208
208
Jun 17, 2010
06/10
by
Mcfarland, D. R
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No Abstract Available
Topics: DETONATION WAVES, SHOCK WAVES, WINGS
The ability to enhance detonation wave transmission at a diffraction plane through various shock reflection/focusing conditions was evaluated numerically. The geometry dimensions were generally representative of the condition existing in a valve-less pulse detonation engine developed by the Naval Postgraduate School and consisted of a small cylindrical \"initiator\" combustor, which transmitted a shock wave to a larger diameter combustor. The wall cross section of the larger combustor...
Topics: Combustion chambers, Fluid dynamics, Detonation waves
Oblique detonation wave (ODW) stabilized over a ramp or a wedge can be used for combustion in a supersonic combustion chamber. This paper numerically studies the conditions for an ODW to be stabilized over a finite ramp length at different temperature, pressure and Mach number conditions, and examines potential combustor control methods in order to achieve desirable ODW combustor characteristics for a propulsion system. At given operating conditions, ramp length and for a given amount of...
Topics: Oblique Detonation Waves, Induction Length, Combustor Flow Control
The purpose of this study was to drive a planar shock wave into a layer of sand for use in armor effectiveness studies. We proposed to use an explosively-driven flyer plate to impact the sand layer and launch a shock wave. In detail, our concept is to use a slanted flyer plate, with an explosive layer underneath it, and accelerate the flyer plate by detonating the explosive. As the resulting detonation wave runs through the explosive layer, it pushes the flyer plate. If all the geometry is...
Topics: Armor, Testing, Explosives, Safety measures, Detonation waves, Experiments
Elimination or reduction of auxiliary oxygen use in Pulse Detonation Engines (PDEs) is necessary if the technology is to compete with existing Ramjet systems. This thesis investigated a Transient Plasma Ignition (TPI) system and found that the technology can at least reduce and may be able to completely remove the auxiliary oxygen requirement of current PDE systems. TPI was tested and compared with a traditional capacitive discharge spark plug system in a dynamic flow, ethylene/air mixture...
Topics: Propulsion systems, Detonation waves, Spark ignition engines, Ethylene
Detonation waves were examined in axisymmetric and two-dimensional test configurations to determine the limits at which a detonation will successfully initiate and diffract from a small initiator tube into a larger main combustor. Tests were conducted for various initiator-to-main combustor area ratios. Additionally, for each area ratio, the fuel-oxygen initiator mixture was diluted with various nitrogen concentrations attempting to approach the mass fraction of nitrogen in air (79%). Results...
Topics: Detonation waves, Pulse detonation engines, PDE, Detonation diffraction
Journal of Research of the National Bureau of Standards
Topics: missile, detonation waves, combustion, propulsion, schlieren photographs, wave shape, detachment
Topics: DTIC Archive, COOK, MELVIN A., PICATINNY ARSENAL DOVER NJ, *DETONATION WAVES, PROPAGATION
Topics: DTIC Archive, JACOBS, SIGMUND J., NAVAL ORDNANCE LAB WHITE OAK MD, *DETONATION WAVES, ENERGY
Operational characteristics of a valveless pulse detonation engine system were characterized by experimental measurements of thrust, fuel flow, and internal gas dynamics. The multi-cycle detonation experiments were performed on an axis-symmetric engine geometry operating on an ethylene/air mixtures. The detonation diffraction process from a small 'initiator' combustor to a larger diameter main combustor in a continuous airflow configuration was evaluated during multi-cycle operation of a pulse...
Topics: Detonation waves, Combustion, Airplanes, Motors, Thrust, Pulse detonation engine, Supersonic air...
Smear camera observations were made of detonation waves in nitromethane, 1,2-DP, and 2,2-DP. The nitromethane gave essentially conventional results, the detonation wave having a velocity of 6.5-6.7 mm/microsec. Possibly the velocity was still decreasing very slowly 30 cm from the liquid-donor interface. This compares with a steady velocity of 6.3 mm/microsec reported by earlier observers. The 1,2-DP and 2,2-DP, however, again exhibited the anomalous behavior (observed in previous report...
Topics: DTIC Archive, Amster, A B, STANFORD RESEARCH INST MENLO PARK CA, *NITROMETHANE, *DETONATION WAVES,...
Topics: DTIC Archive, MAJOWICZ, J M, NAVAL ORDNANCE LAB WHITE OAK MD, *DETONATIONS, *EXPLOSIVES, DETONATION...
