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Showing 1 to 20 of 72 for “"Reaction Zone"”.
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Determining the Reaction Zone Length in Shock Initiated PETN
… detonators in the form of a pressed powder. The reaction zone length of PETN is smaller than that of most other explosives, therefore there is a lack of data due to insufficient resolution of existing methods. Furthermore, most prior work has been on steady state behaviour, so the transition …
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Direct methanol fuel cell with extended reaction zone anode : PtRu and PtRuMo supported on fibrous carbon
… be implemented. The methanol electro oxidation reaction is sluggish, mainly due to the strong adsorption of the reaction intermediate carbon monoxide on platinum. Further, methanol crosses over to the cathode, which decreases the fuel utilization and causes cathode catalyst poisoning. Another …
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On the structure of laminar diffusion flames
… in the limiting case of large, although finite, reaction rates. It is shown that the chemical reaction takes place only in a very thin region or "chemical boundary layer" where convection effects may be neglected. Then the temperature and mass fraction distributions within the reaction zone are …
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Investigations on detonation shock dynamics
… an inert shock followed by a region of chemical reaction referred to as the reaction zone. Detonations have a wide variety of engineering applications, from obvious military uses to explosive welding, hard rock mining, and materials processing. Detonations can occur in a variety of materials, …
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Characteristics of flame-turbulence interactions in freely propagating turbulent premixed flames under decaying and forced isotropic turbulence conditions
… flames are simulated, corresponding to the thin reaction zone and broken/distributed reaction zone regimes. The comparative analysis focuses on the instantaneous reacting flow field, mean flame structure in both physical and state space, and the transport and dynamics of enstrophy. The results …
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An experimental study of controlled gas phase synthesis of nanosize TO2 powders
… diffusion flame located around the outside of reaction zone. The effect on the powder size, shape, and size distribution due to particle charging, applied electric fields, and varying reactant concentrations were investigated. The temperature field within the reaction zone was uniform radially …
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Flame Structure and Emissions of Strongly-Pulsed Turbulent Diffusion Flames with Swirl
… work studies the turbulent flame structure, the reaction-zone structure and the exhaust emissions of strongly-pulsed, non-premixed flames with co-flow swirl. The fuel injection is controlled by strongly-pulsing the fuel flow by a fast-response solenoid valve such that the fuel flow is completely …
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High-temperature microfluidic systems for thermally-efficient fuel processing
… silicon nitride tubes and a suspended silicon reaction zone. This structure couples the energy between catalytic combustion and decomposition or steam reforming reactions to produce hydrogen. The design enables a high level of thermal isolation of the reaction zone while allowing heat exchange …
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The dynamics of multi-dimensional detonation
… steady Chapman-Jouguet (CJ) detonation reaction-zone thickness. The analysis considers additional time-dependence in the slowly-varying reaction zone than that considered in previous works. The detonation is assumed to have a sonic point in the reaction-zone structure behind the shock, …
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DESIGN OF AN EFFICIENT AND RAPID CHEMICAL VAPOR INFILTRATION (CVI) RE-CIRCULATION SYSTEM
… carbon deposition efficiency of 5-30% using a reaction zone filled with carbon fiber preforms. Total processing time varies from 50 to 2000 hours depending on the type of system and its temperature, pressure and residence time. Unused hydrocarbon reaction exhaust (effluent) gases are either …
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A Lean-Premixed Hydrogen Injector with Vane Driven Swirl for Application in Gas Turbines
… and air in fuel lean proportions prior to the reaction zone. Application of this technique to hydrogen combustion has been limited due to hydrogen's high flame rate and the concern of the reaction zone propagating into the premixing injector, commonly referred to as flashback. In this …
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Numerical Modelling of Detonation and Ignition of Condensed Phase Explosives
… phenomenon arises due to the finite width of the reaction zone, which causes the properties of the detonation wave to deviate from the predictions of the ZND model. If numerical models are to predict the attributes of the explosive to greater accuracy, then the dynamics of the reaction zone must …
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Translational Non-Equilibrium Effects in Reactive Dynamics of Detonations
… transient cellular structure and a turbulent reaction zone coupled with transverse shocks. The role of out-of-equilibrium phenomena in these waves remains unclear despite extensive research on the underlying physics. On the small scales, translational non-equilibrium associated with shocks, as …
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Shock Physics of Non-Ideal Detonations for Energetic Explosives With Aluminum Particles
… processes, alter the structure of the reaction zone, and produce a secondary shock wave which never reaches the detonation wave front. Additionally, under certain combinations of heat transfer rate and chemical release rate, the measured behavior can be reproduced, and the model results …
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Propagation and topology in turbulent premixed flames
… as the reactant mixture burning in the thin reaction zone regime. Here, preliminary break-up (through self-interaction) of the reaction zone is seen with increasing turbulence intensity, as the flame speed is simultaneously inhibited. Critical points in the reaction progress field - where the …
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Thermal Ignition Analysis in the Laminar Boundary Layer Behind a Propagating Shock Front
… is based on a one-step, irreversible Arrhenius reaction of a premixed gas; therefore, the ignition phenomenon is thermally induced. The boundary layer consists of a thin, diffusive, reaction region at the point where the temperature is maximum and diffusive-convective non-reacting regions …
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Downdraft gasification of biomass
… controlling the position and shape of the reaction zones. The stability of the reaction zone was found to be governed by the superficial gas velocity within the reactor. A superficial gas velocity below 0.2 Nms-1 resulted in a rising reaction zone in both gasifiers. Turndown is achieved …
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Geochemistry of hydrothermal vent fluids from the northern Juan de Fuca Ridge
… either to higher temperatures in the subsurface reaction zone, or a greater residence time of the fluids at high temperatures. Higher reaction zone temperatures at the ODP Mound field than at the Dead Dog field are consistent with differences in endmember C1 concentrations between the two fields. …
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Spatio-Temporal Dynamics of Reaction Zones in Catalytic Monolith Reactors
… of this model with the full washcoat diffusion–reaction model, we have also shown that the internal mass transfer coefficient approximation is valid for all practical purposes. In the second part, we investigated in detail three main reasons for failure of scale-up in monolith reactors: mass …
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Nonlinear oscillation and control in the BZ chemical reaction.
… oscillation of the Belousov-Zhabotinsky(BZ) reaction in a closed isothermal chemical system. The reaction zone can be divided into two zones, oscillation zone and transition zone, where the oscillation time and the transition time and the number of the complete oscillations are estimated. By …
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