Download or read book Numerical Study of Upstream and Downstream Regions of One Dimensional Detonation Wave in a Dusty Gas Medium written by Shubhadeep Banik and published by . This book was released on 2015 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In detonative combustion very high temperatures are attained by the burned gases. As a result, a large amount of thermal energy is produced during the combustion process. This heat can affect the state of the unburned fuel through radiation of heat from the burned gases. In this study a one-dimensional model was deemed appropriate to gain insight into the fundamental structure of the detonation wave. In this model, the detonation wave divides the fluid stream into an upstream region, consisting of fuel and oxidant, and a downstream region, consisting of burned gases. A set of computer programs, some developed during the present work and others developed by other investigators, were used in combination. These codes, when used in conjunction with an appropriate chemical reaction mechanism, can work for most gaseous fuel/oxidant mixtures. Ethane-air, methane-air, syngas-air and acetylene-oxygen mixtures, seeded with solid carbon particles, were used. Variation in flow properties were obtained for both the unburned and burned regions. The temperature levels observed in the burned region supports the previous statement regarding high thermal energy generation. The flame structure of the detonation wave region was studied. To study the effect of radiative heating in the unburned upstream region, appropriate emissivity and absorptivity models from literature were used. Carbon particles have a significant role in the upstream side, and as the results reveal, they have a relatively higher heat absorbing capacity than the gaseous components. A study of the amount of burned gas considered represented by the path length in evaluating the amount of heat radiated was also done to understand its effect on the upstream side."--Abstract, page iv.

Download or read book Detonation in Spatially Inhomogeneous Media written by XiaoCheng Mi and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Detonation propagation in a compressible medium wherein the energy release has been made spatially inhomogeneous is examined via numerical simulations. The inhomogeneity is introduced via concentrating reactive material into regions which are separated by inert gaps while maintaining the same average energy density. The propagation velocity and propagation limit of detonation waves under the influence of these imposed inhomogeneities are put to a rigorous examination.Spatial inhomogeneities are introduced to adiabatic detonation systems with a hierarchy of complexities. In a system governed by one-dimensional Euler equations with a simplified mechanism of instantaneous energy deposition, i.e., a source triggered by the passage of leading shock after a prescribed delay time, the resulting averaged propagation speed over hundreds of spatially discrete sources is compared to the ideal Chapman-Jouguet (CJ) speed for an equivalent amount of energy release. Velocities in excess of the CJ speed are found as the reactive regions are made increasingly discrete, with deviation above CJ being as great as 15%. The deviation above the CJ value increases with decreasing values of specific heat ratio [gamma]. When the sources are sufficiently spread out so as to make the energy release of the media nearly continuous, the classic CJ solution is obtained for the average wave speed. In the limit of highly discrete sources, time-averaged mean wave structure shows that the effective sonic surface does not correspond to an equilibrium state. The average state of the flow leaving the wave in this case does eventually reach the equilibrium Hugoniot, but only after the effective sonic surface has been crossed. Thus, the super-CJ waves observed in the limit of highly discretized sources can be understood as weak detonations due to the non-equilibrium state at the effective sonic surface. The investigation on how detonation velocity is influenced by the presence of spatial inhomogeneities is then extended to one- and two-dimensional systems with a more realistic mechanism of energy release, i.e., single-step Arrhenius kinetics. In the case of sufficiently inhomogeneous media wherein the spacing between the reactive zones is greater than the inherent reaction zone length, average wave speeds significantly greater than the corresponding CJ speed of the homogenized medium are obtained. If the shock transit time between reactive zones is less than the reaction time scale, then the classical CJ detonation velocity is recovered. The super-CJ wave propagation is also identified in the cases with a two-dimensional arrangement of spatial inhomogeneities. The correspondence of the super-CJ behavior identified in this study with real detonation phenomena that may be observed in experiments is discussed. Finally, a random distribution of spatially discrete sources is implemented into a two-dimensional detonation system confined by an inert, compressible layer of gas. In this system, detonation waves experience losses due to lateral expansion behind a curved shock front and, thus, propagate at a velocity lower than the ideal CJ velocity. As the thickness of the reactive layer within the confinement decreases, the deficit in propagation velocity increases; below a critical thickness, detonations can no longer propagate in a self-sustained manner. The critical thickness for a steady propagation is determined for a homogeneous reactive medium and a mixture with randomly distributed, discrete reactive sources. The simulation results show that, for a sufficiently high activation energy, the spatial inhomogeneities assist a detonation wave to propagate beyond the limit that is encountered in a homogeneous reactive medium. This enhancing effect of the spatial inhomogeneities on the near-limit propagation of detonation waves is found to be more pronounced with increasing activation energy." --

Download or read book Numerical Modelling of One dimensional Discrete Source Detonation written by Mehshan Javaid and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessment of Numerical Issues in One dimensional Detonation Wave Representation written by Ramanan Sankaran and published by . This book was released on 2000 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Numerical Computation of One dimensional Detonation Waves written by Adriaan Cornelis Berkenbosch and published by . This book was released on 1994 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Detonation and Two Phase Flow written by S Penner and published by Elsevier. This book was released on 2012-12-02 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress in Astronautics and Rocketry, Volume 6: Detonation and Two-Phase Flow compiles technical papers presented at the ARS Propellants, Combustion, and Liquid Rockets Conference held in Palm Beach, Florida on April 26-28, 1961. This book provides an excellent illustration of research and development on a selected group of problems relating to detonations, two-phase nozzle flow, and combustion in liquid fuel rocket engines. This volume is divided into two parts. Part 1 covers the entire range of physical conditions under which detonation may be initiated or sustained, such as high explosives, solid propellants, liquid sprays, and gases. Experimental and theoretical studies are also discussed, including the significant progress of the basic phenomena involved in transition from deflagration to detonation, and nature of stable detonations in dilute sprays and other systems. The perennial problems associated with high frequency instabilities in liquid fuel rocket engines are considered in Part 2. This publication is valuable to students and investigators working in the field of propulsion research and development.