The objective of theoretical, computational and experimental studies outlined in this lecture note was to evaluate the design principles and propulsion performance of prospective air-breathing engines operating on pulse detonations of realistic hydrocarbon fuels with a realistic technique of detonation initiation via deflagration-to-detonation transition (DDT).
Topics: DTIC Archive, SEMENOV INST OF CHEMICAL PHYSICS MOSCOW (RUSSIA), *AIR BREATHING ENGINES,...
The rotating detonation engine (RDE) is a propulsion system that obtains thrust using continuously existing detonation waves. A rotating detonation combustor (RDC) usually has an annular shape that allows detonation waves to propagate in the circumferential direction. In this study, we used a disk-shaped RDC with a combustion chamber with flat-plane glass walls to observe the structure of the phenomena. Self-luminescence, shadowgraphs and schlieren visualization experiments were performed and...
Topics: DTIC Archive, Mizukaki, Toshiharu, TOKAI UNIVERSITY HIRATSUKA Japan, combustion, DETONATION WAVES,...
This research conducted from FY 2006 through FY 2009 addressed to main objectives: 1) determination of the combustion kinetics of fine aluminum particles under conditions relevant to enhanced blast devices, and 2) examination of the effects of the passage of the detonation wave on the reactivity of aluminum particles in aluminized explosives. These to research thrust were conducted in parallel.
Topics: DTIC Archive, ILLINOIS UNIV CHAMPAIGN, *COMBUSTION, *EXPLOSIVES, *REACTION KINETICS, ALUMINUM,...
Topics: DTIC Archive, OFFICE OF NAVAL RESEARCH ARLINGTON VA, *EXPLOSIVES, *DETONATIONS, *DETONATION WAVES,...
238
238
Jul 23, 2010
07/10
by
Deyoung, R. J.; Lee, J. H.; Williams, M. D.; Schuster, G.; Conway, E. J
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High-power lasers in space could provide power for a variety of future missions such as spacecraft electric power requirements and laser propulsion. This study investigates four electrically pumped laser systems, all scaled to 1-MW laser output, that could provide power to spacecraft. The four laser systems are krypton fluoride, copper vapor, laser diode array, and carbon dioxide. Each system was powered by a large solar photovoltaic array which, in turn, provided power for the appropriate...
Topics: DETONATION WAVES, HYDRAZINE NITRATE, HYDRAZINIUM COMPOUNDS, PROPAGATION VELOCITY, WAVE PROPAGATION,...
Topics: DTIC Archive, Stresau, R. H., NAVAL ORDNANCE LAB WHITE OAK MD, *PRIMERS, *DETONATIONS, *EXPLOSIVES,...
Topics: DTIC Archive, HAMPTON, L D, NAVAL ORDNANCE LAB WHITE OAK MD, *VELOCITY, *MEASUREMENT, *DETONATIONS,...
On the hypothesis of thermal initiation and estimates of the absolute rate constant and free energy of activation of the explosion reaction, the width of the reaction zone in a detonation wave, both in the homogeneous case and in the heterogeneous case, in which evaporation is the rate-determining step, is calculated. The distribution of temperature and pressure within a detonation wave, and the effect of these variables upon the rate of chemical decomposition reaction, are studied in an...
Topics: DTIC Archive, Parlin, Ransom B, PRINCETON UNIV NJ, *DETONATION WAVES, CHEMICAL REACTIONS, EQUATIONS...
Topics: DTIC Archive, OFFICE OF NAVAL RESEARCH ARLINGTON VA, *DETONATIONS, *EXPLOSIVES, DETONATION WAVES,...
Topics: DTIC Archive, Voytsekhovskiy, B V, JOINT PUBLICATIONS RESEARCH SERVICE ARLINGTON VA, *DETONATIONS,...
xvii, 187 p. : 28 cm
Topics: Nuclear explosions -- Mathematical models, Shock waves -- Mathematical models, Detonation waves --...
320
320
May 21, 2011
05/11
by
Tamburello, Vito; Weil, Josep
texts
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Tests were made in the Langley 7- by 10-foot tunnel to determine the lateral-stability characteristics with and without power of a model of a typical low-wing single-engine airplane with flaps neutral, with a full-span single slotted flap, and with a full-span double slotted flap. Power decreased the dihedral effect regardless of flap condition, and the double-slotted flap configuration showed the most marked decrease. The usual effect of power in increasing the directional stability was also...
