larger activation energies, the initiation process of an oblique detonation wave at the tip of a semi-infinite wedge or cone was identified. Unsteady 2D computational simulations were also conducted and showed the cellular structure of an oblique detonation wave. Instabilities in the form of transverse shock waves along the oblique detonation front arise for large activation energies.

Structural stability, vibrational, and bonding properties of potassium 1, 1′-dinitroamino-5, 5′-bistetrazolate: An emerging green primary explosive

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

Yedukondalu, N.; Vaitheeswaran, G., E-mail: gvsp@uohyd.ernet.in

2015-08-14

Potassium 1,1′-dinitroamino-5,5′-bistetrazolate (K{sub 2}DNABT) is a nitrogen rich (50.3% by weight, K{sub 2}C{sub 2}N{sub 12}O{sub 4}) green primary explosive with high performance characteristics, namely, velocity of detonation (D = 8.33 km/s), detonation pressure (P = 31.7 GPa), and fast initiating power to replace existing toxic primaries. In the present work, we report density functional theory (DFT) calculations on structural, equation of state, vibrational spectra, electronic structure, and absorption spectra of K{sub 2}DNABT. We have discussed the influence of weak dispersive interactions on structural and vibrational properties through the DFT-D2 method. We find anisotropic compressibility behavior (b

Novel Rubidium Poly-Nitrogen Energetic Materials

NASA Astrophysics Data System (ADS)

Huff, Ashley; Steele, Brad; Oleynik, Ivan

High-nitrogen content compounds are being actively explored with the goal of discovering new high-energy density materials with performance surpassing the conventional energetic materials such as HMX or RDX. Although pure polynitrogen compounds such as cg-N are predicted to deliver 10-fold increase in detonation pressure and detonation velocity of 30 km/s, their synthesis and recovery at ambient conditions is problematic. Doping polynitrogens with other elements is a viable route to promote metastability while reducing synthesis pressure. In this work, rubidium poly-nitrides are being investigated as candidates for high energy density materials. Using first principles evolutionary structure search methods performed at varying stoichiometries and several pressures ranging from 0 to 100 GPa, several new polynitrogen compounds have been discovered. The phase diagrams containing thermodynamically stable and lowest metastable phases are calculated and the dynamical stability of the promising materials is investigated at various pressures. Raman spectra and XRD patterns are also calculated to provide experimentally relevant information useful for identification of these compounds during their synthesis.

Improving the Explosive Performance of Aluminum Nanoparticles with Aluminum Iodate Hexahydrate (AIH).

PubMed

Gottfried, Jennifer L; Smith, Dylan K; Wu, Chi-Chin; Pantoya, Michelle L

2018-05-23

A new synthesis approach for aluminum particles enables an aluminum core to be passivated by an oxidizing salt: aluminum iodate hexahydrate (AIH). Transmission electron microscopy (TEM) images show that AIH replaces the Al 2 O 3 passivation layer on Al particles that limits Al oxidation. The new core-shell particle reactivity was characterized using laser-induced air shock from energetic materials (LASEM) and results for two different Al-AIH core-shell samples that vary in the AIH concentration demonstrate their potential use for explosive enhancement on both fast (detonation velocity) and slow (blast effects) timescales. Estimates of the detonation velocity for TNT-AIH composites suggest an enhancement of up to 30% may be achievable over pure TNT detonation velocities. Replacement of Al 2 O 3 with AIH allows Al to react on similar timescales as detonation waves. The AIH mixtures tested here have relatively low concentrations of AIH (15 wt. % and 6 wt. %) compared to previously reported samples (57.8 wt. %) and still increase TNT performance by up to 30%. Further optimization of AIH synthesis could result in additional increases in explosive performance.

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.

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

NASA Astrophysics Data System (ADS)

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

2017-01-01

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

Detonation Processes USSR

DTIC Science & Technology

1960-06-06

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

Detonation Diffraction in a Multi-Step Channel

DTIC Science & Technology

2010-12-01

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

Detonation-to-shock wave transmission at a contact discontinuity

NASA Astrophysics Data System (ADS)

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

2018-02-01

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

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

NASA Astrophysics Data System (ADS)

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

2018-05-01

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

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

DOE PAGES

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

2017-03-10

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

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

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

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

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

On the violence of thermal explosion in solid explosives

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

Chidester, S.K.; Tarver, C.M.; Green, L.G.

Heavily confined cylinders of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and triaminotrinitrobenzene (TATB) were heated at rates varying from 2 C/min to 3.3 C/h. Fourteen of the cylinders were hollow, and inner metallic liners with small heaters attached were used to produce uniform temperatures just prior to explosion. A complex thermocouple pattern was used to measure the temperature history throughout the charge and to determine the approximate location where the runaway exothermic reaction first occurred. The violence of the resulting explosion was measured using velocity pin arrays placed inside and outside of the metal confinement cylinders, flash x-rays, overpressure gauges, and fragment collection techniques.more » Five cylinders were intentionally detonated for violence comparisons. The measured temperature histories, times to explosion, and the locations of first reaction agreed closely with those calculated by a two-dimensional heat transfer code using multistep chemical decomposition models. The acceleration of the confining metal cylinders by the explosion process was accurately simulated using a two-dimensional pressure dependent deflagration reactive flow hydrodynamic mode. The most violent HMX thermal explosions gradually accelerated their outer cases to velocities approaching those of intentional detonations approximately 120 {micro}m after the onset of explosion. The measured inner cylinder collapse velocities from thermal explosions were considerably lower than those produced by detonations. In contrast to the HMX thermal reactions, no violent thermal explosions were produced by the TATB-based explosive LX-17. A heavily confined, slowly heated LX-17 test produced sufficient pressure to cause a 0.1 cm bend in a 2 cm thick steel plate.« less

Theoretical studies on 2-diazo-4,6-dinitrophenol derivatives aimed at finding superior propellants.

PubMed

Liu, Yan; Wang, Lianjun; Wang, Guixiang; Du, Hongchen; Gong, Xuedong

2012-04-01

In an attempt to find superior propellants, 2-diazo-4,6-dinitrophenol (DDNP) and its -NO(2), -NH(2), -CN, -NC, -ONO(2), and -NF(2) derivatives were studied at the B3LYP/6-311++G level of density functional theory (DFT). Sensitivity was evaluated using bond dissociation enthalpies (BDEs) and molecular surface electrostatic potentials. The C-NO(2) bond appears to be the trigger bond during the thermolysis process for these compounds, except for the -ONO(2) and -NF(2) derivatives. Electrostatic potential results show that electron-withdrawing substituents make the charge imbalance more anomalous, which may change the strength of the bond, especially the weakest trigger bond. Most of the DDNP derivatives have the impact sensitivities that are higher than that of DDNP, making them favorable for use as solid propellants in micro-rockets. The theoretical densities (ρ), heats of formation (HOFs), detonation energies (Q), detonation pressures (P), and detonation velocities (D) of the compounds were estimated. The effects of various substituent groups on ρ, HOF, Q, D, and P were investigated. Some derivatives exhibit perfect detonation properties. The calculated relative specific impulses (I (r,sp)) of all compounds except for -NH(2) derivatives were higher than that of DDNP, and also meet the requirements of propellants.

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.

W-76 PBX 9501 cylinder tests

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

Hill, L.G.; Catanach, R.A.

1998-07-01

Five 1-inch diameter cylinder tests were fired in support of the W-76 high explosive surveillance program. Three of the tests used baseline material, and two used stockpile return material. The diagnostics were electrical pins to measure detonation velocity and a streak camera to measure wall motion. The data was analyzed for cylinder energy, Gurney energy, and detonation velocity. The results of all three measures were consistent for all five tests, to within the experimental accuracy.

Reactive flow modeling of initial density effect on divergence JB-9014 detonation driving

NASA Astrophysics Data System (ADS)

Yu, Xin; Huang, Kuibang; Zheng, Miao

2016-06-01

A serious of experiments were designed and the results were represented in this paper, in which 2mm thickness cooper shells were impacted by explosives named JB-9014 with different densities, and the surface velocities of the OFHC shells were measured. The comparison of experimental data shows the free surface velocity of the OFHC shell increase with the IHE density. Numerical modeling, which occupied phenomenological reactive flow rate model using the two-dimensional Lagrange hydrodynamic code, were carried out to simulate the above experiments, and empirical adjustments on detonation velocity and pressure and Pier Tang's adjustments on EOS of detonation products were both introduced in our numerical simulation work. The computational results agree well with that of experiments, and the numerical results with original parameters of products and the adjusted ones of JB-9014 could describe the density effect distinctly.

Measurements of multiple gas parameters in a pulsed-detonation combustor using time-division-multiplexed Fourier-domain mode-locked lasers.

PubMed

Caswell, Andrew W; Roy, Sukesh; An, Xinliang; Sanders, Scott T; Schauer, Frederick R; Gord, James R

2013-04-20

Hyperspectral absorption spectroscopy is being used to monitor gas temperature, velocity, pressure, and H(2)O mole fraction in a research-grade pulsed-detonation combustor (PDC) at the Air Force Research Laboratory. The hyperspectral source employed is termed the TDM 3-FDML because it consists of three time-division-multiplexed (TDM) Fourier-domain mode-locked (FDML) lasers. This optical-fiber-based source monitors sufficient spectral information in the H(2)O absorption spectrum near 1350 nm to permit measurements over the wide range of conditions encountered throughout the PDC cycle. Doppler velocimetry based on absorption features is accomplished using a counterpropagating beam approach that is designed to minimize common-mode flow noise. The PDC in this study is operated in two configurations: one in which the combustion tube exhausts directly to the ambient environment and another in which it feeds an automotive-style turbocharger to assess the performance of a detonation-driven turbine. Because the enthalpy flow [kilojoule/second] is important in assessing the performance of the PDC in various configurations, it is calculated from the measured gas properties.

Explosively generated shock wave processing of metal powders by instrumented detonics

NASA Astrophysics Data System (ADS)

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

2013-06-01

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

An exact solution for axial flow in cylindrically symmetric, steady-state detonation in polytropic explosive with an arbitrary rate of decomposition

NASA Astrophysics Data System (ADS)

Cowperthwaite, M.

1994-03-01

Methods of differential geometry and Bernoulli's equation, written as B=0, are used to develop a new approach for constructing an exact solution for axial flow in a classical, two-dimensional, ZND detonation wave in a polytropic explosive with an arbitrary rate of decomposition. This geometric approach is fundamentally different from the traditional approaches to this axial flow problem formulated by Wood and Kirkwood (WK) and Fickett and Davis (FD), and gives equations for the axial particle velocity (u), the sound speed (c), the pressure (p), and the density (ρ), that are expressed in terms of the detonation velocity (D), the extent of decomposition (λ), the polytropic index (K), and two nonideal parameters ɛ3 and ɛ1, and reduce to the equations for steady-state, one-dimensional detonation as ɛ3 and ɛ1 approach zero. In contrast to the FD approach, the equations for u and c are obtained from first integrals of a tangent vector à on (u,c,λ) space, and the invariant condition, ÃB=aB=0, bypasses the FD eigenvalue problem by defining ɛ3 in terms of the detonation velocity deficit D/D∞ and K. In contrast to the WK approach, the equations for p and ρ are obtained from equations expressing the conservation of axial momentum and energy. Because the equations for these flow variables are derived without using the conservation of mass, the axial radial particle velocity gradient (war) associated with the flow can be obtained from the continuity equation without making approximations. The relationship between ɛ1 and ɛ3 that closes the solution is obtained from equations expressing constraints imposed on the axial flow at the shock front by the axial and radial momentum equations, the curved shock and the decomposition rate law, and a particular solution is constructed from the ɛ1-ɛ3 relationship determined by a prescribed rate law and value of K. Properties of particular solutions are presented to provide a better understanding of two-dimensional detonation, and a new axial condition for detonation failure is used to show that detonation failure can occur before the curve relating D/D∞ to the axial radius of curvature of the shock (Sa) becomes infinite.

Investigation of an Unusually Shallow Earthquake Sequence in Mogul, NV from a Discrimination Perspective

DTIC Science & Technology

2014-08-31

shows that polarity is occasionally flipped between events due to rotation of the focal mechanism. A total of 233,357 cross-correlation times were...model NEIS PDE 2008/04/26 06:40:10.61 39.520 -119.930 1.40 model unknown NSL original catalog 2008/04/26, 06:40:10.6 39.5247 -119.9180 3.08... detonated at Yucca Flat the P-velocity was 1.6 km/s and for nuclear explosions detonated at Pahute Mesa the P-velocity was 2.7 km/s. The S- velocity was

Equations of state of detonation products: ammonia and methane

NASA Astrophysics Data System (ADS)

Lang, John; Dattelbaum, Dana; Goodwin, Peter; Garcia, Daniel; Coe, Joshua; Leiding, Jeffery; Gibson, Lloyd; Bartram, Brian

2015-06-01

Ammonia (NH3) and methane (CH4) are two principal product gases resulting from explosives detonation, and the decomposition of other organic materials under shockwave loading (such as foams). Accurate thermodynamic descriptions of these gases are important for understanding the detonation performance of high explosives. However, shock compression data often do not exist for molecular species in the dense gas phase, and are limited in the fluid phase. Here, we present equation of state measurements of elevated initial density ammonia and methane gases dynamically compressed in gas-gun driven plate impact experiments. Pressure and density of the shocked gases on the principal Hugoniot were determined from direct particle velocity and shock wave velocity measurements recorded using optical velocimetry (Photonic Doppler velocimetry (PDV) and VISAR (velocity interferometer system for any reflector)). Streak spectroscopy and 5-color pyrometry were further used to measure the emission from the shocked gases, from which the temperatures of the shocked gases were estimated. Up to 0.07 GPa, ammonia was not observed to ionize, with temperature remaining below 7000 K. These results provide quantitative measurements of the Hugoniot locus for improving equations of state models of detonation products.

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

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

A New Method for Determining the Equation of State of Aluminized Explosive

NASA Astrophysics Data System (ADS)

Zhou, Zheng-Qing; Nie, Jian-Xin; Guo, Xue-Yong; Wang, Qiu-Shi; Ou, Zhuo-Cheng; Jiao, Qing-Jie

2015-01-01

The time-dependent Jones—Wilkins—Lee equation of state (JWL-EOS) is applied to describe detonation state products for aluminized explosives. To obtain the time-dependent JWL-EOS parameters, cylinder tests and underwater explosion experiments are performed. According to the result of the wall radial velocity in cylinder tests and the shock wave pressures in underwater explosion experiments, the time-dependent JWL-EOS parameters are determined by iterating these variables in AUTODYN hydrocode simulations until the experimental values are reproduced. In addition, to verify the reliability of the derived JWL-EOS parameters, the aluminized explosive experiment is conducted in concrete. The shock wave pressures in the affected concrete bodies are measured by using manganin pressure sensors, and the rod velocity is obtained by using a high-speed camera. Simultaneously, the shock wave pressure and the rod velocity are calculated by using the derived time-dependent JWL equation of state. The calculated results are in good agreement with the experimental data.

Reconstruction and Modelling of Cylinder Test Wall Expansion from Heterodyne Velocimetry Data

NASA Astrophysics Data System (ADS)

Hodgson, Alexander

2015-06-01

The `cylinder test' is comprised of a cylinder of explosive encased in a copper tube and detonated at one end. Analysis of the copper wall expansion can be used to generate a JWL equation of state for the explosive. The wall arrival times are traditionally measured using angled probe boards. These times are converted to radial expansion times using the measured steady state detonation velocity. This expansion represents the intersection of the wall with a radial line, hence its differential is the radial intersection velocity. The true radial wall velocity is different due to the small component of particle velocity along the axis. Wall velocities can be directly measured using a Heterodyne Velocimetry (HetV) diagnostic, to a high degree of temporal resolution. However, the wall profile cannot be reconstructed from a standard HetV probe due to a lack of spatial information. This work describes how velocity traces from two HetV probes at different angles can be combined to evaluate the path of a particle on the copper wall, and how the wall profile may then be reconstructed. The method is applied to data from cylinder test experiments on a conventional high explosive. Results are validated using hydrocode modelling coupled with Detonation Shock Dynamics theory.

Acceleration of plates using non-conventional explosives heavily-loaded with inert materials

NASA Astrophysics Data System (ADS)

Loiseau, J.; Petel, O. E.; Huneault, J.; Serge, M.; Frost, D. L.; Higgins, A. J.

2014-05-01

The detonation behavior of high explosives containing quantities of dense additives has been previously investigated with the observation that such systems depart dramatically from the approximately "gamma law" behavior typical of conventional explosives due to momentum transfer and thermalization between particles and detonation products. However, the influence of this non-ideal detonation behavior on the divergence speed of plates has been less thoroughly studied and existing literature suggests that the effect of dense additives cannot be explained solely through the straightforward application of the Gurney method with energy and density averaging of the explosive. In the current study, the acceleration history and terminal velocity of aluminum flyers launched by packed beds of granular material saturated by amine-sensitized nitromethane is reported. It was observed that terminal flyer velocity scales primarily with the ratio of flyer mass to mass of the explosive component; a fundamental feature of the Gurney method. Velocity decrement from the addition of particles was only 20%-30% compared to the resulting velocity if propelled by an equivalent quantity of neat explosive.

Generalized Pseudo-Reaction Zone Model for Non-Ideal Explosives

NASA Astrophysics Data System (ADS)

Wescott, B. L.

2007-12-01

The pseudo-reaction zone model was proposed to improve engineering scale simulations with high explosives that have a slow reaction component. In this work an extension of the pseudo-reaction zone model is developed for non-ideal explosives that propagate well below the steady-planar Chapman-Jouguet velocity. A programmed burn method utilizing Detonation Shock Dynamics (DSD) and a detonation velocity dependent pseudo-reaction rate has been developed for non-ideal explosives and applied to the explosive mixture of ammonium nitrate and fuel oil (ANFO). The pseudo-reaction rate is calibrated to the experimentally obtained normal detonation velocity—shock curvature relation. Cylinder test simulations predict the proper expansion to within 1% even though significant reaction occurs as the cylinder expands.

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

NASA Astrophysics Data System (ADS)

Tarver, Craig M.

2017-01-01

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

Advanced Initiation Systems Manufacturing Level 2 Milestone Completion Summary

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

Chow, R; Schmidt, M

2009-10-01

Milestone Description - Advanced Initiation Systems Detonator Design and Prototype. Milestone Grading Criteria - Design new generation chip slapper detonator and manufacture a prototype using advanced manufacturing processes, such as all-dry chip metallization and solvent-less flyer coatings. The advanced processes have been developed for manufacturing detonators with high material compatibility and reliability to support future LEPs, e.g. the B61, and new weapons systems. Perform velocimetry measurements to determine slapper velocity as a function of flight distance. A prototype detonator assembly and stripline was designed for low-energy chip slappers. Pictures of the prototype detonator and stripline are shown. All-dry manufacturing processesmore » were used to address compatibility issues. KCP metallized the chips in a physical vapor deposition system through precision-aligned shadow masks. LLNL deposited a solvent-less polyimide flyer with a processes called SLIP, which stands for solvent-less vapor deposition followed by in-situ polymerization. LANL manufactured the high-surface-area (HSA) high explosive (HE) pellets. Test fires of two chip slapper designs, radius and bowtie, were performed at LLNL in the High Explosives Application Facility (HEAF). Test fires with HE were conducted to establish the threshold firing voltages. pictures of the chip slappers before and after test fires are shown. Velocimetry tests were then performed to obtain slapper velocities at or above the threshold firing voltages. Figure 5 shows the slapper velocity as a function of distance and time at the threshold voltage, for both radius and bowtie bridge designs. Both designs were successful at initiating the HE at low energy levels. Summary of Accomplishments are: (1) All-dry process for chip manufacture developed; (2) Solventless process for slapper materials developed; (3) High-surface area explosive pellets developed; (4) High performance chip slappers developed; (5) Low-energy chip slapper detonator designs; and (6) Low-voltage threshold chip slapper detonator demonstrated.« less

Synthesis, characterization, and thermal analysis of a new energetic salt based on 1'-hydroxy-1H,1'H-5,5'-bitetrazol-1-olate

NASA Astrophysics Data System (ADS)

Niu, Chunhuan; Jin, Bo; Shang, Yu; Liu, Qiangqiang; Peng, Rufang

2018-04-01

4-Amino-1,2,4-triazolium 1'-hydroxy-1H,1'H-5,5'-bitetrazol-1-olate (ATHBTO) was synthesized by reacting 4-amino-1,2,4-triazole (AT) and 1H,1‧H-5,5‧-bistetrazole-1,1‧-diolate dihydrate (H2BTO.2H2O). Its crystal structure was characterized through single-crystal X-ray diffraction. Meanwhile, FTIR, 1H NMR, 13C NMR, and elemental analysis were also introduced to analyze its composition. The thermal stability was investigated by differential scanning calorimetry, thermogravimetric analysis, and thermogravimetric tandem infrared spectrum. Results indicated that ATHBTO exhibited excellent resistance to thermal decompositions reaching 511.4 K and had a 64.6% mass loss between 475.7 and 552.3 K. The kinetics parameters were calculated by Kissinger's method and Ozawa-Doyle's method. Moreover, according to the Kamlet-Jacobs formula, the calculated detonation velocity and detonation pressure of ATHBTO attained 8218 m/s and 28.69 GPa, respectively.

Experimental Measurements of the Chemical Reaction Zone of Detonating Liquid Explosives

NASA Astrophysics Data System (ADS)

Bouyer, Viviane; Sheffield, Stephen A.; Dattelbaum, Dana M.; Gustavsen, Richard L.; Stahl, David B.; Doucet, Michel

2009-06-01

We have a joint project between CEA-DAM Le Ripault and Los Alamos National Laboratory (LANL) to study the chemical reaction zone in detonating high explosives using several different laser velocimetry techniques. The short temporal duration of the features (von Neumann spike and sonic locus) of the reaction zone make these measurements difficult. Here, we report results obtained from using and PDV (photon Doppler velocimetry) methods to measure the particle velocity history at a detonating HE (nitromethane)/PMMA interface. Experiments done at CEA were high-explosive-plane-wave initiated and those at LANL were gas-gun-projectile initiated with a detonation run of about 6 charge diameters in all experiments, in either glass or brass confinement. Excellent agreement of the interface particle velocity measurements at both Laboratories were obtained even though the initiation systems and the velocimetry systems were different. Some differences were observed in the von Neumann spike height because of the approximately 2 nanosecond time resolution of the techniques -- in some or all cases the spike top was truncated.

Propagation of detonation wave in hydrogen-air mixture in channels with sound-absorbing surfaces

NASA Astrophysics Data System (ADS)

Bivol, G. Yu.; Golovastov, S. V.; Golub, V. V.

2015-12-01

The possibility of using sound-absorbing surfaces for attenuating the intensity of detonation waves propagating in hydrogen-air mixtures has been experimentally studied in a cylindrical detonation tube open at one end, with an explosive initiated by spark discharge at the closed end. Sound-absorbing elements were made of an acoustic-grade foamed rubber with density of 0.035 g/cm3 containing open pores with an average diameter of 0.5 mm. The degree of attenuation of the detonation wave front velocity was determined as dependent on the volume fraction of hydrogen in the gas mixture.

Multi-shock experiments on a TATB-based composition

NASA Astrophysics Data System (ADS)

Sorin, Remy

2017-06-01

Temperature based models for condensed explosive need an unreacted equation of state (EOS) that allows a realistic estimation of the temperature for a shock compression driven at detonation velocity. To feed the detonation models, we aim at exploring the high pressure shock Hugoniot of unreacted TATB composition up to 30 GPa with both hydrodynamic and temperature measurements. We performed on the gas gun facility ARES, multi-shock experiments where the first shock is designed to desensitize the explosive and inhibit the reactivity of the composition. The hydrodynamic behavior was measured via the velocity of a TATB/LiF interface with PDV probes. We attempted to measure the temperature of the shocked material via surface emissivity with a pyrometer calibrated to the expected low temperature range. Based on single shock experiments and on ab-initio calculation, we built a complete EOS for the unreacted phase of the TATB explosive. The hydrodynamic data are in good agreement with our unreacted EOS. Despite the record of multi-stage emissivity signals, the temperature measurements were difficult to interpret dur to high-luminisity phenomena pertubation. In collaboration with: Nicolas Desbiens, Vincent Dubois and Fabrice Gillot, CEA DAM DIF.

Jack Rabbit Pretest Data For TATB Based IHE Model Development

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

Hart, M M; Strand, O T; Bosson, S T

The Jack Rabbit Pretest series consisted of 5 focused hydrodynamic experiments, 2021E PT3, PT4, PT5, PT6, and PT7. They were fired in March and April of 2008 at the Contained Firing Facility, Site 300, Lawrence Livermore National Laboratory, Livermore, California. These experiments measured dead-zone formation and impulse gradients created during the detonation of TATB based insensitive high explosive. This document contains reference data tables for all 5 experiments. These data tables include: (1) Measured laser velocimetry of the experiment diagnostic plate (2) Computed diagnostic plate profile contours through velocity integration (3) Computed center axis pressures through velocity differentiation. All timesmore » are in microseconds, referenced from detonator circuit current start. All dimensions are in millimeters. Schematic axi-symmetric cross sections are shown for each experiment. These schematics detail the materials used and dimensions of the experiment and component parts. This should allow anyone wanting to evaluate their TATB based insensitive high explosive detonation model against experiment. These data are particularly relevant in examining reactive flow detonation model prediction in computational simulation of dead-zone formation and resulting impulse gradients produced by detonating TATB based explosive.« less

Development of multi-component explosive lenses for arbitrary phase velocity generation

NASA Astrophysics Data System (ADS)

Loiseau, Jason; Huneault, Justin; Petel, Oren; Goroshin, Sam; Frost, David; Higgins, Andrew; Zhang, Fan

2013-06-01

The combination of explosives with different detonation velocities and lens-like geometric shaping is a well-established technique for producing structured detonation waves. This technique can be extended to produce nearly arbitrary detonation phase velocities for the purposes of sequentially imploding pressurized tubes or driving Mach disks through high-density metalized explosives. The current study presents the experimental development of accelerating, multi-component lenses designed using simple geometric optics and idealized front curvature. The fast explosive component is either Composition C4 (VOD = 8 km/s) or Primasheet 1000 (VOD = 7 km/s), while the slow component varies from heavily amine-diluted nitromethane (amine mass fraction exceeding 20%) to packed metal and glass particle beds wetted with amine-sensitized nitromethane. The applicability of the geometric optic analog to such highly heterogeneous explosives is also investigated. The multi-layered lens technique is further developed as a means of generating a directed mass and momentum flux of metal particles via Mach-disk formation and jetting in circular and oval planar lenses.

An explanation for the anomalous wave profiles obtained in composition B-3 impacted by flat nosed steel rods

NASA Astrophysics Data System (ADS)

James, H. R.; Gustavsen, R. L.; Dattelbaum, D. M.

2017-01-01

In previous work involving firing flat nosed steel rods into the 60/40 RDX/TNT explosive Composition B-3, we found an apparently anomalous "hump" in particle velocity wave profiles. The "hump" occurred on the center-line established by the rod, and at relatively late times, > 1 µs, after detonation onset. Several explanations, including that of a late time reaction, were postulated. This report will present evidence that the anomalous late time "hump" is due to the arrival of rarefaction waves from the rod's periphery. Simple analytic calculations and reactive-burn hydro-code calculations will be presented supporting this hypothesis.

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

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

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

2014-04-10

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

Property study of poly nitro compounds of cis-syn-cis-2, 6-dioxodecahydro-lH, 5H-diimidazo [4, 5-b: 4', 5'-e] pyrazine

NASA Astrophysics Data System (ADS)

Liu, Yang; Xu, Zhibin; Xu, Yudong; Xu, Liang; Meng, Zihui

2017-03-01

Poly nitro group substituted cis-syn-cis-2, 6-dioxodecahydro-lH, 5H-diimidazo [4, 5-b: 4', 5'-e] pyrazine derivatives are synthesized by modified method and adequately characterized. All compounds have good performance both in density (ρ> 1.85 g/cm3) and high detonation velocity (vD > 8800 m/s, calculated). Some representative compounds, for example, 4 (vD: 9405 ms-1; P: 41.6 GPa) and 5 (vD:9781 ms-1; P: 45.6 GPa) exhibit excellent detonation performances, which are comparable with current energetic compounds such as RDX (vD: 8724 ms-1; P: 35.2 GPa) and HMX (vD:9059 ms-1; P: 39.2 GPa). Considering the sensitivity increasing with the number of nitro group, two componds with tetranitro groups (2 and 3) are worthy of deep research.

Comparative theoretical studies of differently bridged nitramino-substituted ditetrazole 2-N-oxides with high detonation performance and an oxygen balance of around zero.

PubMed

Wu, Qiong; Kou, Bo; Hang, Zusheng; Zhu, Weihua

2017-06-01

In this work, six (A-F) nitramino (-NHNO 2 )-substituted ditetrazole 2-N-oxides with different bridging groups (-CH 2 -, -CH 2 -CH 2 -, -NH-, -N=N-, and -NH-NH-) were designed. The six compounds were based on the parent compound tetrazole 2-N-oxide, which possesses a high oxygen balance and high density. The structure, heat of formation, density, detonation properties (detonation velocity D and detonation pressure P), and the sensitivity of each compound was investigated systematically via density functional theory, by studying the electrostatic potential, and using molecular mechanics. The results showed that compounds A-F all have outstanding energetic properties (D: 9.1-10.0 km/s; P: 38.0-46.7 GPa) and acceptable sensitivities (h 50 : 28-37 cm). The bridging group present was found to greatly affect the detonation performance of each ditetrazole 2-N-oxide, and the compound with the -NH-NH- bridging group yielded the best results. Indeed, this compound (F) was calculated to have comparable sensitivity to the famous and widely used high explosive 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX), but with values of D and P that were about 8.7% and 19.4% higher than those for HMX, respectively. The present study shows that tetrazole 2-N-oxide is a useful parent compound which could potentially be used in the design of new and improved high-energy compounds to replace existing energetic compounds such as HMX.

The Physical Effects of Detonation in a Closed Cylindrical Chamber

NASA Technical Reports Server (NTRS)

Draper, C S

1935-01-01

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

Double Shock Experiments on PBX Explosive JOB-9003

NASA Astrophysics Data System (ADS)

Zhang, Xu

2017-06-01

One-dimensional plate impact experiments have been performed to study the double shock to detonation transition and Hugoniot state in the HMX-based explosive JOB-9003. The flyer was a combination with sapphire and Kel-F which could pass two different pressure waves into PBX Explosive JOB-9003 sample after impact. The particle velocities at interface and different depths in the PBX JOB-9003 sample were measured with Al-based electromagnetic particle velocity gauge technique, thus obtaining particle velocity - time diagram. According to the diagram, the corresponding Hugoniot state can be determined based on the particle velocity and shock wave velocity in the sample. Comparing with the single shock experiments, PBX Explosive JOB-9003 shows desensitization features due to the pre-pressed shock wave, the shock to detonation transition distance is longer than those single shock experiments.

Jet Formation and Penetration Study of Double-Layer Shaped Charge

NASA Astrophysics Data System (ADS)

Wang, Zhe; Jiang, Jian-Wei; Wang, Shu-You; Liu, Han

2018-04-01

A theoretical analysis on detonation wave propagation in a double-layer shaped charge (DLSC) is performed. Numerical simulations using the AUTODYN software are carried out to compare the distinctions between jet formations in DLSC and ordinary shaped charge (OSC), in particular, the OSC made using a higher detonation velocity explosive, which is treated as the outer layer charge in the DLSC. The results show that the improved detonation velocity ratio and radial charge percentage of outer-to-inner layer charge are conducive to the formation of a convergent detonation wave, which contributes to enhancement of jet tip velocity in DLSC. The thickness and mass percentages of liner flowing into jet in DLSC closely follow the exponential distribution along the radial direction, but the percentages in DLSC and the mass of effective jet, which have significant influence on the penetration depth, are lower than those in OSC with the outer layer charge. This implies that the total charge energy is the major factor controlling the effective jet formation, which is confirmed by the verification tests using flash X-ray system and following penetration tests. The numerical simulation and test results compare well, while penetration test results indicate that the performance of DLSC is not better than that of OSC with the outer layer charge, due to the differences in jet formation.

Evaluation of Impact Damage to the Burster Detonation Vessel Caused by Fragments from a Drained M121A1 Chemical Munition Detonated with an Initiation Charge

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

KIPP, MARLIN E.

2001-12-01

Explosive charges placed on the fuze end of a drained chemical munition are expected to be used as a means to destroy the fuze and burster charges of the munition. Analyses are presented to evaluate the effect of these additional initiation charges on the fragmentation characteristics for the M121A1 155mm chemical munition, modeled with a T244 fuze attached, and to assess the consequences of these fragment impacts on the walls of a containment chamber--the Burster Detonation Vessel. A numerical shock physics code (CTH) is used to characterize the mass and velocity of munition fragments. Both two- and three-dimensional simulations ofmore » the munition have been completed in this study. Based on threshold fragment velocity/mass results drawn from both previous and current analyses, it is determined that under all fragment impact conditions from the munition configurations considered in this study, no perforation of the inner chamber wall will occur, and the integrity of the Burster Detonation Vessel is retained. However, the munition case fragments have sufficient mass and velocity to locally damage the surface of the inner wall of the containment vessel.« less

Detonation Velocity Measurements from a Digital High-speed Rotating-mirror Framing Camera

DTIC Science & Technology

2012-09-01

information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 2...The intense light emission produced throughout the energetic material detonation process, however, suggests the alternative use of optical measurement...edge, figure 1). As previously stated, the detonation wave position was typically measured as a result of its light emission . Here, however, it was

Controlling the position of a stabilized detonation wave in a supersonic gas mixture flow in a plane channel

NASA Astrophysics Data System (ADS)

Levin, V. A.; Zhuravskaya, T. A.

2017-03-01

Stabilization of a detonation wave in a stoichiometric hydrogen-air mixture flowing at a supersonic velocity into a plane symmetric channel with constriction has been studied in the framework of a detailed kinetic mechanism of the chemical interaction. Conditions ensuring the formation of a thrust-producing f low with a stabilized detonation wave in the channel are determined. The inf luence of the inf low Mach number, dustiness of the combustible gas mixture supplied to the channel, and output cross-section size on the position of a stabilized detonation wave in the f low has been analyzed with a view to increasing the efficiency of detonation combustion of the gas mixture. It is established that thrust-producing flow with a stabilized detonation wave can be formed in the channel without any energy consumption.

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

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

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

2010-01-01

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

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

Ivashchenko, R.K.; Fedorenko, V.K.; Kadryov, V.K.

In this work an attempt was made, by lowering the temperature in the detonation zone, decreasing the particle flight velocity, and employing starting powders in which the WC particle size 20-40 mum predominated, to obtain detonation-deposited VK20 alloy coatings approaching closely in structure and phase composition hard-metal composites produced by the powder metallurgy method.

Development of a reactive burn model based upon an explicit visco-plastic pore collapse model

NASA Astrophysics Data System (ADS)

Bouton, Eric; Lefrançois, Alexandre; Belmas, Robert

2015-06-01

Our aim in this study is to develop a reactive burn model based upon a microscopic hot spot model to compute the initiation and shock to detonation of pressed TATB explosives. For the sake of simplicity, the hot spots are supposed to result from the viscoplastic collapse of spherical micro-voids inside the composition. Such a model has been incorporated in a lagrangian hydrodynamic code. In our calculations, 8 different pore diameters, ranging from 100 nm to 1.2 μm, have been taken into account and the porosity associated to each pore size has been deduced from the PBX-9502 void distribution derived from the SAXS. The last ingredient of our model is the burn rate that depends on two main variables. The first one is the shock pressure as proposed by the developers of the CREST model. The second one is the number of effective chemical reaction sites calculated by the microscopic model. Furthermore, the function of the reaction progress variable of the burn rate is similar to that in the SURF model proposed by Menikoff. Our burn rate has been calibrated by using pressure profile, material velocities wave forms obtained with embedded particle velocity gauges and run distance to detonation. The comparison between the numerical and experimental results is really good and sufficient to perform a wide variety of simulations including single, double shock waves and the desensitization phenomenon. In conclusion, future works are described.

Deflagration to detonation transition in mechanoactivated mixtures of ammonium perchlorate with aluminum

NASA Astrophysics Data System (ADS)

Shevchenko, A. A.; Dolgoborodov, A. Yu; Kirilenko, V. G.; Brazhnikov, M. A.

2016-11-01

Deflagration-to-detonation transition (DDT) in aluminum-ammonium perchlorate (Al/AP) loose-packed charges (80% porosity) has been studied. The charges were manufactured from preliminary mechanoactivated mixtures. The mixtures placed in steel tubes 10 mm in diameter were ignited by Nichrome wire. It was found that it is possible to distinguish three parts corresponding to different stages of DDT process development. Steady-state detonation velocity reached the level of 2500 m/s at the distance of 90 mm from the ignition point.

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.

Computational Modeling of Causal Mechanisms of Blast Wave Induced Traumatic Brain Injury - A Potential Tool for Injury Prevention

DTIC Science & Technology

2009-10-01

detonation and expansion of the TNT explosive materials was described using the JWL (Jones-Wilkins-Lee) equation of state (EOS) along with a high...explosive material definition (Dobratz 1981). The JWL equation is described as: Where V= ρ0 (initial density of an explosive)/ρ (density of detonation...gas). E is specific internal energy. A, B, R1, R2, ω are JWL fitting parameters (Table 2). ρ0 Detonation velocity CJ pressure Material

Characterization and Performance of a Liquid Hydrocarbon-Fueled Pulse Detonation Rocket Engine

DTIC Science & Technology

2001-12-01

head wall pressure (P3) and the two sensors at the end of the tube provided indication of detonation wave passage (Wave1 and Wave2 ). These data...wave speed using the time of passage at Wave1 and Wave2 and the user-defined value of the distance between each sensor (this distance varied slightly...for each tube extension). A detonation velocity of zero was returned for any event in which neither Wave1 or Wave2 sensed a pressure rise of

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.

Photogrammetry of the particle trajectories on DIPOLE WEST Shots 8, 9, 10, and 11. Volume III. Shot 8. Final report, 1 October--31 December 1977

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

Dewey, J.M.; McMillin, D.J.; Trill, D.

1978-01-01

This volume describes the photogrammetry and analysis of the particle trajectories in blast waves produced by the simultaneous detonation of two spherical 1080-lb (490-kg) Pentolite charges (DIPOLE WEST Shot 8). One of the charges was positioned at a height of 25 feet above smooth ground, and the second charge 50 feet above the first. Photogrammetrical measurements were made of the trajectories of air particle flow tracers (smoke puffs), which had been placed in a vertical grid at heights ranging from 3 to 58 feet above the ground and at radial distances ranging from 25 to 140 feet from the verticalmore » axis through the charges. From the measured particle trajectories, calculations were made, as described in AD-A058 377. From the shock front times-of-arrival, calculations were made of the shock velocities and, in turn, the peak particle velocities, air densities and hydrostatic overpressure immediately behind each shock. Calculations were also made of the variation with time of the particle velocity, density, hydrostatic overpressure, dynamic pressure, and total pressure at several fixed points. Results, presented both graphically and in tables, are compared to results previously calculated for the same experiment using shock front photogrammetry.« less

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

NASA Astrophysics Data System (ADS)

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

2014-03-01

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

Determination of detonation parameters for liquid High Explosives

NASA Astrophysics Data System (ADS)

Mochalova, Valentina; Utkin, Alexander

2011-06-01

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

Determination of detonation parameters for liquid high explosives

NASA Astrophysics Data System (ADS)

Mochalova, Valentina; Utkin, Alexander

2012-03-01

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

Detonation energies of explosives by optimized JCZ3 procedures

NASA Astrophysics Data System (ADS)

Stiel, Leonard I.; Baker, Ernest L.

