نتایج جستجو برای: detonation
تعداد نتایج: 2756 فیلتر نتایج به سال:
We present an overview of the current state of detonation stability theory and discuss its implications for propulsion. The emphasis of the review is on the exact or asymptotic treatments of detonations, including various asymptotic limits that appear in the literature. The role that instability plays in practical detonation-based propulsion is of primary importance and is largely unexplored, h...
Emergence of a detonation in a homogeneous, exothermically reacting medium can be deemed to occur in two phases. The first phase processes the medium so as to create conditions ripe for the onset of detonation. The actual events leading up to preconditioning may vary from one experiment to the next, but typically, at the end of this stage the medium is hot and in a state of nonuniformity. The s...
Issues associated with modeling the multiscale nature of detonation are reviewed, and potential applications to detonation-driven propulsion systems are discussed. It is suggested that a failure of most existing computations to simultaneously capture the intrinsic microscales of the underlying continuum model along with engineering macroscales could in part explain existing discrepancies betwee...
Experiments were carried out to determine the effectiveness of a transient plasma, i.e, corona discharge, to initiate a detonation in a short tube. A high-voltage pulse generator used a pseudo-spark switch to discharge a capacitor through a transformer connected to electrodes in the combustion initiator section. The resulting voltage pulse (90 kV for 50 ns) produced a plasma discharge consistin...
A molecular dynamics investigation of the effects of a diluent on the detonation of a model crystalline explosive is presented. The diluent, a heavy material that cannot exothermally react with any species of the system, is inserted into the crystalline explosive in two ways. The first series of simulations investigates the attenuation of the energy of a detonation wave in a pure explosive afte...
The results of experimental studies of organic dust detonation in the presence of chemically inert particles are presented. Tests were carried out using a vertical detonation tube, and direct streak pictures showing the flame acceleration and pressure and temperature records were obtained. Flax dust, dispersed in an oxygen atmosphere, was used as the fuel, and two kinds of quartz sand were intr...
Confirming a conjecture of Lyng–Raoofi–Texier–Zumbrun, we show that stability of strong detonation waves in the ZND, or small-viscosity, limit is equivalent to stability of the limiting ZND detonation together with stability of the viscous profile associated with the component Neumann shock. More, on bounded frequencies the nonstable eigenvalues of the viscous detonation wave converge to those ...
We study the asymptotic stability of a plane CJ detonation wave under the assumption of small resolved heat release (SRHR). We prove that the solution exists globally and that the solution converges uniformly to a shifted CJ detonation wave as t! + 1 for initial data which are small perturbations of the CJ detonation wave. The weighted energy method is used to overcome the diiculty arising from...
Type Ia supernovae are believed to be white dwarfs disrupted by a thermonuclear explosion. Here we investigate the scenario in which a rather low-mass, carbon-oxygen (C + O) white dwarf accumulates helium on its surface in a sufficient amount for igniting a detonation in the helium shell before the Chandrasekhar mass is reached. In principle, this can happen on white dwarfs accreting from a non...
Twomodels are proposed for rotating detonation engine performance. The first model is motivated bymodels of pulse detonation engine performance which are based on the pressure-time history within the detonation tube. The present work extends those ideas to treat rotating detonation engines with a control volume analysis that considers the forces within the combustion chamber. The key scaling pa...
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