Topics: CAMERAS - NACA (MILLER) MOVING-PICTURE (HIGH-SPEED), ENGINES, SPARK-IGNITION, DETONATION WAVES,...
Theoretical studies of an analytical model for the internal gas dynamics associated with a rotating detonation wave engine are presented. The numerical computations to solve the differential equations for the analytical model were carried out for the no mixing case for initial propellant temperatures of 537 and 270 R plots of the various dimensionless gas dynamic parameters versus the dimensionless circumferential coordinate are shown. A modification of the analytical model to handle the case...
Topics: DTIC Archive, MICHIGAN UNIV ANN ARBOR, *LIQUID PROPELLANT ROCKET ENGINES, *DETONATION WAVES,...
This handbook includes chapters on general phenomenology, air blast theory, blast scaling, computational methods, air blast experimentation, compiled blast data, air blast transducers, instrumentation systems, photography of air blast waves, and data reduction methods. It is illustrated by many figures and graphs. Specifically excluded from this handbook are classified aspects of air blast technology, laboratory applications such as shock tubes, and response of structures to blast loading....
Topics: DTIC Archive, ARMY MATERIEL COMMAND ALEXANDRIA VA, *AIRBURST, *EXPLOSIONS, *HANDBOOKS, EXPLOSION...
Permanent reaction products and some explosive properties of two compositions were studied to establish detonability and the post detonation equilibrium products. The compositions were based on aluminum-aq hydrogen peroxide (98%) and aluminum-lithium perchlorate trihydrate. Stable detonation rates were measured for well confined compositions of both types balanced to alumina and steam. The concentration of hydro gen in the reaction products of a series of aluminum-hydrogen peroharges with...
Topics: DTIC Archive, Murphy, M F, NAVAL ORDNANCE LAB WHITE OAK MD, *DETONATION WAVES, *ORGANOMETALLIC...
Topics: DTIC Archive, Gibber, Philip F, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *DETONATION WAVES,...
The purpose of the report is to present results of investigations of the structure of transverse perturbations of the actual detonation front in gases.
Topics: DTIC Archive, FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OH, *GASES, *DETONATIONS, USSR,...
277
277
May 29, 2011
05/11
by
Houts, Mike; VanDyke, Melissa; Godfroy, Tom; Pedersen, Kevin; Martin, James; Dickens, Ricky; Salvail, Pat; Hrbub, Ivan
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Fission technology can enable rapid, affordable access to any point in the solar system. Potential fission-based transportation options include bimodal nuclear thermal rockets, high specific energy propulsion systems, and pulsed fission propulsion systems. In-space propellant re-supply enhances the effective performance of all systems, but requires significant infrastructure development. Safe, timely, affordable utilization of first-generation space fission propulsion systems will enable the...
Topics: LASER PROPULSION, FLIGHT ENVELOPES, LOW EARTH ORBITS, LAUNCHING, COMPUTATIONAL FLUID DYNAMICS, TIME...
It is proposed that the usual energy deposition, e.g., electron beam, experiments, as well as the usual shock introduction, e.g., flyer plate, experiments do not yield a true Gruneisen parameter of porous materials. It is proposed that in a porous material stress relief occurs within the time that energy is being deposited, or before the final state is reached in a flyer plate experiment. Both types of experiments are analyzed and correlated and agree with the ideas put forward here. Energy...
Topics: DTIC Archive, Harris, Paul, PICATINNY ARSENAL DOVER NJ, *PETN, SHOCK WAVES, TEST METHODS, POROUS...
In [18], two of the authors developed a high order accurate numerical boundary condition procedure for hyperbolic conservation laws on a Cartesian mesh, which allows the computation using high order finite difference schemes on Cartesian meshes to solve problems in arbitrary physical domains whose boundaries do not coincide with grid lines. This procedure is based on the so-called inverse Lax-Wendroff (ILW) procedure for inflow boundary conditions and high order extrapolation for outflow...
Topics: DTIC Archive, BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS, *DIFFERENTIAL GEOMETRY, ALGEBRA,...
These experiments were inspired by the work of G. M. Gangel'man (which will be described later) dealing with the solution of the problem of a skew collision of detonation waves. The obtained by him was not accurate enough because the equation of state of the detonation products was not accurate, and the solution of the problem was not confined to the narrow region of the particular collision angles, the analytical solution of which can be two-digital. The critical value of angle (proportion to...
