Turbulent Mixing and Chemical Reactions


Book Description

Turbulent Mixing and Chemical Reactions Jerzy Ba???dyga, Warsaw University of Technology, Poland John R. Bourne, Visiting Professor, University of Birmingham, UK and Emeritus Professor, ETH Zurich, Switzerland The way in which reagents are mixed can greatly influence the yield and range of products formed by fast, multiple chemical reactions. Understanding this phenomenon enables chemists to carry out reactions more selectively, make better use of raw materials and simplify product workup and separation. Turbulent Mixing and Chemical Reactions presents a balanced treatment of the connection between mixing and reaction. It contains theoretical aspects, experimental methods and expected results as well as worked examples to illustrate problem solving. This book will be of interest to all scientists involved in chemical engineering, physical chemistry, and synthetic chemists in the fine chemical and pharmaceuticals industry.




Turbulence in Mixing Operations


Book Description

Turbulence in Mixing Operations: Theory and Application to Mixing and Reaction presents a summary of the current status of research on turbulent motion, mixing, and kinetics. Each chapter of this book discusses turbulence in the context of mixing and reaction in scalar fields. Chapters I and III discuss the classification of turbulent reacting systems and the different possibilities in this context. Chapter II reviews the properties of passive mixing. Chapter IV looks at turbulent mixing in chemically reactive flows. Chapter V uses different techniques to make parallel numerical calculations of both mixing and reaction. Finally, Chapter VI reviews turbulence and actual industrial mixing operations. This book will be of great value for chemical and industrial engineers, especially for those interested in turbulent and industrial mixing.




Chemical Reactions in Turbulent Mixing Flows


Book Description

This program focused on fundamental investigations of mixing, chemical-reaction, and combustion processes, in turbulent, subsonic, and supersonic free-shear flows. The program was comprised of an experimental effort; an analytical, modeling, and computational effort; and a diagnostics, instrumentation, and data-acquisition-development effort, with significant progress in each. With regard to gas-phase shear-layer mixing and combustion, effects of inflow/initial conditions, compressibility, and Reynolds number were experimentally investigated and, to a large extent, clarified. New measures to characterize level sets in turbulence were developed and successfully employed to characterize experimental data of liquid-phase turbulent-jet flows as well as three-dimensional direct-numerical-simulation data of Rayleigh-Taylor-instability flows. The computational effort has added to our understanding of the (H2+NO)/F2 chemical system employed in the shear-layer-mixing investigations as well as mixing in high-speed flows, along with further developments in Riemann-Invariant-Manifold gasdynamic simulation techniques and their application to unsteady detonation phenomena. On the diagnostic front, developments in digital imaging and Image Correlation Velocimetry have continued, and been used to investigate turbulent-jet mixing, the unsteady flow over an accelerating airfoil, to mitigate aliasing problems in the computer reconstruction of (2+1)-dimensional isosurface data, and in other applications.




Chemical Reactions in Turbulent Mixing


Book Description

The combustion facility (H2-F2) is now nearing completion. As of this writing, a high speed mixing layer has been realized in the test section, using high pressure air. This certifies the flow facility down to and including the test section. Preliminary results on the effect of high heat release in a turbulent mixing zone were obtained in the NO-O3 experiment. These results are consistent with predictions based on previously measured p.d.f, 's in non-reacting mixing layers, but in conspicuous disagreements with a variety of accepted model calculations. These results demonstrate again the important influence of the large scale coherent structures on chemical reactions in turbulent flows. The Laser Induced Fluorescence technique has now been extended to allow direct space and time resolved measurements of the reaction products. The first four channels of the multi-channel laser Doppler velocimetry system are essentially completed. The first experiments using this new development are expected in the course of this summer. Digital image analysis of particle streak photography has also been explored as a direct means of two-dimensional measurements of the velocity field in a plane. Finally, a prototype system using a 100 element acoustic detector array has been completed. Initial measurements with four of these channels using 300 kHz sound have been successfully made. (Author).







IUTAM Symposium on Turbulent Mixing and Combustion


Book Description

The goals of the Symposium were to draw together researchers in turbulence and combustion so as to highlight advances and challenge the boundaries to our understanding of turbulent mixing and combus tion from both experimental and simulation perspectives; to facilitate cross-fertilization between leaders in these two fields. These goals were noted to be important given that turbulence itself is viewed as the last great problem in classical physics and the addition of chemical reaction amplifies the difficulties enormously. The papers that have been included here reflect the richness of our subject. Turbulence is rich and complex in its own right. And, its inner structure, hidden in the morass of scales, large and small, can dominate transport. Earlier IUTAM Symposia have considered this field, Eddy Structure Identification in Free Turbulent Flows, Bonnet and Glauser (eds) 1992 and Simulation and Identification of Organized Structures in Flows, Sorensen, Hopfinger and Aubry (eds) 1997. The combustion community is well served by its specialized events, most notable is the bi annual International Combustion Symposium, held under the auspices of the Combustion Institute. Mixing is often considered somewhere in between these two. This broad landscape was addressed in this Sym posium in a somewhat temporal linear fashion of increasing complexity. The lectures considered the many challenges posed by adding one ele ment to the base formed by others: turbulence and turbulent mixing in the absence of combustion through to turbulent mixing dominated by chemistry and combustion.




Mixing of Liquids by Mechanical Agitation


Book Description

First published in 1985. Routledge is an imprint of Taylor & Francis, an informa company.




Effects of Turbulent Mixing on Chemical Reaction in an Aerosol-producing Co-flow Jet


Book Description

Investigates the effects of mixing on chemical reaction in a turbulent co-flow jet. After a jet is produced by a mixture of HCl (hydrogen chloride), air, and N2 (nitrogen) issuing from a pipe into a co-flowing stream of NH3 (gaseous ammonia) and air, a chemical reaction in which NH4Cl (ammonium chloride) aerosol with negligible heat release is produced. The product concentration field as marked by the aerosol is then characterized through the collection of data from which probability density functions can be constructed.




Turbulent Reactive Flows


Book Description

Turbulent reactive flows are of common occurrance in combustion engineering, chemical reactor technology and various types of engines producing power and thrust utilizing chemical and nuclear fuels. Pollutant formation and dispersion in the atmospheric environment and in rivers, lakes and ocean also involve interactions between turbulence, chemical reactivity and heat and mass transfer processes. Considerable advances have occurred over the past twenty years in the understanding, analysis, measurement, prediction and control of turbulent reactive flows. Two main contributors to such advances are improvements in instrumentation and spectacular growth in computation: hardware, sciences and skills and data processing software, each leading to developments in others. Turbulence presents several features that are situation-specific. Both for that reason and a number of others, it is yet difficult to visualize a so-called solution of the turbulence problem or even a generalized approach to the problem. It appears that recognition of patterns and structures in turbulent flow and their study based on considerations of stability, interactions, chaos and fractal character may be opening up an avenue of research that may be leading to a generalized approach to classification and analysis and, possibly, prediction of specific processes in the flowfield. Predictions for engineering use, on the other hand, can be foreseen for sometime to come to depend upon modeling of selected features of turbulence at various levels of sophistication dictated by perceived need and available capability.