1998-07-01

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

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

NASA Astrophysics Data System (ADS)

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

2017-06-01

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

Probing Aluminum Reactions in Combustion and Explosion Via the Kinetic Isotope Effect

NASA Astrophysics Data System (ADS)

Tappan, Bryce

2015-06-01

The mechanism that controls the reaction speed of aluminum in explosion and combustion is poorly understood, and experimentally difficult to measure. Recently, work in our laboratory has demonstrated that during the combustion of nanoparticulate aluminum with H2O or D2O, different reaction rates due to the kinetic isotope effect are observed. This result is the first-ever observed kinetic isotope effect in a metal combustion reaction and verifies that chemical reaction kinetics play a major role in determining the global burning rate. During or shortly after a detonation, however, the reaction rates are dramatically faster and the physical mechanism controlling Al reaction is likely different than during combustion events. To utilize the kinetic isotope effect to probe Al reactions in detonation, formulations were produced that contain powdered Al in deuterated high explosives and high-fidelity detonation velocity were determined along with PDV measurements to observe early wall velocity expansion measurements. The JWL equation of state was solved to determine temperature, pressure and energies at specific time periods, in addition of Gurney energies, which enables the elucidation of Al reaction extent. By comparison of the Al oxidation with LiF, data indicate that Al oxidation occurs on an extremely fast time scale and isotope effects in both the HE detonation and post-detonation Al reactions are discussed.

Comparison of detonation spreading in pressed ultra-fine and nano-TATB

NASA Astrophysics Data System (ADS)

Olles, Joseph; Wixom, Ryan; Knepper, Robert; Yarrington, Cole; Patel, Rajen; Stepanov, Victor

2017-06-01

Detonation spreading behavior in insensitive high explosives is an important performance characteristic for initiation-train design. In the past, several variations of the floret test have been used to study this phenomenon. Commonly, dent blocks or multi-fiber optical probes were employed for reduced cost and complexity. We devised a floret-like test, using minimal explosive material, to study the detonation spreading in nano-TATB as compared to ultra-fine TATB. Our test uses a streak camera, combined with photonic Doppler velocimetry, to image the breakout timing and quantify the output particle velocity. The TATB acceptor pellets are initiated using an explosively-driven aluminum flyer with a well characterized velocity. We characterized the two types of TATB by assessing purity, particle morphology, and the microstructure of the consolidated pellets. Our results align with published data for ultra-fine TATB, however the nano-TATB shows a distinct difference where output has a strong dependence on density. The results indicate that control over pellet pore size and pressing density may be used to optimize detonation spreading behavior.

The three-dimensional simulation analysis of dynamic response on perforated strings

NASA Astrophysics Data System (ADS)

Li, M. F.; Liu, H. F.; Dou, Y. H.; Cao, L. H.; Liu, Y. X.

2018-06-01

It analyzes the dynamic response and stresses of perforating tubular string to detonating impact load in oil-gas well in ANSYS, obtains the response of vibration displacement, velocity and acceleration of perforating tubularstring caused by detonating impact load, finds the influence of the length and wall thickness of perforating tubular string to working stresses. The result shows that:when the detonating impact load exerts the perforating tubular string with compressive and tensile axial force alternatively;the vibration displacement, velocity and acceleration of perfora-ting tubular string change periodically at same cycle;the closer to the perforating gun, the larger the amplitude of vi-bration velocity and acceleration;the closer to the packer the smaller the vibration displacement, the larger the work-ing equivalent stress of perforating tubular string;the longer or the thicker the perforating tubular string, the smaller the working equivalent stress and the higher the strength safety. Therefore, it uses the damping tube between packer and perforating gun as well as thick walled tubing to increase the strength safety of perforating tubular string.

A complete equation of state for non-ideal condensed phase explosives

NASA Astrophysics Data System (ADS)

Wilkinson, S. D.; Braithwaite, M.; Nikiforakis, N.; Michael, L.

2017-12-01

The objective of this work is to improve the robustness and accuracy of numerical simulations of both ideal and non-ideal explosives by introducing temperature dependence in mechanical equations of state for reactants and products. To this end, we modify existing mechanical equations of state to appropriately approximate the temperature in the reaction zone. Mechanical equations of state of the Mie-Grüneisen form are developed with extensions, which allow the temperature to be evaluated appropriately and the temperature equilibrium condition to be applied robustly. Furthermore, the snow plow model is used to capture the effect of porosity on the reactant equation of state. We apply the methodology to predict the velocity of compliantly confined detonation waves. Once reaction rates are calibrated for unconfined detonation velocities, simulations of confined rate sticks and slabs are performed, and the experimental detonation velocities are matched without further parameter alteration, demonstrating the predictive capability of our simulations. We apply the same methodology to both ideal (PBX9502, a high explosive with principal ingredient TATB) and non-ideal (EM120D, an ANE or ammonium nitrate based emulsion) explosives.

The stabilization of unstable detonation waves for the mixture of nitromethane/methanol

NASA Astrophysics Data System (ADS)

Utkin, A. V.; Koldunov, S. A.; Mochalova, V. M.; Torunov, S. I.; Lapin, S. M.

2015-11-01

Using a laser interferometer VISAR the measurements of the particle velocity profiles in detonation waves for nitromethane/methanol mixtures with additions of a sensitizer diethylenetriamine were conducted. It is shown that the detonation front in a mixture of nitromethane/methanol is unstable and sensitizer is an effective method for the flow stabilization. If the diluent concentration is less than 10%, the detonation front is stabilized by adding of 1% diethylenetriamine. At higher concentrations of methanol, the sensitizer does not reject instability, but the amplitude of oscillations decreases in several times. An increase of the limit concentration of methanol at the addition of diethylenetriamine to the mixture was found.

Ignition and Growth Modeling of Detonating LX-04 (85% HMX / 15% VITON) Using New and Previously Obtained Experimental Data

NASA Astrophysics Data System (ADS)

Tarver, Craig

2017-06-01

An Ignition and Growth reactive flow model for detonating LX-04 (85% HMX / 15% Viton) was developed using new and previously obtained experimental data on: cylinder test expansion; wave curvature; failure diameter; and laser interferometric copper and tantalum foil free surface velocities and LiF interface particle velocity histories. A reaction product JWL EOS generated by the CHEETAH code compared favorably with the existing, well normalized LX-04 product JWL when both were used with the Ignition and Growth model. Good agreement with all existing experimental data was obtained. Keywords: LX-04, HMX, detonation, Ignition and Growth PACS:82.33.Vx, 82.40.Fp This work was performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

Explosive component acceptance tester using laser interferometer technology

NASA Technical Reports Server (NTRS)

Wickstrom, Richard D.; Tarbell, William W.

1993-01-01

Acceptance testing of explosive components requires a reliable and simple to use testing method that can discern less than optimal performance. For hot-wire detonators, traditional techniques use dent blocks or photographic diagnostic methods. More complicated approaches are avoided because of their inherent problems with setup and maintenance. A recently developed tester is based on using a laser interferometer to measure the velocity of flying plates accelerated by explosively actuated detonators. Unlike ordinary interferometers that monitor displacement of the test article, this device measures velocity directly and is commonly used with non-spectral surfaces. Most often referred to as the VISAR technique (Velocity Interferometer System for Any Reflecting Surface), it has become the most widely-accepted choice for accurate measurement of velocity in the range greater than 1 mm/micro-s. Traditional VISAR devices require extensive setup and adjustment and therefore are unacceptable in a production-testing environment. This paper describes a new VISAR approach which requires virtually no adjustments, yet provides data with accuracy comparable to the more complicated systems. The device, termed the Fixed-Cavity VISAR, is currently being developed to serve as a product verification tool for hot-wire detonators and slappers. An extensive data acquisition and analysis computer code was also created to automate the manipulation of raw data into final results.

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.

Molecular design of new nitramine explosives: 1,3,5,7-tetranitro-8-(nitromethyl)-4-imidazolino[4,5-b]4-imidazolino-[4,5-e] pyridine and its N-oxide.

PubMed

Liu, Hui; Du, Hongchen; Wang, Guixiang; Liu, Yan; Gong, Xuedong

2012-04-01

Two new nitramine compounds containing pyridine, 1,3,5,7-tetranitro-8-(nitromethyl) -4-imidazolino[4,5-b]4-imidazolino-[4,5-e]pyridine and its N-oxide 1,3,5,7-tetranitro-8- (nitromethyl)-4-imidazolino[4,5-b]4-imidazolino-[4,5-e]pyridine-4-ol were proposed. Density functional theory (DFT) has been employed to study the molecular geometries, electronic structures, infrared spectra, and thermodynamic properties at the B3LYP/6-31G* level. Their detonation performances evaluated using the Kamlet-Jacobs equations with the calculated densities and heats of formation are superior to those of HMX. The predicted densities of them were ca. 2 g cm(-3), detonation velocities were over 9 km s(-1), and detonation pressures were about 40 GPa, showing that they may be potential candidates of high energy density materials (HEDMs). The natural bond orbital analysis indicated that N-NO(2) bond is the trigger bond during thermolysis process. The stability of the title compounds is slightly lower than that of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12- hexaazaisowurtzitane (CL-20). The results of this study may provide basic information for the molecular design of new HEDMs.

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

NASA Astrophysics Data System (ADS)

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

2017-01-01

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

Stability of cosmological detonation fronts

NASA Astrophysics Data System (ADS)

Mégevand, Ariel; Membiela, Federico Agustín

2014-05-01

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

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

NASA Astrophysics Data System (ADS)

Knepper, Robert; Wixom, Ryan; Tappan, Alexander

2015-06-01

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

A Study of SDT in an Ammonium Nitrate (NH4 NO3) Based Granular Explosive

NASA Astrophysics Data System (ADS)

Burns, Malcolm; Taylor, Peter

2007-06-01

In order to study the SDT process in a granular non ideal explosive (NIE) an experimental technique has been developed that allows the granular explosive to be shock initiated at a well controlled ``tap density''. The granular NIE was contained in a PMMA cone and a planar shock was delivered to the explosive through buffer plates of varying material. A combination of piezoelectric probes, ionization pins, PVDF stress gauges and a high speed framing camera were used to measure the input shock pressure and shock and detonation wave positions in the explosive. Four trials were performed to characterize the run to detonation distance versus pressure relationship (Pop plot) of the granular NH4 NO3 explosive. Input pressures ranged from close to the 4GPa predicted CJ pressure of the granular explosive down to 1.4 GPa, giving run distances up to 14mm for the lowest pressure. The data indicates a steady acceleration of the input shock to the detonation velocity, implying significant reaction growth at the shock front. This is in contrast to the behaviour of most high density pressed PBXs which show little growth in shock front velocity before transit to detonation. The experimentally observed initiation behaviour is compared to that predicted by a simple JWL++ reactive burn model for the granular NH4 NO3 explosive which has been fitted to other detonics experiments on this material.

Design of New Bridge-Ring Energetic Compounds Obtained by Diels-Alder Reactions of Tetranitroethylene Dienophile.

PubMed

He, Piao; Mei, Hao-Zheng; Wu, Le; Yang, Jun-Qing; Zhang, Jian-Guo; Cohen, Adva; Gozin, Michael

2018-03-29

The density functional theory method was employed to calculate three-dimensional structures for a series of novel explosophores. The design of new molecules (DA1-DA12) was based on the bridge-ring structures that could be formed via Diels-Alder (DA) reaction of selected nitrogen-rich dienes and tetranitroethylene dienophile. The feasibility of the proposed DA reactions was predicted on the basis of the molecular orbital theory. The strong interactions between the HOMO of dienes, with electron-donating groups (Diene2, Diene6, and Diene8), and the LUMO of tetranitroethylene dienophile suggested thermodynamically favorable formation of the desired DA reaction products. In addition to molecular structures of the explored DA compounds, their physicochemical and energetic properties were also calculated in detail. Due to compact bridge-ring structures, new energetic molecules have highly positive heats of formation (up to 1124.90 kJ·mol -1 ) and high densities (up to 2.04 g·cm -3 ). Also, as a result of all-right ratios of nitrogen and oxygen, most of the new compounds possess high detonation velocities (8.28-10.02 km·s -1 ) and high detonation pressures (30.87-47.83 GPa). Energetic compounds DA1, DA4, and DA12 exhibit a superior detonation performance over widely used HMX explosive, and DA5, DA7, and DA10 could be comparable to the state-of-the-art CL-20 and ONC explosives. Our proposed designs and synthetic methodology should provide a platform for the development of novel energetic materials with superior performance.

GAP/CL-20-Based Compound Explosive: A New Booster Formulation Used in a Small-Sized Initiation Network

NASA Astrophysics Data System (ADS)

Yanju, Wei; Jingyu, Wang; Chongwei, An; Hequn, Li; Xiaomu, Wen; Binshuo, Yu

2017-01-01

With ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and glycidyl azide polymer (GAP) as the solid filler and binder, respectively, GAP/CL-20-based compound explosives were designed and prepared. Using micro injection charge technology, the compound explosives were packed into small grooves to explore their application in a small-sized initiation network. The detonation reliability, detonation velocity, mechanical sensitivity, shock sensitivity, and brisance of the explosive were measured and analyzed. The results show that when the solid content of CL-20 is 82 wt%, the explosive charged in the groove has a smooth surface from a macroscopic view. From a microscopic view, a coarse surface is bonded with many CL-20 particles by GAP binder. The GAP/CL-20-based explosive charge successfully generates detonation waves in a groove larger than 0.6 mm × 0.6 mm. When the charge density in the groove is 1.68 g.cm-3 (90% theoretical maximum density), the detonation velocity reaches 7,290 m.s-1. Moreover, this kind of explosive is characterized by low impact and shock sensitivity.

Influence of Flow Gradients on Mach Stem Initiation of PBX-9502

NASA Astrophysics Data System (ADS)

Hull, Lawrence; Miller, Phillip; Mas, Eric; Focused Experiments Team

2017-06-01

Recent experiments and theory explore the effect of flow gradients on reaction acceleration and stability in the pressure-enhanced region between colliding sub-detonative shock waves in PBX-9502. The experiments are designed to produce divergent curved incident shock waves that interact in a convergent irregular reflection, or ``Mach stem'', configuration. Although this flow is fundamentally unsteady, such a configuration does feature particle paths having a single shock wave that increases the pressure from zero to the wave-reflected enhanced pressure. Thus, the possibility of pre-shock desensitization is precluded in this interaction region. Diagnostics record arrival wave velocity, shape, and material velocity along the angled free surface face of a large wedge. The wedge is large enough to allow observation of the wave structure for distances much larger than the run-to-detonation derived from classical ``Pop plot'' data. The explosive driver system produces the incident shocks and allows some control of the flow gradients in the collision region. Further, the incident shocks are very weak and do not transition to detonation. The experiments discussed feature incident shock waves that would be expected to cause initiation in the Mach stem, based on the Pop plot. Results show that the introduction of pressure/velocity gradients in the reaction zone strongly influences the ability of the flow to build to a steady ``CJ'' detonation. As expected, the ability of the Mach stem to stabilize or accelerate is strongly influenced by the incident shock pressure.

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

Reaugh, J. E.

HE ignition caused by shear localization is the principal concern for safety analyses of postulated mechanical insults to explosive assemblies. Although prompt detonation from shock is certainly a concern, insults that lead to prompt detonation are associated with high velocity, and correspondingly rare. For high-density HMX assemblies, an impact speed (by a steel object) of 400 m/s is needed to develop a detonation in a run distance less than 30 mm. To achieve a steady plane shock, which results in the shortest run distance to detonation for a given peak pressure, the impactor diameter must exceed 60 mm, and thicknessmore » approach 20 mm. Thinner plates and/or smaller diameter ones require even higher impact velocity. Ignitions from shear localization, however, have been observed from impacts less than 50 m/s in Steven tests, less than 30 m/s from spigot impact tests, and less than 10 m/s from various drop tests. This lower velocity range is much frequent in postulated mechanical insults. Preliminary computer simulations and analyses of a variety of such tests have suggested that although each is accompanied by shear localization, there are differing detailed mechanisms at work that cause the ignitions. We identify those mechanisms that may be at work in a variety of such tests, and suggest how models of shear ignition, such as HERMES, may be revised and calibrated to conform to experiment. We suggest combining additional experiments with computer simulations and model development to begin confirm or uncover mechanisms that may be at work in a specific postulated event.« less

Appraisal of UTIAS implosion-driven hypervelocity launchers and shock tubes.

NASA Technical Reports Server (NTRS)

Glass, I. I.

1972-01-01

A critical appraisal is made of the design, research, development, and operation of the novel UTIAS implosion-driven hypervelocity launchers and shock tubes. Explosively driven (PbN6-lead azide, PETN-pentaerythritetetranitrate) implosions in detonating stoichiometric hydrogen-oxygen mixtures have been successfully developed as drivers for hypervelocity launchers and shock tubes in a safe and reusable facility. Intense loadings at very high calculated pressures, densities, and temperatures, at the implosion center, cause severe problems with projectile integrity. Misalignment of the focal point can occur and add to the difficulty in using small caliber projectiles. In addition, the extreme driving conditions cause barrel expansion, erosion, and possible gas leakage from the base to the head of the projectile which cut the predicted muzzle velocities to half or a third of the lossless calculated values. However, in the case of a shock-tube operation these difficulties are minimized or eliminated and the possibilities of approaching Jovian reentry velocities are encouraging.

Simulation of the Reflected Blast Wave froma C-4 Charge

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

Howard, W M; Kuhl, A L; Tringe, J W

2011-08-01

The reflection of a blast wave from a C4 charge detonated above a planar surface is simulated with our ALE3D code. We used a finely-resolved, fixed Eulerian 2-D mesh (167 {micro}m per cell) to capture the detonation of the charge, the blast wave propagation in nitrogen, and its reflection from the surface. The thermodynamic properties of the detonation products and nitrogen were specified by the Cheetah code. A programmed-burn model was used to detonate the charge at a rate based on measured detonation velocities. Computed pressure histories are compared with pressures measured by Kistler 603B piezoelectric gauges at 8 rangesmore » (GR = 0, 2, 4, 8, 10, and 12 inches) along the reflecting surface. Computed and measured waveforms and positive-phase impulses were similar, except at close-in ranges (GR < 2 inches), which were dominated by jetting effects.« less

Simulation of the reflected blast wave from a C-4 charge

NASA Astrophysics Data System (ADS)

Howard, W. Michael; Kuhl, Allen L.; Tringe, Joseph

2012-03-01

The reflection of a blast wave from a C4 charge detonated above a planar surface is simulated with our ALE3D code. We used a finely-resolved, fixed Eulerian 2-D mesh (167 μm per cell) to capture the detonation of the charge, the blast wave propagation in nitrogen, and its reflection from the surface. The thermodynamic properties of the detonation products and nitrogen were specified by the Cheetah code. A programmed-burn model was used to detonate the charge at a rate based on measured detonation velocities. Computed pressure histories are compared with pressures measured by Kistler 603B piezoelectric gauges at 7 ranges (GR = 0, 5.08, 10.16, 15.24, 20.32, 25.4, and 30.48 cm) along the reflecting surface. Computed and measured waveforms and positive-phase impulses were similar, except at close-in ranges (GR < 5 cm), which were dominated by jetting effects.

Computer code for the optimization of performance parameters of mixed explosive formulations.

PubMed

Muthurajan, H; Sivabalan, R; Talawar, M B; Venugopalan, S; Gandhe, B R

2006-08-25

LOTUSES is a novel computer code, which has been developed for the prediction of various thermodynamic properties such as heat of formation, heat of explosion, volume of explosion gaseous products and other related performance parameters. In this paper, we report LOTUSES (Version 1.4) code which has been utilized for the optimization of various high explosives in different combinations to obtain maximum possible velocity of detonation. LOTUSES (Version 1.4) code will vary the composition of mixed explosives automatically in the range of 1-100% and computes the oxygen balance as well as the velocity of detonation for various compositions in preset steps. Further, the code suggests the compositions for which least oxygen balance and the higher velocity of detonation could be achieved. Presently, the code can be applied for two component explosive compositions. The code has been validated with well-known explosives like, TNT, HNS, HNF, TATB, RDX, HMX, AN, DNA, CL-20 and TNAZ in different combinations. The new algorithm incorporated in LOTUSES (Version 1.4) enhances the efficiency and makes it a more powerful tool for the scientists/researches working in the field of high energy materials/hazardous materials.

Influencing Factors of the Initiation Point in the Parachute-Bomb Dynamic Detonation System

NASA Astrophysics Data System (ADS)

Qizhong, Li; Ye, Wang; Zhongqi, Wang; Chunhua, Bai

2017-12-01

The parachute system has been widely applied in modern armament design, especially for the fuel-air explosives. Because detonation of fuel-air explosives occurs during flight, it is necessary to investigate the influences of the initiation point to ensure successful dynamic detonation. In fact, the initiating position exist the falling area in the fuels, due to the error of influencing factors. In this paper, the major influencing factors of initiation point were explored with airdrop and the regularity between initiation point area and factors were obtained. Based on the regularity, the volume equation of initiation point area was established to predict the range of initiation point in the fuel. The analysis results showed that the initiation point appeared area, scattered on account of the error of attitude angle, secondary initiation charge velocity, and delay time. The attitude angle was the major influencing factors on a horizontal axis. On the contrary, secondary initiation charge velocity and delay time were the major influencing factors on a horizontal axis. Overall, the geometries of initiation point area were sector coupled with the errors of the attitude angle, secondary initiation charge velocity, and delay time.

Equations of state for explosive detonation products: The PANDA model

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

Kerley, G.I.

1994-05-01

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

Discrete charge diagnostics on Pre-DIRECT COURSE

NASA Astrophysics Data System (ADS)

Guice, R. L.; Bryant, C.

1984-02-01

The Air Force Weapons Laboratory attempted to make 100 time-of-arrival measurements on Pre-DIRECT COURSE. With an 88 percent success rate, the detonation wave propagation within the charge was measured. The top and bottom hemispheres detonated at two different rates. However, the detonation velocities were well within the existing data base for Ammonium-Nitrate Fuel Oil charges. One large jet was observed on the charge but its location should not have caused any problems for ground level measurements. Twenty experimental time-of-arrival crystals were also fielded; however, the results are skeptical due to the grounding system of the support structure.

Shock behavior of explosives about the c-j (Chapman-Juget) point

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

Cooper, P.W.

1989-01-01

Experimental data for pressure and particle velocity along the Hugoniot of detonation reaction products for a number of explosives are correlated in a reduced parameter form P/P/sub cj/ versus u/u/sub cj/. Two correlations are found: P/P/sub cj/ = a + b(u/u/sub cj/) + c(u/u/sub cj/)/sup 2/ when P/P/sub cj/>0.08, and P/P/sub cj/ = m(u/u/sub cj/)/sup n/ when P/P/sub cj/<0.08. The correlations yield results that agree reasonably with code calculations. 13 refs., 3 figs., 1 tab.

Gasdynamic model of turbulent combustion in an explosion

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

Kuhl, A.L.; Ferguson, R.E.; Chien, K.Y.

1994-08-31

Proposed here is a gasdynamic model of turbulent combustion in explosions. It is used to investigate turbulent mixing aspects of afterburning found in TNT charges detonated in air. Evolution of the turbulent velocity field was calculated by a high-order Godunov solution of the gasdynamic equations. Adaptive Mesh Refinement (AMR) was used to follow convective-mixing processes on the computational grid. Combustion was then taken into account by a simplified sub-grid model, demonstrating that it was controlled by turbulent mixing. The rate of fuel consumption decayed inversely with time, and was shown to be insensitive to grid resolution.

Changes in Blow-Off Velocity Observed in Two Explosives at the Threshold for Sustained Ignition Using the Modified Gap Test

NASA Astrophysics Data System (ADS)

Lee, R. J.; Forbes, J. W.; Tasker, D. G.; Orme, R. S.

2009-12-01

The Modified Gap Test was used to quantify different levels of partial reaction for various input stresses. This test configuration has been historically useful in highlighting thresholds for first reaction, sustained ignition, and detonation. Two different HMX based compositions were studied; a cast-cured composition with 87% HMX and a pressed composition with 92% HMX. Each explosive was prepared from large industrially produced batches consisting of different unreactive polymeric binder systems. Short samples (50.8 mm in diameter and 12.7 mm thick) were shock loaded using the standard large-scale gap test donor system. Product-cloud blow-off velocities at the opposite end of the sample were measured using a high-speed digital-camera. Velocity versus input pres sure plots provided changes in reactivity that had developed by the 12.7 mm run distance. Results appear consistent for the lower input stresses. In contrast, the results varied widely in a range of input stresses around the transition to detonation in both explosives. These results indicate that both explosives are subject to large variation in blow-off velocity in a range of input stresses near the threshold for prompt detonation. This is explained by localized variations of HMX particle size and density in industrially prepared samples. Approved for public release, Distribution unlimited, IHDIV Log No. 09-108.

Star of Condor - A strontium critical velocity experiment, Peru, 1983

NASA Technical Reports Server (NTRS)

Wescott, E. M.; Stenbaek-Nielsen, H. C.; Hallinan, T.; Foeppl, H.; Valenzuela, A.

1986-01-01

'Star of Condor' was a critical velocity experiment using Sr vapor produced in a radial shaped charge, which was carried to 571.11 km altitude on a Taurus-Tomahawk rocket launched from Punto Lobos, Peru, and detonated in the plane of the magnetic field lines so that all ranges of pitch angles from parallel to B to perpendicular to B were covered. Sr has a critical velocity of 3.3 km/s, and from observation, 42.5 percent of the neutral Sr gas had a velocity component perpendicular to B exceeding that value. No Sr ion emissions were detected shortly after the burst with usual TV integration times. However, about 10 min after the detonation a faint field-aligned streak was discovered with long TV integration times. The brightness is estimated as 5 R, which, combined with the streak geometry, implies an ion production of 2.4 x 10 to the 19th ions. This is only 0.0036 percent ionization of the Sr vapor. All the ions could easily have been produced by thermal ionization from the original detonation thermal distribution. The breakup of the Sr gas into small bloblike structures may have allowed the high-energy electrons to escape before an ionization cascade could be produced. For whatever reason, the Alfven mechanism proposed for space plasmas in the absence of laboratory walls did not produce an ionization cascade in the experiment.

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

NASA Astrophysics Data System (ADS)

Ciccarelli, G.; Cross, M.

2016-09-01

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

Equation of State of Detonation Products for TNT by Aquarium Technique

NASA Astrophysics Data System (ADS)

Han, Yong

2017-06-01

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

Experimental study on incident wave speed and the mechanisms of deflagration-to-detonation transition in a bent geometry

NASA Astrophysics Data System (ADS)

Li, L.; Li, J.; Teo, C. J.; Chang, P. H.; Khoo, B. C.

2018-03-01

The study of deflagration-to-detonation transition (DDT) in bent tubes is important with many potential applications including fuel pipeline and mine tunnel designs for explosion prevention and detonation engines for propulsion. The aim of this study is to exploit low-speed incident shock waves for DDT using an S-shaped geometry and investigate its effectiveness as a DDT enhancement device. Experiments were conducted in a valveless detonation chamber using ethylene-air mixture at room temperature and pressure (303 K, 1 bar). High-speed Schlieren photography was employed to keep track of the wave dynamic evolution. Results showed that waves with velocity as low as 500 m/s can experience a successful DDT process through this S-shaped geometry. To better understand the mechanism, clear images of local explosion processes were captured in either the first curved section or the second curved section depending on the inlet wave velocity, thus proving that this S-shaped tube can act as a two-stage device for DDT. Owing to the curved wall structure, the passing wave was observed to undergo a continuous compression phase which could ignite the local unburnt mixture and finally lead to a local explosion and a detonation transition. Additionally, the phenomenon of shock-vortex interaction near the wave diffraction region was also found to play an important role in the whole process. It was recorded that this interaction could not only result in local head-on reflection of the reflected wave on the wall that could ignite the local mixture, and it could also contribute to the recoupling of the shock-flame complex when a detonation wave is successfully formed in the first curved section.

High fidelity studies of exploding foil initiator bridges, Part 1: Experimental method

NASA Astrophysics Data System (ADS)

Bowden, Mike; Neal, William

2017-01-01

Simulations of high voltage detonators, such as Exploding Bridgewire (EBW) and Exploding Foil Initiators (EFI), have historically been simple, often empirical, one-dimensional models capable of predicting parameters such as current, voltage and in the case of EFIs, flyer velocity. Correspondingly, experimental methods have in general been limited to the same parameters. With the advent of complex, first principles magnetohydrodynamic codes such as ALEGRA and ALE-MHD, it is now possible to simulate these components in three dimensions, predicting a much greater range of parameters than before. A significant improvement in experimental capability was therefore required to ensure these simulations could be adequately validated. In this first paper of a three part study, the experimental method for determining the current, voltage, flyer velocity and multi-dimensional profile of detonator components is presented. This improved capability, along with high fidelity simulations, offer an opportunity to gain a greater understanding of the processes behind the functioning of EBW and EFI detonators.

Sparse Partial Equilibrium Tables in Chemically Resolved Reactive Flow

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

Vitello, P; Fried, L E; Pudliner, B

2003-07-14

The detonation of an energetic material is the result of a complex interaction between kinetic chemical reactions and hydrodynamics. Unfortunately, little is known concerning the detailed chemical kinetics of detonations in energetic materials. CHEETAH uses rate laws to treat species with the slowest chemical reactions, while assuming other chemical species are in equilibrium. CHEETAH supports a wide range of elements and condensed detonation products and can also be applied to gas detonations. A sparse hash table of equation of state values, called the ''cache'' is used in CHEETAH to enhance the efficiency of kinetic reaction calculations. For large-scale parallel hydrodynamicmore » calculations, CHEETAH uses MPI communication to updates to the cache. We present here details of the sparse caching model used in the CHEETAH. To demonstrate the efficiency of modeling using a sparse cache model we consider detonations in energetic materials.« less

Sparse Partial Equilibrium Tables in Chemically Resolved Reactive Flow

NASA Astrophysics Data System (ADS)

Vitello, Peter; Fried, Laurence E.; Pudliner, Brian; McAbee, Tom

2004-07-01

The detonation of an energetic material is the result of a complex interaction between kinetic chemical reactions and hydrodynamics. Unfortunately, little is known concerning the detailed chemical kinetics of detonations in energetic materials. CHEETAH uses rate laws to treat species with the slowest chemical reactions, while assuming other chemical species are in equilibrium. CHEETAH supports a wide range of elements and condensed detonation products and can also be applied to gas detonations. A sparse hash table of equation of state values is used in CHEETAH to enhance the efficiency of kinetic reaction calculations. For large-scale parallel hydrodynamic calculations, CHEETAH uses parallel communication to updates to the cache. We present here details of the sparse caching model used in the CHEETAH coupled to an ALE hydrocode. To demonstrate the efficiency of modeling using a sparse cache model we consider detonations in energetic materials.

Effects of Fuel Distribution on Detonation Tube Performance

NASA Technical Reports Server (NTRS)

Perkins, H. Douglas; Sung, Chih-Jen

2003-01-01

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

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

NASA Astrophysics Data System (ADS)

Biss, Matthew; Murphy, Michael; Lieber, Mark

2017-06-01

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

Prediction of the Chapman-Jouguet chemical equilibrium state in a detonation wave from first principles based reactive molecular dynamics.

PubMed

Guo, Dezhou; Zybin, Sergey V; An, Qi; Goddard, William A; Huang, Fenglei

2016-01-21

The combustion or detonation of reacting materials at high temperature and pressure can be characterized by the Chapman-Jouguet (CJ) state that describes the chemical equilibrium of the products at the end of the reaction zone of the detonation wave for sustained detonation. This provides the critical properties and product kinetics for input to macroscale continuum simulations of energetic materials. We propose the ReaxFF Reactive Dynamics to CJ point protocol (Rx2CJ) for predicting the CJ state parameters, providing the means to predict the performance of new materials prior to synthesis and characterization, allowing the simulation based design to be done in silico. Our Rx2CJ method is based on atomistic reactive molecular dynamics (RMD) using the QM-derived ReaxFF force field. We validate this method here by predicting the CJ point and detonation products for three typical energetic materials. We find good agreement between the predicted and experimental detonation velocities, indicating that this method can reliably predict the CJ state using modest levels of computation.

Impact of the lateral boundary conditions resolution on dynamical downscaling of precipitation in mediterranean spain

NASA Astrophysics Data System (ADS)

Amengual, A.; Romero, R.; Homar, V.; Ramis, C.; Alonso, S.

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.

High-Temperature and Pressure Aluminum Reactions in Carbon Dioxide Rich Post-Detonation Environments

NASA Astrophysics Data System (ADS)

Tappan, Bryce; Manner, Virginia; Pemberton, Steven; Lieber, Mark; Johnson, Carl; Sanders, Eric

2013-06-01

Powdered aluminum is a common additive to energetic materials, but little is understood regarding its reaction rate at very high temperatures and pressures in specific oxidizing gases such as carbon dioxide. Aluminum reaction kinetics in carbon dioxide have been studied in various reaction conditions, but difficulties arise in the more specific study of Al oxidation at the high pressures and temperatures in detonation reactions. To study these reactions, small particle size Al or the inert surrogate, LiF, was added to the energetic material benzotrifuroxan (BTF). BTF is a hydrogen-free material that selectively forms CO2 as the major oxidizing species for post-detonation Al oxidation. High-fidelity PDV measurements were utilized for early wall velocity expansion measurements in 12.7 mm copper cylinders. The JWL equation of state was solved to determine temperature, pressure and energies at specific time periods. A genetic algorithm was used in conjunction with a numerical simulation hydrocode, ALE3D, which enables the elucidation of aluminum reaction extent. By comparison of the Al oxidation with LiF, data indicate that Al oxidation occurs on an extremely fast time scale, beginning and completing between 1 and 25 microseconds. Unconfined, 6.4 mm diameter rate-sticks were also utilized to determine the effect of Al compared to LiF on detonation velocity.

High-temperature and pressure aluminum reactions in carbon dioxide rich post-detonation environments

NASA Astrophysics Data System (ADS)

Tappan, B. C.; Hill, L. G.; Manner, V. W.; Pemberton, S. J.; Lieber, M. A.; Johnson, C. E.; Sanders, V. E.

2014-05-01

Powdered aluminum is a common additive to energetic materials, but little is understood regarding its reaction rate at very high temperatures and pressures in specific oxidizing gases such as carbon dioxide. Aluminum reaction kinetics in carbon dioxide have been studied in various reaction conditions, but difficulties arise in the more specific study of Al oxidation at the high pressures and temperatures in detonation reactions. To study these reactions, small particle size Al or the inert surrogate, LiF, was added to the energetic material benzotrifuroxan (BTF). BTF is a hydrogen-free material that selectively forms CO2 as the major oxidizing species for post-detonation Al oxidation. High-fidelity PDV measurements were utilized for early wall velocity expansion measurements in 12.7 mm copper cylinders. The JWL equation of state was solved to determine temperature, pressure and energies at specific time periods. A genetic algorithm was used in conjunction with a numerical simulation hydrocode, ALE3D, which enables the elucidation of aluminum reaction extent. By comparison of the Al oxidation with LiF, data indicate that Al oxidation occurs on an extremely fast time scale, beginning and completing between 1 and 25 microseconds. Unconfined, 6.4 mm diameter rate-sticks were also utilized to determine the effect of Al compared to LiF on detonation velocity.

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

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.

Energetic Salts Based on 3,5-Bis(dinitromethyl)-1,2,4-triazole Monoanion and Dianion: Controllable Preparation, Characterization, and High Performance.

PubMed

Zhang, Jiaheng; Dharavath, Srinivas; Mitchell, Lauren A; Parrish, Damon A; Shreeve, Jean'ne M

2016-06-22

Molecular modification of known explosives is considered to be an efficient route to design new energetic materials. A new family of energetic salts based on the 3,5-bis(dinitromethyl)-1,2,4-triazole monoanion and dianion were controllably synthesized by using 1-diamino-2,2-dinitroethene as a precursor. X-ray structure determination of monohydrazinium 3,5-bis(dinitromethyl)-1,2,4-triazolate (5) and monoammonium (6) and diammonium 3,5-bis(dinitromethyl)-1,2,4-triazolate hydrate (8·H2O) further confirmed the structures of these anions. In addition, as supported by X-ray data, in the monoanion system, the roving proton on the ring nitrogen rather than on the gem-dinitro carbon results in extensive hydrogen-bonding interactions and higher packing coefficients. Interestingly, 5 and 6 possess the highest calculated crystal densities, 1.965 and 1.957 g cm(-3) at 150 K, for hydrazinium and ammonium energetic salts, respectively. Energetic evaluation indicates that 5 (detonation velocity vD = 9086 m s(-1); detonation pressure P = 38.7 GPa) and 6 (vD, 9271 m s(-1); P = 41.0 GPa) exhibit great detonation properties, superior to those of current highly explosive benchmarks, such as 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX).

A novel method for the measurement of the von Neumann spike in detonating high explosives

NASA Astrophysics Data System (ADS)

Sollier, A.; Bouyer, V.; Hébert, P.; Doucet, M.

2016-06-01

We present detonation wave profiles measured in T2 (97 wt. % TATB) and TX1 (52 wt. % TATB and 45 wt. % HMX) high explosives. The experiments consisted in initiating a detonation wave in a 15 mm diameter cylinder of explosive using an explosive wire detonator and an explosive booster. Free surface velocity wave profiles were measured at the explosive/air interface using a Photon Doppler Velocimetry system. We demonstrate that a comparison of these free surface wave profiles with those measured at explosive/window interfaces in similar conditions allows to bracket the von Neumann spike in a narrow range. For T2, our measurements show that the spike pressure lies between 35.9 and 40.1 GPa, whereas for TX1, it lies between 42.3 and 47.0 GPa. The numerical simulations performed in support to these measurements show that they can be used to calibrate reactive burn models and also to check the accuracy of the detonation products equation of state at low pressure.

Explosion containment device

DOEpatents

Benedick, William B.; Daniel, Charles J.

1977-01-01

The disclosure relates to an explosives storage container for absorbing and containing the blast, fragments and detonation products from a possible detonation of a contained explosive. The container comprises a layer of distended material having sufficient thickness to convert a portion of the kinetic energy of the explosion into thermal energy therein. A continuous wall of steel sufficiently thick to absorb most of the remaining kinetic energy by stretching and expanding, thereby reducing the momentum of detonation products and high velocity fragments, surrounds the layer of distended material. A crushable layer surrounds the continuous steel wall and accommodates the stretching and expanding thereof, transmitting a moderate load to the outer enclosure. These layers reduce the forces of the explosion and the momentum of the products thereof to zero. The outer enclosure comprises a continuous pressure wall enclosing all of the layers. In one embodiment, detonation of the contained explosive causes the outer enclosure to expand which indicates to a visual observer that a detonation has occurred.

Sub-Chandrasekhar-mass White Dwarf Detonations Revisited

NASA Astrophysics Data System (ADS)

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

2018-02-01

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

Line-imaging velocimetry for observing spatially heterogeneous mechanical and chemical responses in plastic bonded explosives during impact.

PubMed

Bolme, C A; Ramos, K J

2013-08-01

A line-imaging velocity interferometer was implemented on a single-stage light gas gun to probe the spatial heterogeneity of mechanical response, chemical reaction, and initiation of detonation in explosives. The instrument is described in detail, and then data are presented on several shock-compressed materials to demonstrate the instrument performance on both homogeneous and heterogeneous samples. The noise floor of this diagnostic was determined to be 0.24 rad with a shot on elastically compressed sapphire. The diagnostic was then applied to two heterogeneous plastic bonded explosives: 3,3(')-diaminoazoxyfurazan (DAAF) and PBX 9501, where significant spatial velocity heterogeneity was observed during the build up to detonation. In PBX 9501, the velocity heterogeneity was consistent with the explosive grain size, however in DAAF, we observed heterogeneity on a much larger length scale than the grain size that was similar to the imaging resolution of the instrument.

Line-imaging velocimetry for observing spatially heterogeneous mechanical and chemical responses in plastic bonded explosives during impact

NASA Astrophysics Data System (ADS)

Bolme, C. A.; Ramos, K. J.

