Deflagration-to-Detonation Transition and Detonation Propagation in H2-Air Mixtures with Transverse Concentration Gradients
01 Jan 2015-
TL;DR: In this paper, the authors identify and quantifies the underlying physical mechanisms of H2-air mixtures explosion in nuclear reactors during severe loss-of-coolant accidents and demonstrate that Mixture inhomogeneity can lead to significantly stronger explosions as compared to homogeneous mixtures.
Abstract: Explosion of H2-air mixtures portrays a major hazard in nuclear reactors during severe loss-of-coolant accidents. Spatial gradients in H2 concentration prevail in real-world scenarios. Mixture inhomogeneity can lead to significantly stronger explosions as compared to homogeneous mixtures. The present work identifies and quantifies the underlying physical mechanisms.
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Book•
26 Apr 2002
TL;DR: In this paper, the authors assembled a world-class group of contributors who address the questions the combustion diagnostic community faces, including chemists who identify the species to be measured and the interfering substances that may be present; physicists who push the limits of laser spectroscopy and laser devices and who conceive suitable measuremen.
Abstract: The editors have assembled a world-class group of contributors who address the questions the combustion diagnostic community faces. They are chemists who identify the species to be measured and the interfering substances that may be present; physicists, who push the limits of laser spectroscopy and laser devices and who conceive suitable measuremen
492 citations
TL;DR: Bone, Newitt and Townend as mentioned in this paper published a comprehensive monograph "Flame and Combustion in Gases" by Prof. W. de C. Ellis and W. A. Townend.
Abstract: ELEVEN years ago appeared the comprehensive monograph entitled “Flame and Combustion in Gases” by Prof. W. A. Bone and D. T. A. Townend, followed a year or two later by “Gaseous Combustion at High Pressures” by Bone, Newitt and Townend. Except for a small volume on "Flame"by 0. C. de C. Ellis and W. A. Kirkby (1936), the subject has not since been treated as a whole in English, until the recent appearance of the work by Bernard Lewis and G. von Elbe now under review. Combustion, Flames and Explosions of Gases By Dr. Bernard Lewis Dr. Guenther von Elbe. (The Cambridge Series of Physical Chemistry.) Pp. xiv + 415. (Cambridge: At the University Press, 1938.) 21s. net.
290 citations
01 Sep 1991
TL;DR: In this article, a complex, dynamic shock-detonation structure formed by the glancing interaction of a primary detonation with a secondary explosive is studied by using time-dependent two-dimensional simulations and related experiments.
Abstract: The complex, dynamic shock-detonation structure formed by the glancing interaction of a primary detonation with a secondary explosive is studied by using time-dependent two-dimensional simulations and related experiments. The materials considered in the simulations are stoichiometric and lean mixtures of hydrogen and oxygen diluted with argon. Related experiments have used undiluted hydrogen and oxygen as well as other gases. For the conditions simulated: (a) the primary mixture is stoichiometric and the secondary inert; (b) both the primary and secondary mixtures are the same and stoichiometric; (c) the primary mixture is lean and the secondary is stoichiometric; and (d) the primary mixture is stoichiometric and the secondary is lean. In addition, for cases (b) and (d) , comparisons are made between simulations in which the primary mixture is overdriven and when it is a Chapman-Jouguet detonation. For the overdriven stoichiometric primary detonation interacting with the lean mixture, a complex detonation structure forms and quickly asymptotes to the detonation velocity of the primary mixture. For this same case, but when the primary detonation is initially at Chapman-Jouguet velocity, the detonation appears to die but then reignites due to a series of shock reflections and then propagates as a complex structure. The lowest velocity of the complex structure is always greater than the Chapman-Jouguet velocity of the lean mixture and it increases in time, appearing to approach the Chapman-Jouguet velocity of the stoichiometric mixture. The dynamics of this decay and reignition process are described and discussed in detail.
44 citations
TL;DR: In this article, the influence of methane addition on the critical layer thickness h* and its relation to detonation cell size (λ ) for stable detonation propagating in semi-confined, non-obstructed channel filled with uniform, stoichiometric hydrogen-methane-air mixtures was determined.
28 citations
TL;DR: In this article, the authors investigated the effect of obstacle spacing and mixture concentration on the deflagration-to-detonation transition in a homogeneous and inhomogeneous hydrogen-air mixture.
25 citations
References
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Book•
01 Jan 1983
TL;DR: This book describes the fundamental aspects of fluorescence, the biochemical applications of this methodology, and the instrumentation used in fluorescence spectroscopy.
Abstract: Fluorescence methods are being used increasingly in biochemical, medical, and chemical research. This is because of the inherent sensitivity of this technique. and the favorable time scale of the phenomenon of fluorescence. 8 Fluorescence emission occurs about 10- sec (10 nsec) after light absorp tion. During this period of time a wide range of molecular processes can occur, and these can effect the spectral characteristics of the fluorescent compound. This combination of sensitivity and a favorable time scale allows fluorescence methods to be generally useful for studies of proteins and membranes and their interactions with other macromolecules. This book describes the fundamental aspects of fluorescence. and the biochemical applications of this methodology. Each chapter starts with the -theoreticalbasis of each phenomenon of fluorescence, followed by examples which illustrate the use of the phenomenon in the study of biochemical problems. The book contains numerous figures. It is felt that such graphical presentations contribute to pleasurable reading and increased understand ing. Separate chapters are devoted to fluorescence polarization, lifetimes, quenching, energy transfer, solvent effects, and excited state reactions. To enhance the usefulness of this work as a textbook, problems are included which illustrate the concepts described in each chapter. Furthermore, a separate chapter is devoted to the instrumentation used in fluorescence spectroscopy. This chapter will be especially valuable for those perform ing or contemplating fluorescence measurements. Such measurements are easily compromised by failure to consider a number of simple principles."
