Transport Processes At Taylor Bubbles In Vertical Channels

Gas / liquid contact apparatuses are widely used in chemical, biochemical or pharmaceutical industry to provide and transfer gas species as reactant from the gaseous phase to pre-dissolved reactants in the liquid phase enabling a preferred reaction. The global and local transport are complex interlinked processes and therefore in practice in reactor design industry, mostly empirically correlated. For a secure control of the overall process and a more efficient reactor design, the local transport processes at gas / liquid interfaces need to be investigated in complexity reduced systems to be understood. Elongated bubbles, Taylor bubbles, in vertical channels 5.5 < D < 8 mm overcome the problem of dynamic shape deformation, complex 3D rise trajectories and they have a volume independent rise velocity, which make them the ideal experiment for reliable and reproducible investigations. Detailed optical measurements of global and local processes via high-speed Shadowgraphy, 2D2C PIV and p-2D LIF give new insights into the dependency of local bubble shape and global terminal rise velocity, establish a Sherwood correlation of shrinking CO2 bubbles in various channel sizes and shows the coupling of local transport phenomena at the bubble interface and the mixing in the wake region.

There are several physico-chemical processes that determine the behavior of multiphase fluid systems – e.g., the fluid dynamics in the different phases and the dynamics of the interface(s), mass transport between the fluids, adsorption effects at the interface, and transport of surfactants on the interface – and result in heterogeneous interface properties. In general, these processes are strongly coupled and local properties of the interface play a crucial role. A thorough understanding of the behavior of such complex flow problems must be based on physically sound mathematical models, which especially account for the local processes at the interface. This book presents recent findings on the rigorous derivation and mathematical analysis of such models and on the development of numerical methods for direct numerical simulations. Validation results are based on specifically designed experiments using high-resolution experimental techniques. A special feature of this book is its focus on an interdisciplinary research approach combining Applied Analysis, Numerical Mathematics, Interface Physics and Chemistry, as well as relevant research areas in the Engineering Sciences. The contributions originated from the joint interdisciplinary research projects in the DFG Priority Programme SPP 1506 “Transport Processes at Fluidic Interfaces.”

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.

Describes the advances in the transport phenomena of particles, drops and bubbles in complex fluids. This book contains contributions from experts in areas such as particle deposition in membranes, flow of granular mixtures, food suspensions, foams, electro kinetic and thermo capillary driven flows, and two-phase flows.

Microfluidics represent great potential for chemical processes design, development, optimization, and chemical engineering bolsters the project design of industrial processes often found in large chemical plants. Together, microfluidics and chemical engineering can lead to a more complete and comprehensive process. Process Analysis, Design, and Intensification in Microfluidics and Chemical Engineering provides emerging research exploring the theoretical and practical aspects of microfluidics and its application in chemical engineering with the intention of building pathways for new processes and product developments in industrial areas. Featuring coverage on a broad range of topics such as design techniques, hydrodynamics, and numerical modelling, this book is ideally designed for engineers, chemists, microfluidics and chemical engineering companies, academicians, researchers, and students.

Computational Methods for Complex Liquid-Fluid Interfaces highlights key computational challenges involved in the two-way coupling of complex liquid-fluid interfaces. The book covers a variety of cutting-edge experimental and computational techniques ranging from macro- to meso- and microscale approaches (including pivotal applications). As examples, the text: defines the most important interfacial quantities and their experimental investigations, providing theoretical background and detailed solutions, describes vital techniques used in interfacial flow problems, such as modern meshless numerical methods and conventional computational fluid dynamics methods, and discusses the technicalities of correctly using the computational methods developed for interfacial flows, as well as the simulation of interesting interfacial flow physics. Edited and authored by leading scientists and researchers, Computational Methods for Complex Liquid-Fluid Interfaces offers an authoritative and state-of-the-art overview of computational methodologies and simulation techniques for the quantification of interfacial quantities.

The design of chemical reactors and their safety are as critical to the success of a chemical process as the actual chemistry taking place within the reactor. This book provides a comprehensive overview of the practical aspects of multiphase reactor design and operation with an emphasis on safety and clean technology. It considers not only standard operation conditions, but also the problems of runaway reaction conditions and protection against ensuing over-pressure. Hydrodynamics of Multiphase Reactors addresses both practical and theoretical aspects of this topic. Initial chapters discuss various different types of gas/liquid reactors from a practical viewpoint, and later chapters focus on the modelling of multiphase systems and computational methods for reactor design and problem solving. The material is written by experts in their specific fields and will include chapters on the following topics: Multiphase flow, Bubble columns, Sparged stirred vessels, Macroscale modelling, Microscale modelling, Runaway conditions, Behaviour of vessel contents, Choked flow, Measurement techniques.

Microchannel Heat transfer is the cooling application of high power density microchips in the CPU system, micropower systems and many other large scale thermal systems requiring effective cooling capacity. This book offers the latest research and recommended models on the microsize cooling system which not only significantly reduces the weight load, but also enhances the capability to remove much greater amount of heat than any of large scale cooling systems. A detailed reference in microchannel phase change (boiling and condensation) including recommended models and correlations for various requirements such as pressure loss, and heat transfer coefficient. Researchers, engineers, designers and students will benefit from the collated, state-of-the-art of the research put together in this book and its systematic, addressing all the relevant issues and providing a good reference for solving problems of critical analysis. Up-to-date information will help delineate further research direction in the microchannel heat transfer The latest modeling information and recommendations will help in design method and purpose