2013-08-01

A line-imaging velocity interferometer was implemented on a single-stage light gas gun to probe the spatial heterogeneity of mechanical response, chemical reaction, and initiation of detonation in explosives. The instrument is described in detail, and then data are presented on several shock-compressed materials to demonstrate the instrument performance on both homogeneous and heterogeneous samples. The noise floor of this diagnostic was determined to be 0.24 rad with a shot on elastically compressed sapphire. The diagnostic was then applied to two heterogeneous plastic bonded explosives: 3,3'-diaminoazoxyfurazan (DAAF) and PBX 9501, where significant spatial velocity heterogeneity was observed during the build up to detonation. In PBX 9501, the velocity heterogeneity was consistent with the explosive grain size, however in DAAF, we observed heterogeneity on a much larger length scale than the grain size that was similar to the imaging resolution of the instrument.

Detonation Velocity-Diameter Relation in Gelled Explosive with Inert Inclusions

NASA Astrophysics Data System (ADS)

Higgins, Andrew; Loiseau, Jason; Mi, Xiaocheng

2017-06-01

The detonation velocity is measured in a gelled explosive that has been sensitized via the addition of glass microballoons (GMBs) and additionally diluted via the inclusion of large scale (300-700 micron) inert inclusions. The base explosive is nitromethane that has been gelled via the addition of poly(methyl methacrylate) and then sensitized via hot-spot inducing glass microballoons. Inert inclusions (e.g., glass, steel beads) are then added to the explosive to make a heterogeneous explosive with heterogeneities that are at a scale disparate from those of the microballoons. This system has the potential to be a synthetic explosive that can be tuned to have the properties of more complex commercial blasting agents. The velocity-diameter relation is studied using weak confinement (polyvinyl chloride) and time-of-arrival gages. The results are also used to further explore the phenomenon of anomalous scaling between axisymmetric charges (cylinders) and two-dimensional (slab) charges.

Reaction Buildup of PBX Explosives JOB-9003 under Different Initiation Pressures

NASA Astrophysics Data System (ADS)

Zhang, Xu; Wang, Yan-fei; Hung, Wen-bin; Gu, Yan; Zhao, Feng; Wu, Qiang; Yu, Xin; Yu, Heng

2017-04-01

Aluminum-based embedded multiple electromagnetic particle velocity gauge technique has been developed in order to measure the shock initiation behavior of JOB-9003 explosives. In addition, another gauge element called a shock tracker has been used to monitor the progress of the shock front as a function of time, thus providing a position-time trajectory of the wave front as it moves through the explosive sample. The data are used to determine the position and time for shock to detonation transition. All the experimental results show that: the rising-up time of Al-based electromagnetic particle velocity gauge was very fast and less than 20 ns; the reaction buildup velocity profiles and the position-time for shock to detonation transition of HMX-based PBX explosive JOB-9003 with 1-8 mm depth from the origin of impact plane under different initiation pressures are obtained with high accuracy.

Dimensional Analysis of Impulse Loading Resulting from Detonation of Shallow-Buried Charges

DTIC Science & Technology

2013-01-01

lines running along the floor, floor-bolted seats , ammunition storage racks, power-train lines, etc.). MMMS 9,3 368 Traditionally, the floor-rupture...The power of dimensional analysis is that the functional relations offered are generalized, i.e. the effect of geometrical, kinematic , ambient, loading... ejected vdet Explosive detonation velocity L/T A new quantity added which controls the time of sand-overburden bubble burst Charge/plate positioning

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

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

Effects of Fuel Distribution on Detonation Tube Performance

NASA Technical Reports Server (NTRS)

Perkins, Hugh Douglas

2002-01-01

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

Effects of control parameters of three-point initiation on the formation of an explosively formed projectile with fins

NASA Astrophysics Data System (ADS)

Li, R.; Li, W. B.; Wang, X. M.; Li, W. B.

2018-03-01

The effects of the initiation diameter and synchronicity error on the formation of fins and stable-flight velocity of an explosively formed projectile (EFP) with three-point initiation are investigated. The pressure and area of the Mach wave acting on the metal liner at different initiation diameters are calculated employing the Whitham method. LS-DYNA software is used to investigate the asymmetric collision of detonation waves resulting from three-point initiation synchronicity error, the distortion characteristics of the liner resulting from the composite detonation waves, and the performance parameters of the EFP with fins. Results indicate that deviations of the Y-shaped high-pressure zone and central ultrahigh-pressure zone from the liner center can be attributed to the error of three-point initiation, which leads to the irregular formation of EFP fins. It is noted that the area of the Mach wave decreases, but the pressure of the Mach wave and the final speed and length-to-diameter ( L/ D) ratio of the EFP increase, benefiting the formation of the EFP fins, as the initiation diameter increases.

Computational screening of oxetane monomers for novel hydroxy terminated polyethers.

PubMed

Sarangapani, Radhakrishnan; Ghule, Vikas D; Sikder, Arun K

2014-06-01

Energetic hydroxy terminated polyether prepolymers find paramount importance in search of energetic binders for propellant applications. In the present study, density functional theory (DFT) has been employed to screen the various novel energetic oxetane derivatives, which usually construct the backbone for these energetic polymers. Molecular structures were investigated at the B3LYP/6-31G* level, and isodesmic reactions were designed for calculating the gas phase heats of formation. The condensed phase heats of formation for designed compounds were calculated by the Politzer approach using heats of sublimation. Among the designed oxetane derivatives, T4 and T5 possess condensed phase heat of formation above 210 kJ mol(-1). The crystal packing density of the designed oxetane derivatives varied from 1.2 to 1.6 g/cm(3). The detonation velocities and pressures were evaluated using the Kamlet-Jacobs equations, utilizing the predicted densities and HOFCond. It was found that most of the designed oxetane derivatives have detonation performance comparable to the monomers of benchmark energetic polymers viz., NIMMO, AMMO, and BAMO. The strain energy (SE) for the oxetane derivatives were calculated using homodesmotic reactions, while intramolecular group interactions were predicted through the disproportionation energies. The concept of chemical hardness is used to analyze the susceptibility of designed compounds to reactivity and chemical transformations. The heats of formation, density, and predicted performance imply that the designed molecules are expected to be candidates for polymer synthesis and potential molecules for energetic binders.

Explosive Welding of Aluminum, Titanium and Zirconium to Copper Sheet Metal

NASA Technical Reports Server (NTRS)

Hegazy, A. A.; Mote, J. D.

1985-01-01

The main material properties affecting the explosive weldability of a certain metal combination are the yield strength, the ductility, the density and the sonic velocity of the two metals. Successful welding of the metal combination depends mainly on the correct choice of the explosive welding parameters; i.e., the stand off distance, the weight of the explosive charge relative to the weight of the flyer plate and the detonation velocity of the explosive. Based on the measured and the handbook values of the properties of interest, the explosive welding parameters were calculated and the arrangements for the explosive welding of the Al alloy 6061-T6, titanium and zirconium to OFHC copper were determined. The relatively small sheet metal thickness (1/8") and the fact that the thickness of the explosive layer must exceed a certain minimum value were considered during the determination of the explosive welding conditions. The results of the metallographic investigations and the measurements of the shear strength at the interface demonstrate the usefulness of these calculations to minimize the number of experimental trials.

Initiation of insensitive explosives by laser energy

NASA Technical Reports Server (NTRS)

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

1972-01-01

Instantaneous longitudinal detonations were observed in confined columns of pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX), and tetryl when these materials were pulsed with light energy from a focused Q-switch ruby laser. The laser energy ranged from 0.5 to 4.2 J with a pulse width of 25 ns. Enhancement of the ignition mechanism is hypothesized when a 100-nm (1000-A) thick aluminum film is vacuum-deposited on the explosive side of the window. Upon irradiation from the laser, a shock is generated at the aluminum explosive interface. Steady state detonations can be reached in less than 0.5 microseconds with less than 10% variation in detonation velocity for PETN and RDX.

Interaction Between a Steady Detonation Wave in Nitromethane and Geometrical Complex Confinement Defects

NASA Astrophysics Data System (ADS)

Crouzet, B.; Soulard, L.; Carion, N.; Manczur, P.

2007-12-01

Two copper cylinder expansion tests were carried out on nitromethane. They differ from the classical cylinder test in that the liner includes evenly-spaced protruding circular defects. The aim is to study how a detonation front propagating in the liquid explosive interacts with the confining material defects. The subsequent motion of the metal, accelerated by the expanding detonation products, is measured using a range of diagnostic techniques: electrical probes, a rapid framing camera, a glass block associated with a streak camera and velocity laser interferometers. The different experimental records have been examined in the light of previous classical cylinder test measurements, simple 2D theoretical shock polar analysis results and 2D numerical simulations.

Laser diode initiated detonators for space applications

NASA Technical Reports Server (NTRS)

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

1993-01-01

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

The measured temperature and pressure of EDC37 detonation products

NASA Astrophysics Data System (ADS)

Ferguson, J. W.; Richley, J. C.; Sutton, B. D.; Price, E.; Ota, T. A.

2017-01-01

We present the experimentally determined temperature and pressure of the detonation products of EDC37; a HMX based conventional high explosive. These measurements were performed on a series of cylinder tests. The temperature measurements were undertaken at the end of the cylinder with optical fibres observing the bare explosive through a LiF window. The temperature of the products was measured for approximately 2 µs using single colour pyrometry, multicolour pyrometry and also using time integrated optical emission spectroscopy with the results from all three methods being broadly consistent. The peak temperature was found to be ≈ 3600 K dropping to ≈ 2400 K at the end of the measurement window. The spectroscopy was time integrated and showed that the emission spectra can be approximated using a grey body curve between 520 - 800 nm with no emission or absorption lines being observed. The pressure was obtained using an analytical method which requires the velocity of the expanding cylinder wall and the velocity of detonation. The pressure drops from an initial CJ value of ≈ 38 GPa to ≈ 4 GPa after 2 µs.

Interaction between a steady detonation wave in nitromethane and geometrical complex confinement defects.

NASA Astrophysics Data System (ADS)

Crouzet, Blandine; Carion, Noel; Manczur, Philippe

2007-06-01

It is well known that detonation propagation is altered if the explosive is encased in an inert confining material. But in practice, explosives are rarely used without confinement and particular attention must be paid to the problem of explosive/confinement interactions. In this work, we have carried out two copper cylinder expansion tests on nitromethane. They differ from the classical cylinder test in that the liner includes evenly-spaced protruding circular defects. The aim is to study how a detonation front propagating in the liquid explosive interacts with the confining material defects. The subsequent motion of the metal, accelerated by the expanding detonation products, is measured using a range of diagnostic techniques: electrical probes, rapid framing camera, glass block associated with streak camera and velocity laser interferometers. The different experimental records have been examined in the light of a simple 2D theoretical shock polar analysis and 2D numerical simulations.

Controlled Detonation Dynamics in Additively Manufactured High Explosives

NASA Astrophysics Data System (ADS)

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

2017-06-01

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

Detonation Properties Measurements for Inorganic Explosives

NASA Astrophysics Data System (ADS)

Morgan, Brent A.; Lopez, Angel

2005-03-01

Many commonly available explosive materials have never been quantitatively or theoretically characterized in a manner suitable for use in analytical models. This includes inorganic explosive materials used in spacecraft ordnance, such as zirconium potassium perchlorate (ZPP). Lack of empirical information about these materials impedes the development of computational techniques. We have applied high fidelity measurement techniques to experimentally determine the pressure and velocity characteristics of ZPP, a previously uncharacterized explosive material. Advances in measurement technology now permit the use of very small quantities of material, thus yielding a significant reduction in the cost of conducting these experiments. An empirical determination of the explosive behavior of ZPP derived a Hugoniot for ZPP with an approximate particle velocity (uo) of 1.0 km/s. This result compares favorably with the numerical calculations from the CHEETAH thermochemical code, which predicts uo of approximately 1.2 km/s under ideal conditions.

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

PubMed

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

2016-03-01

Compared with traditional sampling-based sensing method, absorption spectroscopy technology is well suitable for detonation flow diagnostics, since it can provide with us fast response, nonintrusive, sensitive solution for situ measurements of multiple flow-field parameters. The temperature and concentration test results are the average values along the laser path with traditional absorption spectroscopy technology, while the boundary of detonation flow external field is unknown and it changes all the time during the detonation engine works, traditional absorption spectroscopy technology is no longer suitable for detonation diagnostics. The trend of line strength with temperature varies with different absorption lines. By increasing the number of absorption lines in the test path, more information of the non-uniform flow field can be obtained. In this paper, based on multispectral absorption technology, the reconstructed model of detonation flow external field distribution was established according to the simulation results of space-time conservation element and solution element method, and a diagnostic method of detonation flow external field was given. The model deviation and calculation error of the least squares method adopted were studied by simulation, and the maximum concentration and temperature calculation error was 20.1% and 3.2%, respectively. Four absorption lines of H2O were chosen and detonation flow was scanned at the same time. The detonation external flow testing system was set up for the valveless gas-liquid continuous pulse detonation engine with the diameter of 80 mm. Through scanning H2O absorption lines with a high frequency of 10 kHz, the on-line detection of detonation external flow was realized by direct absorption method combined with time-division multiplexing technology, and the reconstruction of dynamic temperature distribution was realized as well for the first time, both verifying the feasibility of the test method. The test results show that both of the temperature and H2O concentration rose with the arrival of detonation wave. With the increase of the vertical distance between the detonation tube nozzle and the laser path, the time of temperature and concentration coming to the peak delayed, and the temperature variation trend tended to slow down. At 20 cm from detonation tube nozzle, the maximum temperature hit 1 329 K and the maximum H2O concentration of 0.19 occurred at 4 ms after ignition. The research can provide with us the support for expanding the detonation test field with absorption spectroscopy technology, and can also help to promote the detonation mechanism research and to enhance the level of detonation engine control technology.

Calculated concentrations of any radionuclide deposited on the ground by release from underground nuclear detonations, tests of nuclear rockets, and tests of nuclear ramjet engines

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

Hicks, H.G.

1981-11-01

This report presents calculated gamma radiation exposure rates and ground deposition of related radionuclides resulting from three types of event that deposited detectable radioactivity outside the Nevada Test Site complex, namely, underground nuclear detonations, tests of nuclear rocket engines and tests of nuclear ramjet engines.

Development of a Gas-Fed Pulse Detonation Research Engine

NASA Technical Reports Server (NTRS)

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

2001-01-01

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

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

NASA Astrophysics Data System (ADS)

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

2018-03-01

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

Determination of performance of non-ideal aluminized explosives.

PubMed

Keshavarz, Mohammad Hossein; Mofrad, Reza Teimuri; Poor, Karim Esmail; Shokrollahi, Arash; Zali, Abbas; Yousefi, Mohammad Hassan

2006-09-01

Non-ideal explosives can have Chapman-Jouguet (C-J) detonation pressure significantly different from those expected from existing thermodynamic computer codes, which usually allows finding the parameters of ideal detonation of individual high explosives with good accuracy. A simple method is introduced by which detonation pressure of non-ideal aluminized explosives with general formula C(a)H(b)N(c)O(d)Al(e) can be predicted only from a, b, c, d and e at any loading density without using any assumed detonation products and experimental data. Calculated detonation pressures show good agreement with experimental values with respect to computed results obtained by complicated computer code. It is shown here how loading density and atomic composition can be integrated into an empirical formula for predicting detonation pressure of proposed aluminized explosives.

Application and principles of photon-doppler velocimetry for explosives testing

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

Briggs, Matthew Ellsworth; Hill, Larry; Hull, Larry

2010-01-01

The velocimetry technique PDV is easier to field than its predecessors VISAR and Fabry-Perot, works on a broader variety of experiments, and is more accurate and simple to analyze. Experiments and analysis have now demonstrated the accuracy, precision and interpretation of what PDV does and does not measure, and the successful application of POV to basic and applied detonation problems. We present a selection of results intended to help workers assess the capabilities of PDV. First we present general considerations about the technique: various PDV configurations, single-signal, multisignal (e.g., triature) and frequency-shifted PDV; what types of motion are sensed andmore » missed by PDV; analysis schemes for velocity and position extraction; accuracy and precision of the results; and, experimental considerations for probe selection and positioning. We then present the status of various applications: detonation speeds and wall motion in cylinder tests, breakout velocity distributions from bare HE, ejecta, measurements from fibers embedded in HE, projectile velocity, resolving 2 and 3-D velocity vectors. This paper is an overview of work done by many groups around the world.« less

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

NASA Astrophysics Data System (ADS)

Chambers, Jessica; Ahmed, Kareem

2016-11-01

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

Comparison Between Surf and Multi-Shock Forest Fire High Explosive Burn Models

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

Greenfield, Nicholas Alexander

PAGOSA1 has several different burn models used to model high explosive detonation. Two of these, Multi-Shock Forest Fire and Surf, are capable of modeling shock initiation. Accurately calculating shock initiation of a high explosive is important because it is a mechanism for detonation in many accident scenarios (i.e. fragment impact). Comparing the models to pop-plot data give confidence that the models are accurately calculating detonation or lack thereof. To compare the performance of these models, pop-plots2 were created from simulations where one two cm block of PBX 9502 collides with another block of PBX 9502.

A fast, low resistance switch for small slapper detonators

NASA Astrophysics Data System (ADS)

Richardson, D. D.; Jones, D. A.

1986-10-01

A novel design for a shock compression conduction switch for use with slapper detonators is described. The switch is based on the concept of an explosively driven flyer plate impacting a plastic insulator and producing sufficient pressure within the insulator to produce a conduction transition. An analysis of the functioning of the switch is made using a simple Gurney model for the explosive, and basic shock wave theory to calculate impact pressure and switch closure times. The effect of explosive tamping is considered, and calculations are carried out for two donor explosive thicknesses and a range of flyer plate thicknesses. The new switch has been successfully tested in a series of experimental slapper detonator firings. The results of these tests show trends in overall agreement with those predicted by the calculations.

Close-in Blast Waves from Spherical Charges*

NASA Astrophysics Data System (ADS)

Howard, William; Kuhl, Allen

2011-06-01

We study the close-in blast waves created by the detonation of spherical high explosives (HE) charges, via numerical simulations with our Arbitrary-Lagrange-Eulerian (ALE3D) code. We used a finely-resolved, fixed Eulerian 2-D mesh (200 μm per cell) to capture the detonation of the charge, the blast wave propagation in air, and the reflection of the blast wave from an ideal surface. The thermodynamic properties of the detonation products and air were specified by the Cheetah code. A programmed-burn model was used to detonate the charge at a rate based on measured detonation velocities. The results were analyzed to evaluate the: (i) free air pressure-range curves: Δps (R) , (ii) free air impulse curves, (iii) reflected pressure-range curves, and (iv) reflected impulse-range curves. A variety of explosives were studied. Conclusions are: (i) close-in (R < 10 cm /g 1 / 3) , each explosive had its own (unique) blast wave (e.g., Δps (R , HE) ~ a /Rn , where n is different for each explosive); (ii) these close-in blast waves do not scale with the ``Heat of Detonation'' of the explosive (because close-in, there is not enough time to fully couple the chemical energy to the air via piston work); (iii) instead they are related to the detonation conditions inside the charge. Scaling laws will be proposed for such close-in blast waves.

Detonation Reaction Zones in Condensed Explosives

NASA Astrophysics Data System (ADS)

Tarver, Craig M.

2006-07-01

Experimental measurements using nanosecond time resolved embedded gauges and laser interferometric techniques, combined with Non-Equilibrium Zeldovich - von Neumann - Doling (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 are 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).

Molecular dynamic simulations for FOX-7 and FOX-7 based PBXs.

PubMed

Wang, Junying; Jin, Shaohua; Chen, Shusen; Li, Lijie; Wang, Dongxu; Lu, Zhiyan; Wang, Na; Wang, Junfeng

2018-06-01

Molecular dynamic (MD) simulations were applied to investigate the binding energies and mechanical properties of 1,1-diamino-2,2-dinitroethene (FOX-7) based polymer bonded explosives (PBXs) with ethylenevinylacetate copolymer (EVA), fluorine (F2641), hydroxyl-terminated polybutadiene (HTPB), and styrene butadiene styrene block copolymer (SBS). The binding energies between FOX-7 and the four polymer binders are different, of which the descending order is FOX-7/HTPB ≈ FOX-7/SBS > FOX-7/EVA > FOX-7/F2641. Furthermore, the (002) surface of FOX-7 has the strongest interaction with the four polymers. The mechanical properties (elastic moduli and Poisson's ratio) of pure FOX-7 and FOX-7 based PBXs were obtained. The results show that the descending order of the ability of polymer binders to improve plasticity of PBXs is SBS > F2641 > EVA > HTPB. The formability of FOX-7 based PBXs is better than that of pure FOX-7, as the order of FOX-7/SBS > FOX-7/EVA > FOX-7/F2641 > FOX-7/HTPB > FOX-7 shows. Poisson's ratio of SBS is the highest. The calculated detonation performances for pure FOX-7 and FOX-7 based PBXs show that the detonation properties of explosives slightly decreases when the mass ratio of binder is about 5%. All the theoretical detonation velocities of FOX-7 based PBXs are higher than 8500 m/s.

Model comparisons of the reactive burn model SURF in three ASC codes

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

Whitley, Von Howard; Stalsberg, Krista Lynn; Reichelt, Benjamin Lee

A study of the SURF reactive burn model was performed in FLAG, PAGOSA and XRAGE. In this study, three different shock-to-detonation transition experiments were modeled in each code. All three codes produced similar model results for all the experiments modeled and at all resolutions. Buildup-to-detonation time, particle velocities and resolution dependence of the models was notably similar between the codes. Given the current PBX 9502 equations of state and SURF calibrations, each code is equally capable of predicting the correct detonation time and distance when impacted by a 1D impactor at pressures ranging from 10-16 GPa, as long as themore » resolution of the mesh is not too coarse.« less

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.

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

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

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

2013-10-20

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

Flowfield characterization and model development in detonation tubes

NASA Astrophysics Data System (ADS)

Owens, Zachary Clark

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

Impact, thermal, and shock sensitivity of molten TNT and of asphalt-contaminated molten TNT

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

Mainiero, R.J.; Miron, Y.; Kwak, S.S.W.

1996-12-01

The research reported here was part of an effort to evaluate the safety of a process to recover TNT from MK-9 depth bombs by the autoclave meltout process. In this process the depth bombs are heated to 121 C so that the TNT will melt and run into a vat. Unfortunately, asphalt lining the inside surface of the bomb also melts and flows out with the TNT. Testing was conducted on molten TNT and molten TNT contaminated with 2 pct asphalt at 90, 100, 110, 120, 125, and 130 C. In the liquid drop test apparatus with a 2-kg weight,more » the molten TNT yielded a 50 pct probability of initiation at a drop height of 6.5 cm at 110 C, decreasing to 4.5 cm at 130 C. Asphalt-contaminated TNT was somewhat less impact-sensitive than pure TNT at temperatures of 110 to 125 C, but became more sensitive at 130 C. There is a 50 pct probability of initiation at a drop height of 7.8 cm at 110 C, decreasing to 3.3 cm at 130 C. In the card gap test, the molten TNT detonated at high velocity for a gap of 0.25 inches at 90 to 125 C and detonated at high velocity for a gap of 0.5 inches at 130 C. For gaps of 0.5 to 3 inches at 90 to 125 C and 0.75 inches to 3 inches at 130 C, the TNT did not detonate at high velocity but produced a violent explosion that caused significant damage to the test fixture. The thermal analysis test results showed that when asphalt is present in TNT, it greatly accelerates the exothermic decomposition of TNT, starting at temperatures near 200 C. It appears that at relatively low shock stimulus levels, the molten TNT may be undergoing a low velocity detonation, wherein the shock wave traveling through the gap test pipe cavitates the molten TNT, greatly increasing its sensitivity. These results are crucial for assuring continued safety in recovering TNT from munitions through the autoclave meltout process.« less

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

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

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

2008-08-15

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

Apparatus and method for the acceleration of projectiles to hypervelocities

DOEpatents

Hertzberg, Abraham; Bruckner, Adam P.; Bogdanoff, David W.

1990-01-01

A projectile is initially accelerated to a supersonic velocity and then injected into a launch tube filled with a gaseous propellant. The projectile outer surface and launch tube inner surface form a ramjet having a diffuser, a combustion chamber and a nozzle. A catalytic coated flame holder projecting from the projectile ignites the gaseous propellant in the combustion chamber thereby accelerating the projectile in a subsonic combustion mode zone. The projectile then enters an overdriven detonation wave launch tube zone wherein further projectile acceleration is achieved by a formed, controlled overdriven detonation wave capable of igniting the gaseous propellant in the combustion chamber. Ultrahigh velocity projectile accelerations are achieved in a launch tube layered detonation zone having an inner sleeve filled with hydrogen gas. An explosive, which is disposed in the annular zone between the inner sleeve and the launch tube, explodes responsive to an impinging shock wave emanating from the diffuser of the accelerating projectile thereby forcing the inner sleeve inward and imparting an acceleration to the projectile. For applications wherein solid or liquid high explosives are employed, the explosion thereof forces the inner sleeve inward, forming a throat behind the projectile. This throat chokes flow behind, thereby imparting an acceleration to the projectile.

Predicted detonation properties at the Chapman-Jouguet state for proposed energetic materials (MTO and MTO3N) from combined ReaxFF and quantum mechanics reactive dynamics.

PubMed

Zhou, Tingting; Zybin, Sergey V; Goddard, William A; Cheng, Tao; Naserifar, Saber; Jaramillo-Botero, Andres; Huang, Fenglei

2018-02-07

The development of new energetic materials (EMs) with improved detonation performance but low sensitivity and environmental impact is of considerable importance for applications in civilian and military fields. Often new designs are difficult to synthesize so predictions of performance in advance is most valuable. Examples include MTO (2,4,6-triamino-1,3,5-triazine-1,3,5-trioxide) and MTO3N (2,4,6-trinitro-1,3,5-triazine-1,3,5-trioxide) suggested by Klapötke as candidate EMs but not yet successfully synthesized. We propose and apply to these materials a new approach, RxMD(cQM), in which ReaxFF Reactive Molecular Dynamics (RxMD) is first used to predict the reaction products and thermochemical properties at the Chapman Jouguet (CJ) state for which the system is fully reacted and at chemical equilibrium. Quantum mechanics dynamics (QMD) is then applied to refine the pressure of the ReaxFF predicted CJ state to predict a more accurate final CJ point, leading to a very practical calculation that includes accurate long range vdW interactions needed for accurate pressure. For MTO, this RxMD(cQM) method predicts a detonation pressure of P CJ = 40.5 GPa and a detonation velocity of D CJ = 8.8 km s -1 , while for MTO3N it predicts P CJ = 39.9 GPa and D CJ = 8.4 km s -1 , making them comparable to HMX (P CJ = 39.5 GPa, D CJ = 9.1 km s -1 ) and worth synthesizing. This first-principles-based RxMD(cQM) methodology provides an excellent compromise between computational cost and accuracy including the formation of clusters that burn too slowly, providing a practical mean of assessing detonation performances for novel candidate EMs. This RxMD(cQM) method that links first principles atomistic molecular dynamics simulations with macroscopic properties to promote in silico design of new EMs should also be of general applicability to materials synthesis and processing.

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

Sollier, A., E-mail: arnaud.sollier@cea.fr; Bouyer, V.; Hébert, P.

We present detonation wave profiles measured in T2 (97 wt. % TATB) and TX1 (52 wt. % TATB and 45 wt. % HMX) high explosives. The experiments consisted in initiating a detonation wave in a 15 mm diameter cylinder of explosive using an explosive wire detonator and an explosive booster. Free surface velocity wave profiles were measured at the explosive/air interface using a Photon Doppler Velocimetry system. We demonstrate that a comparison of these free surface wave profiles with those measured at explosive/window interfaces in similar conditions allows to bracket the von Neumann spike in a narrow range. For T2, our measurements show that the spike pressuremore » lies between 35.9 and 40.1 GPa, whereas for TX1, it lies between 42.3 and 47.0 GPa. The numerical simulations performed in support to these measurements show that they can be used to calibrate reactive burn models and also to check the accuracy of the detonation products equation of state at low pressure.« less

Structure and characteristics of heterogeneous detonation

NASA Astrophysics Data System (ADS)

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

1983-09-01

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

Measurement and reactive burn modeling of the shock to detonation transition for the HMX based explosive LX-14

NASA Astrophysics Data System (ADS)

Jones, J. D.; Ma, Xia; Clements, B. E.; Gibson, L. L.; Gustavsen, R. L.

2017-06-01

Gas-gun driven plate-impact techniques were used to study the shock to detonation transition in LX-14 (95.5 weight % HMX, 4.5 weight % estane binder). The transition was recorded using embedded electromagnetic particle velocity gauges. Initial shock pressures, P, ranged from 2.5 to 8 GPa and the resulting distances to detonation, xD, were in the range 1.9 to 14 mm. Numerical simulations using the SURF reactive burn scheme coupled with a linear US -up / Mie-Grueneisen equation of state for the reactant and a JWL equation of state for the products, match the experimental data well. Comparison of simulation with experiment as well as the ``best fit'' parameter set for the simulations is presented.

The effect of post-burst energy on exploding bridgewire output

NASA Astrophysics Data System (ADS)

Lee, Elizabeth; Bowden, Mike

2017-01-01

For an EBW detonator, as the fireset energy is increased from threshold to all-fire level the post-burst energy delivered to the detonator increases, and the function times decrease. To gain an understanding of the processes through which the post-burst electrical energy influences the function times the effect of the post-burst energy on the explosion of bridgewires was studied. A fireset was developed which enabled the post-burst energy to be varied independently of the burst energy by terminating the current flow at pre-selected times. The effect of this on the bridgewires was characterized at a range of firing voltages and a range of termination times. The expansion and explosion of the bridgewire was characterized using Photonic Doppler Velocimetry. The velocimetry trace detected two families of velocities. The first family had initial velocities in the range 1-2 km.s-1 and the second family had velocities in the range 0-0.5 km.s-1. The relative position of the two families depended on the post burst energy. The results show that a reduction in the post-burst energy corresponds to a decrease in the acceleration and peak velocity of the bridgewire / plasma at burst.

Computational and experimental investigation of plasma deflagration jets and detonation shocks in coaxial plasma accelerators

NASA Astrophysics Data System (ADS)

Subramaniam, Vivek; Underwood, Thomas C.; Raja, Laxminarayan L.; Cappelli, Mark A.

2018-02-01

We present a magnetohydrodynamic (MHD) numerical simulation to study the physical mechanisms underlying plasma acceleration in a coaxial plasma gun. Coaxial plasma accelerators are known to exhibit two distinct modes of operation depending on the delay between gas loading and capacitor discharging. Shorter delays lead to a high velocity plasma deflagration jet and longer delays produce detonation shocks. During a single operational cycle that typically consists of two discharge events, the plasma acceleration exhibits a behavior characterized by a mode transition from deflagration to detonation. The first of the discharge events, a deflagration that occurs when the discharge expands into an initially evacuated domain, requires a modification of the standard MHD algorithm to account for rarefied regions of the simulation domain. The conventional approach of using a low background density gas to mimic the vacuum background results in the formation of an artificial shock, inconsistent with the physics of free expansion. To this end, we present a plasma-vacuum interface tracking framework with the objective of predicting a physically consistent free expansion, devoid of the spurious shock obtained with the low background density approach. The interface tracking formulation is integrated within the MHD framework to simulate the plasma deflagration and the second discharge event, a plasma detonation, formed due to its initiation in a background prefilled with gas remnant from the deflagration. The mode transition behavior obtained in the simulations is qualitatively compared to that observed in the experiments using high framing rate Schlieren videography. The deflagration mode is further investigated to understand the jet formation process and the axial velocities obtained are compared against experimentally obtained deflagration plasma front velocities. The simulations are also used to provide insight into the conditions responsible for the generation and sustenance of the magnetic pinch. The pinch width and number density distribution are compared to experimentally obtained data to calibrate the inlet boundary conditions used to set up the plasma acceleration problem.

Reactive Flow Modeling of Liquid Explosives via ALE3D/Cheetah Simulations

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

Kuo, I W; Bastea, S; Fried, L E

2010-03-10

We carried out reactive flow simulations of liquid explosives such as nitromethane using the hydrodynamic code ALE3D coupled with equations of state and reaction kinetics modeled by the thermochemical code Cheetah. The simulation set-up was chosen to mimic cylinder experiments. For pure unconfined nitromethane we find that the failure diameter and detonation velocity dependence on charge diameter are in agreement with available experimental results. Such simulations are likely to be useful for determining detonability and failure behavior for a wide range of experimental conditions and explosive compounds.

Size Effect and Cylinder test on Several Commercial Explosives

NASA Astrophysics Data System (ADS)

Lauderbach, Lisa; Moua, Kou; Garza, Raul; Souers, Clark

2011-06-01

The size (diameter) effect and the Cylinder test results for ammonium nitrate/nitromethane, some ammonium nitrate/fuel oil mixes, Red Dot shotgun powder, Semtex 1A and Semtex H will be presented. A generalized detonation velocity format, valid for all detonation rates, will be discussed. A shot in cylindrical symmetry will be compared with the 1-D cylindrical size effect data. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Historical Survey: German Research on Hydrogen Peroxide/Alcohol Explosives

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

Parmeter, John E.

Discussion of HP/fuel explosives in the scientific literature dates back to at least 1927. A paper was published that year in a German journal entitled On Hydrogen Peroxide Explosives [Bamberger and Nussbaum 1927]. The paper dealt with HP/cotton/Vaseline formulations, specifically HP89/cotton/Vaseline (76/15/9) and (70/8.5/12.5). The authors performed experiments with charge masses of 250-750 g and charge diameters of 35-45 mm. This short paper provides brief discussion on the observed qualitative effects of detonations but does not report detonation velocities.

Impact initiation of explosives and propellants via statistical crack mechanics

NASA Astrophysics Data System (ADS)

Dienes, J. K.; Zuo, Q. H.; Kershner, J. D.

2006-06-01

A statistical approach has been developed for modeling the dynamic response of brittle materials by superimposing the effects of a myriad of microcracks, including opening, shear, growth and coalescence, taking as a starting point the well-established theory of penny-shaped cracks. This paper discusses the general approach, but in particular an application to the sensitivity of explosives and propellants, which often contain brittle constituents. We examine the hypothesis that the intense heating by frictional sliding between the faces of a closed crack during unstable growth can form a hot spot, causing localized melting, ignition, and fast burn of the reactive material adjacent to the crack. Opening and growth of a closed crack due to the pressure of burned gases inside the crack and interactions of adjacent cracks can lead to violent reaction, with detonation as a possible consequence. This approach was used to model a multiple-shock experiment by Mulford et al. [1993. Initiation of preshocked high explosives PBX-9404, PBX-9502, PBX-9501, monitored with in-material magnetic gauging. In: Proceedings of the 10th International Detonation Symposium, pp. 459-467] involving initiation and subsequent quenching of chemical reactions in a slab of PBX 9501 impacted by a two-material flyer plate. We examine the effects of crack orientation and temperature dependence of viscosity of the melt on the response. Numerical results confirm our theoretical finding [Zuo, Q.H., Dienes, J.K., 2005. On the stability of penny-shaped cracks with friction: the five types of brittle behavior. Int. J. Solids Struct. 42, 1309-1326] that crack orientation has a significant effect on brittle behavior, especially under compressive loading where interfacial friction plays an important role. With a reasonable choice of crack orientation and a temperature-dependent viscosity obtained from molecular dynamics calculations, the calculated particle velocities compare well with those measured using embedded velocity gauges.

A Novel Energetic Perchlorate Amine Salt: Synthesis, Properties, and Density Functional Theory Calculation

NASA Astrophysics Data System (ADS)

Ma, Peng; Pan, Yong; Jiang, Juncheng; Zhu, Shunguan

2017-10-01

A novel explosive, ethylenediamine triethylenediamine tetraperchlorate (ETT), was synthesized by a rapid " one-pot" method. The molecular and crystal structures of ETT were determined by X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. The purity of the ETT was characterized by hydrogen nuclear magnetic resonance (H-NMR) spectra and elemental analysis (EA). The chemical and physical properties of the co-crystal ETT were further explored including impact sensitivity, velocity of detonation, and thermal behavior. The impact sensitivity of the ETT (h50% = 9.50 cm) is much lower than that of its components, ethylenediamine diperchlorate (ED) (h50% = 5.60 cm) and triethylenediamine diperchlorate (TD) (h50% = 2.10 cm). The measured detonation velocity is 8956 m/s (ρ = 1.873 g/cm3), which is much higher than that of TNT (6900 m/s) or RDX (8350 m/s). The co-crystal ETT shows a unique thermal behavior with a decomposition peak temperature at 365 °C. Band structure and density of states (DOS) of the ETT were confirmed by the CASTEP code. The first-principles tight-binding method within the general gradient approximation (GGA) was employed to study the electronic band structure as well as the DOS and Fermi energy. Hirshfeld surfaces were applied to analyze the intermolecular interactions in the co-crystal, and the results showed that weak interaction was dominantly mediated by H … O hydrogen bond. By analyzing the bond length at different temperatures, N-H covalent bond is the trigger bond for the ETT.

Impulse generation by detonation tubes

NASA Astrophysics Data System (ADS)

Cooper, Marcia Ann

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

The Universal Role of Tubulence in the Propagation of Strong Shocks and Detonation Waves

NASA Astrophysics Data System (ADS)

Lee, John H.

2001-06-01

The passage of a strong shock wave usually results in irreversible physical and chemical changes in the medium. If the chemical reactions are sufficiently exothermic, the shock wave can be self-propagating, i.e., sustained by the chemical energy release via the expansion work of the reaction products. Although shocks and detonations can be globally stable and propagate at constant velocities (in the direction of motion), their structure may be highly unstable and exhibit large hydrodynamic fluctuations, i.e., turbulence. Recent investigations on plastic deformation of polycrystalline material behind shock waves have revealed particle velocity dispersion at the mesoscopic level, a result of vortical rotational motion similar to that of turbulent fluid flows at high Reynolds number.1 Strong ionizing shocks in noble gases2, as well as dissociating shock waves in carbon dioxide,3 also demonstrate a turbulent density fluctuation in the non-equilibrium shock transition zone. Perhaps the most thoroughly investigated unstable structure is that of detonation waves in gaseous explosives.4 Detonation waves in liquid explosives such as nitromethane also take on similar unstable structure as gaseous detonations.5 There are also indications that detonations in solid explosives have a similar unsteady structure under certain conditions. Thus, it appears that it is more of a rule than an exception that the structure of strong shocks and detonations are unstable and exhibit turbulent-like fluctuations as improved diagnostics now permit us to look more closely at the meso- and micro-levels. Increasing attention is now devoted to the understanding of the shock waves at the micro-scale level in recent years. This is motivated by the need to formulate physical and chemical models that contain the correct physics capable of describing quantitatively the shock transition process. It should be noted that, in spite of its unstable 3-D structure, the steady 1-D conservation laws (in the direction of propagation) apply across the shock transition zone if the downstream equilibrium plane is taken far enough away to ensure the decay of the turbulent fluctuations. Thus, the Hugoniot properties of one-dimensional propagation of shock and detonation waves remain valid. However, the conservation laws do not describe the important propagation mechanisms (i.e., the physical and chemical processes that effect the transition from initial to the final state) in the wave structure. Since gaseous detonations enjoy the advantage of being able to be observed experimentally in great detail, its complex turbulent structure is now quite well established. Furthermore, the equation of state for perfect gases is well known and the chemistry of most gas phase reactions is also sufficiently understood quantitatively to permit detailed numerical simulation of the complex detonation structure. Thus, a good database of information exists for gaseous detonation, and in this paper we shall explore the turbulent structure of gaseous detonation with the aim of answering the question as to "why nature prefers to evoke such a complicated manner to effect its propagation." We will then attempt to generalize the discussion to the "terra incognita" of condensed phase materials where the structure is much less understood. 1. Meshcheryakov, Yu.I., and Atroshenko, S.A., Izv. Vyssh. Uchebn. Zaved. Fiz., 4, 105-123 (1992). 2. Glass, I.I, and Liu, W.S., J. Fluid Mech., 84(1), 55-77 (1978). 3. Griffiths, R.W., Sanderman, R.J., and Hornung, H.G., J. Phys. D., 8, 1681-1691 (1975). 4. Lee, J.H.S., Ann. Rev. Fluid Mech., 16, 311-336 (1984). 5. Mallory, H.D., J. Appl. Physics, 38, 5302-5306 (1967).

