Global ETD Search
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Showing 1 to 20 of 31 for “"deflagration"”.
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Design and Optimization of a Deflagration to Detonation Transition (DDT) Section
… the `traditional' combustion process called deflagration (subsonic combustion). An alternative form of combustion, detonation (supersonic combustion), can increase the thermal efficiency of the process by anywhere from 20 - 50%. Even though several authors have studied detonation waves since …
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Fluidic Jet Turbulence Generators for Deflagration to Detonation Transition in Pulsed Detonation Combustors
… required to effectively accelerate the turbulent deflagration flame front to detonation velocity in the shortest possible distance while using a single Jet in Cross Flow (JICF). Jets in crossflow, depending on orientation and momentum ratio, can induce two types of flow structures that propagate …
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Modeling and numerical simulation of deflagration-to-detonation transition in porous energetic materials
An understanding of the deflagration-to-detonation transition (DDT) in porous energetic materials is important for various engineering applications. Safety issues for damaged explosives is one example. In this work, two topics related to multi-dimensional simulation of DDT in energetic materials …
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Theoretical, computational and experimental analysis of the deflagration plasma accelerator and plasma beam characteristics
… and the acceleration process is termed "“deflagration". Devices that operate below the threshold are called “over-fed" and the plasma undergoes a compressive energy conversion process termed "detonation". Over-fed (detonation) plasma accelerators add energy to the plasma through plasma …
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An experimental study of solid propellant deflagration using high speed motion pictures and postfire residue analysis
Six aluminized propellants were investigated through strand burning in a windowed combustion bomb at 500 psi and 1000 psi. Postfire particle residues were analyzed with a scanning electron microscope and found to have bi-modal size distributions. The mean diameter of the fine particle distribution …
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Investigation of Pulse Detonation Engines: the Effect of Variable Blockage Ratio on the Deflagration to Detonation Transition
… approaches of achieving detonation through deflagration-to-detonation transition most of which use evenly spaced obstacles with a specified constant blockage ratio to generate turbulence and pressure fluctuations. There have been few efforts to study effects of varying blockage ratio as a …
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The Effect of Axial Spacing of Constant and Variable Blockages on the Deflagration-to-Detonation Transition in a Pulse Detonation Engine
… into the effects of obstacle spacing on the deflagration-to-detonation transition section length in a pulse detonation engine. Testing was conducted with one hundred and ninety-five different obstacle, and spacing configurations. The configurations included constant, as well as variable …
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The Blast Waves From Unconfined Axisymmetric Vapour-Cloud Explosions
… and constant velocity as well as accelerating deflagration waves propagating through homogeneous axisymmetric clouds whose energy density approximate that of a typical hydrocarbon-air mixture. The behavior of the blast wave was studied in a compressible medium surrounding a flammable mixture …
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Optical spectroscopy of HMX reaction regimes
… spectroscopy. Two different impact initiated deflagration reactions were performed. Improvements were made to the fallhammer sensitivity test to allow for more quantitative measurements, and the Split Hopkinson Pressure Bar (SHPB) was used for the first time to purposely initiate deflagration, …
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Development of Total Vaporization Solid Phase Microextraction and Its Application to Explosives and Automotive Racing
… their commonality, research into the pipe bomb deflagration process and subsequent chemical analysis is necessary.
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Hadronization in Ultra-Relativistic Heavy Ion Collisions
… find that the hadronization is accomplished by deflagration solutions in both scenarios. We argue that hadronization will occur before the quark-gluon plasma reaches a temperature that is low enough to admit detonations.
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The development of an optically active laser Schlieren system with application to high pressure solid propellant combustion
… the system are discussed. Ammonium perchlorate deflagration was observed to pressures of 2500 psi. Distinct surface reaction sites were evidenced in the gas phase at high and low pressures by alternating density gradients across the surface. These sites were found to be very small or nonexistent …
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Characterization framework to develop ball-milled thermites as additives to polymer-bound explosives
… governs fast phenomena such as detonation and deflagration. In many formulations, the sluggish oxidation of Al can even interfere with the primary decomposition chemistry of explosives, leading to reduced detonation velocity and peak pressure. To address these limitations, arrested reactive …
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Untersuchung von Deflagrationen selbstzersetzlicher Feststoffe und Entwicklung einer neuartigen Prüfmethode zur Beurteilung der Deflagrationsfähigkeit in geschlossenen Systemen
Das Deflagrationsverhalten selbstzersetzlicher fester Stoffe wurde bei unterschiedlichen Randbedingungen untersucht. Darüber hinaus wurde eine neue Prüfmethode entwickelt, mit welcher das Deflagrationsverhalten in geschlossenen Systemen beurteilt werden kann. Es wurden drei neue Messsysteme mit …
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Investigation of Pulse Detonation Engine Flow Conditions for Turbomachinery Integration
… its constant pressure counterpart, which employs deflagration. Integration of pressure gain combustors into gas turbine engines has been and still is one of the most important challenges facing the gas turbine industry. Pressure gain combustion devices are inherently unsteady. This unsteadiness …
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Detonation shock and ignition dynamics in condensed phase explosives
… analysis. We develop a model to simulate deflagration to detonation transition in pentaerythritol tetranitrate powders. The model uses a continuum mechanics formulation of conservation laws for a mixture of solid reactants and gas products, written in terms of mixture quantities, plus two …
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A Computational Study of Thermo-Fluid Dynamics of Pulse Detonation Engines
… to model highly structured phenomena such as Deflagration to Detonation Transition (DDT) and fuel injection in supersonic flow for PDE applications.</p>
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Combustion characteristics of alternative liquid fuels
… or furnaces requires extensive tests on the deflagration properties of biodiesel. The laminar flame speeds of Palm Methyl Esters (PME) and blends of PME with conventional fuels are determined using the jet-wall stagnation flame configuration. The same technique is also used to measure the …
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An Investigation of Blast Waves Generated by Constant Velocity Flames
… characterized by the nearly constant pressure deflagration associated with low Mach number laminar flames. The properties noted included peak pressure, positive impulse, energy distribution, and the blast wave flow field. Results were computed for the case of a methane-air mixture assuming an …
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On the simulation and modeling for the reaction mechanism and solid state detonation phenomena in non-conventional explosives
… Mass Spectroscopy (TOFMS). It monitors the Deflagration to Detonation Transition phenomena of small-scale explosive samples in vacuum subjected to short duration shock stimuli. To support the experiment in vacuum chamber, the numerical simulation of particle expanding toward vacuum is …
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