Topics: DTIC Archive, Fooktstova, Ye A, JOINT PUBLICATIONS RESEARCH SERVICE ARLINGTON VA, *EXPLOSIVES,...
The research program involved the modification and use of an existing pulse detonation engine (PDE) to investigate the detonability of a JP-10/air aerosol. The detonation of a JP-10 aerosol in air proved more difficult than was originally anticipated. The use of a small JP- 10/oxygen pre-detonator to provide direct initiation results in a transition region with a geometric diffraction and compositional discontinuity. Propagation of a detonation into such a region is very complex but critical to...
Topics: DTIC Archive, Hofstedt, Todd A, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *DETONATIONS, *ROCKET...
It is anticipated that the introduction of high currents will increase the energy content of the conduction gases in the vicinity of the detonation front and lead to an increase in detonation velocity through ohmic heating. The approach is to transfer the stored electrical energy from a 5.5-kV, 0.010-F, 200-kJ capacitor bank into the conductive zone behind the detonation front of Primasheet-1000 explosive reaction. Upon initiation of the explosive, an explosive switch allows the energy stored...
Topics: DTIC Archive, ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD, *ELECTRIC POWER, *EXPLOSIVES,...
It is common knowledge in the detonation community that streak camera velocity traces should be near 45 degrees for best results. Yet, there seems to be no systematic explanation for that belief. In this report some derivations are presented to show that such belief is indeed grounded in fact. The Naval Weapons Center is particularly interested in the Los Alamos Wedge Test. This test has in fact shown itself to be important in understanding the complex phenomenon of sensitivity. The derivations...
Topics: DTIC Archive, Mallory,H D, NAVAL WEAPONS CENTER CHINA LAKE CA, *PHOTOGRAPHIC ANALYSIS,...
Detonation waves were examined in axisymmetric and two-dimensional test configurations to determine the limits at which a detonation will successfully initiate and diffract from a small initiator tube into a larger main combustor. Tests were conducted for various initiator-to-main combustor area ratios. Additionally, for each area ratio, the fuel-oxygen initiator mixture was diluted with various nitrogen concentrations attempting to approach the mass fraction of nitrogen in air (79%). Results...
Topics: DTIC Archive, Touse, Elizabeth J, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *DETONATION WAVES, TWO...
Topics: DTIC Archive, HAMPTON, L. D., OFFICE OF NAVAL RESEARCH ARLINGTON VA, *EXPLOSIVES, *DETONATIONS,...
370
370
May 27, 2011
05/11
by
Martin, Norman J
texts
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Pressure coefficients were measured over the vehicle and over the forward part of the booster at Reynolds numbers of 3.0 x 10(exp 6) per foot. Tabular results are presented for two nose shapes at Mach numbers of 1.55, 1.75, 2.00, and 2.35, at angles of attack from -4 deg to 10 deg, and at 0 deg sideslip.
Topics: BLUNT LEADING EDGES, WEDGES, PREDICTIONS, HYPERSONIC FLOW, HYPERSONIC SPEED, LEADING EDGES,...
Genetic algorithms, which simulate evolution in natural systems, have been used to find solutions to optimization problems that seem intractable to standard approaches. In this study, the feasibility of using a GA to find an optimum, fixed profile nozzle for a pulse detonation engine (PDE) is demonstrated. The objective was to maximize impulse during the detonation wave passage and blow-down phases of operation. Impulse of each profile variant was obtained by using the CFD code Mozart/2.0 to...
Topics: NASA Technical Reports Server (NTRS), DETONATION WAVES, GENETIC ALGORITHMS, OPTIMAL CONTROL,...
In this paper, we develop a three-dimensional parallel solver using the fifth order high-resolution weighted essentially non-oscillatory (WENO) finite difference scheme to perform extensive simulation for three-dimensional gaseous detonations. A careful study is conducted for the propagation modes of the three-dimensional gaseous detonation wave-front structure in a long square duct with different widths under different initial perturbations. The numerical results indicate that, with a...
Topics: DTIC Archive, BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS, *DETONATIONS, DETONATION WAVES,...