Low-frequency RF Coupling To Unconventional (Fat Unbalanced) Dipoles

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

Ong, M M; Brown, C G; Perkins, M P

2010-12-07

The report explains radio frequency (RF) coupling to unconventional dipole antennas. Normal dipoles have thin equal length arms that operate at maximum efficiency around resonance frequencies. In some applications like high-explosive (HE) safety analysis, structures similar to dipoles with ''fat'' unequal length arms must be evaluated for indirect-lightning effects. An example is shown where a metal drum-shaped container with HE forms one arm and the detonator cable acts as the other. Even if the HE is in a facility converted into a ''Faraday cage'', a lightning strike to the facility could still produce electric fields inside. The detonator cable concentratesmore » the electric field and carries the energy into the detonator, potentially creating a hazard. This electromagnetic (EM) field coupling of lightning energy is the indirect effect of a lightning strike. In practice, ''Faraday cages'' are formed by the rebar of the concrete facilities. The individual rebar rods in the roof, walls and floor are normally electrically connected because of the construction technique of using metal wire to tie the pieces together. There are two additional requirements for a good cage. (1) The roof-wall joint and the wall-floor joint must be electrically attached. (2) All metallic penetrations into the facility must also be electrically connected to the rebar. In this report, it is assumed that these conditions have been met, and there is no arcing in the facility structure. Many types of detonators have metal ''cups'' that contain the explosives and thin electrical initiating wires, called bridge wires mounted between two pins. The pins are connected to the detonator cable. The area of concern is between the pins supporting the bridge wire and the metal cup forming the outside of the detonator. Detonator cables usually have two wires, and in this example, both wires generated the same voltage at the detonator bridge wire. This is called the common-mode voltage. The explosive component inside a detonator is relatively sensitive, and any electrical arc is a concern. In a safety analysis, the pin-to-cup voltage, i.e., detonator voltage, must be calculated to decide if an arc will form. If the electric field is known, the voltage between any two points is simply the integral of the field along a line between the points. Eq. 1.1. For simplicity, it is assumed that the electric field and dipole elements are aligned. Calculating the induced detonator voltage is more complex because of the field concentration caused by metal components. If the detonator cup is not electrically connected to the metal HE container, the portion of the voltage generated by the dipole at the detonator will divide between the container-to-cup and cup-to-pin gaps. The gap voltages are determined by their capacitances. As a simplification, it will be assumed the cup is electrically attached, short circuited, to the HE container. The electrical field in the pin-to-cup area is determined by the field near the dipole, the length of the dipole, the shape of the arms, and the orientation of the arms. Given the characteristics of a lightning strike and the inductance of the facility, the electric fields in the ''Faraday cage'' can be calculated. The important parameters for determining the voltage in an empty facility are the inductance of the rebars and the rate of change of the current, Eq. 1.3. The internal electric fields are directly related to the facility voltages, however, the electric fields in the pin-to-cup space is much higher than the facility fields because the antenna will concentrate the fields covered by the arms. Because the lightning current rise-time is different for every strike, the maximum electric field and the induced detonator voltage should be described by probability distributions. For pedantic purposes, the peak field in the simulations will be simply set to 1 V/m. Lightning induced detonator voltages can be calculated by scaling up with the facility fields. Any metal object around the explosives, such as a work stand, will also distort the electric fields. A computer simulation of the electric fields in a facility with a work stand and HE container is shown. In this configuration, the work stand is grounded, and the intensity of field around the HE (denoted in dark blue) is reduced relative to the rest of the work bay (denoted lighter blue). The area above work stand posts has much higher fields indicated by red. The fields on top of the container are also affected. Without an understanding of how the electric fields are distributed near the detonator cable and container, it is not possible to calculate the induced detonator voltage. The average lightning current has rise- and fall-times of 3 us and 50 us respectively, and this translates to a wavelength that is long when compared with the length of the HE container or detonator cable.« less

Detonative propagation and accelerative expansion of the Crab Nebula shock front.

PubMed

Gao, Yang; Law, Chung K

2011-10-21

The accelerative expansion of the Crab Nebula's outer envelope is a mystery in dynamics, as a conventional expanding blast wave decelerates when bumping into the surrounding interstellar medium. Here we show that the strong relativistic pulsar wind bumping into its surrounding nebula induces energy-generating processes and initiates a detonation wave that propagates outward to form the current outer edge, namely, the shock front, of the nebula. The resulting detonation wave, with a reactive downstream, then provides the needed power to maintain propagation of the shock front. Furthermore, relaxation of the curvature-induced reduction of the propagation velocity from the initial state of formation to the asymptotic, planar state of Chapman-Jouguet propagation explains the observed accelerative expansion. Potential richness in incorporating reactive fronts in the description of various astronomical phenomena is expected. © 2011 American Physical Society

Parametric study of the dynamic JWL-EOS for detonation products

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

Urtiew, P.A.; Hayes, B.

1990-03-01

The JWL equation of state describing the adiabatic expansion of detonation products is revisited to complete the description of the principal eigenvalue, to reset the secondary eigenvalue to produce a well-behaved adiabatic gamma profile, and to normalize the characteristic equation of state in terms of conventional parameters having a clear experimental interpretation. This is accomplished by interjecting a dynamic flow condition concerning the value of the relative specific volume when the particle velocity of the detonation products is zero. In addition, a set of generic parameters based on the statistical distribution of the primary explosives making up the available datamore » base is presented. Unlike theoretical and statistical mechanical models, the adiabatic gamma function for these materials is seen to have a positive initial slope in accord with experimental findings. 10 refs., 4 figs.« less

Ignition and Growth Reactive Flow Modeling of Shock Initiation of PBX 9502 at -55∘C and -196∘C

NASA Astrophysics Data System (ADS)

Chidester, Steven; Tarver, Craig

2015-06-01

Recently Gustavsen et al. and Hollowell et al. published two stage gas gun embedded particle velocity gauge experiments on PBX 9502 (95%TATB, 5% Kel-F800) cooled to -55°C and -196°C, respectively. At -196°C, PBX 9502 was shown to be much less shock sensitive than at -55°C, but it did transition to detonation. Previous Ignition and Growth model parameters for shock initiation of PBX 9502 at -55°C are modified based on the new data, and new parameters for -196°C PBX 9502 are created to accurately simulate the measured particle velocity histories and run distances to detonation versus shock pressures. This work was performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

Modeling Blast Loading on Buried Reinforced Concrete Structures with Zapotec

DOE PAGES

Bessette, Greg C.

2008-01-01

A coupled Euler-Lagrange solution approach is used to model the response of a buried reinforced concrete structure subjected to a close-in detonation of a high explosive charge. The coupling algorithm is discussed along with a set of benchmark calculations involving detonations in clay and sand.

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

NASA Astrophysics Data System (ADS)

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

2010-12-01

The existence of a supersonic second combustion mode — detonation — discovered by Mallard and Le Chatelier and by Berthélot and Vieille in 1881 posed the question of mechanisms for transition from one mode to the other. In the period 1959-1969, experiments by Salamandra, Soloukhin, Oppenheim, and their coworkers provided insights into this complex phenomenon. Since then, among all the phenomena related to combustion processes, deflagration-to-detonation transition is, undoubtedly, the most intriguing one. Deflagration-to-detonation transition (DDT) in gases is connected with gas and vapor explosion safety issues. Knowing mechanisms of detonation onset control is of major importance for creating effective mitigation measures addressing two major goals: to prevent DDT in the case of mixture ignition, or to arrest the detonation wave in the case where it has been initiated. A new impetus to the increase in interest in deflagration-to-detonation transition processes was given by the recent development of pulse detonation devices. The probable application of these principles to creation of a new generation of engines put the problem of effectiveness of pulse detonating devices at the top of current research needs. The effectiveness of the pulse detonation cycle turned out to be the key factor characterizing the Pulse Detonation Engine (PDE), whose operation modes were shown to be closely related to periodical onset and degeneration of a detonation wave. Those unsteady-state regimes should be self-sustained to guarantee a reliable operation of devices using the detonation mode of burning fuels as a constitutive part of their working cycle. Thus deflagration-to-detonation transition processes are of major importance for the issue. Minimizing the predetonation length and ensuring stability of the onset of detonation enable one to increase the effectiveness of a PDE. The DDT turned out to be the key factor characterizing the PDE operating cycle. Thus, the problem of DDT control in gaseous fuel-air mixtures became very acute. This paper contains results of theoretical and experimental investigations of DDT processes in combustible gaseous mixtures. In particular, the paper investigates the effect of cavities incorporated in detonation tubes at the onset of detonation in gases. Extensive numerical modeling and simulations allowed studying the features of deflagration-to-detonation transition in gases in tubes incorporating cavities of a wider cross section. The presence of cavities substantially affects the combustion modes being established in the device and their dependence on the governing parameters of the problem. The influence of geometrical characteristics of the confinement and flow turbulization on the onset of detonation and the influence of temperature and fuel concentration in the unburned mixture are discussed. It was demonstrated both experimentally and theoretically that the presence of cavities of wider cross section in the ignition part of the tube promotes DDT and shortens the predetonation length. At the same time, cavities incorporated along the whole length or in the far-end section inhibit detonation and bring about the onset of low-velocity galloping detonation or galloping combustion modes. The presence of cavities in the ignition section turns an increase in the initial mixture temperature into a DDT-promoting factor instead of a DDT-inhibiting factor.

NUclear EVacuation Analysis Code (NUEVAC) : a tool for evaluation of sheltering and evacuation responses following urban nuclear detonations.

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

Yoshimura, Ann S.; Brandt, Larry D.

2009-11-01

The NUclear EVacuation Analysis Code (NUEVAC) has been developed by Sandia National Laboratories to support the analysis of shelter-evacuate (S-E) strategies following an urban nuclear detonation. This tool can model a range of behaviors, including complex evacuation timing and path selection, as well as various sheltering or mixed evacuation and sheltering strategies. The calculations are based on externally generated, high resolution fallout deposition and plume data. Scenario setup and calculation outputs make extensive use of graphics and interactive features. This software is designed primarily to produce quantitative evaluations of nuclear detonation response options. However, the outputs have also proven usefulmore » in the communication of technical insights concerning shelter-evacuate tradeoffs to urban planning or response personnel.« less

Comparison of Bacillus atrophaeus spore viability following exposure to detonation of C4 and to deflagration of halogen-containing thermites

NASA Astrophysics Data System (ADS)

Tringe, J. W.; Létant, S. E.; Dugan, L. C.; Levie, H. W.; Kuhl, A. L.; Murphy, G. A.; Alves, S. W.; Vandersall, K. S.; Pantoya, M. L.

2013-12-01

Energetic materials are being considered for the neutralization of spore-forming bacteria. In this study, the neutralization effects of a monomolecular explosive were compared to the effects of halogen-containing thermites. Bacillus atrophaeus spores were exposed to the post-detonation environment of a 100 g charge of the military explosive C-4 at a range of 50 cm. These tests were performed in the thermodynamically closed environment of a 506-l barometric calorimeter. Associated temperatures were calculated using a thermodynamic model informed by calculations with the Cheetah thermochemical code. Temperatures in the range of 2300-2800 K were calculated to persist for nearly the full 4 ms pressure observation time. After the detonation event, spores were characterized using optical microscopy and the number of viable spores was assessed. Results showed live spore survival rates in the range of 0.01%-1%. For the thermite tests, a similar, smaller-scale configuration was employed that examined the spore neutralization effects of two thermites: aluminum with iodine pentoxide and aluminum with potassium chlorate. Only the former mixture resulted in spore neutralization. These results indicate that the detonation environment produced by an explosive with no chemical biocides may provide effective spore neutralization similar to a deflagrating thermite containing iodine.

Particle velocity measurements of the reaction zone in nitromethane

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

Sheffield, S. A.; Engelke, R. P.; Alcon, R. R.

2002-01-01

The detonation reaction-zone length in neat, deuterated, and chemically sensitized nitromethane (NM) has been measured by using several different laser-based velocity interferometry systems. The experiments involved measuring the particle velocity history at a NM/PMMA (polymethylmethacrylate) window interface during the time a detonation in the NM interacted with the interface. Initially, Fabry-Perot interferometry was used, but, because of low time resolution (>5 ns), several different configurations of VISAR interferometry were subsequently used. Early work was done with VISARs with a time resolution of about 3 ns. By making changes to the recording system, we were able to improve this to {approx}1more » ns. Profiles measured at the NM/PMMA interface agree with the ZND theory, in that a spike ({approx}2.45 mm/{micro}s) is measured that is consistent with an extrapolated reactant NM Hugoniot matched to the PMMA window. The spike is rather sharp, followed by a rapid drop in particle velocity over a time of 5 to 10 ns; this is evidence of early fast reactions. Over about 50 ns, a much slower particle velocity decrease occurs to the assumed CJ condition - indicating a total reaction zone length of {approx}300 {micro}m. When the NM is chemically changed, such as replacing the hydrogen atoms with deuterium or chemically sensitizing with a base, some changes are observed in the early part of the reaction zone.« less

Self-Remediating Energetic Fills Based on Cyclic Dinitroureas

DTIC Science & Technology

2016-12-01

159 ° C (sample- dependent) c ,e Detonation pressure PCJ (GPa) 38.7h 46.2i - 37.98 g Detonation velocity D (km/sec) 9.07 j ~9.75 k,l 8.67 b 8.81 g...Gao, S.-L.; Zhu, C .-H.; Ning, B.-K.; Chen, P.; Luo, Y.; Song, J .- R.; Shi, Q.-Z. Chin. J . Chem. 2004, 22, 1075. TNGU was chosen to move forward...R.E.; DeSesso, J . II; Vogel, C . M. Comparison of the Relative Risks of CL-20 and RDX. Noblis Technical Report, July 2007; http://www.serdp- estcp.org

Mode transition of plasma expansion for laser induced breakdown in Air

NASA Astrophysics Data System (ADS)

Shimamura, Kohei; Matsui, Kohei; Ofosu, Joseph A.; Yokota, Ippei; Komurasaki, Kimiya

2017-03-01

High-speed shadowgraph visualization experiments conducted using a 10 J pulse transversely excited atmospheric (TEA) CO2 laser in ambient air provided a state transition from overdriven to Chapman-Jouguet in the laser-supported detonation regime. At the state transition, the propagation velocity of the laser-supported detonation wave and the threshold laser intensity were 10 km/s and 1011 W/m2, respectively. State transition information, such as the photoionization caused by plasma UV radiation, of the avalanche ionization ahead of the ionization wave front can be elucidated from examination of the source seed electrons.

Recent Combined Effects Explosives Technology

DTIC Science & Technology

2010-07-01

flow velocities are relative to the detonation velocity, D. Using the Jones-Wilkens-Lee-Baker [ JWLB (ref. 7)] thermo- dynamic equation of state...cylinder test modeling using identical JWLB equations of state for TNT and LX-14. The JWLB equations of state were parameterized using JAGUAR...thermochemical equation of state modeling (ref. 11). Table 1 presents the TNT and LX-14 JWLB parameters. The 1.2 in. outer diameter, 1 in. inner diameter

Detonation initiation in a model of explosive: Comparative atomistic and hydrodynamics simulations

NASA Astrophysics Data System (ADS)

Murzov, S. A.; Sergeev, O. V.; Dyachkov, S. A.; Egorova, M. S.; Parshikov, A. N.; Zhakhovsky, V. V.

2016-11-01

Here we extend consistent simulations to reactive materials by the example of AB model explosive. The kinetic model of chemical reactions observed in a molecular dynamics (MD) simulation of self-sustained detonation wave can be used in hydrodynamic simulation of detonation initiation. Kinetic coefficients are obtained by minimization of difference between profiles of species calculated from the kinetic model and observed in MD simulations of isochoric thermal decomposition with a help of downhill simplex method combined with random walk in multidimensional space of fitting kinetic model parameters.

The Effect of Post-Burst Energy on Exploding Bridgewire Output

NASA Astrophysics Data System (ADS)

Lee, Elizabeth; Bowden, Mike

2015-06-01

For an EBW detonator, as the fireset energy is increased from threshold to all-fire level the post-burst energy delivered to the detonator increases, and the function times decrease. To gain an understanding of the processes through which the post-burst electrical energy influences the function times the effect of the post-burst energy on the explosion of bridgewires was studied. A fireset was developed which enabled the post-burst energy to be varied independent of the burst energy by terminating the current flow at pre-selected times. The effect of this on the bridgewires was characterised at a range of firing voltages and a range of termination times. The response of the bridgewire was characterised using Photonic Doppler Velocimetry. The velocimetry trace detected two families of velocities. The first family had initial velocities in the range 1-2 km.s-1 and the second family had velocities in the range 0-0.5 km.s-1. The relative position of the two families depended on the post burst energy. The results show that a reduction in the post-burst energy and therefore the total delivered energy, but for a constant energy delivered to burst, corresponds to a decrease in the acceleration and peak velocity of the bridgewire / plasma at burst.

Combustion and Magnetohydrodynamic Processes in Advanced Pulse Detonation Rocket Engines

NASA Astrophysics Data System (ADS)

Cole, Lord Kahil

A number of promising alternative rocket propulsion concepts have been developed over the past two decades that take advantage of unsteady combustion waves in order to produce thrust. These concepts include the Pulse Detonation Rocket Engine (PDRE), in which repetitive ignition, propagation, and reflection of detonations and shocks can create a high pressure chamber from which gases may be exhausted in a controlled manner. The Pulse Detonation Rocket Induced Magnetohydrodynamic Ejector (PDRIME) is a modification of the basic PDRE concept, developed by Cambier (1998), which has the potential for performance improvements based on magnetohydrodynamic (MHD) thrust augmentation. The PDRIME has the advantage of both low combustion chamber seeding pressure, per the PDRE concept, and efficient energy distribution in the system, per the rocket-induced MHD ejector (RIME) concept of Cole, et al. (1995). In the initial part of this thesis, we explore flow and performance characteristics of different configurations of the PDRIME, assuming quasi-one-dimensional transient flow and global representations of the effects of MHD phenomena on the gas dynamics. By utilizing high-order accurate solvers, we thus are able to investigate the fundamental physical processes associated with the PDRIME and PDRE concepts and identify potentially promising operating regimes. In the second part of this investigation, the detailed coupling of detonations and electric and magnetic fields are explored. First, a one-dimensional spark-ignited detonation with complex reaction kinetics is fully evaluated and the mechanisms for the different instabilities are analyzed. It is found that complex kinetics in addition to sufficient spatial resolution are required to be able to quantify high frequency as well as low frequency detonation instability modes. Armed with this quantitative understanding, we then examine the interaction of a propagating detonation and the applied MHD, both in one-dimensional and two-dimensional transient simulations. The dynamics of the detonation are found to be affected by the application of magnetic and electric fields. We find that the regularity of one-dimensional cesium-seeded detonations can be significantly altered by reasonable applied magnetic fields (Bz ≤ 8T), but that it takes a stronger applied field (Bz > 16T) to significantly alter the cellular structure and detonation velocity of a two-dimensional detonation in the time in which these phenomena were observed. This observation is likely attributed to the additional coupling of the two-dimensional detonation with the transverse waves, which are not captured in the one-dimensional simulations. Future studies involving full ionization kinetics including collisional-radiative processes, will be used to examine these processes in further detail.

Self-assembly of silver(i)-based high-energy metal-organic frameworks (HE-MOFs) at ambient temperature and pressure: synthesis, structure and superior explosive performance.

PubMed

Shen, Cheng; Liu, Yang; Zhu, Zhong-Qin; Xu, Yuan-Gang; Lu, Ming

2017-07-04

Two new high-energy metal-organic frameworks (HE-MOFs), {Ag 2 (DNMAF)(H 2 O) 2 } n (1) and {Ag 2 (DNMAF)} n (2) were prepared using potassium 4,4'-bis(dinitromethyl)-3,3'-azofurazanate (K 2 DNMAF) in a self-assembly strategy. Compound 1 exhibits a 3D HE-MOF structure with coordinated water molecules. Compound 2 exhibits compact solvent-free 3D HE-MOFs. Both compounds show good thermostability (decomposition temperature (T d ) of 211 and 218 °C) and superior detonation velocities (D) of 9673 m s -1 and 10 242 m s -1 , detonation pressures (P) of 50.01 GPa and 58.30 GPa, and heat of detonation (Q) of 1.95 kcal g -1 and 2.19 kcal g -1 , respectively, which are even higher than those of RDX and HMX.

Detonation propagation in annular arcs of condensed phase explosives

NASA Astrophysics Data System (ADS)

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

2017-11-01

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

Indirect Lightning Safety Assessment Methodology

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

Ong, M M; Perkins, M P; Brown, C G

2009-04-24

Lightning is a safety hazard for high-explosives (HE) and their detonators. In the However, the current flowing from the strike point through the rebar of the building The methodology for estimating the risk from indirect lighting effects will be presented. It has two parts: a method to determine the likelihood of a detonation given a lightning strike, and an approach for estimating the likelihood of a strike. The results of these two parts produce an overall probability of a detonation. The probability calculations are complex for five reasons: (1) lightning strikes are stochastic and relatively rare, (2) the quality ofmore » the Faraday cage varies from one facility to the next, (3) RF coupling is inherently a complex subject, (4) performance data for abnormally stressed detonators is scarce, and (5) the arc plasma physics is not well understood. Therefore, a rigorous mathematical analysis would be too complex. Instead, our methodology takes a more practical approach combining rigorous mathematical calculations where possible with empirical data when necessary. Where there is uncertainty, we compensate with conservative approximations. The goal is to determine a conservative estimate of the odds of a detonation. In Section 2, the methodology will be explained. This report will discuss topics at a high-level. The reasons for selecting an approach will be justified. For those interested in technical details, references will be provided. In Section 3, a simple hypothetical example will be given to reinforce the concepts. While the methodology will touch on all the items shown in Figure 1, the focus of this report is the indirect effect, i.e., determining the odds of a detonation from given EM fields. Professor Martin Uman from the University of Florida has been characterizing and defining extreme lightning strikes. Using Professor Uman's research, Dr. Kimball Merewether at Sandia National Laboratory in Albuquerque calculated the EM fields inside a Faraday-cage type facility, when the facility is struck by lightning. In the following examples we will use Dr. Merewether's calculations from a poor quality Faraday cage as the input for the RF coupling analysis. coupling of radio frequency (RF) energy to explosive components is an indirect effect of currents [1]. If HE is adequately separated from the walls of the facility that is struck by disassembled have been turned into Faraday-cage structures to protect against lightning is initiation of the HE. last couple of decades, DOE facilities where HE is manufactured, assembled, stored or lightning. The most sensitive component is typically a detonator, and the safety concern lightning, electrons discharged from the clouds should not reach the HE components. radio receiver, the metal cable of a detonator can extract energy from the EM fields. This to the earth will create electromagnetic (EM) fields in the facility. Like an antenna in a« less

The Relevance of the De Broglie Velocity (V sub 1 = h/2md sub 1) to Shock Loading Induced Reactions in Lead Azide

DTIC Science & Technology

1991-09-01

CODES 18. SUBJECT TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP De Broglie Velocity Detonation Particle...Velocity Shock Induced Reaction I Lead Azide 19. ABSTRACT (Continue on reverse if necessary and identify by biock number) Availabl e experimental shock...induced reactive pressure levels for dextrinated and single crystal lead azide are compared to predicted Pv1 magnitudes. PV1 = P. CL V1 where V, = h

Frequency power analyses of seismic sources on firn

NASA Astrophysics Data System (ADS)

Sanz, Christopher; Diez, Anja; Coen, Hofstede; Kristoffersen, Yngve; Mayer, Christoph; Lambrecht, Astrid; Miller, Heinz; Eisen, Olaf

2013-04-01

A great obstacle for seismic surveys on firn-covered ice masses is the ability of firn to strongly attenuate seismic energy and divert downward ray paths away from the vertical because of the velocity gradient. The standard way to overcome these limitations is the drilling of shotholes about 10-30 m deep. However, drilling of shotholes is a time and energy consuming task. Another possibility is to use vibroseismic sources at the surface and increase the signal-to-noise ratio by repeated stacking. However, compared to explosive charges, vibroseismic signals are bandlimited per se. As a third variant, we investigate the usage of ordered patterns of surface charges consisting of detonation cord. Previous applications of detonation cord only explored their general comparison to bulk explosives when deployed in a linear fashion, i.e. a single line. Our approach extends these results to other geometries, like fan- or comb-shaped patterns. These have two advantages: first, over the pattern area a locally plane wave is generated, limiting the spherical and velocity-gradient induced spreading of energy during propagation; second, the ratio between seismic wave speed of the firn and the detonation cord of typically about 1:5 causes the wave to propagate in an angle downward. When using large offsets like a snow streamer, it is possible to direct the refected energy towards the streamer, depending on offset range and reflector depth. We compare the different source types for several surveys conducted in Antarctica in terms of frequency spectra. Our results show that ordered patterns of detonation cord serve as suitable seismic surface charges, avoiding the need to drill shotholes. Moreover, an example of a short profile with patterned surface charges is presented. The technique can be of advantage for surveys in remote areas, which can only be accessed by aircrafts.

Detonation wave compression in gas turbines

NASA Technical Reports Server (NTRS)

Wortman, A.

1986-01-01

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

Structural stability, vibrational, and bonding properties of potassium 1, 1'-dinitroamino-5, 5'-bistetrazolate: An emerging green primary explosive.

PubMed

Yedukondalu, N; Vaitheeswaran, G

2015-08-14

Potassium 1,1'-dinitroamino-5,5'-bistetrazolate (K2DNABT) is a nitrogen rich (50.3% by weight, K2C2N12O4) green primary explosive with high performance characteristics, namely, velocity of detonation (D = 8.33 km/s), detonation pressure (P = 31.7 GPa), and fast initiating power to replace existing toxic primaries. In the present work, we report density functional theory (DFT) calculations on structural, equation of state, vibrational spectra, electronic structure, and absorption spectra of K2DNABT. We have discussed the influence of weak dispersive interactions on structural and vibrational properties through the DFT-D2 method. We find anisotropic compressibility behavior (b

Structural stability, vibrational, and bonding properties of potassium 1, 1'-dinitroamino-5, 5'-bistetrazolate: An emerging green primary explosive

NASA Astrophysics Data System (ADS)

Yedukondalu, N.; Vaitheeswaran, G.

2015-08-01

Potassium 1,1'-dinitroamino-5,5'-bistetrazolate (K2DNABT) is a nitrogen rich (50.3% by weight, K2C2N12O4) green primary explosive with high performance characteristics, namely, velocity of detonation (D = 8.33 km/s), detonation pressure (P = 31.7 GPa), and fast initiating power to replace existing toxic primaries. In the present work, we report density functional theory (DFT) calculations on structural, equation of state, vibrational spectra, electronic structure, and absorption spectra of K2DNABT. We have discussed the influence of weak dispersive interactions on structural and vibrational properties through the DFT-D2 method. We find anisotropic compressibility behavior (b

Comparison of Bacillus atrophaeus spore viability following exposure to detonation of C4 and to deflagration of halogen-containing thermites

DOE PAGES

Tringe, J. W.; Letant, S. E.; Dugan, L. C.; ...

2013-12-17

We found that energetic materials are being considered for the neutralization of spore-forming bacteria. In this study, the neutralization effects of a monomolecular explosive were compared to the effects of halogen-containing thermites. Bacillus atrophaeus spores were exposed to the post-detonation environment of a 100 g charge of the military explosive C-4 at a range of 50 cm. These tests were performed in the thermodynamically closed environment of a 506-l barometric calorimeter. Associated temperatures were calculated using a thermodynamic model informed by calculations with the Cheetah thermochemicalcode. Temperatures in the range of 2300–2800 K were calculated to persist for nearly themore » full 4 ms pressure observation time. After the detonation event, spores were characterized using optical microscopy and the number of viable spores was assessed. These results showed live spore survival rates in the range of 0.01%–1%. For the thermite tests, a similar, smaller-scale configuration was employed that examined the spore neutralization effects of two thermites: aluminum with iodine pentoxide andaluminum with potassium chlorate. Only the former mixture resulted in spore neutralization. Our results indicate that the detonation environment produced by an explosive with no chemical biocides may provide effective spore neutralization similar to a deflagrating thermite containing iodine.« less

Comparison of Bacillus atrophaeus spore viability following exposure to detonation of C4 and to deflagration of halogen-containing thermites

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

Tringe, J. W.; Létant, S. E.; Dugan, L. C.

2013-12-21

Energetic materials are being considered for the neutralization of spore-forming bacteria. In this study, the neutralization effects of a monomolecular explosive were compared to the effects of halogen-containing thermites. Bacillus atrophaeus spores were exposed to the post-detonation environment of a 100 g charge of the military explosive C-4 at a range of 50 cm. These tests were performed in the thermodynamically closed environment of a 506-l barometric calorimeter. Associated temperatures were calculated using a thermodynamic model informed by calculations with the Cheetah thermochemical code. Temperatures in the range of 2300–2800 K were calculated to persist for nearly the full 4 ms pressure observation time.more » After the detonation event, spores were characterized using optical microscopy and the number of viable spores was assessed. Results showed live spore survival rates in the range of 0.01%–1%. For the thermite tests, a similar, smaller-scale configuration was employed that examined the spore neutralization effects of two thermites: aluminum with iodine pentoxide and aluminum with potassium chlorate. Only the former mixture resulted in spore neutralization. These results indicate that the detonation environment produced by an explosive with no chemical biocides may provide effective spore neutralization similar to a deflagrating thermite containing iodine.« less

A novel simultaneous streak and framing camera without principle errors

NASA Astrophysics Data System (ADS)

Jingzhen, L.; Fengshan, S.; Ningwen, L.; Xiangdong, G.; Bin, H.; Qingyang, W.; Hongyi, C.; Yi, C.; Xiaowei, L.

2018-02-01

A novel simultaneous streak and framing camera with continuous access, the perfect information of which is far more important for the exact interpretation and precise evaluation of many detonation events and shockwave phenomena, has been developed. The camera with the maximum imaging frequency of 2 × 106 fps and the maximum scanning velocity of 16.3 mm/μs has fine imaging properties which are the eigen resolution of over 40 lp/mm in the temporal direction and over 60 lp/mm in the spatial direction and the framing frequency principle error of zero for framing record, and the maximum time resolving power of 8 ns and the scanning velocity nonuniformity of 0.136%~-0.277% for streak record. The test data have verified the performance of the camera quantitatively. This camera, simultaneously gained frames and streak with parallax-free and identical time base, is characterized by the plane optical system at oblique incidence different from space system, the innovative camera obscura without principle errors, and the high velocity motor driven beryllium-like rotating mirror, made of high strength aluminum alloy with cellular lateral structure. Experiments demonstrate that the camera is very useful and reliable to take high quality pictures of the detonation events.

Atomistic Simulations of Detonation Instabilities in Condensed Phase Systems

NASA Astrophysics Data System (ADS)

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

2007-06-01

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

Synthesis and theoretical studies on nitrogen-rich salts of bis[4-nitraminofurazanyl-3-azoxy]azofurazan (ADNAAF).

PubMed

Zheng, Chunmei; Chu, Yuting; Xu, Liwen; Lei, Wu; Wang, Fengyun; Xia, Mingzhu

2017-01-01

Multi-furazan compounds bis[4-nitramino- furazanyl-3-azoxy]azofurazan (ADNAAF) and its derivatives were first synthesized by our research group, and their structures were characterized by IR, 1 H-NMR, 13 C-NMR spectrums, and element analysis. ADNAAF was synthesized by nitration reaction of bis[4-aminofurazanyl-3-azoxy]azofurazan (ADAAF), and then reacted with ammonium hydroxide, hydrazine hydrate, and guanidine nitrate to obtain three salts marked as salt 1, 2, and 3, respectively. The thermal stabilities of the three salts were supported by the results of DSC analysis, which shows the decomposition temperatures are all above 190 °C. Their densities, enthalpies of formation, and detonation properties were studied by density functional theory (DFT) method. Salt 1 has the best detonation pressure (P), 37.42 GPa, and detonation velocity (D), 8.88 km/s, while salt 2 has the best nitrogen content and heat of detonation (Q), 1.27 kcal mol -1 . The detonation properties of salt 1 is similar to that of 1,3,5-trinitro-1,3,5-triazineane (RDX). It means that the ammonium cation can provide the better D and P than the cation of hydrazine and guanidine. The three cations offer the enthalpies of formations in the order of hydrazinium > guanidinium > ammonium. Graphical Abstract Nitrogen-rich salts of bis[4-nitraminofurazanyl-3-azoxy]azofurazan(ADNAAF).

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.

Experiment and Reactive-Burn Modeling in the RDX Based Explosive XTX 8004

NASA Astrophysics Data System (ADS)

Johnson, Carl; Murphy, Mike; Gustavsen, Rick; Jackson, Scott; Vincent, Samuel

2015-06-01

XTX 8004 consists of 80 wt. % cyclotrimethylenetrinitramine (RDX), and 20 wt. % Sylgard 182, a silicone rubber used as a binder. Nominal density is 1.5 g/cm3. Uncured XTX 8004 is putty like and can be molded or extruded. The XTX 8004 detonation product Hugoniot calibration was obtained from cylinder tests using a genetic algorithm approach to parameterize a Jones-Wilkins-Lee (JWL) equation of state. Additionally, we conducted four gas-gun experiments that were instrumented with embedded electromagnetic particle velocity gauges. These provided wave profiles to which we calibrated an Ignition and Growth reactive burn (IGRB) model in ALE3D for 1-D shock to detonation transitions. Further, acceptor and donor XTX 8004 were extruded into opposite sides of a monolithic polymethylmethacrylate (PMMA) block with a known thickness of PMMA forming the attenuator plate, the so-called monolithic gap test (MGT). Detonation and initiation in the XTX 8004 was recorded using multiple ultra-high-speed images of the position of the shock front in the PMMA. Input to the acceptor charge was estimated from stress wave profiles photographed inside the attenuator as well as with photonic Doppler velocimetry (PDV) measurements of the free surface velocity beneath the attenuator plate. Results were simulated using IGRB in ALE3D. Parameterization of IGRB to 1-D vs. 2-D experiments will be discussed.

Steady-state shock-driven reactions in mixtures of nano-sized aluminum and dilute hydrogen peroxide

DOE PAGES

Schmitt, Matthew Mark; Bowden, Patrick Robert; Tappan, Bryce C.; ...

2017-09-21

Mixtures of nanoaluminum (nAl) and dilute hydrogen peroxide (HP) were studied to determine their potential to detonate when subjected to explosive shock. Results of explosively driven rate stick experiments revealed steady shock propagation for stoichiometric mixtures of nAl and 10 wt% HP. The critical diameter of this composition is estimated to be between 27.7 and 34.5 mm. Detonation velocities between 3.034 and 3.187 mm/μs were obtained, varying with charge diameter and density. Furthermore this represents the first measured shock-driven, self-sustained reaction in nAl and dilute HP mixtures.

Detonation performance measurements of cyclotol 80/20

NASA Astrophysics Data System (ADS)

Kuiper, T. A.; Anderson, E. K.; Short, M.; Jackson, S. I.

2017-01-01

Cyclotol is a melt-castable high explosive composed of RDX and TNT, and typically a small amount of HMX. The term Cyclotol may apply to other mixtures of these components, but for the present work, experiments were conducted using Cyclotol containing 80 wt% RDX and HMX and 20 wt% TNT (we will refer to mixtures of RDX and TNT using the notation RDX%/TNT%). In the current effort, we report detonation velocity measurements at several diameters for unconfined rate sticks. The results are compared to prior diameter-effect data for Cyclotol 77/23, and a density-corrected Eyring-form fit for all available rate-stick data is reported.

Reduced chemical kinetic model of detonation combustion of one- and multi-fuel gaseous mixtures with air

NASA Astrophysics Data System (ADS)

Fomin, P. A.

2018-03-01

Two-step approximate models of chemical kinetics of detonation combustion of (i) one hydrocarbon fuel CnHm (for example, methane, propane, cyclohexane etc.) and (ii) multi-fuel gaseous mixtures (∑aiCniHmi) (for example, mixture of methane and propane, synthesis gas, benzene and kerosene) are presented for the first time. The models can be used for any stoichiometry, including fuel/fuels-rich mixtures, when reaction products contain molecules of carbon. Owing to the simplicity and high accuracy, the models can be used in multi-dimensional numerical calculations of detonation waves in corresponding gaseous mixtures. The models are in consistent with the second law of thermodynamics and Le Chatelier's principle. Constants of the models have a clear physical meaning. The models can be used for calculation thermodynamic parameters of the mixture in a state of chemical equilibrium.

Driving Ability of HMX based Aluminized Explosive Affected by the Reaction Degree of Aluminum Powder

NASA Astrophysics Data System (ADS)

Duan, Yingliang

2017-06-01

Due to the time scale of aluminum reaction, the detonation process of the aluminized explosive becomes very complex, and there is less agreement on the reaction mechanism of aluminum powder. If the reaction of aluminum occurs in the reaction zone, the energy released will further strengthen the work ability of detonation wave. So it is very important for characterizing the detonation parameters and detonation driving ability to accurately understand the role of aluminum powder in the reaction zone. In this paper, detonation driving process of HMX based aluminized explosive was studied by cylinder test, obtaining the expansion track of cylinder wall. In order to further research the reaction degree (λ) of aluminum in the reaction zone, the thermodynamic program VHL was used to calculate the detonation process at different reaction degrees, obtaining the parameters of detonation products thermodynamic state. Using the dynamic software LS-DYNA and the JWL equation of state by fitting the pressure and relative volume relationship, the cylinder test was simulated. Compared with the experimental results, when the reaction degree is 20%, the driving ability is found to be in agreement with measured ones. It is concluded that the driving ability of HMX based aluminized explosive can be more accurately characterized by considering the reaction degree of aluminum powder in the reaction zone.

Reactive Burn Model Calibration for PETN Using Ultra-High-Speed Phase Contrast Imaging

NASA Astrophysics Data System (ADS)

Johnson, Carl; Ramos, Kyle; Bolme, Cindy; Sanchez, Nathaniel; Barber, John; Montgomery, David

2017-06-01

A 1D reactive burn model (RBM) calibration for a plastic bonded high explosive (HE) requires run-to-detonation data. In PETN (pentaerythritol tetranitrate, 1.65 g/cc) the shock to detonation transition (SDT) is on the order of a few millimeters. This rapid SDT imposes experimental length scales that preclude application of traditional calibration methods such as embedded electromagnetic gauge methods (EEGM) which are very effective when used to study 10 - 20 mm thick HE specimens. In recent work at Argonne National Laboratory's Advanced Photon Source we have obtained run-to-detonation data in PETN using ultra-high-speed dynamic phase contrast imaging (PCI). A reactive burn model calibration valid for 1D shock waves is obtained using density profiles spanning the transition to detonation as opposed to particle velocity profiles from EEGM. Particle swarm optimization (PSO) methods were used to operate the LANL hydrocode FLAG iteratively to refine SURF RBM parameters until a suitable parameter set attained. These methods will be presented along with model validation simulations. The novel method described is generally applicable to `sensitive' energetic materials particularly those with areal densities amenable to radiography.

