Download or read book Differential Diffusion in a Turbulent Jet written by Thomas Michael Lavertu and published by . This book was released on 2006 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Also presented are the first experimental measurements of the spectrum of the normalized concentration difference, EZ(K1 eta). These revealed the scales at which differential diffusion manifests itself. In all instances, these spectra were observed to decrease with wavenumber over all wavenumbers, consistent with a flow dominated by the decay of its scalar field. Although differential diffusion effects are molecular in origin, they persist at scales larger than the Kolmogorov scale." --

Download or read book Turbulent Diffusion in Liquid Jets written by and published by . This book was released on 1974 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Differential Diffusion on Flame Stabilization in a Syngas Jet in Turbulent Cross flow written by and published by . This book was released on 2015 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Differential Diffusion Effects in Turbulent Hydrogen Jet Flame Using Conditional Moment Closure Method written by Man Ching Ma and published by . This book was released on 2014 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of differential diffusion in the numerical modelling of a turbulent non-premixed hydrogen-air jet flame using a Conditional Moment Closure (CMC) method are investigated. The CMC calculations, which are coupled with computational fluid dynamics (CFD) calculations, relax the commonly used assumption of equal species mass diffusivities. The focus is on the predictions of species mass fractions and temperatures, especially the production of NO. The results of the calculations are compared with available experimental measurements. The formulation of the CMC species transport equation including differential diffusion is presented and the closure of the terms are discussed. Further, the CMC equation for conditional enthalpy is also derived in the present study. The implementation of the CMC equations using two dimensional finite volume method is discussed, including a presentation of the discretised forms of the equations. The results of the CMC calculations including the effects of differential diffusion show that NO mass fractions are increased from the large underpredictions observed for equal diffusivity results near the jet nozzle. Improvements are also found for other species such as H2 and H2O. The results show physical behaviours, such as a shift in the location of the reaction zone and increased reaction rates due to increased diffusion rates of H2. It is also found that differential diffusion effects persist downstream from the nozzle, where the effects are expected to be small, and reasons for the discrepancies are discussed in the present study. The profiles obtained from the CMC calculations show large radial variations, much larger than in equal diffusivity calculations. An analysis isolating the differential diffusion effects of various species shows that the largest changes occur due to the accounting for the differential diffusivity of H2. A budget of the terms in the CMC equations for the differentially diffusing chemical species and enthalpy is also investigated.

Download or read book Opposed Jet Turbulent Diffusion Flames written by Lawrence Talbot and published by . This book was released on 1990 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Diffusion in Submerged Circular Vertical Turbulent Water Jets with Density Difference Between the Jet and the Surrounding Water written by Gerrit Abraham and published by . This book was released on 1959 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamentals of Turbulent and Multiphase Combustion written by Kenneth Kuan-yun Kuo and published by John Wiley & Sons. This book was released on 2012-04-24 with total page 914 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed coverage of advanced combustion topics from the author of Principles of combustion, Second Edition Turbulence, turbulent combustion, and multiphase reacting flows have become major research topics in recent decades due to their application across diverse fields, including energy, environment, propulsion, transportation, industrial safety, and nanotechnology. Most of the knowledge accumulated from this research has never been published in book form—until now. Fundamentals of Turbulent and Multiphase Combustion presents up-to-date, integrated coverage of the fundamentals of turbulence, combustion, and multiphase phenomena along with useful experimental techniques, including non-intrusive, laser-based measurement techniques, providing a firm background in both contemporary and classical approaches. Beginning with two full chapters on laminar premixed and non-premixed flames, this book takes a multiphase approach, beginning with more common topics and moving on to higher-level applications. In addition, Fundamentals of Turbulent and Multiphase Combustion: Addresses seven basic topical areas in combustion and multiphase flows, including laminar premixed and non-premixed flames, theory of turbulence, turbulent premixed and non-premixed flames, and multiphase flows Covers spray atomization and combustion, solid-propellant combustion, homogeneous propellants, nitramines, reacting boundary-layer flows, single energetic particle combustion, and granular bed combustion Provides experimental setups and results whenever appropriate Supported with a large number of examples and problems as well as a solutions manual, Fundamentals of Turbulent and Multiphase Combustion is an important resource for professional engineers and researchers as well as graduate students in mechanical, chemical, and aerospace engineering.

