Bubbly Flows

The book summarises the outcom of a priority research programme: 'Analysis, Modelling and Computation of Multiphase Flows'. The results of 24 individual research projects are presented. The main objective of the research programme was to provide a better understanding of the physical basis for multiphase gas-liquid flows as they are found in numerous chemical and biochemical reactors. The research comprises steady and unsteady multiphase flows in three frequently found reactor configurations, namely bubble columns without interiors, airlift loop reactors, and aerated stirred vessels. For this purpose new and improved measurement techniques were developed. From the resulting knowledge and data, new and refined models for describing the underlying physical processes were developed, which were used for the establishment and improvement of analytic as well as numerical methods for predicting multiphase reactors. Thereby, the development, lay-out and scale-up of such processes should be possible on a more reliable basis.

This book presents experimental and numerical methods that have been developed during six years of targeted research within the DFG priority program SPP 1740, elucidating the interaction between hydrodynamics, mass transfer and transport as well as chemical reactions in bubbly flows. A special feature of this book is its focus on an interdisciplinary research approach with contributions from chemistry, mathematics and engineering sciences, providing enhanced or novel experimental methods, models and numerical simulations. This book provides fundamental knowledge to students about the current state of knowledge regarding transport processes in reactive bubbly flows as well as to scientists, emphasizing pressing research questions and further current demands for fundamental research. Engineers from the chemical industries will get valuable insights into relevant gas-liquid processes and benefit from recommendations concerning the design of gas-liquid reactors and laboratory experiments for studying the performance of gas-liquid reactions in their own lab.

Cavitation and Bubble Dynamics deals with fundamental physical processes of bubble dynamics and cavitation for graduate students and researchers.

In various branches of fluid mechanics, our understanding is inhibited by the presence of turbulence. Although many experimental and theoretical studies have significantly helped to increase our physical understanding, a comp- hensive and predictive theory of turbulent flows has not yet been established. Therefore, the prediction of turbulent flow relies heavily on simulation stra- gies. The development of reliable methods for turbulent flow computation will have a significant impact on a variety of technological advancements. These range from aircraft and car design, to turbomachinery, combustors, and process engineering. Moreover, simulation approaches are important in materials - sign, prediction of biologically relevant flows, and also significantly contribute to the understanding of environmental processes including weather and climate forecasting. The material that is compiled in this book presents a coherent account of contemporary computational approaches for turbulent flows. It aims to p- vide the reader with information about the current state of the art as well as to stimulate directions for future research and development. The book puts part- ular emphasis on computational methods for incompressible and compressible turbulent flows as well as on methods for analysing and quantifying nume- cal errors in turbulent flow computations. In addition, it presents turbulence modelling approaches in the context of large eddy simulation, and unfolds the challenges in the field of simulations for multiphase flows and computational fluid dynamics (CFD) of engineering flows in complex geometries. Apart from reviewing main research developments, new material is also included in many of the chapters.

Mixed or multiphase flows of solid/liquid or solid/gas are commonly found in many industrial fields, and their behavior is complex and difficult to predict in many cases. The use of computational fluid dynamics (CFD) has emerged as a powerful tool for the understanding of fluid mechanics in multiphase reactors, which are widely used in the chemical, petroleum, mining, food, beverage and pharmaceutical industries. Computational Techniques for Multiphase Flows enables scientists and engineers to the undertand the basis and application of CFD in muliphase flow, explains how to use the technique, when to use it and how to interpret the results and apply them to improving aplications in process enginering and other multiphase application areas including the pumping, automotive and energy sectors. Understandable guide to a complex subject Important in many industries Ideal for potential users of CFD

This book develops an analysis of the air entrainment processes in free-surface flows. These flows are investigated as homogeneous mixtures with variable density. Several types of air-water free-surface flows are studied: plunging jet flows, open channel flows, and turbulent water jets discharging into air. Experimental observations reported by the author confirm the concept that the air-water mixture behaves as a homogeneous compressible fluid in each case. This book will be of great interest to professionals working in many fields of engineering: chemical, civil, environmental, mechanical, mining, metallurgy, and nuclear. Covers new information on the air-water flow field: air bubble distributions, air-water velocity profiles, air bubble sizes and bubble-turbulence interactions Features new analysis is developed for each flow configuration and compared successfully with model and prototype data Includes over 372 references and more than 170 figures with over 60 photographs Presents useful information for design engineers and research-and-development scientists who require a better understanding of the fluid mechanics of air-water flows