The characteristics of void distribution in spalled high purity copper cylinder under sweeping detonation

NASA Astrophysics Data System (ADS)

Yang, Yang; Jiang, Zhi; Chen, Jixinog; Guo, Zhaoliang; Tang, Tiegang; Hu, Haibo

2018-03-01

The effects of different peak compression stresses (2-5 GPa) on the spallation behaviour of high purity copper cylinder during sweeping detonation were examined by Electron Backscatter Diffraction Microscopy, Doppler Pins System and Optical Microscopy techniques. The velocity history of inner surface and the characteristics of void distributions in spalled copper cylinder were investigated. The results indicated that the spall strength of copper in these experiments was less than that revealed in previous reports concerning plate impact loading. The geometry of cylindrical copper and the obliquity of incident shock during sweeping detonation may be the main reasons. Different loading stresses seemed to be responsible for the characteristics of the resultant damage fields, and the maximum damage degree increased with increasing shock stress. Spall planes in different cross-sections of sample loaded with the same shock stress of 3.29 GPa were found, and the distance from the initiation end has little effect on the maximum damage degree (the maximum damage range from 12 to 14%), which means that the spallation behaviour was stable along the direction parallel to the detonation propagation direction under the same shock stress.

Experimental and computational investigation of microwave interferometry (MI) for detonation front characterization

NASA Astrophysics Data System (ADS)

Mays, Owen; Tringe, Joe; Souers, Clark; Lauderbach, Lisa; Baluyot, Emer; Converse, Mark; Kane, Ron

2017-06-01

Microwave interferometry (MI) presents several advantages over more traditional existing shock and deflagration front diagnostics. Most importantly, it directly interrogates these fronts, instead of measuring the evolution of containment surfaces or explosive edges. Here we present the results of MI measurements on detonator-initiated cylinder tests, as well as on deflagration-to-detonation transition experiments, with emphasis on optimization of signal strength through coupling devices and through microwave-transparent windows. Full-wave electromagnetic field finite element simulations were employed to better understand microwave coupling into porous and near full theoretical maximum density (TMD) explosives. HMX and TATB-based explosives were investigated. Data was collected simultaneously at 26.5 GHz and 39 GHz, allowing for direct comparison of the front characteristics and providing insight into the dielectric properties of explosives at these high frequencies. MI measurements are compared against detonation velocity results from photonic Doppler velocimetry probes and high speed cameras, demonstrating the accuracy of the MI technique. Our results illustrate features of front propagation behavior that are difficult to observe with other techniques. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Instrumentation techniques for monitoring shock and detonation waves

NASA Astrophysics Data System (ADS)

Dick, R. D.; Parrish, R. L.

1985-09-01

CORRTEX (Continuous Reflectometry for Radius Versus Time Experiments), SLIFER (Shorted Location Indication by Frequency of Electrical Resonance), and pin probes were used to monitor several conditions of blasting such as the detonation velocity of the explosive, the functioning of the stemming column confining the explosive, and rock mass motion. CORRTEX is a passive device that employs time-domain reflectometry to interrogate the two-way transit time of a coaxial cable. SLIFER is an active device that monitors the changing frequency resulting from a change in length of a coaxial cable forming an element of an oscillator circuit. Pin probes in this application consist of RG-174 coaxial cables, each with an open circuit, placed at several known locations within the material. Each cable is connected to a pulse-forming network and a voltage source. When the cables are shorted by the advancing wave, time-distance data are produced from which a velocity can be computed. Each technique, installation of the gauge, examples of the signals, and interpretation of the records are described.

Laser Light Scattering Diagnostic for Measurement of Flow Velocity in Vicinity of Propagating Shock Waves

NASA Technical Reports Server (NTRS)

Seasholtz, Richard G.; Buggele, Alvin E.

2002-01-01

A laser light scattering diagnostic for measurement of dynamic flow velocity at a point is described. The instrument is being developed for use in the study of propagating shock waves and detonation waves in pulse detonation engines under development at the NASA Glenn Research Center (GRC). The approach uses a Fabry-Perot interferometer to measure the Doppler shift of laser light scattered from small (submicron) particles in the flow. The high-speed detection system required to resolve the transient response as a shock wave crosses the probe volume uses fast response photodetectors, and a PC based data acquisition system. Preliminary results of measurements made in the GRC Mach 4, 10 by 25 cm supersonic wind tunnel are presented. Spontaneous condensation of water vapor in the flow is used as seed. The tunnel is supplied with continuous air flow at up to 45 psia and the flow is exhausted into the GRC laboratory-wide altitude exhaust system at pressures down to 0.3 psia.

Thermal Explosion Violence of HMX-Based and RDX-Based Explosives - Effects of Composition, Confinement, and Solid Phase Using the Scaled Thermal Explosion Experiment

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

Maienschein, J L; Wardell, J F

The Scaled Thermal Explosion Experiment (STEX) has been developed to quantify the violence of thermal explosion under well defined and carefully controlled initial and boundary conditions. Here we present results with HMX-based explosives (LX-04 and PBX-9501) and with Composition B. Samples are 2 inches (50 mm) in diameter and 8 inches (200 mm) in length, under confinement of 7,500-30,000 psi (50-200 MPa), with heating rates of 1-3 C/hr. We quantify reaction violence by measuring the wall velocity in the ensuing thermal explosion, and relate the measured velocity to that expected from a detonation. Results with HMX-based explosives (LX-04 and PBX-9501)more » have shown the importance of confinement and HMX solid phase, with reaction violence ranging from mild pressure bursts to near detonations. By contrast, Composition B has shown very violent reactions over a wide range of conditions.« less

Computational Study of Near-limit Propagation of Detonation in Hydrogen-air Mixtures

NASA Technical Reports Server (NTRS)

Yungster, S.; Radhakrishnan, K.

2002-01-01

A computational investigation of the near-limit propagation of detonation in lean and rich hydrogen-air mixtures is presented. The calculations were carried out over an equivalence ratio range of 0.4 to 5.0, pressures ranging from 0.2 bar to 1.0 bar and ambient initial temperature. The computations involved solution of the one-dimensional Euler equations with detailed finite-rate chemistry. The numerical method is based on a second-order spatially accurate total-variation-diminishing (TVD) scheme, and a point implicit, first-order-accurate, time marching algorithm. The hydrogen-air combustion was modeled with a 9-species, 19-step reaction mechanism. A multi-level, dynamically adaptive grid was utilized in order to resolve the structure of the detonation. The results of the computations indicate that when hydrogen concentrations are reduced below certain levels, the detonation wave switches from a high-frequency, low amplitude oscillation mode to a low frequency mode exhibiting large fluctuations in the detonation wave speed; that is, a 'galloping' propagation mode is established.

The Attenuation of a Detonation Wave by an Aircraft Engine Axial Turbine Stage

NASA Technical Reports Server (NTRS)

VanZante, Dale; Envia, Edmane; Turner, Mark G.

2007-01-01

A Constant Volume Combustion Cycle Engine concept consisting of a Pulse Detonation Combustor (PDC) followed by a conventional axial turbine was simulated numerically to determine the attenuation and reflection of a notional PDC pulse by the turbine. The multi-stage, time-accurate, turbomachinery solver TURBO was used to perform the calculation. The solution domain consisted of one notional detonation tube coupled to 5 vane passages and 8 rotor passages representing 1/8th of the annulus. The detonation tube was implemented as an initial value problem with the thermodynamic state of the tube contents, when the detonation wave is about to exit, provided by a 1D code. Pressure time history data from the numerical simulation was compared to experimental data from a similar configuration to verify that the simulation is giving reasonable results. Analysis of the pressure data showed a spectrally averaged attenuation of about 15 dB across the turbine stage. An evaluation of turbine performance is also presented.

Modeling normal shock velocity curvature relations for heterogeneous explosives

NASA Astrophysics Data System (ADS)

Yoo, Sunhee; Crochet, Michael; Pemberton, Steven

2017-01-01

The theory of Detonation Shock Dynamics (DSD) is, in part, an asymptotic method to model a functional form of the relation between the shock normal, its time rate and shock curvature κ. In addition, the shock polar analysis provides a relation between shock angle θ and the detonation velocity Dn that is dependent on the equations of state (EOS) of two adjacent materials. For the axial detonation of an explosive material confined by a cylinder, the shock angle is defined as the angle between the shock normal and the normal to the cylinder liner, located at the intersection of the shock front and cylinder inner wall. Therefore, given an ideal explosive such as PBX-9501 with two functional models determined, a unique, smooth detonation front shape ψ can be determined that approximates the steady state detonation shock front of the explosive. However, experimental measurements of the Dn(κ) relation for heterogeneous explosives such as PBXN-111 [D. K. Kennedy, 2000] are challenging due to the non-smoothness and asymmetry usually observed in the experimental streak records of explosion fronts. Out of many possibilities the asymmetric character may be attributed to the heterogeneity of the explosives; here, material heterogeneity refers to compositions with multiple components and having a grain morphology that can be modeled statistically. Therefore in extending the formulation of DSD to modern novel explosives, we pose two questions: (1) is there any simple hydrodynamic model that can simulate such an asymmetric shock evolution, and (2) what statistics can be derived for the asymmetry using simulations with defined structural heterogeneity in the unreacted explosive? Saenz, Taylor and Stewart [1] studied constitutive models for derivation of the Dn(κ) relation for porous homogeneous explosives and carried out simulations in a spherical coordinate frame. In this paper we extend their model to account for heterogeneity and present shock evolutions in heterogeneous explosives using 2-D hydrodynamic simulations with some statistical examination. As an initial work, we assume that the heterogeneity comes from the local density variation or porosity only.

Removing Full-scale Testing Barriers: Energetic Material Detonation Characterization at the Laboratory Scale

DTIC Science & Technology

2012-03-01

3708Unclassified Unclassified Unclassified ii Contents List of Figures iv List of Tables v Acknowledgments vi 1. Introduction 1 2. Theory/ Methodology ...Theory/ Methodology A shock wave is fully defined through knowledge of five state variables: shock pressure P , shock velocity U , particle velocity u...DIRECTOR US ARMY RESERACH LAB RDRL D 2800 POWDER MILL RD ADELPHI MD 20783-1197 21 NO. OF NO. OF COPIES ORGANIZATION COPIES ORGANIZATION 3 US ARMY RSRCH OFC

Remarks on Certain Aspects of Solid Explosive Detonation Via Small Projectile Impact

DTIC Science & Technology

1989-05-01

S [CURITY CL.ASSIFICATION OF TWI.rI5rAG Form, Approved REPORT DOCUMENTATION PAGE OMS 4o 0 7U -0188 __________________________________________I Exp...PIERFORMIWG OftGANLZATION REPO"t NUM5ER( S S . MONITORING ORGANIZATION REPORT NUMBER( S ) RDl-SS-88-11. b B. NAME Of PtRFORMIPANG O*CLANLZATION 6 b. DFfsC...SHOCK VELOCITY (U s ), AND PROJECTILE IMPACT VELOCITY VI) .................................... A-I APPENDIX B - SHOCK COMPRESSION INFORMATION FOR

Macro-Scale Reactive Flow Model for High-Explosive Detonation in Support of ASCI Weapon Safety Milepost

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

Reaugh, J E

2002-01-03

Explosive grain-scale simulations are not practical for weapon safety simulations. Indeed for nearly ideal explosives with reaction zones of order 500 {micro}m, even reactive flow models are not practical for weapon safety simulations. By design, reactive flow models must resolve the reaction zone, which implies computational cells with dimension of order 50 {micro}m for such explosives. The desired result for a simulation in which the reaction zone is not resolved is that the explosive behaves as an ideal one. The pressure at the shock front rises to the Chapman-Jouget (CJ) pressure with a reaction zone dimension that is like thatmore » of a shock propagating in an unreactive medium, on the order of a few computational cells. It should propagate with the detonation velocity that is determined by the equation of state of the products. In the past, this was achieved in one dimensional simulations with ''beta-burn'', a method in which the extent of conversion to final product is proportional to the approach of the specific volume in the shock front to the specific volume of the CJ state. One drawback with this method is that there is a relatively long build-up to steady detonation that is typically 50 to 100 computational cells. The need for relatively coarsely zoned simulations in two dimensions lead to ''program-burn'' by which the time to detonation can be determined by a simple ray-tracing algorithm when there are no barriers or shadows. Complications arise in two and three dimensions to the extent that some calculations of the lighting time in complex geometry can give incorrect results. We sought to develop a model based on reactive flow that might help the needs of the Weapon Safety Simulation milepost. Important features of the model are: (1) That it be useable with any equation of state description of the explosive product gases including both JWL and LEOS table forms. (2) That it exhibits the desired dependence on zone size. We believe that the model described here does exhibit these features.« less

Computer Program for Calculation of Complex Chemical Equilibrium Compositions, Rocket Performance, Incident and Reflected Shocks, and Chapman-Jouguet Detonations. Interim Revision, March 1976

NASA Technical Reports Server (NTRS)

Gordon, S.; Mcbride, B. J.

1976-01-01

A detailed description of the equations and computer program for computations involving chemical equilibria in complex systems is given. A free-energy minimization technique is used. The program permits calculations such as (1) chemical equilibrium for assigned thermodynamic states (T,P), (H,P), (S,P), (T,V), (U,V), or (S,V), (2) theoretical rocket performance for both equilibrium and frozen compositions during expansion, (3) incident and reflected shock properties, and (4) Chapman-Jouguet detonation properties. The program considers condensed species as well as gaseous species.

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.

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.

Influence of the Fluid on the Parameters and Limits of Bubble Detonation

NASA Astrophysics Data System (ADS)

Pinaev, A. V.; Prokhorov, E. S.

2017-12-01

The compression and inflammation of reactive gas bubbles in bubble detonation waves have been studied, and the considerable influence of the fluid (liquid or vapor) on the detonation parameters has been found. It has been shown numerically that the final values of the pressure and temperature significantly decrease if the temperature dependence of the adiabatic index is taken into account at the compression stage. The parameters of reactive gas combustion products in the bubble have been calculated in terms of an equilibrium model, and the influence of the fluid that remains in the bubble in the form of microdroplets and vapor on these parameters has been investigated.

Simulation of moving boundaries interacting with compressible reacting flows using a second-order adaptive Cartesian cut-cell method

NASA Astrophysics Data System (ADS)

Muralidharan, Balaji; Menon, Suresh

2018-03-01

A high-order adaptive Cartesian cut-cell method, developed in the past by the authors [1] for simulation of compressible viscous flow over static embedded boundaries, is now extended for reacting flow simulations over moving interfaces. The main difficulty related to simulation of moving boundary problems using immersed boundary techniques is the loss of conservation of mass, momentum and energy during the transition of numerical grid cells from solid to fluid and vice versa. Gas phase reactions near solid boundaries can produce huge source terms to the governing equations, which if not properly treated for moving boundaries, can result in inaccuracies in numerical predictions. The small cell clustering algorithm proposed in our previous work is now extended to handle moving boundaries enforcing strict conservation. In addition, the cell clustering algorithm also preserves the smoothness of solution near moving surfaces. A second order Runge-Kutta scheme where the boundaries are allowed to change during the sub-time steps is employed. This scheme improves the time accuracy of the calculations when the body motion is driven by hydrodynamic forces. Simple one dimensional reacting and non-reacting studies of moving piston are first performed in order to demonstrate the accuracy of the proposed method. Results are then reported for flow past moving cylinders at subsonic and supersonic velocities in a viscous compressible flow and are compared with theoretical and previously available experimental data. The ability of the scheme to handle deforming boundaries and interaction of hydrodynamic forces with rigid body motion is demonstrated using different test cases. Finally, the method is applied to investigate the detonation initiation and stabilization mechanisms on a cylinder and a sphere, when they are launched into a detonable mixture. The effect of the filling pressure on the detonation stabilization mechanisms over a hyper-velocity sphere launched into a hydrogen-oxygen-argon mixture is studied and a qualitative comparison of the results with the experimental data are made. Results indicate that the current method is able to correctly reproduce the different regimes of combustion observed in the experiments. Through the various examples it is demonstrated that our method is robust and accurate for simulation of compressible viscous reacting flow problems with moving/deforming boundaries.

Emulsion based cast booster - a priming system

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

Gupta, R.N.; Mishra, A.K.

2005-07-01

This paper explores the potential of emulsion based cast booster to be used as primer to initiate bulk delivered emulsion explosives used in mines. An attempt has been made for comparative study between conventional cast booster and emulsion based cast booster in terms of the initiation process developed and their capability to develop and maintain the stable detonation process in the column explosives. The study has been conducted using a continuous velocity of detonation (VOD) measuring instrument. During this study three blasts have been monitored. In each blast two holes have been selected for study, the first hole being initiatedmore » with conventional cast booster while the other one with emulsion based cast booster. The findings of the study advocates that emulsion based cast booster is capable of efficient priming of bulk delivered column explosive with stable detonation process in the column. Further, the booster had advantages over the conventional PETN/TNT based cast booster. 5 refs., 2 figs., 1 tab., 1 photo.« less

Nanoengineered explosives

DOEpatents

Makowiecki, D.M.

1996-04-09

A complex modulated structure is described for reactive elements that have the capability of considerably more heat than organic explosives while generating a working fluid or gas. The explosive and method of fabricating same involves a plurality of very thin, stacked, multilayer structures, each composed of reactive components, such as aluminum, separated from a less reactive element, such as copper oxide, by a separator material, such as carbon. The separator material not only separates the reactive materials, but it reacts therewith when detonated to generate higher temperatures. The various layers of material, thickness of 10 to 10,000 angstroms, can be deposited by magnetron sputter deposition. The explosive detonates and combusts a high velocity generating a gas, such as CO, and high temperatures. 2 figs.

Theoretical Insight into the Influences of Molecular Ratios on Stabilities and Mechanical Properties, Solvent Effect of HMX/FOX-7 Cocrystal Explosive

NASA Astrophysics Data System (ADS)

Wei, Yan-Ju; Ren, Fu-De; Shi, Wen-Jing; Zhao, Qi

2016-10-01

A molecular dynamics method was employed to study the binding energies of the selected crystal planes of the 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane/1,1-diamino-2,2-dinitroethylene (HMX/FOX-7) cocrystal in different molecular molar ratios. Mechanical properties, densities, and detonation velocities of the cocrystals in different ratios were estimated. The intermolecular interactions and bond dissociation energies (BDEs) of the N-NO2 bond in the HMX:FOX-7 (1:1) complex were calculated using the B3LYP and MP2(full) methods at the 6-311++G (d,p) and 6-311++G(2df,2p) basis sets. Solvent effects on stability are discussed. The results indicate that HMX/FOX-7 cocrystals prefer cocrystalizing in a 1:1 molar ratio, which has good mechanical properties. The N-NO2 bond becomes strong upon the formation of a complex and the sensitivity of HMX might decrease in cocrystals. The sensitivity change of HMX/FOX-7 originates from not only the formation of intermolecular interaction but also the increment in the N-NO2 BDE. HMX/FOX-7 cocrystals exhibit good detonation performance and meet the requirements of high-density energetic materials. Solvents with low dielectric constants may be chosen to obtain stable HMX/FOX-7 cocrystals.

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.

DSD/WBL-consistent JWL equations of state for EDC35

NASA Astrophysics Data System (ADS)

Hodgson, Alexander N.; Handley, Caroline Angela

2012-03-01

The Detonation Shock Dynamics (DSD) model allows the calculation of curvature-dependent detonation propagation. It is of particular use when applied to insensitive high explosives, such as EDC35, since they have a greater non-ideal behaviour. The DSD model is used in conjunction with experimental cylinder test data to obtain the JWL Equation of State (EOS) for EDC35. Adjustment of parameters in the JWL equation changes the expansion profile of the cylinder wall in hydrocode simulations. The parameters are iterated until the best match can be made between simulation and experiment. Previous DSD models used at AWE have no mechanism to adjust the chemical energy release to match the detonation conditions. Two JWL calibrations are performed using the DSD model, with and without Hetherington's energy release model (these proceedings). Also in use is a newly-calibrated detonation speed-curvature relation.

Deflagration to Detonation Transition (DDT) Simulations of HMX Powder Using the HERMES Model

NASA Astrophysics Data System (ADS)

White, Bradley; Reaugh, John; Tringe, Joseph

2017-06-01

We performed computer simulations of DDT experiments with Class I HMX powder using the HERMES model (High Explosive Response to MEchanical Stimulus) in ALE3D. Parameters for the model were fitted to the limited available mechanical property data of the low-density powder, and to the Shock to Detonation Transition (SDT) test results. The DDT tests were carried out in steel-capped polycarbonate tubes. This arrangement permits direct observation of the event using both flash X-ray radiography and high speed camera imaging, and provides a stringent test of the model. We found the calculated detonation transition to be qualitatively similar to experiment. Through simulation we also explored the effects of confinement strength, the HMX particle size distribution and porosity on the computed detonation transition location. This work was performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344.

A simple model for the dependence on local detonation speed of the product entropy

NASA Astrophysics Data System (ADS)

Hetherington, David C.; Whitworth, Nicholas J.

2012-03-01

The generation of a burn time field as a pre-processing step ahead of a hydrocode calculation has been mostly upgraded in the explosives modelling community from the historical model of singlespeed programmed burn to DSD/WBL (Detonation Shock Dynamics / Whitham Bdzil Lambourn). The problem with this advance is that the previously conventional approach to the hydrodynamic stage of the model results in the entropy of the detonation products (s) having the wrong correlation with detonation speed (D). Instead of being higher where D is lower, the conventional method leads to s being lower where D is lower, resulting in a completely fictitious enhancement of available energy where the burn is degraded! A technique is described which removes this deficiency of the historical model when used with a DSD-generated burn time field. By treating the conventional JWL equation as a semi-empirical expression for the local expansion isentrope, and constraining the local parameter set for consistency with D, it is possible to obtain the two desirable outcomes that the model of the detonation wave is internally consistent, and s is realistically correlated with D.

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.

A Performance Map for Ideal Air Breathing Pulse Detonation Engines

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.

2001-01-01

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

CAN HELIUM ENVELOPES CHANGE THE OUTCOME OF DIRECT WHITE DWARF COLLISIONS?

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

Holcomb, Cole; Kushnir, Doron

2016-08-01

A pivotal feature for the viability of white dwarf (WD) collisions as SN Ia progenitors is that a significant fraction of the mass is highly compressed to the densities required for efficient {sup 56}Ni production before the ignition of the detonation wave. Previous studies have employed model WDs composed of carbon–oxygen (CO), whereas WDs typically have a non-negligible helium envelope. Given that helium is more susceptible to explosive burning than CO under the conditions of WD collision, a legitimate concern is whether or not early time He detonation ignition can lead to early time CO detonation, drastically reducing {sup 56}Nimore » synthesis. We investigate the role of He in determining the fate of WD collisions by performing a series of two-dimensional hydrodynamics calculations. We find that a necessary condition for non-trivial reduction of the CO ignition time is that the He detonation birthed in the contact region successfully propagates into the unshocked shell. We determine the minimal He shell mass as a function of the total WD mass that upholds this condition. Although we utilize a simplified reaction network similar to those used in previous studies, our findings are in good agreement with detailed investigations concerning the impact of network size on He shell detonations. This allows us to extend our results to the case with more realistic burning physics. Based on the comparison of these findings against evolutionary calculations of WD compositions, we conclude that most, if not all, WD collisions will not be drastically impacted by their intrinsic He components.« less

Measuring explosive non-ideality

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

Souers, P C

1999-02-17

The sonic reaction zone length may be measured by four methods: (1) size effect, (2) detonation front curvature, (3) crystal interface velocity and (4) in-situ gauges. The amount of data decreases exponentially from (1) to (4) with there being almost no gauge data for prompt detonation at steady state. The ease and clarity of obtaining the reaction zone length increases from (1) to (4). The method of getting the reaction zone length, , is described for the four methods. A measure of non-ideality is proposed: the reaction zone length divided by the cylinder radius. N = /R{sub o}.more » N = 0 for true ideality. It also decreases with increasing radius as it should. For N < 0.10, an equilibrium EOS like the JWL may be used. For N > 0.10, a time-dependent description is essential. The crystal experiment, which measures the particle velocity of an explosive-transparent material interface, is presently rising in importance. We examine the data from three experiments and apply: (1) an impedance correction that transfers the explosive C-J particle velocity to the corresponding value for the interface, and (2) multiplies the interface time by 3/4 to simulate the explosive speed of sound. The result is a reaction zone length comparable to those obtained by other means. A few explosives have reaction zones so small that the change of slope in the particle velocity is easily seen.« less

Hazards from the Detonation of Buried Explosive Ordnance: Literature Survey

DTIC Science & Technology

1993-09-01

Quantification of Particle Motion 4.9.1. Kuzmina , et al. provided a rather massive data base for describing peak particle velocity versus reduced...explosives present in an area, not just that present in one bay. Kuzmina , N. V., et al.; "Seismic Effect of Eruptive Explosions in Nonrock Coherent Ground

Diameter Effect Curve and Detonation Front Curvature Measurements for ANFO

NASA Astrophysics Data System (ADS)

Catanach, R. A.; Hill, L. G.

2002-07-01

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 fit with an analytic form, from which the local normal velocity Dn, and local total curvature kappa, were generated as a function of radius R, then plotted parametrically to generate a Dn(kappa) function. The observed behavior deviates substantially from that of previous explosives, for which curves for different diameters overlay well for small kappa but diverge for large kappa, and for which kappa increases monotonically with R. For ANFO, we find that Dn(kappa) curves for individual sticks 1) show little or no overlap--with smaller sticks lying to the right of larger ones, 2) exhibit a large velocity deficit with little kappa variation, and 3) reach a peak kappa at an intermediate R.

ISC origin times for announced and presumed underground nuclear explosions at several test sites

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

Rodean, H.C.

1979-12-03

Announced data for US and French underground nuclear explosions indicate that nearly all detonations have occurred within one or two tenths of a second after the minute. This report contains ISC origin-time data for announced explosions at two US test sites and one French test site, and includes similar data for presumed underground nuclear explosions at five Soviet sites. Origin-time distributions for these sites are analyzed for those events that appeared to be detonated very close to the minute. Particular attention is given to the origin times for the principal US and Soviet test sites in Nevada and Eastern Kazakhstan.more » The mean origin times for events at the several test sites range from 0.4 s to 2.8 s before the minute, with the earlier mean times associated with the Soviet sites and the later times with the US and French sites. These times indicate lower seismic velocities beneath the US and French sites, and higher velocities beneath the sites in the USSR 9 figures, 8 tables.« less

Hydrodynamical simulation of detonations in superbursts. I. The hydrodynamical algorithm and some preliminary one-dimensional results

NASA Astrophysics Data System (ADS)

Noël, C.; Busegnies, Y.; Papalexandris, M. V.; Deledicque, V.; El Messoudi, A.

2007-08-01

Aims:This work presents a new hydrodynamical algorithm to study astrophysical detonations. A prime motivation of this development is the description of a carbon detonation in conditions relevant to superbursts, which are thought to result from the propagation of a detonation front around the surface of a neutron star in the carbon layer underlying the atmosphere. Methods: The algorithm we have developed is a finite-volume method inspired by the original MUSCL scheme of van Leer (1979). The algorithm is of second-order in the smooth part of the flow and avoids dimensional splitting. It is applied to some test cases, and the time-dependent results are compared to the corresponding steady state solution. Results: Our algorithm proves to be robust to test cases, and is considered to be reliably applicable to astrophysical detonations. The preliminary one-dimensional calculations we have performed demonstrate that the carbon detonation at the surface of a neutron star is a multiscale phenomenon. The length scale of liberation of energy is 106 times smaller than the total reaction length. We show that a multi-resolution approach can be used to solve all the reaction lengths. This result will be very useful in future multi-dimensional simulations. We present also thermodynamical and composition profiles after the passage of a detonation in a pure carbon or mixed carbon-iron layer, in thermodynamical conditions relevant to superbursts in pure helium accretor systems.

Predicting the Plate Dent Test Output in Order to Assess the Performance of Condensed High Explosives

NASA Astrophysics Data System (ADS)

Frem, Dany

2017-01-01

In the present study, a relationship is proposed that is capable of predicting the output of the plate dent test. It is shown that the initial density ?; condensed phase heat of formation ?; the number of carbon (C), nitrogen (N), oxygen (O); and the composition molecular weight (MW) are the most important parameters needed in order to accurately predict the absolute dent depth ? produced on 1018 cold-rolled steel by a detonating organic explosive. The estimated ? values can be used to predict the detonation pressure (P) of high explosives; furthermore, we show that a correlation exists between ? and the Gurney velocity ? parameter. The new correlation is used to accurately estimate ? for several C-H-N-O explosive compositions.

Injector nozzle for molten salt destruction of energetic waste materials

DOEpatents

Brummond, William A.; Upadhye, Ravindra S.

1996-01-01

An injector nozzle has been designed for safely injecting energetic waste materials, such as high explosives, propellants, and rocket fuels, into a molten salt reactor in a molten salt destruction process without premature detonation or back burn in the injection system. The energetic waste material is typically diluted to form a fluid fuel mixture that is injected rapidly into the reactor. A carrier gas used in the nozzle serves as a carrier for the fuel mixture, and further dilutes the energetic material and increases its injection velocity into the reactor. The injector nozzle is cooled to keep the fuel mixture below the decomposition temperature to prevent spontaneous detonation of the explosive materials before contact with the high-temperature molten salt bath.

Injector nozzle for molten salt destruction of energetic waste materials

DOEpatents

Brummond, W.A.; Upadhye, R.S.

1996-02-13

An injector nozzle has been designed for safely injecting energetic waste materials, such as high explosives, propellants, and rocket fuels, into a molten salt reactor in a molten salt destruction process without premature detonation or back burn in the injection system. The energetic waste material is typically diluted to form a fluid fuel mixture that is injected rapidly into the reactor. A carrier gas used in the nozzle serves as a carrier for the fuel mixture, and further dilutes the energetic material and increases its injection velocity into the reactor. The injector nozzle is cooled to keep the fuel mixture below the decomposition temperature to prevent spontaneous detonation of the explosive materials before contact with the high-temperature molten salt bath. 2 figs.

NASA Astrophysics Data System (ADS)

Kadyrov, E.; Evdokimenko, Y.; Kisel, V.; Kadyrov, V.; Worzala, F.

1994-12-01

Several designs of high-velocity oxygen fuel (HVOF) thermal spray systems have been created during the last decade. The most advanced systems are now producing coatings comparable in quality to detonation (D-gun) coatings. This paper presents numerical analysis of the interaction of dispersive particles with the carrying gas flow for three different HVOF systems, along with a method to calculate the parameters of sprayed particles that highlights the advantages and limitations of each design. The method includes gas dynamical calculations of the gas flow in an accelerating channel and calculations of the injected par-motion and thermal state (temperature and melted mass fraction). The calculations were performed for particles of tungsten carbide, aluminum oxide, and zirconium oxide with size distributions of 10 to 80 μm. Two conventional types of HVOF systems were considered: those with a supersonic accelerating channel and those with a subsonic accelerating channel (without a de Laval nozzle). A novel design is pro-posed that contains a combined gas dynamical path with functionally separated regions of heating and acceleration. The regularities and distinctions in the behavior of the metallic and ceramic oxide particles are discussed for different jet configurations. The results obtained indicate that it is possible to signifi-cantly affect particle parameters by using the new configuration solutions without creating construction complications.

Jack Rabbit Pretest 2021E PT3 Photonic Doppler Velocimetry Data Volume 3 Section 1

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

Hart, M M; Strand, O T; Bosson, S T

The Jack Rabbit Pretest (PT) 2021E PT3 was fired on March 12, 2008 at the Contained Firing Facility, Site 300, Lawrence Livermore National Laboratory. This experiment is part of an effort to determine the properties of LX-17 in a regime where corner-turning behavior and dead-zone formation are not well understood. Photonic Doppler Velocimetry (PDV) measured diagnostic plate velocities confirming the presence of a persistent LX-17 dead-zone formation and the resultant impulse gradient applied under the diagnostic plate. The Jack Rabbit Pretest 2021E PT3, 120 millimeter diameter experiment returned data on all eight PDV probes. The probes measured on the centralmore » axis and at 10, 20, 25, 30, 35, 40, 50 millimeters from the central axis. The experiment was shot at an ambient room temperature of 65 degrees Fahrenheit. The earliest PDV signal extinction was 41.7 microseconds at 30 millimeters. The latest PDV signal extinction time was 65.0 microseconds at 10 millimeters. The measured velocity ranged from meters per second to thousands of meters per second. First detonation wave induced jump-off was measured at 40 millimeters at 10.9 microseconds. The PDV data provided an unambiguous indication of dead-zone formation and an impulse gradient applied to the diagnostic plate. The central axis had a last measured velocity of 1636 meters per second. At 40 millimeters the last measured velocity was 2056 meters per second. The low-to-high velocity ratio was 0.80. Velocity data was integrated to compute diagnostic plate cross section profiles. Velocity data was differentiated to compute a peak pressure under the diagnostic plate at the central axis of 64.6 kilobars at 15.7 microseconds. Substantial motion (>1 m/s) of the diagnostic plate over the dead-zone is followed by detonation region motion within approximately 2.2 microseconds.« less

Jack Rabbit Pretest 2021E PT4 Photonic Doppler Velocimetry Data Volume 4 Section 1

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

Hart, M M; Strand, O T; Bosson, S T

The Jack Rabbit Pretest (PT) 2021E PT4 was fired on March 19, 2008 at the Contained Firing Facility, Site 300, Lawrence Livermore National Laboratory. This experiment is part of an effort to determine the properties of LX-17 in a regime where corner-turning behavior and dead-zone formation are not well understood. Photonic Doppler Velocimetry (PDV) measured diagnostic plate velocities confirming the presence of a persistent LX-17 dead-zone formation and the resultant impulse gradient applied under the diagnostic plate. The Jack Rabbit Pretest 2021E PT4, 120 millimeter diameter experiment returned data on all eight PDV probes. The probes measured on the centralmore » axis and at 10, 20, 25, 30, 35, 40, 50 millimeters from the central axis. The experiment was shot at an ambient room temperature of 64 degrees Fahrenheit. The earliest PDV signal extinction was 44.9 microseconds at 30 millimeters. The latest PDV signal extinction time was 69.5 microseconds at 10 millimeters. The measured velocity ranged from meters per second to thousands of meters per second. First detonation wave induced jump-off was measured at 50 millimeters at 13.3 microseconds. The PDV data provided an unambiguous indication of dead-zone formation and an impulse gradient applied to the diagnostic plate. The central axis had a last measured velocity of 1558 meters per second. At 40 millimeters the last measured velocity was 2019 meters per second. The low-to-high velocity ratio was 0.77. Velocity data was integrated to compute diagnostic plate cross section profiles. Velocity data was differentiated to compute a peak pressure under the diagnostic plate at the central axis of 98.6 kilobars at 15.0 microseconds. Substantial motion (>1 m/s) of the diagnostic plate over the dead-zone is followed by detonation region motion within approximately 0.7 microseconds.« less

Jack Rabbit Pretest 2021E PT6 Photonic Doppler Velocimetry Data Volume 6 Section 1

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

Hart, M M; Strand, O T; Bosson, S T

The Jack Rabbit Pretest (PT) 2021E PT6 experiment was fired on April 1, 2008 at the Contained Firing Facility, Site 300, Lawrence Livermore National Laboratory. This experiment is part of an effort to determine the properties of LX-17 in a regime where corner-turning behavior and dead-zone formation are not well understood. Photonic Doppler Velocimetry (PDV) measured diagnostic plate velocities confirming the presence of a persistent LX-17 dead-zone formation and the resultant impulse gradient applied under the diagnostic plate. The Jack Rabbit Pretest 2021E PT6, 160 millimeter diameter experiment returned data on all eight PDV probes. The probes measured on themore » central axis and at 20, 30, 35, 45, 55, 65, 75 millimeters from the central axis. The experiment was shot at an ambient room temperature of 65 degrees Fahrenheit. The earliest PDV signal extinction was 54.2 microseconds at 30 millimeters. The latest PDV signal extinction time was 64.5 microseconds at the central axis. The measured velocity ranged from meters per second to thousands of meters per second. First detonation wave induced jump-off was measured at 55 millimeters at 14.1 microseconds. The PDV data provided an unambiguous indication of dead-zone formation and an impulse gradient applied to the diagnostic plate. The central axis had a last measured velocity of 1860 meters per second. At 55 millimeters the last measured velocity was 2408 meters per second. The low-to-high velocity ratio was 0.77. Velocity data was integrated to compute diagnostic plate cross section profiles. Velocity data was differentiated to compute a peak pressure under the diagnostic plate at the central axis of 227 kilobars at 20.1 microseconds, indicating a late time chemical reaction in the LX-17 dead-zone. Substantial motion (>1 m/s) of the diagnostic plate over the dead-zone is followed by detonation region motion within approximately 1.7 microseconds.« less

Jack Rabbit Pretest 2021E PT5 Photonic Doppler Velocimetry Data Volume 5 Section 1

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

Hart, M M; Strand, O T; Bosson, S T

The Jack Rabbit Pretest (PT) 2021E PT5 was fired on March 17, 2008 at the Contained Firing Facility, Site 300, Lawrence Livermore National Laboratory. This experiment is part of an effort to determine the properties of LX-17 in a regime where corner-turning behavior and dead-zone formation are not well understood. Photonic Doppler Velocimetry (PDV) measured diagnostic plate velocities confirming the presence of a persistent LX-17 dead-zone formation and the resultant impulse gradient applied under the diagnostic plate. The Jack Rabbit Pretest 2021E PT5, 160 millimeter diameter experiment returned data on all eight PDV probes. The probes measured on the centralmore » axis and at 20, 30, 35, 45, 55, 65, 75 millimeters from the central axis. The experiment was shot at an ambient room temperature of 65 degrees Fahrenheit. The earliest PDV signal extinction was 40.0 microseconds at 45 millimeters. The latest PDV signal extinction time was 64.9 microseconds at 20 millimeters. The measured velocity ranged from meters per second to thousands of meters per second. First detonation wave induced jump-off was measured at 55 millimeters at 12.8 microseconds. The PDV data provided an unambiguous indication of dead-zone formation and an impulse gradient applied to the diagnostic plate. The central axis had a last measured velocity of 1877 meters per second. At 65 millimeters the last measured velocity was 2277 meters per second. The low-to-high velocity ratio was 0.82. Velocity data was integrated to compute diagnostic plate cross section profiles. Velocity data was differentiated to compute a peak pressure under the diagnostic plate at the central axis of 78 kilobars at 11.9 and 21.2 microseconds. Substantial motion (>1 m/s) of the diagnostic plate over the dead-zone is followed by detonation region motion within approximately 4.1 microseconds.« less

Jack Rabbit Pretest 2021E PT7 Photonic Doppler Velocimetry Data Volume 7 Section 1

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

Hart, M M; Strand, O T; Bosson, S T

The Jack Rabbit Pretest (PT) 2021E PT7 experiment was fired on April 3, 2008 at the Contained Firing Facility, Site 300, Lawrence Livermore National Laboratory. This experiment is part of an effort to determine the properties of LX-17 in a regime where corner-turning behavior and dead-zone formation are not well understood. Photonic Doppler Velocimetry (PDV) measured diagnostic plate velocities confirming the presence of a persistent LX-17 dead-zone formation and the resultant impulse gradient applied under the diagnostic plate. The Jack Rabbit Pretest 2021E PT7, 160 millimeter diameter experiment returned data on all eight PDV probes. The probes measured on themore » central axis and at 20, 30, 35, 45, 55, 65, 75 millimeters from the central axis. The experiment was shot at an ambient room temperature of 65 degrees Fahrenheit. The PDV earliest signal extinction was 50.7 microseconds at 45 millimeters. The latest PDV signal extinction time was 65.0 microseconds at 20 millimeters. The measured velocity ranged from meters per second to thousands of meters per second. First detonation wave induced jump-off was measured at 55 millimeters and at 15.2 microseconds. The PDV data provided an unambiguous indication of dead-zone formation and an impulse gradient applied to the diagnostic plate. The central axis had a last measured velocity of 1447 meters per second. At 65 millimeters the last measured velocity was 2360 meters per second. The low-to-high velocity ratio was 0.61. Velocity data was integrated to compute diagnostic plate cross section profiles. Velocity data was differentiated to compute a peak pressure under the diagnostic plate at the central axis of 49 kilobars at 23.3 microseconds. Substantial motion (>1 m/s) of the diagnostic plate over the dead-zone is followed by detonation region motion within approximately 4.6 microseconds.« less

Dimensionality effects in void-induced explosive sensitivity

DOE PAGES

Herring, Stuart Davis; Germann, Timothy Clark; Gronbech-Jensen, Niels

2016-09-02

Here, the dimensionality of defects in high explosives controls their heat generation and the expansion of deflagrations from them. We compare the behaviour of spherical voids in three dimensions to that of circular voids in two dimensions. The behaviour is qualitatively similar, but the additional focusing along the extra transverse dimension significantly reduces the piston velocity needed to initiate reactions. However, the reactions do not grow as well in three dimensions, so detonations require larger piston velocities. Pressure exponents are seen to be similar to those for the two-dimensional system.