Download or read book Turbulent Diffusion in Liquid Jets written by and published by . This book was released on 1974 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulence and Molecular Processes in Combustion written by T. Takeno and published by Elsevier. This book was released on 2012-12-02 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: An understanding of the intricacies in the turbulent combustion process may be a key to solving many of the current energy and environmental problems. The essential nature of turbulent combustion can be derived from the interaction between stochastic flow fluctuations and deterministic molecular processes, such as chemical reaction and transport processes. Undoubtedly, this is one of the most challenging fields of engineering science today, requiring as it does the interaction of scientists and engineers in the respective fields of chemical kinetics and fluid mechanics. The 28 papers in this volume review recent advances in these two disciplines providing new insights into the fundamental processes, addressing a great deal of recent progress. This progress ranges from descriptions of elementary chemical kinetics, to working those descriptions into combustion calculations with large numbers of elementary steps, to improved understanding of turbulent reacting flows and advances in simulations of turbulent combustion. The contributions will inspire further research on many fronts, advancing the understanding of combustion processes, as well as fostering a growing interdisciplinary cooperation.

Download or read book A DNS Study of Differential Diffusion in Nonpremixed Reacting Turbulent Flows Using a Generalized Burke Schumann Formulation written by Tamara Kaye Grimmett and published by . This book was released on 2001 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spectrums and Diffusion in a Round Turbulent Jet written by Stanley Corrsin and published by . This book was released on 1950 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a round turbulent jet at room temperature, measurement of the shear correlation coefficient as a function of frequency (through band-pass filters) has given a rather direct verification of Kolmogoroff's local-isotropy hypothesis.

Download or read book The Diffusion of Two Fluids of Different Density in a Homogeneous Turbulent Field written by Donald R. F. Harleman and published by . This book was released on 1959 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction: Industrial communities situated near large bodies of water or in drainage systems connected with such bodies dispose their waste water after treatment by dilution. Disposal by irrigation or evaporation after removing the solids by filtering, drying and incineration is justified in circumstances where the necessity outweighs the increased cost. However, comparatively few large industrial communities in the United States are situated away from either ocean, estuary, lake or river, so that the predominant form of ultimate waste water disposal is by dilution. In waste disposal by dilution a certain degree of primary treatment is usually required to reduce the concentrations of constituents that are toxic, odoriferous or otherwise chemically or physically detrimental or objectionable to human, animal or vegetable existence. Industrial and other wastes, varying widely in composition, coming from a diversity of establishments, such as dye or fertilizer factories, paper mills; primary treated sewage and supernatant liquor from digested sewage, radioactive waste products; wastes from hospitals, dairies, slaughter houses, etc., present different treatment problems and different standards for their effective disposal. After a sufficient time interval has elapsed following disposal, harmful chemicals will be oxidized to well below allowable levels, organic material digested by bacterial action, low level radioactive waste products; subjected to decay and a natural balance will be obtained. This can, however, be achieved only if the dilution process is aided by dispersion with currents due to winds and tidal action. Conversely, inadequate primary treatment or initial dilution can lead to widespread contamination by dispersion of harmful constituents endangering life. of property. The disposal of the water-borne waste products should be made in such, a fashion and at such regions in the body of water that tendencies for segregation of the influent will be minimized. The nature of the solution of this problem is twofold: (1) the achievement of optimum mixing characteristics with economical energy input at the disposal point, (2) the location of the disposal area in a region where hydrographic or oceanographic evidence indicates degrees of boundary shear, of wave and wind generated turbulence, and thermal or tidal convection currents that will continue the dispersion of the diluted effluent in order that concentrates would not tend to accumulate with passage of time or segregate into tidal backwaters or be absorbed by vegetation or soil on the shores. Allied problems, which have in most cases direct bearing on the flushing of disposal areas, are the salt water intrusion into river mouths and the fresh and salt water balance in tidal estuaries. Apart from the estuary flushing, there is also the consideration of contamination of public or industrial water supply intakes due to salinity intrusion. All of the problems mentioned above, in general terms, involve the mechanics of mass transfer according to the combined operation of turbulent diffusion and convection. Turbulent diffusion processes thus fall into two general categories. In the first, the turbulent diffusion is due entirely to the momentum of the diffusion which is being introduced into a quiescent diffusing medium: this process being governed by the mechanics of momentum and mass transfer in submerged turbulent jets. In the second category, the turbulent diffusion is due largely to the turbulent energy of the receiving fluid, the diffusion being introduced without materially increasing the turbulent activity at the region of introduction. In practice the ideal dilution process would be a combination of the two processes in the above sequence. The diffusing substance would be discharged with as high a momentum as practical into the receiving medium in the form of submerged jets, and the diffusion process in the vicinity of the disposal points would be entirely governed by the energy of introduction of the diffusion. At sufficiently large distances from its source the momentum of a jet would have decayed to levels comparable to the turbulence level in the receiving body of fluid. Further dispersion will occur according to mechanics of diffusion due to the turbulence in the receiving fluid body itself. (That is, if one considers momentarily turbulence as including all sizes of eddies present and hence also what would be customarily considered convection currents). The analysis will be simplified, however if it is considered that the motion of the fluid body consists of a field of homogeneous turbulence in which a convection pattern may be superimposed. With further simplification, the general problem may be made feasible for mathematical and experimental analysis in particular cases. Thus all of the above-enumerated disposal problems involve ultimately the mechanism of turbulent (eddy) diffusion which can accordingly be treated in two distinct parts.