28,073 citations
"Deflagration-to-Detonation Transiti..." refers background in this paper
...For further information on quantitative measurements for the determination of local species concentrations, including in particular relevant quenching effects, please refer to [77, 86, 100, 122]....
[...]
Book•
01 Jan 1972
TL;DR: In this paper, the authors present a reference record created on 2005-11-18, modified on 2016-08-08 and used for the analysis of turbulence and transport in the context of energie.
Abstract: Keywords: turbulence ; transport ; contraintes ; transport ; couche : limite ; ecoulement ; tourbillon ; energie Reference Record created on 2005-11-18, modified on 2016-08-08
8,276 citations
"Deflagration-to-Detonation Transiti..." refers background in this paper
...Since lη decreases with an increase in dissipation rate ǫ, which in turn rises with flow velocity u (ǫ∝ u(3)/lT) [140], high flow velocity in a given fluid yields a lower smallest eddy size than flow at lower velocity....
[...]
Journal Article•
TL;DR: In this article, the authors consider the problem of finding the components of the velocity at every point of a point with rectangular cartesian coordinates x 1, x 2, x 3, x 4, x 5, x 6, x 7, x 8.
Abstract: §1. We shall denote by uα ( P ) = uα ( x 1, x 2, x 3, t ), α = 1, 2, 3, the components of velocity at the moment t at the point with rectangular cartesian coordinates x 1, x 2, x 3. In considering the turbulence it is natural to assume the components of the velocity uα ( P ) at every point P = ( x 1, x 2, x 3, t ) of the considered domain G of the four-dimensional space ( x 1, x 2, x 3, t ) are random variables in the sense of the theory of probabilities (cf. for this approach to the problem Millionshtchikov (1939) Denoting by Ᾱ the mathematical expectation of the random variable A we suppose that ῡ 2 α and (d uα /d xβ )2― are finite and bounded in every bounded subdomain of the domain G .
6,063 citations
"Deflagration-to-Detonation Transiti..." refers background in this paper
...∗ Excited state of a molecule ′ RMS value Subscripts a Activation abs Absolute C Channel CJ Chapman-Jouguet d Diffusion eff Effective F Flame grad Gradient hom Homogeneous ind Induction L Laminar M Markstein pr Products r Reflected re Reactants S Stretched stoich Stoichiometric T Turbulent VN Von Neumann δ Heat release zone η Kolmogorov parameters xxv...
[...]
...Eddy sizes between the integral length scale lT and the Kolmogorov micro scale of length lη, going back to the analysis of turbulent flow by Kolmogorov [78, 79], exist in fully developed turbulent flows....
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TL;DR: Kolmogorov and Oboukhov as discussed by the authors investigated the local structure of turbulence at high Reynolds number, based on Richardson's idea of the existence in the turbulent flow of vortices on all possible scales.
Abstract: The hypotheses concerning the local structure of turbulence at high Reynolds number, developed in the years 1939-41 by myself and Oboukhov (Kolmogorov 1941 a,b,c; Oboukhov 1941 a,b) were based physically on Richardson's idea of the existence in the turbulent flow of vortices on all possible scales l < r < L between the ‘external scales’ L and the ‘internal scale’ l and of a certain uniform mechanism of energy transfer from the coarser-scaled vortices to the finer.
2,682 citations
"Deflagration-to-Detonation Transiti..." refers background in this paper
...∗ Excited state of a molecule ′ RMS value Subscripts a Activation abs Absolute C Channel CJ Chapman-Jouguet d Diffusion eff Effective F Flame grad Gradient hom Homogeneous ind Induction L Laminar M Markstein pr Products r Reflected re Reactants S Stretched stoich Stoichiometric T Turbulent VN Von Neumann δ Heat release zone η Kolmogorov parameters xxv...
[...]
...Eddy sizes between the integral length scale lT and the Kolmogorov micro scale of length lη, going back to the analysis of turbulent flow by Kolmogorov [78, 79], exist in fully developed turbulent flows....
[...]
Book•
01 Jan 1973
TL;DR: In this article, the physical concepts of fluid mechanics and methods of analysis, beginning from first principles, are discussed, and a more orderly approach to problem solving is presented, starting from basic equations, states all assumptions clearly, and relates results to expected physical behavior with the aid of 103 example problems.
Abstract: This introductory text emphasizes the physical concepts of fluid mechanics and methods of analysis, beginning from first principles. In helping readers develop a more orderly approach to problem solving, the book starts from basic equations, states all assumptions clearly, and relates results to expected physical behavior with the aid of 103 example problems. The third edition features the use of SI units in approximately 70% of the more than 1,100 problems, 500 of which are new.
2,344 citations
"Deflagration-to-Detonation Transiti..." refers background in this paper
...For broad background information on fluid mechanics, combustion and gasdynamics, the reader is referred to standard literature like [48], [91] and [98]....
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