Development of a reactive burn model based on an explicit viscoplastic pore collapse model

NASA Astrophysics Data System (ADS)

Bouton, E.; Lefrançois, A.; Belmas, R.

2017-01-01

The aim of this study is to develop a reactive burn model based upon a microscopic hot spot model to compute the shock-initiation of pressed TATB high explosives. Such a model has been implemented in a lagrangian hydrodynamic code. In our calculations, 8 pore radii, ranging from 40 nm to 0.63 μm, have been taken into account and the porosity fraction associated to each void radius has been deduced from the Ultra-Small-Angle X-ray Scattering measurements (USAXS) for PBX-9502. The last parameter of our model is a burn rate that depends on three variables. The first two are the reaction progress variable and the lead shock pressure, the last one is the chemical reaction site number produced in the flow and calculated by the microscopic model. This burn rate has been calibrated by fitting pressure, velocity profiles and run distances to detonation. As the computed results are in close agreement with the measured ones, this model is able to perform a wide variety of numerical simulations including single, double shock waves and the desensitization phenomenon.

Dynamic transition in the structure of an energetic crystal during chemical reactions at shock front prior to detonation.

PubMed

Nomura, Ken-Ichi; Kalia, Rajiv K; Nakano, Aiichiro; Vashishta, Priya; van Duin, Adri C T; Goddard, William A

2007-10-05

Mechanical stimuli in energetic materials initiate chemical reactions at shock fronts prior to detonation. Shock sensitivity measurements provide widely varying results, and quantum-mechanical calculations are unable to handle systems large enough to describe shock structure. Recent developments in reactive force-field molecular dynamics (ReaxFF-MD) combined with advances in parallel computing have paved the way to accurately simulate reaction pathways along with the structure of shock fronts. Our multimillion-atom ReaxFF-MD simulations of l,3,5-trinitro-l,3,5-triazine (RDX) reveal that detonation is preceded by a transition from a diffuse shock front with well-ordered molecular dipoles behind it to a disordered dipole distribution behind a sharp front.

Using Underwater Explosion and Cylinder Expansion Tests to Calibrate Afterburn Models for Aluminized Explosives

NASA Astrophysics Data System (ADS)

Wedberg, Rasmus

2017-06-01

The study explores the combined use of underwater performance tests and cylinder expansion tests in order to parameterize detonation models for aluminized explosives which exhibit afterburning. The approach is suggested to be used in conjunction with thermochemical computation. A formulation containing RDX and aluminum powder is considered and several charges with varying masses are submerged and detonated. Pressure gauges are employed at horizontal distances scaling with the charge diameter, and the specific shock wave energy is shown to increase with charge mass. This is attributed to the combustion of aluminum particles after the Chapman-Jouguet plane. Cylinder expansion tests are carried out using Photon Doppler Velocimetry to register the wall expansion velocity. The tests are modeled using a multi-material arbitrary Lagrangian-Eulerian approach with the Guirguis-Miller model describing detonation with afterburning. The equation of state and afterburn rate law parameters are adjusted such that the model reproduces the results from the cylinder expansion and underwater tests. The approach seems promising, and might be valuable for aluminized explosive formulations intended to be used in a variety of confinement conditions. Swedish Armed Forces.

Microscopic evidence that the nitromethane aci ion is a rate controlling species in the detonation of liquid nitromethane

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

Engelke, R.; Earl, W.L.; Rohlfing, C.M.

1986-01-01

We present microscopic evidence that the aci ion (H/sub 2/CNO/sup -//sub 2/) of nitromethane (H/sub 3/CNO/sub 2/) plays an important role in the detonation kinetics of liquid-phase nitromethane. It is known from previous detonation experiments that very minute additions of organic bases (e.g., amines) have a profound effect on the detonation properties of nitromethane; i.e., the explosive is strongly sensitized. Here we show that, under conditions similar to the detonation experiments, the only new chemical species generated in nitromethane by the bases sodium hydroxide (NaOH), diethylenetriamine (NH/sub 2/CH/sub 2/CH/sub 2/NHCH/sub 2/CH/sub 2/NH/sub 2/), and pyridine (C/sub 5/H/sub 5/N) is themore » aci ion, within the sensitivity of the experiments. The primary tool used to demonstrate this is /sup 13/C NMR spectroscopy. Ab initio quantum-mechanical calculations of the chemical shifts are used to support the experimental interpretation. Qualitative arguments concerning the increased reactivity of the aci ion, relative to normal nitromethane, are given. We review earlier work and relate it to the current findings.« less

High-speed velocity measurements on an EFI-system

NASA Astrophysics Data System (ADS)

Prinse, W. C.; van't Hof, P. G.; Cheng, L. K.; Scholtes, J. H. G.

2007-01-01

For the development of an Exploding Foil Initiator for Insensitive Munitions applications the following topics are of interest: the electrical circuit, the exploding foil, the velocity of the flyer, the driver explosive, the secondary flyer and the acceptor explosive. Several parameters of the EFI have influences on the velocity of the flyer. To investigate these parameters a Fabry-Perot Velocity Interferometer System (F-PVIS) has been used. The light to and from the flyer is transported by a multimode fibre terminated with a GRIN-lens. By this method the velocity of very tiny objects (0.1 mm), can be measured. The velocity of flyer can be recorded with nanosecond resolution, depending on the Fabry-Perot etalon and the streak camera. With this equipment the influence of the dimensions of the exploding foil and the flyer on the velocity and the acceleration of the flyer are investigated. Also the integrity of the flyer during flight can be analyzed. To characterize the explosive material, to be used as driver explosive in EFI's, the initiation behaviour of the explosive has been investigated by taking pictures of the explosion with a high speed framing and streak camera. From these pictures the initiation distance and the detonation behaviour of the explosive has been analyzed. Normally, the driver explosive initiates the acceptor explosive (booster) by direct contact. This booster explosive is embedded in the main charge of the munitions. The combination of initiator, booster explosive and main charge explosive is called the detonation train. In this research the possibility of initiation of the booster by an intermediate flyer is investigated. This secondary flyer can be made of different materials, like aluminium, steel and polyester with different sizes. With the aid of the F-PVIS the acceleration of the secondary flyer is investigated. This reveals the influence of the thickness and density of the flyer on the acceleration and final velocity. Under certain circumstances the flyer breaks up in several parts and several velocities at the same time have been recorded. Several flyer materials and dimensions exist that are able to initiate very insensitive explosives like TATB.

Equation of state, initiation, and detonation of pure ammonium nitrate

NASA Astrophysics Data System (ADS)

Robbins, D. L.; Sheffield, S. A.; Dattelbaum, D. M.; Velisavljevic, N.; Stahl, D. B.

2009-06-01

Ammonium nitrate (AN) is a widely used fertilizer and mining explosive throughout the world. One of the more common explosives using AN is called ANFO, a mixture of AN prills and fuel oil in a 94:6 ratio by weight. The AN prills are specially made to absorb the fuel oil, forming a mixture that reacts under shock loading through a diffusion-controlled process, resulting in a non-ideal explosive with detonation velocities around 4 km/s. While there are a number of studies on ANFO, there are only a few studies relating to the equation of state (EOS) and detonation properties of pure AN - resulting mainly from studies of accidents that have occurred during transportation of large quantities of AN. We present the results of a series of gas gun-driven plate impact experiments on pressed AN ranging in density from 1.72 to 0.9 g/cm^3. Several of the high density experiments were performed in front surface impact geometry, in which pressed AN disks were built into the projectile front and impacted onto LiF windows. Additional experiments at low density have been done in ``half cell'' multiple magnetic gauge gun experiments. From this work a complete unreacted EOS has been developed, as well as some initiation and detonation information. Additional high pressure x-ray diffraction experiments in diamond anvil cells have provided a static isotherm for AN.

FY06 L2C2 HE program report Zaug et al.

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

Zaug, J M; Crowhurst, J C; Howard, W M

2008-08-01

The purpose of this project is to advance the improvement of LLNL thermochemical computational models that form the underlying basis or input for laboratory hydrodynamic simulations. Our general work approach utilizes, by design, tight experimental-theoretical research interactions that allow us to not empirically, but rather more scientifically improve LLNL computational results. The ultimate goal here is to confidently predict through computer models, the performance and safety parameters of currently maintained, modified, and newly designed stockpile systems. To attain our goal we make relevant experimental measurements on candidate detonation products constrained under static high-pressure and temperature conditions. The reduced information frommore » these measurements is then used to construct analytical forms that describe the potential surface (repulsive energy as a function of interatomic separation distance) of single and mixed fluid or detonation product species. These potential surface shapes are also constructed using input from well-trusted shock wave physics and assorted thermodynamic data available in the open literature. Our potential surfaces permit one to determine the equations of state (P,V,T), the equilibrium chemistry, phase, and chemical interactions of detonation products under a very wide range of extreme pressure temperature conditions. Using our foundation of experimentally refined potential surfaces we are in a position to calculate, with confidence, the energetic output and chemical speciation occurring from a specific combustion and/or detonation reaction. The thermochemical model we developed and use for calculating the equilibrium chemistry, kinetics, and energy from ultrafast processes is named 'Cheetah'. Computational results from our Cheetah code are coupled to laboratory ALE3D hydrodynamic simulation codes where the complete response behavior of an existing or proposed system is ultimately predicted. The Cheetah thermochemical code is also used by well over 500 U.S. government DoD and DOE community users who calculate the chemical properties of detonated high explosives, propellants, and pyrotechnics. To satisfy the growing needs of LLNL and the general user community we continue to improve the robustness of our Cheetah code. The P-T range of current speed of sound experiments will soon be extended by a factor of four and our recently developed technological advancements permit us to, for the first time, study any chemical specie or fluid mixture. New experiments will focus on determining the miscibility or coexistence curves of detonation product mixtures. Our newly constructed ultrafast laser diagnostics will permit us to determine what chemical species exist under conditions approaching Chapman-Jouguet (CJ) detonation states. Furthermore we will measure the time evolution of candidate species and use our chemical kinetics data to develop new and validate existing rate laws employed in future versions of our Cheetah thermochemical code.« less

Development and testing of pulsed and rotating detonation combustors

NASA Astrophysics Data System (ADS)

St. George, Andrew C.

Detonation is a self-sustaining, supersonic, shock-driven, exothermic reaction. Detonation combustion can theoretically provide significant improvements in thermodynamic efficiency over constant pressure combustion when incorporated into existing cycles. To harness this potential performance benefit, countless studies have worked to develop detonation combustors and integrate these devices into existing systems. This dissertation consists of a series of investigations on two types of detonation combustors: the pulse detonation combustor (PDC) and the rotating detonation combustor (RDC). In the first two investigations, an array of air-breathing PDCs is integrated with an axial power turbine. The system is initially operated with steady and pulsed cold air flow to determine the effect of pulsed flow on turbine performance. Various averaging approaches are employed to calculate turbine efficiency, but only flow-weighted (e.g., mass or work averaging) definitions have physical significance. Pulsed flow turbine efficiency is comparable to steady flow efficiency at high corrected flow rates and low rotor speeds. At these conditions, the pulse duty cycle expands and the variation of the rotor incidence angle is constrained to a favorable range. The system is operated with pulsed detonating flow to determine the effect of frequency, fill fraction, and rotor speed on turbine performance. For some conditions, output power exceeds the maximum attainable value from steady constant pressure combustion due to a significant increase in available power from the detonation products. However, the turbine component efficiency estimated from classical thermodynamic analysis is four times lower than the steady design point efficiency. Analysis of blade angles shows a significant penalty due to the detonation, fill, and purge processes simultaneously imposed on the rotor. The latter six investigations focus on fundamental research of the RDC concept. A specially-tailored RDC data analysis approach is developed, which employs cross-correlations to detect the combustor operating state as it evolves during a test. This method enables expedient detection of the operating state from sensors placed outside the combustor, and can also identify and quantify instabilities. An investigation is conducted on a tangentially-injecting initiator tube to characterize the RDC ignition process. Maximum energy deposition for this ignition method is an order of magnitude lower than the required energy for direct initiation, and detonation develops via a deflagration-to-detonation transition process. Stable rotating detonation is preceded by a transitory onset phase with a stochastic duration, which appears to be a function of the reactant injection pressure ratio. Hydrogen-ethylene fuel blends are explored as an interim strategy to transition to stable detonation in ethylene-air mixtures. While moderate hydrogen addition enables stable operation, removal of the supplemental hydrogen triggers instability and failure. Chemical kinetic analysis indicates that elevated reactant pressure is far more significant than hydrogen addition, and suggests that the stabilizing effect of hydrogen is physical, rather than kinetic. The role of kinetic effects (e.g., cell width) is also assessed, using H2-O2-N2 mixtures. Detonation is observed when the normalized channel width exceeds the classical limit of wch/lambda = 0.5, and the number of detonations increases predictably when the detonation perimeter exceeds a critical value.

High-temperature explosive development for geothermal well stimulation. Final report

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

Schmidt, E.W.; Mars, J.E.; Wang, C.

1978-03-31

A two-component, temperature-resistant liquid explosive called HITEX has been developed which is capable of withstanding 561/sup 0/K (550/sup 0/F) for 24 hours in a geothermal environment. The explosive is intended for the stimulation of nonproducing or marginally producing geothermal (hot dry rock, vapor-dominated or hydrothermal) reservoirs by fracturing the strata in the vicinity of a borehole. The explosive is inherently safe because it is mixed below ground downhole from two nondetonable liquid components. Development and safety tests included differential scanning calorimetry, thermal stability, minerals compatibility, drop-weight sensitivity, adiabatic compression, electrostatic discharge sensitivity, friction sensitivity, detonation arrest capability, cook-off tests, detonabilitymore » at ambient and elevated pressure, detonation velocity and thin film propagation in a wedge.« less

High speed radiometric measurements of IED detonation fireballs

NASA Astrophysics Data System (ADS)

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

2010-04-01

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

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.

Optical spectroscopy to study confined and semi-closed explosions of homogeneous and composite charges

NASA Astrophysics Data System (ADS)

Maiz, Lotfi; Trzciński, Waldemar A.; Paszula, Józef

2017-01-01

Confined and semi-closed explosions of new class of energetic composites as well as TNT and RDX charges were investigated using optical spectroscopy. These composites are considered as thermobarics when used in layered charges or enhanced blast explosives when pressed. Two methods to estimate fireball temperature histories of both homogeneous and metallized explosives from the spectroscopic data are also presented, compared and analyzed. Fireball temperature results of the charges detonated in a small explosion chamber under air and argon atmospheres, and detonated in a semi-closed bunker are presented and compared with theoretical ones calculated by a thermochemical code. Important conclusions about the fireball temperatures and the physical and chemical phenomena occurring after the detonation of homogeneous explosives and composite formulations are deduced.

Far Field Modeling Methods For Characterizing Surface Detonations

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

Garrett, A.

2015-10-08

Savannah River National Laboratory (SRNL) analyzed particle samples collected during experiments that were designed to replicate tests of nuclear weapons components that involve detonation of high explosives (HE). SRNL collected the particle samples in the HE debris cloud using innovative rocket propelled samplers. SRNL used scanning electronic microscopy to determine the elemental constituents of the particles and their size distributions. Depleted uranium composed about 7% of the particle contents. SRNL used the particle size distributions and elemental composition to perform transport calculations that indicate in many terrains and atmospheric conditions the uranium bearing particles will be transported long distances downwind.more » This research established that HE tests specific to nuclear proliferation should be detectable at long downwind distances by sampling airborne particles created by the test detonations.« less

Combined Effects Aluminized Explosives

DTIC Science & Technology

2010-07-01

1 4 5 AREA EXPANSIONS Figure 4 Cylinder velocities for PAX-3 (left) and an empirical PAX-30 JWL (right) THERMODYNAMIC EQUATIONS OF...STATE The JWLB and Jones-Wilkins-Lee ( JWL ) equations of state were parameterized for combined effects explosives using fairly conventional methodology...state. Such warning messages should be ignored when using these JWLB and JWL equations of state representing eigenvalue detonation behavior. Table 1

The influence of a fire-induced convection column on radiological fallout patterns

Treesearch

A. Broido; A.W. McMasters

1959-01-01

Since no nuclear devices have been detonated by the United States under conditions leading to both mass fires and radiological fallout, a theoretical and small-scale experimental study was undertaken to see if fire-induced convection columns could significantly affect fallout patterns. Experiments were conducted in a 6- by 6-foot low-velocity wind tunnel using full-...

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.

Nonideal detonation regimes in low density explosives

NASA Astrophysics Data System (ADS)

Ershov, A. P.; Kashkarov, A. O.; Pruuel, E. R.; Satonkina, N. P.; Sil'vestrov, V. V.; Yunoshev, A. S.; Plastinin, A. V.

2016-02-01

Measurements using Velocity Interferometer System for Any Reflector (VISAR) were performed for three high explosives at densities slightly above the natural loose-packed densities. The velocity histories at the explosive/window interface demonstrate that the grain size of the explosives plays an important role. Fine-grained materials produced rather smooth records with reduced von Neumann spike amplitudes. For commercial coarse-grained specimens, the chemical spike (if detectable) was more pronounced. This difference can be explained as a manifestation of partial burn up. In fine-grained explosives, which are more sensitive, the reaction can proceed partly within the compression front, which leads to a lower initial shock amplitude. The reaction zone was shorter in fine-grained materials because of higher density of hot spots. The noise level was generally higher for the coarse-grained explosives, which is a natural stochastic effect of the highly non-uniform flow of the heterogeneous medium. These results correlate with our previous data of electrical conductivity diagnostics. Instead of the classical Zel'dovich-von Neumann-Döring profiles, violent oscillations around the Chapman-Jouguet level were observed in about half of the shots using coarse-grained materials. We suggest that these unusual records may point to a different detonation wave propagation mechanism.

Impurity-doped optical shock, detonation and damage location sensor

DOEpatents

Weiss, Jonathan D.

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.

Weakly nonlinear dynamics of near-CJ detonation waves

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

Bdzil, J.B.; Klein, R.

1993-01-01

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

Weakly nonlinear dynamics of near-CJ detonation waves

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

Bdzil, J.B.; Klein, R.

1993-02-01

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

Offsite radiological consequence analysis for the bounding flammable gas accident

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

CARRO, C.A.

2003-03-19

The purpose of this analysis is to calculate the offsite radiological consequence of the bounding flammable gas accident. DOE-STD-3009-94, ''Preparation Guide for U.S. Department of Energy Nonreactor Nuclear Facility Documented Safety Analyses'', requires the formal quantification of a limited subset of accidents representing a complete set of bounding conditions. The results of these analyses are then evaluated to determine if they challenge the DOE-STD-3009-94, Appendix A, ''Evaluation Guideline,'' of 25 rem total effective dose equivalent in order to identify and evaluate safety class structures, systems, and components. The bounding flammable gas accident is a detonation in a single-shell tank (SST).more » A detonation versus a deflagration was selected for analysis because the faster flame speed of a detonation can potentially result in a larger release of respirable material. As will be shown, the consequences of a detonation in either an SST or a double-shell tank (DST) are approximately equal. A detonation in an SST was selected as the bounding condition because the estimated respirable release masses are the same and because the doses per unit quantity of waste inhaled are generally greater for SSTs than for DSTs. Appendix A contains a DST analysis for comparison purposes.« less

Characterizing the energy output generated by a standard electric detonator using shadowgraph imaging

NASA Astrophysics Data System (ADS)

Petr, V.; Lozano, E.

2017-09-01

This paper overviews a complete method for the characterization of the explosive energy output from a standard detonator. Measurements of the output of explosives are commonly based upon the detonation parameters of the chemical energy content of the explosive. These quantities provide a correct understanding of the energy stored in an explosive, but they do not provide a direct measure of the different modes in which the energy is released. This optically based technique combines high-speed and ultra-high-speed imaging to characterize the casing fragmentation and the detonator-driven shock load. The procedure presented here could be used as an alternative to current indirect methods—such as the Trauzl lead block test—because of its simplicity, high data accuracy, and minimum demand for test repetition. This technique was applied to experimentally measure air shock expansion versus time and calculating the blast wave energy from the detonation of the high explosive charge inside the detonator. Direct measurements of the shock front geometry provide insight into the physics of the initiation buildup. Because of their geometry, standard detonators show an initial ellipsoidal shock expansion that degenerates into a final spherical wave. This non-uniform shape creates variable blast parameters along the primary blast wave. Additionally, optical measurements are validated using piezoelectric pressure transducers. The energy fraction spent in the acceleration of the metal shell is experimentally measured and correlated with the Gurney model, as well as to several empirical formulations for blasts from fragmenting munitions. The fragment area distribution is also studied using digital particle imaging analysis and correlated with the Mott distribution. Understanding the fragmentation distribution plays a critical role when performing hazard evaluation from these types of devices. In general, this technique allows for characterization of the detonator within 6-8% error with no knowledge of the amount or type of explosive contained within the shell, making it also suitable for the study of unknown improvised explosive devices.

Double-detonation Sub-Chandrasekhar Supernovae: Synthetic Observables for Minimum Helium Shell Mass Models

NASA Astrophysics Data System (ADS)

Kromer, M.; Sim, S. A.; Fink, M.; Röpke, F. K.; Seitenzahl, I. R.; Hillebrandt, W.

2010-08-01

In the double-detonation scenario for Type Ia supernovae, it is suggested that a detonation initiates in a shell of helium-rich material accreted from a companion star by a sub-Chandrasekhar-mass white dwarf. This shell detonation drives a shock front into the carbon-oxygen white dwarf that triggers a secondary detonation in the core. The core detonation results in a complete disruption of the white dwarf. Earlier studies concluded that this scenario has difficulties in accounting for the observed properties of Type Ia supernovae since the explosion ejecta are surrounded by the products of explosive helium burning in the shell. Recently, however, it was proposed that detonations might be possible for much less massive helium shells than previously assumed (Bildsten et al.). Moreover, it was shown that even detonations of these minimum helium shell masses robustly trigger detonations of the carbon-oxygen core (Fink et al.). Therefore, it is possible that the impact of the helium layer on observables is less than previously thought. Here, we present time-dependent multi-wavelength radiative transfer calculations for models with minimum helium shell mass and derive synthetic observables for both the optical and γ-ray spectral regions. These differ strongly from those found in earlier simulations of sub-Chandrasekhar-mass explosions in which more massive helium shells were considered. Our models predict light curves that cover both the range of brightnesses and the rise and decline times of observed Type Ia supernovae. However, their colors and spectra do not match the observations. In particular, their B - V colors are generally too red. We show that this discrepancy is mainly due to the composition of the burning products of the helium shell of the Fink et al. models which contain significant amounts of titanium and chromium. Using a toy model, we also show that the burning products of the helium shell depend crucially on its initial composition. This leads us to conclude that good agreement between sub-Chandrasekhar-mass explosions and observed Type Ia supernovae may still be feasible but further study of the shell properties is required.

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.

DSD-Consistent JWL Equations of State for EDC35

NASA Astrophysics Data System (ADS)

Hodgson, Alexander

2011-06-01

The Detonation Shock Dynamics model (DSD) allows the calculation of curvature-dependent detonation propagation. It is of particular use when applied to insensitive high explosives, such as EDC35, since they have a greater non-ideal behaviour. The DSD model has been used in conjunction with an experimental cylinder test to obtain the JWL Equation of State (EoS) for EDC35. Adjustment of parameters in the JWL equation changes the expansion profile of the simulated wall expansion. The parameters are iterated until the best match can be made between simulation and experiment. Previous DSD models used at AWE have no energy release mechanism to adjust the release of chemical energy to match the detonation conditions. Two JWL calibrations are performed using the DSD model, with and without Hetherington's energy release model (these proceedings). Also in use is a newly-calibrated detonation speed-curvature relation that is much closer, compared to previous calibrations, to Bdzil's equivalent for PBX9502. This paper discusses the possible improvements that this approach makes to the EDC35 JWL EoS.

Computational studies on the crystal structure, thermodynamic properties, detonation performance, and pyrolysis mechanism of 2,4,6,8-tetranitro-1,3,5,7-tetraazacubane as a novel high energy density material.

PubMed

Wang, Fang; Du, Hongchen; Zhang, Jianying; Gong, Xuedong

2011-10-27

Studies have suggested that octanitrocubane (ONC) is one of the most powerful non-nuclear high energy density material (HEDM) currently known. 2,4,6,8-Tetranitro-1,3,5,7-tetraazacubane (TNTAC) studied in this work may also be a novel HEDM due to its high nitrogen content and crystal density. Density functional theory and molecular mechanics methods have been employed to study the crystal structure, IR spectrum, electronic structure, thermodynamic properties, gas-phase and condensed-phase heat of formation, detonation performance, and pyrolysis mechanism of TNTAC. The TNTAC has a predicted density of about 2.12 g/cm(3), and its detonation velocity (10.42 km/s) and detonation pressure (52.82 GPa) are higher than that of ONC. The crystalline packing is P2(1)2(1)2(1), and the corresponding cell parameters are Z = 4, a = 8.87 Å, b = 8.87 Å, and c = 11.47 Å. Both the density of states of the predicted crystal and the bond dissociation energy of the molecule in gas phase show that the cage C-N bond is the trigger bond during thermolysis. The activation energy of the pyrolysis initiation reaction obtained from the B3LYP/6-311++G(2df,2p) level is 125.98 kJ/mol, which indicates that TNTAC meets the thermal stability request as an exploitable HEDM.

TYPE Ia SUPERNOVAE: CAN CORIOLIS FORCE BREAK THE SYMMETRY OF THE GRAVITATIONAL CONFINED DETONATION EXPLOSION MECHANISM?

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

García-Senz, D.; Cabezón, R. M.; Thielemann, F. K.

Currently the number of models aimed at explaining the phenomena of type Ia supernovae is high and distinguishing between them is a must. In this work we explore the influence of rotation on the evolution of the nuclear flame that drives the explosion in the so-called gravitational confined detonation models. Assuming that the flame starts in a pointlike region slightly above the center of the white dwarf (WD) and adding a moderate amount of angular velocity to the star we follow the evolution of the deflagration using a smoothed particle hydrodynamics code. We find that the results are very dependentmore » on the angle between the rotational axis and the line connecting the initial bubble of burned material with the center of the WD at the moment of ignition. The impact of rotation is larger for angles close to 90° because the Coriolis force on a floating element of fluid is maximum and its principal effect is to break the symmetry of the deflagration. Such symmetry breaking weakens the convergence of the nuclear flame at the antipodes of the initial ignition volume, changing the environmental conditions around the convergence region with respect to non-rotating models. These changes seem to disfavor the emergence of a detonation in the compressed volume at the antipodes and may compromise the viability of the so-called gravitational confined detonation mechanism.« less

Time-resolved optical measurements of the post-detonation combustion of aluminized explosives

NASA Astrophysics Data System (ADS)

Carney, Joel R.; Miller, J. Scott; Gump, Jared C.; Pangilinan, G. I.

2006-06-01

The dynamic observation and characterization of light emission following the detonation and subsequent combustion of an aluminized explosive is described. The temporal, spatial, and spectral specificity of the light emission are achieved using a combination of optical diagnostics. Aluminum and aluminum monoxide emission peaks are monitored as a function of time and space using streak camera based spectroscopy in a number of light collection configurations. Peak areas of selected aluminum containing species are tracked as a function of time to ascertain the relative kinetics (growth and decay of emitting species) during the energetic event. At the chosen streak camera sensitivity, aluminum emission is observed for 10μs following the detonation of a confined 20g charge of PBXN-113, while aluminum monoxide emission persists longer than 20μs. A broadband optical emission gauge, shock velocity gauge, and fast digital framing camera are used as supplemental optical diagnostics. In-line, collimated detection is determined to be the optimum light collection geometry because it is independent of distance between the optics and the explosive charge. The chosen optical configuration also promotes a constant cylindrical collection volume that should facilitate future modeling efforts.

Diameter Effect Curve and Detonation Front Curvature Measurements for ANFO

NASA Astrophysics Data System (ADS)

Catanach, R. A.; Hill, L. G.

2001-06-01

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 shape was fit with an analytic form, from which the local normal velocity Dn and total curvature κ were generated as a function of radius R, then plotted parametrically to generate a D_n(κ) function. The resulting behavior deviates substantially from that of previous explosives,(Hill,L.G., Bdzil,J.B., and Aslam,T.D., 11^th) Detonation Symposium, 1998^,(Hill,L.G., Bdzil,J.B., Davis,W.C., and Engelke,R., Shock Compression of Condensed Matter, 1999) in which curves for different stick sizes overlay well for small κ but diverge for large κ, and for which κ increases monotonically with R to achieve a maximum value at the charge edge. For ANFO, we find that κ achieves a maximum at an intermediate R and that D_n(κ) curves for different stick sizes are widely separated with no overlap whatsoever.

Chemistry resolved kinetic flow modeling of TATB based explosives

NASA Astrophysics Data System (ADS)

Vitello, Peter; Fried, Laurence E.; William, Howard; Levesque, George; Souers, P. Clark

2012-03-01

Detonation waves in insensitive, TATB-based explosives are believed to have multiple time scale regimes. The initial burn rate of such explosives has a sub-microsecond time scale. However, significant late-time slow release in energy is believed to occur due to diffusion limited growth of carbon. In the intermediate time scale concentrations of product species likely change from being in equilibrium to being kinetic rate controlled. We use the thermo-chemical code CHEETAH linked to an ALE hydrodynamics code to model detonations. We term our model chemistry resolved kinetic flow, since CHEETAH tracks the time dependent concentrations of individual species in the detonation wave and calculates EOS values based on the concentrations. We present here two variants of our new rate model and comparison with hot, ambient, and cold experimental data for PBX 9502.

Energy and Biocides Storage Compounds: Synthesis and Characterization of Energetic Bridged Bis(triiodoazoles).

PubMed

He, Chunlin; Zhao, Gang; Hooper, Joseph P; Shreeve, Jean'ne M

2017-11-06

Energetic bridged triiodopyrazoles and triiodoimidazoles were designed and synthsized by reacting potassium triiodopyrazolate or triiodoimidazolate with corresponding dichloro compounds. All compounds were fully characterized by 1 H and 13 C NMR spectroscopy, IR spectroscopy, and elemental analyses. The structure of compound 1 was further confirmed by single-crystal X-ray diffraction. All of the compounds exhibit good thermal stability with decomposition temperatures between 199 and 270 °C and high densities ranging from 2.804 to 3.358 g/cm 3 . The detonation performances and the detonation products were calculated by CHEETAH 7. Compound 3 (D v = 4765 m s -1 ; P = 17.9 GPa) and compound 7 (D v = 4841 m s -1 ; P = 18.5 GPa) show comparable detonation pressure to TNT, and high iodine content makes them promising as energy and biocides storage compounds.

Analysis of supercritical vapor explosions using thermal detonation wave theory

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

Shamoun, B.I.; Corradini, M.L.

The interaction of certain materials such as Al{sub 2}O{sub 3} with water results in vapor explosions with very high (supercritical) pressures and propagation velocities. A quasi-steady state analysis of supercritical detonation in one-dimensional multiphase flow was applied to analyze experimental data of the KROTOS (26-30) set of experiments conducted at the Joint Research Center at Ispra, Italy. In this work we have applied a new method of solution which allows for partial fragmentation of the fuel in the shock adiabatic thermodynamic model. This method uses known experiment values of the shock pressure and propagation velocity to estimate the initial mixingmore » conditions of the experiment. The fuel and coolant were both considered compressible in this analysis. In KROTOS 26, 28, 29, and 30 the measured values of the shock pressure by the experiment were found to be higher than 25, 50, 100, and 100 Mpa respectively. Using the above data for the wave velocity and our best estimate for the values of the pressure, the predicted minimum values of the fragmented mass of the fuel were found to be 0.026. 0.04, 0.057, and 0.068 kg respectively. The predicted values of the work output corresponding to the above fragmented masses of the fuel were found to be 40, 84, 126, and 150 kJ respectively, with predicted initial void fractions of 112%, 12.5%, 8%, and 6% respectively.« less

Incorporation of 2,4,6-trinitrotoluene (TNT) transforming bacteria into explosive formulations.

PubMed

Nyanhongo, G S; Aichernig, N; Ortner, M; Steiner, Walter; Guebitz, G M

2009-06-15

Pseudomonas putida GG04 and Bacillus SF have been successfully incorporated into an explosive formulation to enhance biotransformation of TNT residues and/or explosives which fail to detonate due to technical faults. The incorporation of the microorganisms into the explosive did not affect the quality of the explosive (5 years storage) in terms of detonation velocity while complete biotransformation of TNT moieties upon transfer in liquid media was observed after 5 days. The incorporated microorganisms reduced TNT sequentially leading to the formation of hydroxylaminodinitrotoluenes (HADNT), 4-amino-2,6-dinitrotoluenes; 2-amino-4,6-dinitrotoluenes, different azoxy compounds; 2,6-diaminonitrotoluenes (2,4-DAMNT) and 2,4-diaminonitrotoluenes (2,6-DAMNT). However, the accumulation of AMDNT and DAMNT (major dead-end metabolites) was effectively prevented by incorporating guaiacol and catechol during the biotransformation process.

Thermal Behaviors and Their Correlations of Mg(BH4)2-Contained Explosives

NASA Astrophysics Data System (ADS)

Yue, Yue; Chen, Liping; Peng, Jinhua

2018-01-01

In order to explore the effect of metal hydride on energetic materials' thermal behaviors and their correlations, we studied the heats of combustion and detonation of RDX, TNT, and Mg(BH4)2-containing explosives both theoretically and experimentally. The results showed that Mg(BH4)2 can significantly improve the energy of explosive. As the mass fraction of Mg(BH4)2 increases, the combustion heat of composite explosives increases gradually, while the combustion efficiency decreases. When its mass fraction is about 30%, the theoretical heats of detonation of RDX/Mg(BH4)2 and TNT/Mg(BH4)2 reach maximum, which are 7418.47 and 7032.46 kJ/kg, respectively. When we compared the errors between calculation and experimental values, we found that L-C method is more accurate in calculating oxygen-enriched and oxygen-balanced explosives, and that minimum free energy method is more suitable for seriously negative oxygen-balanced explosive. For single explosive, there are three kinds of relationships between heat of combustion and detonation according to the oxygen balance. For Mg(BH4)2-containing explosives, the relationship is in accordance with Boltzmann function.

Free radical explosive composition

DOEpatents

Walker, Franklin E.; Wasley, Richard J.

1979-01-01

An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1500 and 10,000 meters per second and a minor amount of a getter additive comprising a compound or mixture of compounds capable of capturing or deactivating free radicals or ions under mechanical or electrical shock conditions and which is not an explosive. Exemplary getter additives are isocyanates, olefins and iodine.

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-D Velocity Model of the Coachella Valley, Southern California Based on Explosive Shots from the Salton Seismic Imaging Project

NASA Astrophysics Data System (ADS)

Persaud, P.; Stock, J. M.; Fuis, G. S.; Hole, J. A.; Goldman, M.; Scheirer, D. S.

2014-12-01

We have analyzed explosive shot data from the 2011 Salton Seismic Imaging Project (SSIP) across a 2-D seismic array and 5 profiles in the Coachella Valley to produce a 3-D P-wave velocity model that will be used in calculations of strong ground shaking. Accurate maps of seismicity and active faults rely both on detailed geological field mapping and a suitable velocity model to accurately locate earthquakes. Adjoint tomography of an older version of the SCEC 3-D velocity model shows that crustal heterogeneities strongly influence seismic wave propagation from moderate earthquakes (Tape et al., 2010). These authors improve the crustal model and subsequently simulate the details of ground motion at periods of 2 s and longer for hundreds of ray paths. Even with improvements such as the above, the current SCEC velocity model for the Salton Trough does not provide a match of the timing or waveforms of the horizontal S-wave motions, which Wei et al. (2013) interpret as caused by inaccuracies in the shallow velocity structure. They effectively demonstrate that the inclusion of shallow basin structure improves the fit in both travel times and waveforms. Our velocity model benefits from the inclusion of known location and times of a subset of 126 shots detonated over a 3-week period during the SSIP. This results in an improved velocity model particularly in the shallow crust. In addition, one of the main challenges in developing 3-D velocity models is an uneven stations-source distribution. To better overcome this challenge, we also include the first arrival times of the SSIP shots at the more widely spaced Southern California Seismic Network (SCSN) in our inversion, since the layout of the SSIP is complementary to the SCSN. References: Tape, C., et al., 2010, Seismic tomography of the Southern California crust based on spectral-element and adjoint methods: Geophysical Journal International, v. 180, no. 1, p. 433-462. Wei, S., et al., 2013, Complementary slip distributions of the largest earthquakes in the 2012 Brawley swarm, Imperial Valley, California: Geophysical Research Letters, v. 40, no. 5, p. 847-852.

Spall response of annealed copper to direct explosive loading

NASA Astrophysics Data System (ADS)

Finnegan, S. G.; Burns, M. J.; Markland, L.; Goff, M.; Ferguson, J. W.

2017-01-01

Taylor wave spall experiments were conducted on annealed copper targets using direct explosive loading. The targets were mounted on the back of an explosive disc which was being used for a shock to detonation transition (SDT) test in a gas gun. This technique allows two experiments to be conducted with one piece of explosive. Explosive loading creates a high stress state within the target with a lower strain rate than an equivalent plate impact experiment, although the shock front will also have some curvature. Three shots were performed on two differently annealed batches of copper to investigate the viability of the technique and the effect of annealing on the spall response. One pair of targets was annealed at 850°C for four hours and the other target was annealed at 600°C for one hour. The free surface velocity (FSV) profiles were recorded using a Photonic Doppler Velocimetry (PDV) probe focused on the center of the target. The profiles were compared to predictions from the CREST reactive burn model. One profile recorded a significantly lower peak velocity which was attributed to the probe being located off center. Despite this, all three calculated spall strengths closely agreed and it was concluded that the technique is a viable one for loading an inert target.

Laser High-Cycle Thermal Fatigue of Pulse Detonation Engine Combustor Materials Tested

NASA Technical Reports Server (NTRS)

Zhu, Dong-Ming; Fox, Dennis S.; Miller, Robert A.

2001-01-01

Pulse detonation engines (PDE's) have received increasing attention for future aerospace propulsion applications. Because the PDE is designed for a high-frequency, intermittent detonation combustion process, extremely high gas temperatures and pressures can be realized under the nearly constant-volume combustion environment. The PDE's can potentially achieve higher thermodynamic cycle efficiency and thrust density in comparison to traditional constant-pressure combustion gas turbine engines (ref. 1). However, the development of these engines requires robust design of the engine components that must endure harsh detonation environments. In particular, the detonation combustor chamber, which is designed to sustain and confine the detonation combustion process, will experience high pressure and temperature pulses with very short durations (refs. 2 and 3). Therefore, it is of great importance to evaluate PDE combustor materials and components under simulated engine temperatures and stress conditions in the laboratory. In this study, a high-cycle thermal fatigue test rig was established at the NASA Glenn Research Center using a 1.5-kW CO2 laser. The high-power laser, operating in the pulsed mode, can be controlled at various pulse energy levels and waveform distributions. The enhanced laser pulses can be used to mimic the time-dependent temperature and pressure waves encountered in a pulsed detonation engine. Under the enhanced laser pulse condition, a maximum 7.5-kW peak power with a duration of approximately 0.1 to 0.2 msec (a spike) can be achieved, followed by a plateau region that has about one-fifth of the maximum power level with several milliseconds duration. The laser thermal fatigue rig has also been developed to adopt flat and rotating tubular specimen configurations for the simulated engine tests. More sophisticated laser optic systems can be used to simulate the spatial distributions of the temperature and shock waves in the engine. Pulse laser high-cycle thermal fatigue behavior has been investigated on a flat Haynes 188 alloy specimen, under the test condition of 30-Hz cycle frequency (33-msec pulse period and 10-msec pulse width including a 0.2-msec pulse spike; ref. 4). Temperature distributions were calculated with one-dimensional finite difference models. The calculations show that that the 0.2-msec pulse spike can cause an additional 40 C temperature fluctuation with an interaction depth of 0.08 mm near the specimen surface region. This temperature swing will be superimposed onto the temperature swing of 80 C that is induced by the 10-msec laser pulse near the 0.53-mm-deep surface interaction region.

Report on Transport and Loading of Explosives in the Femtosecond Tank, Room 1711A HEAF 00-010

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

Hill, D L

2002-04-25

The current OSP associated with Room 1711A located in Building 191 (HEAF) sets a limit of 5 grams Net Explosive Weight (NEW) of explosives for the room. A question was raised as to the capability of that room to withstand the overpressure created by a detonation of 5 grams NEW of explosives. Calculations were inconclusive, but indicated the wallboard would not remain intact if there was a detonation of 5 grams NEW at a distance of eight feet from the wall. These calculations did not seem logical. To verify the hypothesis, a series of experiments were conducted in the 1more » Kilogram tank. The experiments consisted of exposing a pre-built double-sided wall with the same stud spacing and drywall thickness found in the walls of Room 1711A to various amounts of explosives to create expected overpressures. The objective of this test was to prove or disprove that the walls in room 1711A could withstand a detonation of 5 grams of high explosives and to determine if larger quantities of explosives could be worked on in the room while still providing the required level of protection for personnel outside the room. Testing has verified that not only can the walls withstand a 5 gram explosion, but a 10.75 gram explosion as well. A second test was conducted using 20 grams of explosive plus a detonator. Although the inner piece of drywall cracked, the outer piece of drywall maintained its integrity, thereby confining the effects of the anticipated overpressure to the room.« less

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 photo-detectors were compared for the diagnostics of the detonation wave. The ion detector is found to be a safe, cheap and effective choice for obtaining detonation or flame velocities, and better than the optical detector, which is not practical for long-duration PDE operations. The piezoelectric dynamic pressure transducer has problems with heating and requires an effective cooling system to enable it to function in a PDE. Other diagnostics studied include thrust measurement and mass flow rate measurement techniques. Additionally, fuel sensitizing techniques, such as hydrogen blending, along with the DDT devices can ensure that detonations are produced successfully.

CHEETAH: A fast thermochemical code for detonation

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

Fried, L.E.

1993-11-01

For more than 20 years, TIGER has been the benchmark thermochemical code in the energetic materials community. TIGER has been widely used because it gives good detonation parameters in a very short period of time. Despite its success, TIGER is beginning to show its age. The program`s chemical equilibrium solver frequently crashes, especially when dealing with many chemical species. It often fails to find the C-J point. Finally, there are many inconveniences for the user stemming from the programs roots in pre-modern FORTRAN. These inconveniences often lead to mistakes in preparing input files and thus erroneous results. We are producingmore » a modern version of TIGER, which combines the best features of the old program with new capabilities, better computational algorithms, and improved packaging. The new code, which will evolve out of TIGER in the next few years, will be called ``CHEETAH.`` Many of the capabilities that will be put into CHEETAH are inspired by the thermochemical code CHEQ. The new capabilities of CHEETAH are: calculate trace levels of chemical compounds for environmental analysis; kinetics capability: CHEETAH will predict chemical compositions as a function of time given individual chemical reaction rates. Initial application: carbon condensation; CHEETAH will incorporate partial reactions; CHEETAH will be based on computer-optimized JCZ3 and BKW parameters. These parameters will be fit to over 20 years of data collected at LLNL. We will run CHEETAH thousands of times to determine the best possible parameter sets; CHEETAH will fit C-J data to JWL`s,and also predict full-wall and half-wall cylinder velocities.« less

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

Doebling, Scott William

This paper documents the escape of high explosive (HE) products problem. The problem, first presented by Fickett & Rivard, tests the implementation and numerical behavior of a high explosive detonation and energy release model and its interaction with an associated compressible hydrodynamics simulation code. The problem simulates the detonation of a finite-length, one-dimensional piece of HE that is driven by a piston from one end and adjacent to a void at the other end. The HE equation of state is modeled as a polytropic ideal gas. The HE detonation is assumed to be instantaneous with an infinitesimal reaction zone. Viamore » judicious selection of the material specific heat ratio, the problem has an exact solution with linear characteristics, enabling a straightforward calculation of the physical variables as a function of time and space. Lastly, implementation of the exact solution in the Python code ExactPack is discussed, as are verification cases for the exact solution code.« less

ZEPrompt: An Algorithm for Rapid Estimation of Building Attenuation for Prompt Radiation from a Nuclear Detonation

DTIC Science & Technology

2014-01-01

and 50 kT, to within 30% of first-principles code ( MCNP ) for complicated cities and 10% for simpler cities. 15. SUBJECT TERMS Radiation Transport...Use of MCNP for Dose Calculations .................................................................... 3 2.3 MCNP Open-Field Absorbed Dose...Calculations .................................................. 4 2.4 The MCNP Urban Model

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

Chiappetta, R.F.

An explosive`s velocity of detonation (VOD), can be used to indicate a number of important characteristics regarding the product`s performance under specific field and test conditions. A number of new characteristic and transient VOD curves have been identified in the field, which can be used to evaluate explosive performance, control ground vibration amplitudes and frequencies, select the correct amount and type of stemming for use at the collar and in stem decks, eliminate explosive desensitization, evaluate primer performance, design air deck based blasts, evaluate contaminated explosives and to overcome post blast noxious fumes. Tests were conducted over a six yearmore » period in single and multi-hole blasts using laboratory and full scale blast environments. Explosives tested ranged from pure Emulsion to Anfo and various grades of Emulsion/Anfo blends. Field test parameters were; borehole diameter (1 1/2--30 inches), hole depths (10--120 feet), primer size (0.5--6.4 pounds) and the blast environment varied from soft, jelly-like tar sands to some of the hardest iron ore formations. Most tests were instrumented with an array of blast monitoring instrumentation systems consisting of continuous velocity of detonation recorders, high-speed 16 mm cameras, laser-surveying instrumentation and seismographs which were placed in the near and far fields.« less

Channel effect of the modified powdery mixture of ammonium nitrate and fuel oil

NASA Astrophysics Data System (ADS)

Wu, Chun-Ping; Liu, Lian-Sheng; Wang, Xu-Guang; Liu, Yong; Wang, Yin-Jun

2010-10-01

The modified powdery mixture of ammonium nitrate and fuel oil (MPANFO) is a new breed of industrial explosives developed years ago in China. As one of the important properties of an industrial explosive, the channel effect of MPANFO was reported in this paper. A series of experiments were conducted to determine the channel effect of MPANFO. The blasthole diameter range was estimated to avoid the channel effect of MPANFO. Three empirical formulae for predicting the detonation length of MPANFO were provided in terms of the channel effect. Experiments and theoretical analysis indicate that the channel effect of MPANFO is very serious. The reason why the channel effect of MPANFO is worse than that of other industrial explosives is explained at a theoretical level. In addition, some properties of MPANFO, such as sympathetic distance, detonation velocity and brisance, are determined.

CORRTEX Diagnostic Deployment for the SPE-III experiment, 24 July 2012: Fielding Report and Preliminary Data Analysis

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

Sandoval, Thomas D.; Schultz-Fellenz, Emily S.

2012-08-29

The Continuous Reflectometry for Radius vs Time Experiments (CORRTEX) diagnostic system was deployed for the third explosives test in the Source Physics Experiment (SPE) sequence to monitor and verify several conditions of the experiment including the detonation velocity of the explosive package and functioning of explosive initiators. Six distance-marked coaxial cables were installed on the SPE-III explosives canister, and key locations documented through along-cable length measurements and photography. CORRTEX uses electrical-pulse time-domain reflectometry to continuously record the two-way transit time (TWTT) of the cables. As the shock front of the detonation advances, the coaxial cable is shorted or destroyed, andmore » the resulting TWTT also decreases. Interpretation of these changes as a function of TWTT can be converted to positional measurements using known parameters of the cables.« less

Explosive Spot Joining of Metals

NASA Technical Reports Server (NTRS)

Bement, Laurence J. (Inventor); Perry, Ronnie B. (Inventor)

1997-01-01

The invention is an apparatus and method for wire splicing using an explosive joining process. The apparatus consists of a prebend, U-shaped strap of metal that slides over prepositioned wires. A standoff means separates the wires from the strap before joining. An adhesive means holds two ribbon explosives in position centered over the U-shaped strap. A detonating means connects to the ribbon explosives. The process involves spreading strands of each wire to be joined into a flat plane. The process then requires alternating each strand in alignment to form a mesh-like arrangement with an overlapped area. The strap slides over the strands of the wires. and the standoff means is positioned between the two surfaces. The detonating means then initiates the ribbon explosives that drive the strap to accomplish a high velocity. angular collision between the mating surfaces. This collision creates surface melts and collision bonding resulting in electron-sharing linkups.

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

Baer, M.R.; Hobbs, M.L.; McGee, B.C.

Exponential-13,6 (EXP-13,6) potential pammeters for 750 gases composed of 48 elements were determined and assembled in a database, referred to as the JCZS database, for use with the Jacobs Cowperthwaite Zwisler equation of state (JCZ3-EOS)~l) The EXP- 13,6 force constants were obtained by using literature values of Lennard-Jones (LJ) potential functions, by using corresponding states (CS) theory, by matching pure liquid shock Hugoniot data, and by using molecular volume to determine the approach radii with the well depth estimated from high-pressure isen- tropes. The JCZS database was used to accurately predict detonation velocity, pressure, and temperature for 50 dif- 3more » Accurate predictions were also ferent explosives with initial densities ranging from 0.25 glcm3 to 1.97 g/cm . obtained for pure liquid shock Hugoniots, static properties of nitrogen, and gas detonations at high initial pressures.« less

Method for loading explosive laterally from a borehole

DOEpatents

Ricketts, Thomas E.

1981-01-01

There is provided a method for forming an in situ oil shale retort in a subterranean formation containing oil shale. At least one void is excavated in the formation, leaving zones of unfragmented formation adjacent the void. An array of main blastholes is formed in the zone of unfragmented formation and at least one explosive charge which is shaped for forming a high velocity gas jet is placed into a main blasthole with the axis of the gas jet extending transverse to the blasthole. The shaped charge is detonated for forming an auxiliary blasthole in the unfragmented formation adjacent a side wall of the main blasthole. The auxiliary blasthole extends laterally away from the main blasthole. Explosive is placed into the main blasthole and into the auxiliary blasthole and is detonated for explosively expanding formation towards the free face for forming a fragmented permeable mass of formation particles in the in situ oil shale retort.

Simulation of detonation cell kinematics using two-dimensional reactive blast waves

NASA Astrophysics Data System (ADS)

Thomas, G. O.; Edwards, D. H.

1983-10-01

A method of generating a cylindrical blast wave is developed which overcomes the disadvantages inherent in the converging-diverging nozzle technique used by Edwards et al., 1981. It is demonstrated than an exploding wire placed at the apex of a two-dimensional sector provides a satisfactory source of the generation of blast waves in reactive systems. The velocity profiles of the blast waves are found to simulate those in freely propagating detonations very well, and this method does not suffer from the disadvantage of having the mass flow at the throat as in the nozzle method. The density decay parameter is determined to have a constant value of 4 in the systems investigated, and it is suggested that this may be a universal value. It is proposed that suitable wedges could be used to create artificial Mach stems in the same manner as Strehlow and Barthel (1971) without the attendant disadvantages of the nozzle method.

Bis(4-nitraminofurazanyl-3-azoxy)azofurazan and Derivatives: 1,2,5-Oxadiazole Structures and High-Performance Energetic Materials.

PubMed

Liu, Yuji; Zhang, Jiaheng; Wang, Kangcai; Li, Jinshan; Zhang, Qinghua; Shreeve, Jean'ne M

2016-09-12

Bis(4-nitraminofurazanyl-3-azoxy)azofurazan (1) and ten of its energetic salts were prepared and fully characterized. Computational analysis based on isochemical shielding surface and trigger bond dissociation enthalpy provide a better understanding of the thermal stabilities for nitramine-furazans. These energetic compounds exhibit good densities, high heats of formation, and excellent detonation velocity and pressure. Some representative compounds, for example, 1 (vD : 9541 m s(-1) ; P: 40.5 GPa), and 4 (vD : 9256 m s(-1) ; P: 38.0 GPa) exhibit excellent detonation performances, which are comparable with current high explosives such as RDX (vD : 8724 m s(-1) ; P: 35.2 GPa) and HMX (vD : 9059 m s(-1) ; P: 39.2 GPa). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Permanent wire splicing by an explosive joining process

NASA Technical Reports Server (NTRS)

Bement, Laurence J. (Inventor); Kushnick, Anne C. (Inventor)

1991-01-01

The invention is an apparatus and method for wire splicing using an explosive joining process. The apparatus consists of a prebent, U-shaped strap of metal that slides over prepositioned wires. A standoff means separates the wires from the strap before joining. An adhesive means holds two ribbon explosives in position centered over the U-shaped strap. A detonating means connects to the ribbon explosives. The process involves spreading strands of each wire to be joined into a flat plane. The process then requires alternating each strand in alignment to form a mesh-like arrangement with an overlapped area. The strap slides over the strands of the wires, and the standoff means is positioned between the two surfaces. The detonating means then initiates the ribbon explosives that drive the strap to accomplish a high velocity, angular collision between the mating surfaces. This collision creates surface melts and collision bonding results in electron sharing linkups.

High fidelity studies of exploding foil initiator bridges, Part 3: ALEGRA MHD simulations

NASA Astrophysics Data System (ADS)

Neal, William; Garasi, Christopher

2017-01-01

Simulations of high voltage detonators, such as Exploding Bridgewire (EBW) and Exploding Foil Initiators (EFI), have historically been simple, often empirical, one-dimensional models capable of predicting parameters such as current, voltage, and in the case of EFIs, flyer velocity. Experimental methods have correspondingly generally been limited to the same parameters. With the advent of complex, first principles magnetohydrodynamic codes such as ALEGRA and ALE-MHD, it is now possible to simulate these components in three dimensions, and predict a much greater range of parameters than before. A significant improvement in experimental capability was therefore required to ensure these simulations could be adequately verified. In this third paper of a three part study, the experimental results presented in part 2 are compared against 3-dimensional MHD simulations. This improved experimental capability, along with advanced simulations, offer an opportunity to gain a greater understanding of the processes behind the functioning of EBW and EFI detonators.

Portable, solid state, fiber optic coupled Doppler interferometer system for detonation and shock diagnostics

NASA Technical Reports Server (NTRS)

Fleming, K. J.; Crump, O. B.

1994-01-01

VISAR (Velocity Interferometer System for Any Reflector) is a specialized Doppler interferometer system that is gaining world-wide acceptance as the standard for shock phenomena analysis. The VISAR's large power and cooling requirements, and the sensitive and complex nature of the interferometer cavity have restricted the traditional system to the laboratory. This paper describes the new portable VISAR, its peripheral sensors, and the role it played in optically measuring ground shock of and underground nuclear detonation. The Solid State VISAR uses a prototype diode pumped Nd:YAG laser and solid state detectors that provide a suitcase-size system with low power requirements. A special window and sensors were developed for fiber optic coupling (1 kilometer long) to the VISAR. The system has proven itself as a reliable, easy to use instrument that is capable of field test use and rapid data reduction using only a notebook personal computer (PC).

Fundamental Properties of Non-equilibrium Laser-Supported Detonation Wave

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

Shiraishi, Hiroyuki

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.

Transatmospheric vehicle research

NASA Technical Reports Server (NTRS)

Adelman, Henry G.; Cambier, Jean-Luc

1990-01-01

Research was conducted into the alternatives to the supersonic combustion ramjet (scramjet) engine for hypersonic flight. A new engine concept, the Oblique Detonation Wave Engine (ODWE) was proposed and explored analytically and experimentally. Codes were developed which can couple the fluid dynamics of supersonic flow with strong shock waves, with the finite rate chemistry necessary to model the detonation process. An additional study was conducted which compared the performance of a hypersonic vehicle powered by a scramjet or an ODWE. Engineering models of the overall performances of the two engines are included. This information was fed into a trajectory program which optimized the flight path to orbit. A third code calculated the vehicle size, weight, and aerodynamic characteristics. The experimental work was carried out in the Ames 20MW arc-jet wind tunnel, focusing on mixing and combustion of fuel injected into a supersonic airstream. Several injector designs were evaluated by sampling the stream behind the injectors and analyzing the mixture with an on-line mass spectrometer. In addition, an attempt was made to create a standing oblique detonation wave in the wind tunnel using hydrogen fuel. It appeared that the conditions in the test chamber were marginal for the generation of oblique detonation waves.

Delayed detonation models for normal and subluminous type Ia sueprnovae: Absolute brightness, light curves, and molecule formation

NASA Technical Reports Server (NTRS)

Hoflich, P.; Khokhlov, A. M.; Wheeler, J. C.

1995-01-01

We compute optical and infrared light curves of the pulsating class of delayed detonation models for Type Ia supernovae (SN Ia's) using an elaborate treatment of the Local Thermodynamic Equilbrium (LTE) radiation transport, equation of state and ionization balance, expansion opacity including the cooling by CO, Co(+), and SiO, and a Monte Carlo gamma-ray deposition scheme. The models have an amount of Ni-56 in the range from approximately or equal to 0.1 solar mass up to 0.7 solar mass depending on the density at which the transition from a deflagration to a detonation occurs. Models with a large nickel production give light curves comparable to those of typical Type Ia supernovae. Subluminous supernovae can be explained by models with a low nickel production. Multiband light curves are presented in comparison with the normally bright event SN 1992bc and the subluminous events Sn 1991bg and SN 1992bo to establish the principle that the delayed detonation paradigm in Chandrasekhar mass models may give a common explosion mechanism accounting for both normal and subluminous SN Ia's. Secondary IR-maxima are formed in the models of normal SN Ia's as a photospheric effect if the photospheric radius continues to increase well after maximum light. Secondary maxima appear later and stronger in models with moderate expansion velocities and with radioactive material closer to the surface. Model light curves for subluminous SN Ia's tend to show only one 'late' IR-maximum. In some delayed detonation models shell-like envelopes form, which consist of unburned carbon and oxygen. The formation of molecules in these envelopes is addressed. If the model retains a C/O-envelope and is subluminous, strong vibration bands of CO may appear, typically several weeks past maximum light. CO should be very weak or absent in normal Sn Ia's.

Diamonds in detonation soot

NASA Technical Reports Server (NTRS)

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

1990-01-01

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

Theoretical investigations on the structures and properties of CL-20/TNT cocrystal and its defective models by molecular dynamics simulation.

PubMed

Hang, Gui-Yun; Yu, Wen-Li; Wang, Tao; Wang, Jin-Tao

2018-06-09

"Perfect" and defective models of CL-20/TNT cocrystal explosive were established. Molecular dynamics methods were introduced to determine the structures and predict the comprehensive performances, including stabilities, sensitivity, energy density and mechanical properties, of the different models. The influences of crystal defects on the properties of these explosives were investigated and evaluated. The results show that, compared with the "perfect" model, the rigidity and toughness of defective models are decreased, while the ductility, tenacity and plastic properties are enhanced. The binding energies, interaction energy of the trigger bond, and the cohesive energy density of defective crystals declined, thus implying that stabilities are weakened, the explosive molecule is activated, trigger bond strength is diminished and safety is worsened. Detonation performance showed that, owing to the influence of crystal defects, the density is lessened, detonation pressure and detonation velocity are also declined, i.e., the power of defective explosive is decreased. In a word, the crystal defects may have a favorable effect on the mechanical properties, but have a disadvantageous influence on sensitivity, stability and energy density of CL-20/TNT cocrystal explosive. The results could provide theoretical guidance and practical instructions to estimate the properties of defective crystal models.

Quantitative analysis for the determination of aluminum percentage and detonation performance of aluminized plastic bonded explosives by laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Rezaei, A. H.; Keshavarz, M. H.; Kavosh Tehrani, M.; Darbani, S. M. R.

2018-06-01

The aluminized plastic-bonded explosive (PBX) is a composite material in which solid explosive particles are dispersed in a polymer matrix, which includes three major components, i.e. polymeric binder, metal fuel (aluminum) and nitramine explosive. This work introduces a new method on the basis of the laser-induced breakdown spectroscopy (LIBS) technique in air and argon atmospheres to investigate the determination of aluminum content and detonation performance of aluminized PBXs. Plasma emissions of aluminized PBXs are recorded where atomic lines of Al, C and H as well as molecular bands of AlO and CN are identified. The experimental results demonstrate that a good discrimination and separation between the aluminized PBXs is possible using LIBS and principle component analysis, although they have similar atomic composition. Relative intensity of the AlO/Al is used to determine aluminum percentage of the aluminized PBXs. The obtained quantitative calibration curve using the relative intensity of the AlO/Al is better than the resulting calibration curve using only the intensity of Al. By using the LIBS method and the measured intensity ratio of CN/C, an Al content of 15% is found to be the optimum value in terms of velocity of detonation of the RDX/Al/HTPB standard samples.

Detonation equation of state at LLNL, 1995. Revision 3

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

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

1996-02-01

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

Explosive composition with group VIII metal nitroso halide getter

DOEpatents

Walker, Franklin E.; Wasley, Richard J.

1982-01-01

An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1,500 and 10,000 meters per second and a minor amount of a getter additive comprising a non-explosive compound or mixture of non-explosive compounds capable of chemically reacting with free radicals or ions under shock initiation conditions of 2,000 calories/cm.sup.2 or less of energy fluence.

Explosive composition with group VIII metal nitroso halide getter

DOEpatents

Walker, F.E.; Wasley, R.J.

1982-06-22

An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1,500 and 10,000 meters per second and a minor amount of a getter additive comprising a non-explosive compound or mixture of non-explosive compounds capable of chemically reacting with free radicals or ions under shock initiation conditions of 2,000 calories/cm[sup 2] or less of energy fluence.

Nearly spherical constant power detonation waves driven by focused radiation

NASA Technical Reports Server (NTRS)

George, Y. H.

1973-01-01

Shape and inner flow of a tridimensional spark are studied. The spark is created by focusing a laser beam in a gas. A second order fully non-linear equation is derived for the radial velocity on the axis of symmetry in the neighborhood of the origin. Solutions to that equation display the existence of a forbidden region near the focus, thus indicating the limits of applicability of a small perturbation solution.

Overview of Explosive Initiators

DTIC Science & Technology

2015-11-01

of a relatively small stimulus, be it impact, friction, shock, heat, or electrostatic discharge (ref. 2). On the whole, they tend to be less potent...5200 RDX 7.5 120 > 250 1.82 205 8750 ESD – electrostatic discharge DSC – differential scanning calorimetry VOD – velocity of detonation Current...Center P.O. Box 8000 Corona , CA 91718-8000 gidep@gidep.org UNCLASSIFIED Approved for public release; distribution is unlimited. 18 Steven M. Nicolich Steven M. Nicolich Andrew Pskowski

High explosive compound

DOEpatents

Crawford, Theodore C.

1976-01-01

1. A low detonation velocity explosive consisting essentially of a particulate mixture of ortho-boric acid and trinitrotoluene, said mixture containing from about 25 percent to about 65 percent by weight of ortho-boric acid, said ortho-boric acid comprised of from 60 percent to 90 percent of spherical particles having a mean particle size of about 275 microns and 10 percent to 40 percent of spherical particles having a particle size less than about 44 microns.

New Approach to Predict Hugoniot Properties of Explosives Materials

DTIC Science & Technology

2015-03-12

Cyclotrimethylenetrinitramine (RDX), Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine ( HMX ), Pentaerythritol tetranitrate (PETN) and Triamino-trinitrobenzene...experimental values. The four materials chosen are RDX, HMX , PETN and TATB. The detonation velocity is one of the key performance characteristics of energetic...were used and the gas products of reaction were assumed as an ideal gas. The four materials to be characterised are RDX, HMX , PETN and TATB and their

Shock Initiation of Wedge-shaped Explosive Measured with Smear Camera and Photon Doppler Velocimetry

NASA Astrophysics Data System (ADS)

Gu, Yan

2017-06-01

Triaminotrinitrobenzene (TATB) is an important insensitive high explosive in conventional weapons due to its safety and high energy. In order to have an insight into the shock initiation performance of a TATB-based insensitive high explosive (IHE), experimental measurements of the particle velocity histories of the TATB-based Explosive using Photon Doppler Velocimetry and shock wave profile of the TATB-based explosive using High Speed Rotating Mirror Smear Camera had been performed. In this paper, we would describe the shock initiation performance of the TATB-based explosive by run-to-detonation distance and the particle velocity history at an initialization shock of about 7.9 GPa. The parameters of hugoniot of unreacted the TATB-based explosive and Pop relationship could be derived with the particle velocity history obtained in this paper.

Trade Study for Neutron Transport at Low Earth Orbit: Adding Fidelity to DIORAMA

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

McClanahan, Tucker Caden; Wakeford, Daniel Tyler

The Distributed Infrastructure Offering Real-Time Access to Modeling and Analysis (DIORAMA) software provides performance modeling capabilities of the United States Nuclear Detonation Detection System (USNDS) with a focus on the characterization of Space-Based Nuclear Detonation Detection (SNDD) instrument performance [1]. A case study was done to add the neutron propagation capabilities of DIORAMA to low earth orbit (LEO), and compare the back-calculated incident energy from the time-of- ight (TOF) spectrum with the scored incident energy spectrum. As the scoring altitude lowers, the time increase due to scattering takes up much more of the fraction of total TOF; whereas at geosynchronousmore » earth orbit (GEO), the time increase due to scattering is a negligible fraction of the total TOF [2]. The scattering smears out the TOF enough to make the back-calculation of the initial energy spectrum from the TOF spectrum very convoluted.« less

Neutrinos from type Ia supernovae: The deflagration-to-detonation transition scenario

DOE PAGES

Wright, Warren P.; Nagaraj, Gautam; Kneller, James P.; ...

2016-07-19

It has long been recognized that the neutrinos detected from the next core-collapse supernova in the Galaxy have the potential to reveal important information about the dynamics of the explosion and the nucleosynthesis conditions as well as allowing us to probe the properties of the neutrino itself. The neutrinos emitted from thermonuclear—type Ia—supernovae also possess the same potential, although these supernovae are dimmer neutrino sources. For the first time, we calculate the time, energy, line of sight, and neutrino-flavor-dependent features of the neutrino signal expected from a three-dimensional delayed-detonation explosion simulation, where a deflagration-to-detonation transition triggers the complete disruption ofmore » a near-Chandrasekhar mass carbon-oxygen white dwarf. We also calculate the neutrino flavor evolution along eight lines of sight through the simulation as a function of time and energy using an exact three-flavor transformation code. We identify a characteristic spectral peak at ˜10 MeV as a signature of electron captures on copper. This peak is a potentially distinguishing feature of explosion models since it reflects the nucleosynthesis conditions early in the explosion. We simulate the event rates in the Super-K, Hyper-K, JUNO, and DUNE neutrino detectors with the SNOwGLoBES event rate calculation software and also compute the IceCube signal. Hyper-K will be able to detect neutrinos from our model out to a distance of ˜10 kpc. Here, at 1 kpc, JUNO, Super-K, and DUNE would register a few events while IceCube and Hyper-K would register several tens of events.« less

An Analytic Tool to Investigate the Effect of Binder on the Sensitivity of HMX-Based Plastic Bonded Explosives in the Skid Test

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

Hayden, D. W.

This project will develop an analytical tool to calculate performance of HMX based PBXs in the skid test. The skid-test is used as a means to measure sensitivity for large charges in handling situations. Each series of skid tests requires dozens of drops of large billets. It is proposed that the reaction (or lack of one) of PBXs in the skid test is governed by the mechanical properties of the binder. If true, one might be able to develop an analytical tool to estimate skid test behavior for new PBX formulations. Others over the past 50 years have tried tomore » develop similar models. This project will research and summarize the works of others and couple the work of 3 into an analytical tool that can be run on a PC to calculate drop height of HMX based PBXs. Detonation due to dropping a billet is argued to be a dynamic thermal event. To avoid detonation, the heat created due to friction at impact, must be conducted into the charge or the target faster than the chemical kinetics can create additional energy. The methodology will involve numerically solving the Frank-Kamenetskii equation in one dimension. The analytical problem needs to be bounded in terms of how much heat is introduced to the billet and for how long. Assuming an inelastic collision with no rebound, the billet will be in contact with the target for a short duration determined by the equations of motion. For the purposes of the calculations, it will be assumed that if a detonation is to occur, it will transpire within that time. The surface temperature will be raised according to the friction created using the equations of motion of dropping the billet on a rigid surface. The study will connect the works of Charles Anderson, Alan Randolph, Larry Hatler, Alfonse Popolato, and Charles Mader into a single PC based analytic tool. Anderson's equations of motion will be used to calculate the temperature rise upon impact, the time this temperature is maintained (contact time) will be obtained from the work of Hatler et. al., and the reactive temperature rise will be obtained from Mader's work. Finally, the assessment of when a detonation occurs will be derived from Bowden and Yoffe's thermal explosion theory (hot spot).« less

Chemistry Resolved Kinetic Flow Modeling of TATB Based Explosives

NASA Astrophysics Data System (ADS)

Vitello, Peter; Fried, Lawrence; Howard, Mike; Levesque, George; Souers, Clark

2011-06-01

Detonation waves in insensitive, TATB based explosives are believed to have multi-time scale regimes. The initial burn rate of such explosives has a sub-microsecond time scale. However, significant late-time slow release in energy is believed to occur due to diffusion limited growth of carbon. In the intermediate time scale concentrations of product species likely change from being in equilibrium to being kinetic rate controlled. We use the thermo-chemical code CHEETAH linked to ALE hydrodynamics codes to model detonations. We term our model chemistry resolved kinetic flow as CHEETAH tracks the time dependent concentrations of individual species in the detonation wave and calculate EOS values based on the concentrations. A validation suite of model simulations compared to recent high fidelity metal push experiments at ambient and cold temperatures has been developed. We present here a study of multi-time scale kinetic rate effects for these experiments. Prepared by LLNL under Contract DE-AC52-07NA27344.

1-Amine-1,2,3-triazolium salts with oxidizing anions: A new family of energetic materials with good performance

NASA Astrophysics Data System (ADS)

Zhang, Zhi-Bin; Zhang, Jian-Guo

2018-04-01

A series of 1-amino-1,2,3-triazole (ATZ) based energetic nitrogen-rich salts are prepared by using acid-base neutralization reaction (1:1 M ratio), and fully characterized. Structures of the salts are recrystallized and determined by single-crystal X-ray diffraction, which dominated by a strong hydrogen-bond influence with the densities ranging from 1.692 to 1.868 g cm-3. Thermal behaviors have characterized by using the DSC and TG-DTG technologies. The enthalpies of formation have calculated by using Gaussian 03. The detonation parameters of the salts are determined by using the K-J method, and most salts show promising detonation performances (D: 6699-8231 m s-1, P: 19.2-30.7 GPa), among which the salt of 1-amino-1,2,3-triazolium trinitrophloroglucinate has a detonation properties comparable to RDX. The sensitivities results provided the salts as insensitive energetic materials.

The escape of high explosive products: An exact-solution problem for verification of hydrodynamics codes

DOE PAGES

Doebling, Scott William

2016-10-22

This paper documents the escape of high explosive (HE) products problem. The problem, first presented by Fickett & Rivard, tests the implementation and numerical behavior of a high explosive detonation and energy release model and its interaction with an associated compressible hydrodynamics simulation code. The problem simulates the detonation of a finite-length, one-dimensional piece of HE that is driven by a piston from one end and adjacent to a void at the other end. The HE equation of state is modeled as a polytropic ideal gas. The HE detonation is assumed to be instantaneous with an infinitesimal reaction zone. Viamore » judicious selection of the material specific heat ratio, the problem has an exact solution with linear characteristics, enabling a straightforward calculation of the physical variables as a function of time and space. Lastly, implementation of the exact solution in the Python code ExactPack is discussed, as are verification cases for the exact solution code.« less

Multicale modeling of the detonation of aluminized explosives using SPH-MD-QM method

NASA Astrophysics Data System (ADS)

Peng, Qing; Wang, Guangyu; Liu, Gui-Rong; de, Suvranu

Aluminized explosives have been applied in military industry since decades ago. Compared with ideal explosives, aluminized explosives feature both fast detonation and slow metal combustion chemistry, generating a complex multi-phase reactive flow. Here, we introduce a sequential multiscale model of SPH-MD-QM to simulate the detonation behavior of aluminized explosives. At the bottom level, first-principles quantum mechanics (QM) calculations are employed to obtain the training sets for fitting the ReaxFF potentials, which are used in turn in the reactive molecular dynamics (MD) simulations in the middle level to obtain the chemical reaction rates and equations of states. At the up lever, a smooth particle hydrodynamics (SPH) method incorporated ignition and growth model and afterburning model has been used for the simulation of the detonation and combustion of the aluminized explosive. Simulation is compared with experiment and good agreement is observed. The proposed multiscale method of SPH-MD-QM could be used to optimize the performance of aluminized explosives. The authors would like to acknowledge the generous financial support from the Defense Threat Reduction Agency (DTRA) Grant No. HDTRA1-13-1-0025 and the Office of Naval Research Grants ONR Award No. N00014-08-1-0462 and No. N00014-12-1-0527.

Theoretical insights into the structures and mechanical properties of HMX/NQ cocrystal explosives and their complexes, and the influence of molecular ratios on their bonding energies.

PubMed

Li, Yong-Xiang; Chen, Shu-Sen; Ren, Fu-de

2015-09-01

Molecular dynamics (MD) methods were employed to study the binding energies and mechanical properties of selected crystal planes of 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX)/nitroguanidine (NQ) cocrystals at different molecular molar ratios. The densities and detonation velocities of the cocrystals at different molar ratios were estimated. The intermolecular interaction and bond dissociation energy (BDE) of the N-NO2 bond in the HMX:NQ (1:1) complex were calculated using the B3LYP, MP2(full) and M06-2X methods with the 6-311++G(d,p) and 6-311++G(2df,2p) basis sets. The results indicated that the HMX/NQ cocrystal prefers cocrystalizing in a 1:1 molar ratio, and the cocrystallization is dominated by the (0 2 0) and (1 0 0) facets. The K, G, and E values of the ratio of 1:1 are smaller than those of the other ratios, and the 1:1 cocrystal has the best ductility. The N-NO2 bond becomes stronger upon the formation of the intermolecular H-bonding interaction and the sensitivity of HMX decreases in the cocrystal. This sensitivity change in the HMX/NQ cocrystal originates not only from the formation of the intermolecular interaction but also from the increment of the BDE of N-NO2 bond in comparison with isolated HMX. The HMX/NQ (1:1) cocrystal exhibits good detonation performance. Reduced density gradient (RDG) reveals the nature of cocrystallization. Analysis of the surface electrostatic potential further confirmed that the sensitivity decreases in complex (or cocrystal) in comparison with that in isolated HMX.

FORTRAN 4 computer program for calculation of thermodynamic and transport properties of complex chemical systems

NASA Technical Reports Server (NTRS)

Svehla, R. A.; Mcbride, B. J.

1973-01-01

A FORTRAN IV computer program for the calculation of the thermodynamic and transport properties of complex mixtures is described. The program has the capability of performing calculations such as:(1) chemical equilibrium for assigned thermodynamic states, (2) theoretical rocket performance for both equilibrium and frozen compositions during expansion, (3) incident and reflected shock properties, and (4) Chapman-Jouguet detonation properties. Condensed species, as well as gaseous species, are considered in the thermodynamic calculation; but only the gaseous species are considered in the transport calculations.

AFWL (Air Force Weapons Laboratory) HULL (Hydrodynamics Unlimited) calculations of air blast over a dam slope. Final report

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

Fry, M.A.; Needham, C.E.; Stucker, M.

1976-10-01

This laboratory performed Hydrodynamics Unlimited (HULL) calculations of the air blast over a dam for two yields and two pressure regions. A 5th calculation included a rigid blockhouse at the foot of the dam. Although the shielding effect of the dam reduced the incident blast wave overpressure, reflection of the shock from the valley floor raised the peak overpressure up to at least 40% of the free air value. In almost every case, the overpressure impulses near the foot of the dam were greater than or equal to free air values. The rigid blockhouse experienced the most severe overpressure environments.more » The assumption of a 50-psi hard blockhouse is reasonable. During collapse of the blockhouse, it appears to be rigid to the air flow, since it responds slowly to the rapid air blast. Although there may be other reasons to detonate the weapon on the surface of the reservoir, the best way to destroy the blockhouse and any related structures with air blast, probably would be to detonate the device downstream of the blockhouse.« less

Explosives for Lunar Seismic Profiling Experiment (LSPE)

NASA Technical Reports Server (NTRS)

1973-01-01

Explosive charges of various sizes were investigated for use in lunar seismic studies. Program logistics, and the specifications for procurement of bulk explosives are described. The differential analysis, thermal properties, and detonation velocity measurements on HNS/Teflon 7C 90/10 are reported along with the field tests of the hardware. It is concluded that nearly all large explosive charges crack after fabrication, from aging or thermal shock. The cracks do not affect the safety, or reliability of the explosives.

Demonstration of Lightweight Engineering Solutions for a Low-Cost Safe Explosive Ordnance Destruct Tool

DTIC Science & Technology

2007-12-01

Staff) and Mr. Doug Learned ( Intercity Manufacturing), whose efficiency and expertise was vital in manufacturing the parts required for our tests...detonation products caused by the hollow cavity. Upon initiation of a hollow lined charge, the resulting high pressure shock wave travels outward...5.6 km/s for the brass encased charge at 2 and 3 CD. This indicates that the jet must be traveling at velocities greater than the estimates, which

Elaboration of the Charge Constructions of Explosives for the Structure of Facing Stone

NASA Astrophysics Data System (ADS)

Khomeriki, Sergo; Mataradze, Edgar; Chikhradze, Nikoloz; Losaberidze, Marine; Khomeriki, Davit; Shatberashvili, Grigol

2017-12-01

Increased demand for high-strength facing material caused the enhancement of the volume of explosives use in modern technologies of blocks production. The volume of broken rocks and crushing quality depends on the rock characteristics and on the properties of the explosive, in particular on its brisance and serviceability. Therefore, the correct selection of the explosive for the specific massif is of a considerable practical importance. For efficient mining of facing materials by explosion method the solving of such problems as determination of the method of blasthole drilling as well as of the regime and charge values, selection of the explosive, blastholes distribution in the face and their order is necessary. This paper focuses on technical solutions for conservation of rock natural structure in the blocks of facing material, mined by the use of the explosives. It has been established that the efficient solving of mentioned problem is attained by reducing of shock pulse duration. In such conditions the rigidity of crystalline lattice increases in high pressure area. As a result, the hazard if crack formation in structural unites and the increases of natural cracks are excluded. Short-time action of explosion pulse is possible only by linear charges of the explosives, characterized by high detonation velocity which detonate by the velocity of 7-7.5 km/sec and are characterized by very small critical diameter.

A two-phase model for aluminized explosives on the ballistic and brisance performance

NASA Astrophysics Data System (ADS)

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

2018-02-01

The performance of aluminized high explosives is considered by varying the aluminum (Al) mass fraction in a heterogeneous mixture model. Since the time scales of the characteristic induction and combustion of high explosives and Al particles differ, the process of energy release behind the leading detonation wave front occurs over an extended period of time. For simulating the performance of aluminized explosives with varying Al mass fraction, HMX (1,3,5,7-tetrahexmine-1,3,5,7-tetrazocane) is considered as a base explosive when formulating the multiphase conservation laws of mass, momentum, and energy exchanges between the HMX product gases and Al particles. In the current study, a two-phase model is utilized in order to determine the effects of the Al mass fraction in a condensed phase explosive. First, two types of confined rate stick tests are considered to investigate the detonation velocity and the acceleration ability, which refers to the radial expansion velocity of the confinement shell. The simulation results of the confined rate stick test are compared with the experimental data for the Al mass fraction range of 0%-25%, and the optimal Al mass fraction is provided, which is consistent with the experimental observations. Additionally, a series of plate dent test simulations are conducted, the results of which show the same tendency as those of the experimental tests with varying Al mass fractions.

The History of the Study of Detonation

ERIC Educational Resources Information Center

Bulat, Pavel V.; Volkov, Konstantin N.

2016-01-01

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

Confined Detonations and Pulse Detonation Engines

DTIC Science & Technology

2003-01-01

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

Asymptotic study of pulsating evolution of overdriven and CJ detonation with a chain-branching kinetics model

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

Short, Mark; Chliquete, Carlos

2011-01-20

The pulsating dynamics of gaseous detonations with a model two-step chain-branching kinetic mechanism are studied both numerically and asymptotically. The model studied here was also used in [4], [3] and [2] and mimics the attributes of some chain-branching reaction mechanisms. Specifically, the model comprises a chain-initiationlbranching zone with an Arrhenius temperature-sensitive rate behind the detonation shock where fuel is converted into chain-radical with no heat release. This is followed by a chain-termination zone having a temperature insensitive rate where the exothermic heat of reaction is released. The lengths of these two zones depend on the relative rates of each stage.more » It was determined in [4] and [3] via asymptotic and numerical analysis that the ratio of the length of the chain-branching zone to that of the chain-initation zone relative to the size of the von Neumann state scaled activation energy in the chain initiation/branching zone has a primary influence of the stability of one-dimensional pulsating instability behavior for this model. In [2], the notion of a specific stability parameter related to this ratio was proposed that determines the boundary between stable and unstable waves. In [4], a slow-time varying asymptotic study was conducted of pulsating instability of Chapman-Jouguet (CJ) detonations with the above two-step rate model, assuming a large activation energy for the chain-initiation zone and a chain-termination zone longer than the chain-initiation zone. Deviations D{sub n}{sup (1)} ({tau}) of the detonation velocity from Chapman-Jouguet were of the order of the non-dimensional activation energy. Solutions were sought for a pulsation timescale of the order of the non-dimensional activation energy times the particle transit time through the induction zone. On this time-scale, the evolution of the chain-initation zone is quasi-steady. In [4], a time-dependent non-linear evolution equation for D{sub n}{sup (1)} ({tau}) was then constructed via a perturbation procedure for cases where the ratio of the length of the chain-termination zone to chain-initiation zone was less than the non-dimensional activation energy. To leading order, the steady CJ detonation was found to be unstable; higher-order corrections lead to the construction of a stability limit between stable and unsteady pulsating solutions. One conclusion from this study is that for a stability limit to occur at leading order, the period of pulsation of the detonation must occur on the time scale of particle passage through the longer chain-termination zone, while the length of the chain-termination zone must be of order of the non-dimensional activation energy longer than the chain-initiation zone. The relevance of these suggested scalings was verified via numerical solutions of the full Euler system in [3], and formed the basis of the stability parameter criteria suggested in [2]. In the following, we formulate an asymptotic study based on these new suggested scales, studying the implications for describing pulsating behavior in gaseous chain-branching detonations. Specifically, we find that the chain-induction zone structure is the same as that studied in [4]. However, the study of unsteady evolution in the chain-termination region is now governed by a set of asymptotically derived nonlinear POEs. Equations for the linear stablity behavior of this set of POE's is obtained, while the nonlinear POEs are solved numerically using a shock-attached, shock-fitting method developed by Henrick et aJ. [1]. The results thus far show that the stability threshold calculated using the new ratio of the chain-termination zone length to that of the chain-initiation zone yields a marked improvement over [2]. Additionally, solutions will be compared with predictions obtained from the solution of the full Euler system. Finally, the evolution equation previously derived in [4] has been generalized to consider both arbitrary reaction orders and any degree of overdrive.« less

Reactive flow modeling of small scale detonation failure experiments for a baseline non-ideal explosive

NASA Astrophysics Data System (ADS)

Kittell, David E.; Cummock, Nick R.; Son, Steven F.

2016-08-01

Small scale characterization experiments using only 1-5 g of a baseline ammonium nitrate plus fuel oil (ANFO) explosive are discussed and simulated using an ignition and growth reactive flow model. There exists a strong need for the small scale characterization of non-ideal explosives in order to adequately survey the wide parameter space in sample composition, density, and microstructure of these materials. However, it is largely unknown in the scientific community whether any useful or meaningful result may be obtained from detonation failure, and whether a minimum sample size or level of confinement exists for the experiments. In this work, it is shown that the parameters of an ignition and growth rate law may be calibrated using the small scale data, which is obtained from a 35 GHz microwave interferometer. Calibration is feasible when the samples are heavily confined and overdriven; this conclusion is supported with detailed simulation output, including pressure and reaction contours inside the ANFO samples. The resulting shock wave velocity is most likely a combined chemical-mechanical response, and simulations of these experiments require an accurate unreacted equation of state (EOS) in addition to the calibrated reaction rate. Other experiments are proposed to gain further insight into the detonation failure data, as well as to help discriminate between the role of the EOS and reaction rate in predicting the measured outcome.

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

Steward, G.; Mays, R. O.; Converse, M.

Microwave Interferometry (MI) offers the advantage of a continuous time measurement of detonation front velocity from detonation initiation to disassembly, which is an important step to assure the quality of stockpile high explosives. However, the method is currently characterized by areas of poor signal strength, which lead to low confidence measurements. Experiments in inert materials were conducted to determine if reflective hot spots, pockets of plasma that form during detonation, are responsible due to varying hot spot concentrations. Instead, it was found that the copper tube used in a range of standard HE test configurations is the cause of themore » poor signal reception. Hot spots were represented by microwave reflective aluminum particles. The aluminum was mixed with Titanium Dioxide, a material electrically similar to the insensitive high explosive, triaminotrinitrobenzene (TATB), in volume percent fractions (VPFs) between 0 and 100% aluminum, in increments of 10%. Reflectivity was measured based on input and reflection received from a test apparatus with a layer representing undetonated explosive and another representing an approaching shockwave. The results showed no correlation between VPF and measured reflectivity test cases while enclosed in the standard copper tube. Upon further testing, each sample’s measured reflectivity independent of the copper enclosure did correlate with VPF. This revealed that the test enclosure currently used for MI measurements is causing poor MI signal reception, and new methods must be developed to account for this aberration in MI measurements.« less

Synthesis and characterization of 4-(1,2,4-triazole-5-yl)furazan derivatives as high-performance insensitive energetic materials.

PubMed

Zhen, Xu; Cheng, Guangbin; Yang, Hongwei; Zhang, Jiaheng; Shreeve, Jean'ne M

2018-05-15

3-Nitro-4-(5-nitro-1,2,4-triazol-3-yl)furazan (2), N,N'-bis(trinitroethyl)-3,5'-diamino-4-(1,2,4-triazol-3-yl)furazan (3), N,N'-bis(trinitroethyl)-3,5'-dinitramino-4-(1,2,4-triazol-3-yl)furazan (4) and eighteen nitrogen-rich salts (5a, 5b,5d⁓5i, 5g-1, 6a⁓6i) were designed and synthesized. These 4-(1,2,4-triazole-5-yl)furazan derivatives were fully characterized by IR and NMR spectra, elemental analysis, and differential scanning calorimetry (DSC). The solid-state structures of 2, 5d, 5e, 5h, 5g-1, 6g, and 6i were confirmed via single crystal X-ray analysis. Detonation performance (detonation velocities and pressures) of these energetic compounds was evaluated and the impact and friction sensitivities were measured using standard BAM technology. Some of the compounds, e.g., 2 (D: 9152 m s-1, P = 37.1 GPa) and 4 (D: 9355 m s-1, P = 40.1 GPa) exhibit excellent detonation performance, which are comparable to the highly explosive benchmarks such as RDX (D: 8795 m s-1, P = 34.9 GPa) and HMX (D: 9144 m s-1, P = 39.2 GPa). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reactive flow modeling of small scale detonation failure experiments for a baseline non-ideal explosive

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

Kittell, David E.; Cummock, Nick R.; Son, Steven F.

2016-08-14

Small scale characterization experiments using only 1–5 g of a baseline ammonium nitrate plus fuel oil (ANFO) explosive are discussed and simulated using an ignition and growth reactive flow model. There exists a strong need for the small scale characterization of non-ideal explosives in order to adequately survey the wide parameter space in sample composition, density, and microstructure of these materials. However, it is largely unknown in the scientific community whether any useful or meaningful result may be obtained from detonation failure, and whether a minimum sample size or level of confinement exists for the experiments. In this work, itmore » is shown that the parameters of an ignition and growth rate law may be calibrated using the small scale data, which is obtained from a 35 GHz microwave interferometer. Calibration is feasible when the samples are heavily confined and overdriven; this conclusion is supported with detailed simulation output, including pressure and reaction contours inside the ANFO samples. The resulting shock wave velocity is most likely a combined chemical-mechanical response, and simulations of these experiments require an accurate unreacted equation of state (EOS) in addition to the calibrated reaction rate. Other experiments are proposed to gain further insight into the detonation failure data, as well as to help discriminate between the role of the EOS and reaction rate in predicting the measured outcome.« less

Nanotechnology Investigated for Future Gelled and Metallized Gelled Fuels

NASA Technical Reports Server (NTRS)

Palaszewski, Bryan A.

2003-01-01

The objective of this research is to create combustion data for gelled and metallized gelled fuels using unique nanometer-sized gellant particles and/or nanometer-sized aluminum particles. Researchers at the NASA Glenn Research Center are formulating the fuels for both gas turbine and pulsed detonation engines. We intend to demonstrate metallized gelled fuel ignition characteristics for pulse detonation engines with JP/aluminum fuel and for gas turbine engines with gelled JP, propane, and methane fuel. The fuels to be created are revolutionary as they will deliver the highest theoretically maximum performance of gelled and metallized gelled fuels. Past combustion work has used micrometer-sized particles, which have limited the combustion performance of gelled and metallized gelled fuels. The new fuel used nanometer-sized aluminum oxide particles, which reduce the losses due to mismatch in the gas and solid phases in the exhaust. Gelled fuels provide higher density, added safety, reduced fuel slosh, reduced leakage, and increased exhaust velocity. Altogether, these benefits reduce the overall size and mass of the vehicle, increasing its flexibility.

Shock Initiation of Thermally Expanded TATB

NASA Astrophysics Data System (ADS)

Mulford, Roberta; Swift, Damian

2011-06-01

The plastic-bonded explosive PBX-9502 undergoes unusual hysteretic thermal expansion, or ``ratchet growth'' as a consequence of the uniaxial thermal expansion of the graphitic structure of the major component, TATB explosive. Upon thermal cycling, the density of the material can be reduced by as much as 9%, resulting in a distinct increase in the shock sensitivity of the solid. Run distances to detonation have been measured in thermally expanded samples of PBX-9502, using embedded particle velocity gauges and shock tracker gauges. Uniaxial shocks were generated using a light gas gun, to provide a repeatable stimulus for initiation of detonation. We have applied a porosity model to adjust standard Pop plot data to the reduced density of our samples, to investigate whether the sensitivity of the PBX 9502 increases ideally with the decreasing density, or whether the microscopically non-uniform expansion that occurs during ``ratchet growth'' leads to abnormal sensitivity, possibly as a result of cracking or debonding from the binder, as observed in micrographs of the sample.

Explosive double salts and preparation

DOEpatents

Cady, Howard H.; Lee, Kien-yin

1984-01-01

Applicants have discovered a new composition of matter which is an explosive addition compound of ammonium nitrate (AN) and diethylenetriamine trinitrate (DETN) in a 50:50 molar ratio. The compound is stable over extended periods of time only at temperatures higher than 46.degree. C., decomposing to a fine-grained eutectic mixture (which is also believed to be new) of AN and DETN at temperatures lower than 46.degree. C. The compound of the invention has an x-ray density of 1.61 g/cm.sup.3, explodes to form essentially only gaseous products, has higher detonation properties (i.e., detonation velocity and pressure) than those of any mechanical mixture having the same density and composition as the compound of the invention, is a quite insensitive explosive material, can be cast at temperatures attainable by high pressure steam, and is prepared from inexpensive ingredients. Methods of preparing the compound of the invention and the fine-grained eutectic composition of the invention are given.

Experimental Investigation of a Multi-Cycle Single-Tube Pulse Detonation Rocket Engine with a Coaxial Rotary Valve

NASA Astrophysics Data System (ADS)

Matsuoka, Ken; Esumi, Motoki; Ikeguchi, Ken Bryan; Kasahara, Jiro; Matsuo, Akiko; Funaki, Ikkoh

We developed a novel coaxial rotary valve for a multi-tube PDE. Since this single valve can supply three different gases (fuel, oxidizer and purge gas) into a combustor, the unification of the valve systems for three different gases is possible by using our newly designed valve. A PDRE system can be simple and lightweight by using this valve, and thus its thrust-weight ratio can be increased. We proposed the design of a multi-tube rotary-valved PDRE system by this rotary valve. Moreover, in preparation for a multi-tube rotary-valved PDRE, we carried out the multi-cycle operation experiment by the single-tube rotary-valved PDRE system. The combustion wave velocity was measured to confirm the operation of the PDRE system. Deflagration-to-detonation transition (DDT) was confirmed and DDT distance decreased under the condition of high operation frequency. In addition, a maximum operation frequency was 159 Hz.

Detonation in TATB Hemispheres

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

Druce, B; Souers, P C; Chow, 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. Themore » 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.« less

Method for attenuating seismic shock from detonating explosive in an in situ oil shale retort

DOEpatents

Studebaker, Irving G.; Hefelfinger, Richard

1980-01-01

In situ oil shale retorts are formed in formation containing oil shale by excavating at least one void in each retort site. Explosive is placed in a remaining portion of unfragmented formation within each retort site adjacent such a void, and such explosive is detonated in a single round for explosively expanding formation within the retort site toward such a void for forming a fragmented permeable mass of formation particles containing oil shale in each retort. This produces a large explosion which generates seismic shock waves traveling outwardly from the blast site through the underground formation. Sensitive equipment which could be damaged by seismic shock traveling to it straight through unfragmented formation is shielded from such an explosion by placing such equipment in the shadow of a fragmented mass in an in situ retort formed prior to the explosion. The fragmented mass attenuates the velocity and magnitude of seismic shock waves traveling toward such sensitive equipment prior to the shock wave reaching the vicinity of such equipment.

Estimating Equivalency of Explosives Through A Thermochemical Approach

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

Maienschein, J L

2002-07-08

The Cheetah thermochemical computer code provides an accurate method for estimating the TNT equivalency of any explosive, evaluated either with respect to peak pressure or the quasi-static pressure at long time in a confined volume. Cheetah calculates the detonation energy and heat of combustion for virtually any explosive (pure or formulation). Comparing the detonation energy for an explosive with that of TNT allows estimation of the TNT equivalency with respect to peak pressure, while comparison of the heat of combustion allows estimation of TNT equivalency with respect to quasi-static pressure. We discuss the methodology, present results for many explosives, andmore » show comparisons with equivalency data from other sources.« less

Operational Characteristics of a Rotating Detonation Engine Using Hydrogen and Air

DTIC Science & Technology

2011-06-01

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

White light velocity interferometer

DOEpatents

Erskine, D.J.

1999-06-08

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

Zirconium hydride containing explosive composition

DOEpatents

Walker, Franklin E.; Wasley, Richard J.

1981-01-01

An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1500 and 10,000 meters per second and a minor amount of a donor additive comprising a non-explosive compound or mixture of non-explosive compounds which when subjected to an energy fluence of 1000 calories/cm.sup.2 or less is capable of releasing free radicals each having a molecular weight between 1 and 120. Exemplary donor additives are dibasic acids, polyamines and metal hydrides.

Theoretical Innovations in Combustion Stability Research: Integrated Analysis and Computation

DTIC Science & Technology

2011-04-14

Quirk JJ, Shepherd JE (1997) An analytical model for direct initiation of gaseous detonation waves, in 21st International Symposium on Shock Waves...the initial vorticity thickness, hi is here performed over (x1, x3) planes and ∆U0 is the initial velocity difference across the layer. In all cases...Reynolds numbers were 1452, 1507 and 2004. Selle et al. [9] showed that this database is relevant for fully-turbulent flow modeling . VI. RESULTS In all

Survey of Hydrogen Combustion Properties

NASA Technical Reports Server (NTRS)

Drell, Isadore L; Belles, Frank E

1958-01-01

This literature digest of hydrogen-air combustion fundamentals presents data on flame temperature, burning velocity, quenching distance, flammability limits, ignition energy, flame stability, detonation, spontaneous ignition, and explosion limits. The data are assessed, recommended values are given, and relations among various combustion properties are discussed. New material presented includes: theoretical treatment of variation in spontaneous ignition lag with temperature, pressure, and composition, based on reaction kinetics of hydrogen-air composition range for 0.01 to 100 atmospheres and initial temperatures of 0 degrees to 1400 degrees k.

White light velocity interferometer

DOEpatents

Erskine, David J.

1997-01-01

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

White light velocity interferometer

DOEpatents

Erskine, David J.

1999-01-01

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s.

White light velocity interferometer

DOEpatents

Erskine, D.J.

1997-06-24

The invention is a technique that allows the use of broadband and incoherent illumination. Although denoted white light velocimetry, this principle can be applied to any wave phenomenon. For the first time, powerful, compact or inexpensive sources can be used for remote target velocimetry. These include flash and arc lamps, light from detonations, pulsed lasers, chirped frequency lasers, and lasers operating simultaneously in several wavelengths. The technique is demonstrated with white light from an incandescent source to measure a target moving at 16 m/s. 41 figs.

Utilizing Near-IR Tunable Laser Absorption Spectroscopy to Study Detonation and Combustion Systems

DTIC Science & Technology

2014-03-27

debris, such as soot . Velocity curves for the other equivalence ratios studied in this experiment are shown in Appendix A. Some of these curves show a...James R. Gord. “Measurements of OH mole fraction and temperature up to 20 kHz by using a diode-laser based UV absorption sensor ”. Applied Optics, 44...Davidson, and R.K. Hanson. “CO concentration and temperature sensor for combustion gases using quantum-cascade laser absorption near 4.7µm”. Applied

A Numerical Simulation of the Energy Conversion Process in Microwave Rocket

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

Shibata, Teppei; Oda, Yasuhisa; Komurasaki, Kimiya

2008-04-28

In Microwave Rocket, a high power microwave beam ionizes atmospheric air inside of the thruster and the ionization front drives a shock wave. In this paper, CFD simulation was conducted using measured propagation velocity of the ionization front to evaluate the engine performance. As a result, maximum cycle efficiency was obtained at the power density of about 200 kW/m{sup 2} which is the transitional beam power condition between Microwave Supported Combustion and Microwave Supported Detonation regimes.

Modeling Propagation of Shock Waves in Metals

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

Howard, W M; Molitoris, J D

2005-08-19

We present modeling results for the propagation of strong shock waves in metals. In particular, we use an arbitrary Lagrange Eulerian (ALE3D) code to model the propagation of strong pressure waves (P {approx} 300 to 400 kbars) generated with high explosives in contact with aluminum cylinders. The aluminum cylinders are assumed to be both flat-topped and have large-amplitude curved surfaces. We use 3D Lagrange mechanics. For the aluminum we use a rate-independent Steinberg-Guinan model, where the yield strength and shear modulus depend on pressure, density and temperature. The calculation of the melt temperature is based on the Lindermann law. Atmore » melt the yield strength and shear modulus is set to zero. The pressure is represented as a seven-term polynomial as a function of density. For the HMX-based high explosive, we use a JWL, with a program burn model that give the correct detonation velocity and C-J pressure (P {approx} 390 kbars). For the case of the large-amplitude curved surface, we discuss the evolving shock structure in terms of the early shock propagation experiments by Sakharov.« less

Modeling Propagation of Shock Waves in Metals

NASA Astrophysics Data System (ADS)

Howard, W. M.; Molitoris, J. D.

2006-07-01

We present modeling results for the propagation of strong shock waves in metals. In particular, we use an arbitrary Lagrange Eulerian (ALE3D) code to model the propagation of strong pressure waves (P ˜ 300 to 400 kbars) generated with high explosives in contact with aluminum cylinders. The aluminum cylinders are assumed to be both flat-topped and have large-amplitude curved surfaces. We use 3D Lagrange mechanics. For the aluminum we use a rate-independent Steinberg-Guinan model, where the yield strength and shear modulus depend on pressure, density and temperature. The calculation of the melt temperature is based on the Lindermann law. At melt the yield strength and shear modulus is set to zero. The pressure is represented as a seven-term polynomial as a function of density. For the HMX-based high explosive, we use a JWL, with a program burn model that give the correct detonation velocity and C-J pressure (P ˜ 390 kbars). For the case of the large-amplitude curved surface, we discuss the evolving shock structure in terms of the early shock propagation experiments by Sakharov.

Evidence for a meteoritic origin of the September 15, 2007, Carancas crater

NASA Astrophysics Data System (ADS)

Le Pichon, A.; Antier, K.; Cansi, Y.; Hernandez, B.; Minaya, E.; Burgoa, B.; Drob, D.; Evers, L. G.; Vaubaillon, J.

2008-11-01

On September 15th, 2007, around 11:45 local time in Peru, near the Bolivian border, the atmospheric entry of a meteoroid produced bright lights in the sky and intense detonations. Soon after, a crater was discovered south of Lake Titicaca. These events have been detected by the Bolivian seismic network and two infrasound arrays operating for the Comprehensive Nuclear-Test-Ban Treaty Organization, situated at about 80 and 1620 km from the crater. The localization and origin time computed with the seismic records are consistent with the reported impact. The entry elevation and azimuthal angles of the trajectory are estimated from the observed signal time sequences and back-azimuths. From the crater diameter and the airwave amplitudes, the kinetic energy, mass and explosive energy are calculated. Using the estimated velocity of the meteoroid and similarity criteria between orbital elements, an association with possible parent asteroids is attempted. The favorable setting of this event provides a unique opportunity to evaluate physical and kinematic parameters of the object that generated the first actual terrestrial meteorite impact seismically recorded.

Detonation Jet Engine. Part 2--Construction Features

ERIC Educational Resources Information Center

Bulat, Pavel V.; Volkov, Konstantin N.

2016-01-01

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

Hydrodynamic code calculations of airblast for an explosive test in a shallow underground storage magazine

NASA Astrophysics Data System (ADS)

Kennedy, Lynn W.; Schneider, Kenneth D.

1990-07-01

A large-sclae test of the detonation of 20,000 kilograms of high explosive inside a shallow underground tunnel/chamber complex, simulating an ammunition storage magazine, was carried out in August, 1988, at the Naval Weapons Center, China Lake, California. The test was jointly sponsored by the U.S. Department of Defense Explosives Safety Board; the Safety Services Organisation of the Ministry of Defence, United Kingdom; and the Norwegian Defence Construction Service. The overall objective of the test was to determine the hazardous effects (debris, airblast, and ground motion) produced in this configuration. Actual storage magazines have considerably more overburden and are expected to contain and accidental detonation. The test configuration, on the other hand, was expected to rupture, and to scatter a significant amount of rocks, dirt and debris. Among the observations and measurements made in this test was study of airblast propagation within the storage chamber, in the access tunnel, and outside, on the tunnel ramp, prior to overburden venting. The results of these observations are being used to evaluate and validate current quantity-distance standards for the underground storage of munitions near inabited structures. As part of the prediction effort for this test, to assist with transducer ranging in the access tunnel and with post-test interpretation of the results, S-CUBED was asked to perform two-dimensional inviscid hydrodynamic code calculations of the explosive detonation and subsequent blastwave propagation in the interior chamber and access tunnel. This was accomplished using the S-CUBED Hydrodynamic Advanced Research Code (SHARC). In this paper, details of the calculations configuration will be presented. These will be compared to the actual as-built internal configuration of the tunnel/chamber complex. Results from the calculations, including contour plots and airblast waveforms, will be shown. The latter will be compared with experimental records obtained at several points within the tunnel.

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

DTIC Science & Technology

2009-12-01

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

Numerical simulation of a 100-ton ANFO detonation

NASA Astrophysics Data System (ADS)

Weber, P. W.; Millage, K. K.; Crepeau, J. E.; Happ, H. J.; Gitterman, Y.; Needham, C. E.

2015-03-01

This work describes the results from a US government-owned hydrocode (SHAMRC, Second-Order Hydrodynamic Automatic Mesh Refinement Code) that simulated an explosive detonation experiment with 100,000 kg of Ammonium Nitrate-Fuel Oil (ANFO) and 2,080 kg of Composition B (CompB). The explosive surface charge was nearly hemispherical and detonated in desert terrain. Two-dimensional axisymmetric (2D) and three-dimensional (3D) simulations were conducted, with the 3D model providing a more accurate representation of the experimental setup geometry. Both 2D and 3D simulations yielded overpressure and impulse waveforms that agreed qualitatively with experiment, including the capture of the secondary shock observed in the experiment. The 2D simulation predicted the primary shock arrival time correctly but secondary shock arrival time was early. The 2D-predicted impulse waveforms agreed very well with the experiment, especially at later calculation times, and prediction of the early part of the impulse waveform (associated with the initial peak) was better quantitatively for 2D compared to 3D. The 3D simulation also predicted the primary shock arrival time correctly, and secondary shock arrival times in 3D were closer to the experiment than in the 2D results. The 3D-predicted impulse waveform had better quantitative agreement than 2D for the later part of the impulse waveform. The results of this numerical study show that SHAMRC may be used reliably to predict phenomena associated with the 100-ton detonation. The ultimate fidelity of the simulations was limited by both computer time and memory. The results obtained provide good accuracy and indicate that the code is well suited to predicting the outcomes of explosive detonations.

A TRACER METHOD FOR COMPUTING TYPE IA SUPERNOVA YIELDS: BURNING MODEL CALIBRATION, RECONSTRUCTION OF THICKENED FLAMES, AND VERIFICATION FOR PLANAR DETONATIONS

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

Townsley, Dean M.; Miles, Broxton J.; Timmes, F. X.

2016-07-01

We refine our previously introduced parameterized model for explosive carbon–oxygen fusion during thermonuclear Type Ia supernovae (SNe Ia) by adding corrections to post-processing of recorded Lagrangian fluid-element histories to obtain more accurate isotopic yields. Deflagration and detonation products are verified for propagation in a medium of uniform density. A new method is introduced for reconstructing the temperature–density history within the artificially thick model deflagration front. We obtain better than 5% consistency between the electron capture computed by the burning model and yields from post-processing. For detonations, we compare to a benchmark calculation of the structure of driven steady-state planar detonationsmore » performed with a large nuclear reaction network and error-controlled integration. We verify that, for steady-state planar detonations down to a density of 5 × 10{sup 6} g cm{sup −3}, our post-processing matches the major abundances in the benchmark solution typically to better than 10% for times greater than 0.01 s after the passage of the shock front. As a test case to demonstrate the method, presented here with post-processing for the first time, we perform a two-dimensional simulation of a SN Ia in the scenario of a Chandrasekhar-mass deflagration–detonation transition (DDT). We find that reconstruction of deflagration tracks leads to slightly more complete silicon burning than without reconstruction. The resulting abundance structure of the ejecta is consistent with inferences from spectroscopic studies of observed SNe Ia. We confirm the absence of a central region of stable Fe-group material for the multi-dimensional DDT scenario. Detailed isotopic yields are tabulated and change only modestly when using deflagration reconstruction.« less

Numerical approaches to combustion modeling. Progress in Astronautics and Aeronautics. Vol. 135

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

Oran, E.S.; Boris, J.P.

1991-01-01

Various papers on numerical approaches to combustion modeling are presented. The topics addressed include; ab initio quantum chemistry for combustion; rate coefficient calculations for combustion modeling; numerical modeling of combustion of complex hydrocarbons; combustion kinetics and sensitivity analysis computations; reduction of chemical reaction models; length scales in laminar and turbulent flames; numerical modeling of laminar diffusion flames; laminar flames in premixed gases; spectral simulations of turbulent reacting flows; vortex simulation of reacting shear flow; combustion modeling using PDF methods. Also considered are: supersonic reacting internal flow fields; studies of detonation initiation, propagation, and quenching; numerical modeling of heterogeneous detonations, deflagration-to-detonationmore » transition to reactive granular materials; toward a microscopic theory of detonations in energetic crystals; overview of spray modeling; liquid drop behavior in dense and dilute clusters; spray combustion in idealized configurations: parallel drop streams; comparisons of deterministic and stochastic computations of drop collisions in dense sprays; ignition and flame spread across solid fuels; numerical study of pulse combustor dynamics; mathematical modeling of enclosure fires; nuclear systems.« less

A Simple Model for the Dependence on Local Detonation Speed (D) of the Product Entropy (S)

NASA Astrophysics Data System (ADS)

Hetherington, David

2011-06-01

The generation of a burn time field as a pre-processing step ahead of a hydrocode calculation has been mostly upgraded in the explosives modelling community from the historical model of single-speed programmed burn to DSD. However, with this advance has come the problem that the previously conventional approach to the hydrodynamic stage of the model results in S having the wrong correlation with D. Instead of being higher where the detonation speed is lower, i.e. where reaction occurs at lower compression, the conventional method leads to S being lower where D is lower, resulting in a completely fictitious enhancement of available energy where the burn is degraded! A technique is described which removes this deficiency of the historical model when used with a DSD-generated burn time field. By treating the conventional JWL equation as a semi-empirical expression for the local expansion isentrope, and constraining the local parameter set for consistency with D, it is possible to obtain the two desirable outcomes that the model of the detonation wave is internally consistent, and S is realistically correlated with D.

Theoretical and computer models of detonation in solid explosives

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

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,more » 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.« less

Characterization of hypervelocity metal fragments for explosive initiation

DOE PAGES

Yeager, John D.; Bowden, Patrick R.; Guildenbecher, Daniel R.; ...

2017-07-17

The fragment impact response of two plastic-bonded explosive (PBX) formulations was studied using explosively driven aluminum fragments. A generic aluminum-capped detonator generated sub-mm aluminum particles moving at hypersonic velocities. The ability of these fragments to initiate reaction or otherwise damage two PBX materials was assessed using go/no-go experiments at standoff distances of up to 160 mm. Lower density PBX 9407 (RDX-based) was initiable at up to 115 mm, while higher density PBX 9501 (HMX-based) was only initiable at up to 6 mm. Several techniques were used to characterize the size, distribution, and velocity of the particles. Witness plate materials, includingmore » copper and polycarbonate, and backlit high speed video were used to characterize the distribution of particles, finding that the aluminum cap did not fragment homogeneously but rather with larger particles in a ring surrounding finer particles. Finally, precise digital holography experiments were conducted to measure the three-dimensional shape and size of the fastest-moving fragments, which ranged between 100 and 700 μm and traveled between 2.2 and 3.2 km/s. Crucially, these experiments showed variability in the fragmentation in terms of the number of fragments at the leading edge of the fragment field, indicating that both single and multiple shock impacts could be imparted to the target material. As a result, these types of data are critical for safety experiments and hydrocode simulations to quantify shock-to-detonation transition mechanisms and the associated risk-margins for these materials.« less

Detonation Initiation of Heterogeneous Melt-Cast High Explosives

NASA Astrophysics Data System (ADS)

Chuzeville, Vincent; Baudin, Gerard; Lefrancois, Alexandre; Boulanger, Remi; Catoire, Laurent

2015-06-01

The melt-cast explosives' shock initiation mechanisms are less investigated than pressed and cast-cured ones. If the existence of hot-spots is widely recognized, their formation mechanism is not yet established. We study here two melt-cast explosives, NTO-TNT 60:40 and RDX-TNT 60:40 in order to establish a relation between the microstructure and the reaction rate using a two-phase model based on a ZND approach. Such a model requires the reaction rate, the equations of state of the unreacted phase and of the detonation products and an interaction model between the two phases to describe the reaction zone thermodynamics. The reaction rate law can be written in a factorized form including the number of initiation sites, the explosive's deflagration velocity around hot spots and a function depending on gas volume fraction produced by the deflagration front propagation. The deflagration velocity mainly depends on pressure and is determined from pop-plot tests using the hypothesis of the single curve build-up. This hypothesis has been verified for our two melt-cast explosives. The function depending on gas volume fraction is deduced from microstructural observations and from an analogy with the solid nucleation and growth theory. It has been established for deflagration fronts growing from grain's surface and a given initial grain size distribution. The model requires only a few parameters, calibrated thanks to an inversion method. A good agreement is obtained between experiments and numerical simulations.

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

Yeager, John D.; Bowden, Patrick R.; Guildenbecher, Daniel R.

The fragment impact response of two plastic-bonded explosive (PBX) formulations was studied using explosively driven aluminum fragments. A generic aluminum-capped detonator generated sub-mm aluminum particles moving at hypersonic velocities. The ability of these fragments to initiate reaction or otherwise damage two PBX materials was assessed using go/no-go experiments at standoff distances of up to 160 mm. Lower density PBX 9407 (RDX-based) was initiable at up to 115 mm, while higher density PBX 9501 (HMX-based) was only initiable at up to 6 mm. Several techniques were used to characterize the size, distribution, and velocity of the particles. Witness plate materials, includingmore » copper and polycarbonate, and backlit high speed video were used to characterize the distribution of particles, finding that the aluminum cap did not fragment homogeneously but rather with larger particles in a ring surrounding finer particles. Finally, precise digital holography experiments were conducted to measure the three-dimensional shape and size of the fastest-moving fragments, which ranged between 100 and 700 μm and traveled between 2.2 and 3.2 km/s. Crucially, these experiments showed variability in the fragmentation in terms of the number of fragments at the leading edge of the fragment field, indicating that both single and multiple shock impacts could be imparted to the target material. As a result, these types of data are critical for safety experiments and hydrocode simulations to quantify shock-to-detonation transition mechanisms and the associated risk-margins for these materials.« less

Characterization of hypervelocity metal fragments for explosive initiation

NASA Astrophysics Data System (ADS)

Yeager, John D.; Bowden, Patrick R.; Guildenbecher, Daniel R.; Olles, Joseph D.

2017-07-01

The fragment impact response of two plastic-bonded explosive (PBX) formulations was studied using explosively driven aluminum fragments. A generic aluminum-capped detonator generated sub-mm aluminum particles moving at hypersonic velocities. The ability of these fragments to initiate reaction or otherwise damage two PBX materials was assessed using go/no-go experiments at standoff distances of up to 160 mm. Lower density PBX 9407 (RDX-based) was initiable at up to 115 mm, while higher density PBX 9501 (HMX-based) was only initiable at up to 6 mm. Several techniques were used to characterize the size, distribution, and velocity of the particles. Witness plate materials, including copper and polycarbonate, and backlit high speed video were used to characterize the distribution of particles, finding that the aluminum cap did not fragment homogeneously but rather with larger particles in a ring surrounding finer particles. Finally, precise digital holography experiments were conducted to measure the three-dimensional shape and size of the fastest-moving fragments, which ranged between 100 and 700 μm and traveled between 2.2 and 3.2 km/s. Crucially, these experiments showed variability in the fragmentation in terms of the number of fragments at the leading edge of the fragment field, indicating that both single and multiple shock impacts could be imparted to the target material. These types of data are critical for safety experiments and hydrocode simulations to quantify shock-to-detonation transition mechanisms and the associated risk-margins for these materials.

Synthesis, Chemical and Physical Characterization of TKX-50

NASA Astrophysics Data System (ADS)

Klapoetke, Thomas

2015-06-01

TKX-50 (bis(hydroxylammonium) 5,5'-bis(tetrazolate-1 N-oxide)) is one of the most promising ionic salts as a possible replacement for RDX. The thermal behavior of TKX-50 (bis(hydroxylammonium) 5,5'-(tetrazolate-1 N-oxide)) and the kinetics of its thermal decomposition were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The calculated results of the detonation parameters and equations of state for the detonation products (EOS DP) of explosive materials TKX-50 and MAD-X1 and several of their derivatives were obtained using the computer program EXPLO5 V.6.01. These values were also calculated for standard explosive materials which are commonly used such as TNT, PETN, RDX, HMX as well as for the more powerful explosive material CL-20 to allow comparisons to be made. The determination of the detonation parameters and EOS DP was conducted both for explosive materials having the maximum crystalline density and for porous right up to 50% in volume materials. The influence of the content of plastic binder polyisobutylene used (up to 20% in volume) on all of the investigated properties was also examined. Calculated results on shock wave loading of different inert barriers in a wide range of their dynamic properties under explosion on their surfaces of concrete size charges of different explosive materials in various initial states were obtained with the use of the one-dimensional computer hydrocode EP. Barriers due to materials such as polystyrene, textolite, magnesium, aluminum, zinc, copper, tantalum or tungsten were examined (Fig. 1). Initial values of pressure and other parameters of loading on the interface explosive-barrier were determined in the process of conducted calculations. Phenomena of propagation and attenuation of shock waves in barrier materials were considered too for all possible situations. From these calculations, an essentially complete overview of the explosion properties and characteristics of shock wave action onto barriers was obtained for several new and also for several standard explosive materials as a comparison. Work done in collaboration with Golubev/Fischer/Stierstorfer/Bohanek/Dobrilovic.

Measurements of observables during detonator function

NASA Astrophysics Data System (ADS)

Smilowitz, Laura; Henson, Bryan; Remelius, Dennis

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

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

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

Reaugh, J E

2011-11-22

HERMES (High Explosive Response to MEchanical Stimulus) was developed to fill the need for a model to describe an explosive response of the type described as BVR (Burn to Violent Response) or HEVR (High Explosive Violent Response). Characteristically this response leaves a substantial amount of explosive unconsumed, the time to reaction is long, and the peak pressure developed is low. In contrast, detonations characteristically consume all explosive present, the time to reaction is short, and peak pressures are high. However, most of the previous models to describe explosive response were models for detonation. The earliest models to describe the responsemore » of explosives to mechanical stimulus in computer simulations were applied to intentional detonation (performance) of nearly ideal explosives. In this case, an ideal explosive is one with a vanishingly small reaction zone. A detonation is supersonic with respect to the undetonated explosive (reactant). The reactant cannot respond to the pressure of the detonation before the detonation front arrives, so the precise compressibility of the reactant does not matter. Further, the mesh sizes that were practical for the computer resources then available were large with respect to the reaction zone. As a result, methods then used to model detonations, known as {beta}-burn or program burn, were not intended to resolve the structure of the reaction zone. Instead, these methods spread the detonation front over a few finite-difference zones, in the same spirit that artificial viscosity is used to spread the shock front in inert materials over a few finite-difference zones. These methods are still widely used when the structure of the reaction zone and the build-up to detonation are unimportant. Later detonation models resolved the reaction zone. These models were applied both to performance, particularly as it is affected by the size of the charge, and to situations in which the stimulus was less than that needed for 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 explosives were subjected to a gradual rise in pressure and did not exhibit reaction. More recent models do distinguish between slow pressure rises and shocks, and have had some success in the describing the response of explosives to single and multiple shocks, and the increase of shock sensitivity with porosity, at least over a limited range. The original formulation is appropriate for sustained shocks, but further work is ongoing to describe the response to short pulses. The HERMES model combines features from these prior models. It describes burning and explosion in damaged reactant, and also will develop a detonation if the gradual rise in pressure from burning steepens into a strong-enough shock. The shock strength needed for detonation in a fixed run distance decreases with increasing porosity.« less