Download or read book Laser Raman Scattering Measurements of Differential Molecular Diffusion in Turbulent Nonpremixed Jet Flames of H sub 2 CO sub 2 Fuel written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper explores effects of differential diffusion in nonpremixed turbulent jet flames. Pulsed Raman scattering spectroscopy is used to measure temperature and species concentrations in chemically reacting jets of H[sub 2]/CO[sub 2] into air, over a range of jet Reynolds numbers from 1,000 to 30,000 based on cold jet fluid properties. Results show significant effects of differential diffusion at all jet Reynolds numbers considered. Differential diffusion between H[sub 2] and C0[sub 2] produces differences between the hydrogen element mixture fraction ([xi][sub H]) and the carbon element mixture fraction ([xi][sub c]). The greatest effects occur on the rich side of stoichiometric, where [xi][sub H] is observed to be smaller than [xi][sub C] at all Reynolds numbers. Differential diffusion between H[sub 2] and H[sub 2]O creates a net flux of hydrogen element toward the stoichiometric contour and causes a local maximum in [xi]H that occurs near the stoichiometric condition. A differential diffusion variable [sup Z]H is defined as the difference between [xi][sub H] and [xi][sub C]. The variance Of [sup Z]H conditional on [xi][sub C] also shows that differential diffusion effects are greatest on the rich side of the flame. Conditional variances of [sup Z]H are largest at intermediate Reynolds numbers.

Download or read book Turbulent Diffusion in Liquid Jets written by Strong C. Chaung and published by . This book was released on 1974 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulent Combustion written by Norbert Peters and published by Cambridge University Press. This book was released on 2000-08-15 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: The combustion of fossil fuels remains a key technology for the foreseeable future. It is therefore important that we understand the mechanisms of combustion and, in particular, the role of turbulence within this process. Combustion always takes place within a turbulent flow field for two reasons: turbulence increases the mixing process and enhances combustion, but at the same time combustion releases heat which generates flow instability through buoyancy, thus enhancing the transition to turbulence. The four chapters of this book present a thorough introduction to the field of turbulent combustion. After an overview of modeling approaches, the three remaining chapters consider the three distinct cases of premixed, non-premixed, and partially premixed combustion, respectively. This book will be of value to researchers and students of engineering and applied mathematics by demonstrating the current theories of turbulent combustion within a unified presentation of the field.

Download or read book Turbulent Jets and Plumes written by Joseph Hun-wei Lee and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Jets and plumes are shear flows produced by momentum and buoyancy forces. Examples include smokestack emissions, fires and volcano eruptions, deep sea vents, thermals, sewage discharges, thermal effluents from power stations, and ocean dumping of sludge. Knowledge of turbulent mixing by jets and plumes is important for environmental control, impact and risk assessment. Turbulent Jets and Plumes introduces the fundamental concepts and develops a Lagrangian approach to model these shear flows. This theme persists throughout the text, starting from simple cases and building towards the practically important case of a turbulent buoyant jet in a density-stratified crossflow. Basic ideas are illustrated by ample use of flow visualization using the laser-induced fluorescence technique. The text includes many illustrative worked examples, comparisons of model predictions with laboratory and field data, and classroom tested problems. An interactive PC-based virtual-reality modelling software (VISJET) is also provided. Engineering and science students, researchers and practitioners may use the book both as an introduction to the subject and as a reference in hydraulics and environmental fluid mechanics.

Download or read book Laser Raman Scattering Measurements of Differential Diffusion in Non reacting and Reacting Laminar and Turbulent Jet Flows written by L. L. Smith and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: