Download or read book A Theoretical Analysis of the Effect of Surfactant on the Hydrodynamics and Mass Transfer from Spherical and Spherical cap Bubbles written by Shu-Lun Wong and published by . This book was released on 1991 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Theoretical Study of Bubble Motion in Surfactant Solutions written by Yanping Wang and published by . This book was released on 1999 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: We examine the effect of surfactants on a spherical gas bubble rising steadily in an infinite fluid at low and order one Reynolds number with order one and larger Peclet numbers. Our mathematical model is based on the Navier-Stokes equations coupled with a convection-diffusion equation together with appropriate interfacial conditions. The nonlinearity of the equations and boundary conditions, and the coupling between hydrodynamics and surfactant transport make the problem very challenging. When a bubble rises in a fluid containing surface-active agents, surfactant adsorbs onto the bubble surface at the leading edge, convects to the trailing edge by the surface flow and desorbs into the bulk along the interface. This adsorption develops a surface concentration gradient on the interface that makes the surface tension at the back end relatively lower than that at the front end, and thus retards the bubble velocity. Because of surfactant impurities unavoidably present in materials, this retardation can cause a problem in materials processing in space and glass processing when bubbles are created during chemical reactions. Thus the study of how to remobilize (remove the surfactant gradient on the surface) the bubble surface becomes necessary. Many studies have been done on this retarding effects of the surfactant on a moving bubble. However, most were focused on the retarding effect due to a trace amount of surfactant, in which case the bubble velocity monotonically decreases as the bulk concentration increases. The question of how to remobilize the bubble surface remains unanswered. In this work, we will show that the bubble velocity can be controlled by remobilizing the bubble interface using the surfactant concentration. This technique not only can be used to maximize the bubble velocity, but also can be used to maximize mass transfer on purifying materials and extracting materials from mixtures. In the first part of the work, we illustrate numerically that the bubble interface can be remobilized by increasing the bulk concentration of surfactant, for any fixed Peclet number, at low Reynolds number. For any fixed bulk concentration, the bubble velocity decreases with increasing Peclet number. The larger the Peclet number is the larger the required bulk concentration needed to bring the velocity back to the clean surface value. In the second part of the work, we will show that the remobilization still remains effective for order one Reynolds numbers. Moreover, when the rate of convection on the surface is much larger than the rate of diffusion at the back end, a stagnant cap develops near the back stagnation point that makes the bubble surface there act like a solid boundary. Wakes form at higher Reynolds numbers that drastically reduce the terminal velocity, and disappear as the bubble interface remobilizes. Finally, we consider the problem analytically for asymptotically large Peclet numbers. When the Peclet number is very large, a stagnant cap forms at the back end which makes one part of the bubble surface clean of surfactant, and the other part completely immobile. Also boundary layers develop along the bubble surface with different thicknesses on the clean part of the surface and on the stagnant cap. The asymptotic structures are obtained and the governing equations posed and partly addressed numerically and analytically.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1992 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Separation Process Technology written by Ronald W. Rousseau and published by John Wiley & Sons. This book was released on 1987-05-13 with total page 1028 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surveys the selection, design, and operation of most of the industrially important separation processes. Discusses the underlying principles on which the processes are based, and provides illustrative examples of the use of the processes in a modern context. Features thorough treatment of newer separation processes based on membranes, adsorption, chromatography, ion exchange, and chemical complexation. Includes a review of historically important separation processes such as distillation, absorption, extraction, leaching, and crystallization and considers these techniques in light of recent developments affecting them.
Download or read book Particles Bubbles Drops written by Efstathios Michaelides and published by World Scientific. This book was released on 2006 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of multiphase flows has grown by leaps and bounds in the last thirty years and is now regarded as a major discipline. Engineering applications, products and processes with particles, bubbles and drops have consistently grown in number and importance. An increasing number of conferences, scientific fora and archived journals are dedicated to the dissemination of information on flow, heat and mass transfer of fluids with particles, bubbles and drops. Numerical computations and "thought experiments" have supplemented most physical experiments and a great deal of the product design and testing processes. The literature on computational fluid dynamics with particles, bubbles and drops has grown at an exponential rate, giving rise to new results, theories and better understanding of the transport processes with particles, bubbles and drops. This book captures and summarizes all these advances in a unified, succinct and pedagogical way. Contents: Fundamental Equations and Characteristics of Particles, Bubbles and Drops; Low Reynolds Number Flows; High Reynolds Number Flows; Non-Spherical Particles, Bubbles and Drops; Effects of Rotation, Shear and Boundaries; Effects of Turbulence; Electro-Kinetic, Thermo-Kinetic and Porosity Effects; Effects of Higher Concentration and Collisions; Molecular and Statistical Modeling; Numerical Methods-CFD. Key Features Summarizes the recent important results in the theory of transport processes of fluids with particles, bubbles and drops Presents the results in a unified and succinct way Contains more than 600 references where an interested reader may find details of the results Makes connections from all theories and results to physical and engineering applications Readership: Researchers, practicing engineers and physicists that deal with any aspects of Multiphase Flows. It will also be of interest to academics and researchers in the general fields of mechanical and chemical engineering.
Download or read book Bubbles Drops and Particles written by R. Clift and published by Courier Corporation. This book was released on 2013-04-22 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume offers a unified treatment and critical review of the literature related to the fluid dynamics, heat transfer, and mass transfer of single bubbles, drops, and particles. 1978 edition.
Download or read book Thermo fluid Dynamics of Two Phase Flow written by Mamoru Ishii and published by Springer Science & Business Media. This book was released on 2006-09-28 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book has been written for graduate students, scientists and engineers who need in-depth theoretical foundations to solve two-phase problems in various technological systems. Based on extensive research experiences focused on the fundamental physics of two-phase flow, the authors present the detailed theoretical foundation of multi-phase flow thermo-fluid dynamics as they apply to a variety of scenarios, including nuclear reactor transient and accident analysis, energy systems, power generation systems and even space propulsion.
Download or read book Theoretical Chemical Engineering Abstracts written by and published by . This book was released on 1986 with total page 954 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Methods for Complex Liquid Fluid Interfaces written by Mohammad Taeibi Rahni and published by CRC Press. This book was released on 2015-11-11 with total page 549 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 example
Download or read book The Structure of the Wake Behind Spherical Cap Bubbles and Its Relation to the Mass Transfer Mechanism written by Joannes Henricus Cornelus Coppus and published by . This book was released on 1977 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental and Computational Study of Hydrodynamics and Mass Transfer in Gas liquid Bubble Columns written by Houman Shirzadi and published by . This book was released on 2012 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bubble Wake Dynamics in Liquids and Liquid Solid Suspensions written by Liang-Shih Fan and published by Butterworth-Heinemann. This book was released on 1990-08-21 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is devoted to a fundamental understanding of the fluid dynamic nature of a bubble wake, more specifically the primary wake, in liquids and liquid-solid suspensions, an dto the role it plays in various important flow phenomena of multiphase systems. Examples of these phenomena are liquid/solids mixing, bubble coalescence and disintergration, particle entrainment to the freeboard, and bed contraction.
Download or read book Bubble Dynamics and Interface Phenomena written by John R. Blake and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains papers presented at the IUTAM Symposium on Bubble Dynamics and Interface Phenomena held at the University of Birmingham from 6-9 September 1993. In many respects it follows on a decade later from the very successful IUTAM Symposium held at CALTECH in June 1981 on the Mechanics and physics of bubbles in liquids which was organised by the late Milton Plesset and Leen van Wijngaarden. The intervening period has seen major development with both experiment and theory. On the experimental side there have been ad vances with very high speed photography and data recording that provide detailed information on fluid and interface motion. Major developments in both computer hardware and software have also led to extensive improvement in our understand ing of bubble and interface dynamics although development is still limited by the sheer complexity of the laminar and turbulent flow regimes often associated with bubbly flows. The symposium attracts wide and extensive interest from engineers, physical, chemical, biological and medical scientists and applied mathematicians. The sci entific committee sought to achieve a balance between theory and experiment over a range of fields in bubble dynamics and interface phenomena. It was our intention to emphasise both the breadth and recent developments in these various fields and to encourage cross-fertilisation of ideas on both experimental techniques and theo retical developments. The programme, and the proceedings recorded herein, cover bubble dynamics, sound and wave propagation, bubbles in flow, sonoluminescence, acoustic cavitation, underwater explosions, bursting bubbles and ESWL.
Download or read book Bubbly Flows written by Martin Sommerfeld and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Bubble Hydrodynamics and Mass Transfer in Complex Media written by Feishi Xu and published by . This book was released on 2019 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: The knowledge on the hydrodynamic property and mass transfer of bubbles is important since it will give guidelines for selecting the operation condition and for reactor design in such processes. For this purpose, this PhD manuscript has implemented an experimental investigation of single air bubbles rising in various polymer solutions (Breox, Polyacrylamide (PAAm) and Xanthan gum) which can simulate the property of the sewage. The works can divided into three parts: Firstly, with a review of the current visualization techniques for mass transfer, three techniques have been tested for air bubble (equivalent diameter ≈ 1 mm) rising in water including traditional Planar Laser Induced Fluorescent (PLIF, dye: fluorescent resorufin), Fluorescent quenching technique (PLIF with Inhibition, dye: ruthenium complex) and colorimetric techniques (dye: pink resorufin), respectively. Secondly, based on images captured by a high speed camera, the hydrodynamics of the bubble single air bubbles (equivalent diameters: 0.7-7 mm) rising in the polymer solutions (PAAm and Xanthan) have been investigated including the bubble velocity, trajectory and bubble shape. Finally, based on PLIF-I technique, the mass transfer and diffusion phenomena in the wake of single air bubbles (equivalent diameter ≈ 1 mm) rising in various aqueous polymer solutions (PAAm and Breox) are investigated.
Download or read book The Acoustic Response of a Spherical Bubble written by R. S. Bernard and published by . This book was released on 1972 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The case of a spherical gas bubble surrounded by a slightly compressible inviscid fluid is considered. Steady-state response to a plane pressure wave train is found, and the effect of nonlinearity is determined.
Download or read book Computer Model written by Gerald Lum Sing and published by . This book was released on 1976 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mass transfer from single rising gas bubbles is generally studied by taking motion pictures of the rising bubbles and analyzing the film for the instantaneous mass transfer coefficient. In this study, a different approach was taken for the analysis of mass transfer. This analysis solved the simultaneous differential equations describing mass transfer by numerical techniques. The computer model developed is restricted to pure single gas bubbles in water, with diameters in the size range 0.01 ≤ diameter ≤ 0.30 cm. Given a bubble's initial diameter and height of water over the bubble, the model predicts the bubble's position and moles of gas present in the bubble at any other time. The bubble rise velocity was calculated by considering a force balance on a spherical bubble and used theoretical values of drag coefficients based on a sphere. Correlations presented by Hamerton and Garner, Frossling, and Weiner were used to solve for KL, the convective mass transfer coefficient. The time dependent behavior of KL, attributed to the accumulation of surface active agents at the rising bubble's interface, was accounted for by the development of a bubble age parameter, termed critical time. The differential equations were solved by a Runge-Kutta-Merson routine, and the model applied to a carbon dioxide-water system. The results were compared to data collected in the investigations of Deindoerfer, Garbarini, and Datta. The computer predictions, with the inclusion of the critical time parameter, corresponded closely to data presented by the three investigators. The model, without the critical time parameter, predicted mass transfer rates much higher than those presented in the three investigations. The model was extended to pure oxygen-water and air-water systems to aid in the modeling of gas dispersion equipment used in aeration ponds. Predictions indicate that the initial bubble diameter has a significant role on the overall mass transfer.