The mechanisms of detonation transfer across hermetically sealed interfaces created by necessary interruptions in high explosive trains, such as at detonators to explosive columns, field joints in explosive columns, and components of munitions fuse trains are demostrated. Reliability of detonation transfer is limited by minimizing explosive quantities, the use of intensitive explosives for safety, and requirements to propagate across gaps and angles dictated by installation and production...
Topics: NASA Technical Reports Server (NTRS), DETONATION WAVES, EXPLOSIVES, HERMETIC SEALS, PARTICLE SIZE...
The effect of wave shaping on the MRL 38 mm shaped charge is considered. A simple extension of the Pugh, Eichelberg and Rostoker theory is used to consider the effect of the both spherically diverging and spherically converging detonation waves on jet performance, and then a more sophisticated analytical approach is used to look at the expected increase in jet-tip velocity produced by a conical detonation wave. This predicted jet-tip velocity is compared with the result from a HELP-code...
Topics: DTIC Archive, Jones,D A, MATERIALS RESEARCH LABS ASCOT VALE (AUSTRALIA), *SHAPED CHARGES,...
Measurements have been made of the von Neumann spike pressure and Chapman-Jouguet pressure in TNT and Octol by a modification of the technique of Duff and Houston. Spike pressure of 259 kilobars in TNT and 452 kilobars in Octol and Chapman-Jouguet pressure of 213 kilobars in TNT and 314 kilobars in Octol are reported. Comparisons are made to previous data for TNT, no previous measurements for Octol were found for comparison.
Topics: DTIC Archive, Jameson, Robert L, ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD,...
This report assesses two types of explosive line wave generator which can be used for line initiation of an explosive charge. The two types are a perforated triangle design utilising equal path lengths through the explosive to create a straight detonation wave; and an explosive lens design employing two explosives with different detonation velocities to remove the curvature from the detonation wave. A Cordin high speed camera was used for imaging the detonation wave to assess the degree of...
Topics: DTIC Archive, DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION EDINBURGH (AUSTRALIA), *EXPLOSIVES,...
435
435
Jun 18, 2010
06/10
by
Solovkhin, R. I
texts
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Detonation waves in gases - measuring apparatus, gas ignition behind shock front, and transition from deflagration to detonation
Topics: DEFLAGRATION, GAS DYNAMICS, MEASURING APPARATUS, SHOCK FRONT, DETONATION, DETONATION WAVES, FLAME...
The minimum detonation Mach number, below which detonative combustion is not possible, can be predicted by Belles' explosion limit criterion for H2-O2 mixtures. The criterion predicts also that the addition of water vapor increases this minimum Mach number. The experiments which are described here and which are based on the technique of slowing down an established Chapman-Jouguet detonation wave by exposing one of its sides to a compressible boundary verify this prediction. It is found that the...
Topics: DTIC Archive, MICHIGAN UNIV ANN ARBOR AIRCRAFT PROPULSION LAB, *OXYGEN, *WATER VAPOR, *DETONATIONS,...
Pulse detonation engines (PDEs) are the focus of increasing attention due to their potentially superior performance over constant pressure cycle engines. Yet due to its unsteady chamber pressure, the PDE system will either be over- or under-expanded for the majority of the cycle, with energy being used without maximum gain. Magnetohydrodynamic (MHD) augmentation offers the opportunity to extract energy and apply it to a separate stream where the net thrust can be increased. With MHD...
Topics: DTIC Archive, CALIFORNIA UNIV LOS ANGELES DEPT OF MECHANICAL AND AEROSPACE ENGINEERING, *ROCKET...
A gelled nitromethane explosive has been produced which should be satisfactory for use in clearing mine fields by the method of blanketing the field with an explosive which, on detonation, causes destruction of mines planted in that area. This explosive, a composition of nitromethane, Code No. 1, and ethylenediamine, is a non-syneresing gel which can be projected to form a blanket 1/16 in. thick and which when initiated by a Corps of Engineers Special Blasting Cap detonates high order. A...
Topics: DTIC Archive, PICATINNY ARSENAL DOVER NJ, *EXPLOSIVES, AGING(MATERIALS), LIQUIDS, MINEFIELDS,...
This report contains information concerning the calculation of the characteristics of a detonation wave, stationary propagated in condensed explosives, and the equation of state of the explosion products.
Topics: DTIC Archive, Ratner, S. B., JOINT PUBLICATIONS RESEARCH SERVICE ARLINGTON VA, *EXPLOSION EFFECTS,...