Download or read book An Experimental Investigation of the Possibility of Achieving a Standing Detonation Wave written by J. A. Nicholis and published by . This book was released on 1959 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Toward Detonation Theory written by Anatoly N. Dremin and published by Springer Science & Business Media. This book was released on 1999-06-04 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is known that the Chapman-Jouguet theory of detonation is based on the assumption of an instantaneous and complete transformation of explosives into detonation products in the wave front. Therefore, one should not expect from the theory any interpretations of the detonation limits, such as shock initiation of det onation and kinetic instability and propagation (failure diameter). The Zeldovich-Von Neuman-Doring (ZND) theory of detonation appeared, in fact, as a response to the need for a theory capable of interpreting such limits, and the ZND detonation theory gave qualitative interpretations to the detonation limits. These interpretations were based essentially on the theoretical notion that the mechanism of explosives transformation at detonation is a combustion of a layer of finite thickness of shock-compressed explosive behind the wave shock front with the velocity of the front. However, some experimental findings turned out to be inconsistent with the the ory. A very small change of homogeneous (liquid) explosives detonation velocity with explosive charge diameter near the rather sizable failure diameter is one of the findings. The elucidation of the nature of this finding has led to the discovery of a new phenomenon. This phenomenon has come to be known as the breakdown (BD) of the explosive self-ignition behind the front of shock waves under the effect of rarefaction waves.

Download or read book Gaseous Detonations written by M.A. Nettleton and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: My introduction to the fascinating phenomena associated with detonation waves came through appointments as an external fellow at the Department of Physics, University College of Wales, and at the Department of Mechanical Engineering, University of Leeds. Very special thanks for his accurate guidance through the large body of information on gaseous detonations are due to Professor D. H. Edwards of University College of Wales. Indeed, the onerous task of concisely enumerating the key features of unidimensional theories of detonations was undertaken by him, and Chapter 2 is based on his initial draft. When the text strays to the use of we, it is a deserved acknow ledgement of his contribution. Again, I should like to thank Professor D. Bradley of Leeds University for his enthusiastic encouragement of my efforts at developing a model of the composition limits of detonability through a relationship between run-up distance and composition of the mixture. The text has been prepared in the context of these fellowships, and I am grateful to the Central Electricity Generating Board for its permission to accept these appointments.

Download or read book One Dimensional Detonation Wave Stability Analysis written by Ali Hassan Omar and published by . This book was released on 1992 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Simulations of Gas Phase Detonations written by and published by . This book was released on 1980 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed numerical simulations of supersonic reactive flow and gas phase detonation problems are very expensive due to their computer time and memory requirements. The bulk of this cost is in integrating the ordinary differential equations describing chemical reactions. A global induction parameter model has thus been developed which describes the chemical induction time of a mixture and allows for release of energy over a finite time period. The specific gases for which it has been calibrated are stoichiometric mixtures of hydrogen and methane in air. The relatively inexpensive induction parameter model is then used in time-dependent one- and two-dimensional simulations of supersonic reactive flows. (Author).

Download or read book Effects of fuel distribution on detonation tube performance written by and published by DIANE Publishing. This book was released on with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Gaseous Detonation Physics and Its Universal Framework Theory written by Zonglin Jiang and published by Springer Nature. This book was released on 2022-12-16 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights the theories and research progress in gaseous detonation research, and proposes a universal framework theory that overcomes the current research limitations. Gaseous detonation is an extremely fast type of combustion that propagates at supersonic speed in premixed combustible gas. Being self-sustaining and self-organizing with the unique nature of pressure gaining, gaseous detonation and its gas dynamics has been an interdisciplinary frontier for decades. The research of detonation enjoyed its early success from the development of the CJ theory and ZND modeling, but phenomenon is far from being understood quantitatively, and the development of theories to predict the three-dimensional cellular structure remains a formidable task, being essentially a problem in high-speed compressible reacting flow. This theory proposed by the authors’ research group breaks down the limitation of the one-dimensional steady flow hypothesis of the early theories, successfully correlating the propagation and initiation processes of gaseous detonation, and realizing the unified expression of the three-dimensional structure of cell detonation. The book and the proposed open framework is of high value for researchers in conventional applications such as coal mine explosions and chemical plant accidents, and state-of-the-art research fields such as supernova explosion, new aerospace propulsion engines, and detonation-driven hypersonic testing facilities. It is also a driving force for future research of detonation.

Download or read book A Numerical Study of Overdriven Detonation Waves written by Balu Sekar and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulations of One dimensional Detonation Waves Using a Total Variation Diminishing Scheme written by Ryan Edward Pfeiffer and published by . This book was released on 1998 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Numerical Study of Oblique Detonation Wave Combustion written by Brent Steven Green and published by . This book was released on 1995 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book One dimensional Dense Fluid Detonation written by Mohamed Safwat I. Abdelazim and published by . This book was released on 1982 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: