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Use Of Lagrangian Methods To Describe Particle Deposition And Distribution In Dispersed Flows
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Book Synopsis Use of Lagrangian Methods to Describe Particle Deposition and Distribution in Dispersed Flows by : Jeffrey Louis Binder
Download or read book Use of Lagrangian Methods to Describe Particle Deposition and Distribution in Dispersed Flows written by Jeffrey Louis Binder and published by . This book was released on 1991 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental studies of the interchange processes in vertical gas-liquid annular flow by Leman (1985) and Schadel (1988) in this laboratory have been completed. This work defines the effect of pipe diameter, gas and liquid flow rates on deposition rates in air-water annular flow. An estimate of the droplet slip ratios has been obtained. This provides an improved correlation of measured deposition rates with droplet concentration. In addition droplet slip ratios are useful for correctly estimating the role of the droplets on the two phase pressure drop. An experimental test section has been developed to photograph the dispersed phase in vertical annular flow. The test section allows for end view or side view photographs to be taken. These photographs can provide information on drop size, concentration and velocity. Lagrangian methods have been developed in order to predict particle deposition and distribution in turbulent dispersed flows. The theoretical description developed here is restricted to dilute concentrations and particles with length scales of motion large compared to length scales characterizing non-homogeneities in the flow field. The method focuses on describing the behavior of instantaneous sources. Time dependent turbulent diffusion is considered. Fully developed fields are obtained from an appropriate distribution of ring sources. Specific applications have been made to gas-liquid annular flows and sediment transport. Application of the Lagrangian model to vertical annular flow provides an interpretation of measured deposition rates and concentration distributions that previously were not understood. Particle deposition constants are found to depend on one dimensionless parameter, $betatausb{rm Lf}$, that measures the ability of the particle to follow the gas phase turbulence. The model developed for vertical flows is extended to horizontal annular flows. Deposition is viewed to occur from two mechanisms operating in parallel. The first is due to the turbulence and second is due to gravitational settling. Particle deposition and concentration are found to depend on $betatausb{rm Lf}$ and a Froude number which measures the effect of gravitational settling on the particle. The model is useful for describing deposition measurements in gas-liquid annular flows in channels. The product of $betatausb{rm Lf}$ and the Froude number is found to define transitions from stratified, asymmetric and symmetric flow regimes. The model is also extended to describe sediment transport in channels. A situation is considered where the sand is viewed to enter the flow field from an erodible bed of sediment on the bottom of the channel. Eulerian models that have considered entrainment to be due to the turbulence and deposition to be due to settling have required using particle diffusivities larger than the fluid. This is explained by considering time dependent effects on the diffusion and settling velocities.
Book Synopsis Particles in Wall-Bounded Turbulent Flows: Deposition, Re-Suspension and Agglomeration by : Jean-Pierre Minier
Download or read book Particles in Wall-Bounded Turbulent Flows: Deposition, Re-Suspension and Agglomeration written by Jean-Pierre Minier and published by Springer. This book was released on 2016-07-26 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents an up-to-date review of turbulent two-phase flows with the dispersed phase, with an emphasis on the dynamics in the near-wall region. New insights to the flow physics are provided by direct numerical simuation and by fine experimental techniques. Also included are models of particle dynamics in wall-bounded turbulent flows, and a description of particle surface interactions including muti-layer deposition and re-suspension.
Book Synopsis Physics of Gas-Liquid Flows by : Thomas J. Hanratty
Download or read book Physics of Gas-Liquid Flows written by Thomas J. Hanratty and published by Cambridge University Press. This book was released on 2013-10-31 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unified theory of multiphase flows, providing tools for practical applications.
Book Synopsis Stochastic Lagrangian Modeling for Large Eddy Simulation of Dispersed Turbulent Two-Phase Flows by : Abdallah Sofiane Berrouk
Download or read book Stochastic Lagrangian Modeling for Large Eddy Simulation of Dispersed Turbulent Two-Phase Flows written by Abdallah Sofiane Berrouk and published by Bentham Science Publishers. This book was released on 2011 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the dispersion and the deposition of inertial particles convected by turbulent flows is a domain of research of considerable industrial interest. Inertial particle transport and dispersion are encountered in a wide range of flow configurations, whether they are of industrial or environmental character. Conventional models for turbulent dispersed flows do not appear capable of meeting the growing needs of chemical, mechanical and petroleum industries in this regard and physical environment testing is prohibitive. Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) ha.
Book Synopsis Solid-particles Deposition Through a Turbulent Impinging Jet Using Lattice Boltzmann Method by : Ali Abdulkadhim
Download or read book Solid-particles Deposition Through a Turbulent Impinging Jet Using Lattice Boltzmann Method written by Ali Abdulkadhim and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid particle distribution on an impingement surface has been simulated utilizing a graphical processing unit (GPU). An in-house computational fluid dynamics (CFD) code has been developed to investigate a 3D turbulent impinging jet using the lattice Boltzmann method (LBM) in conjunction with large eddy simulation (LES) and the multiple relaxation time (MRT) models. This work proposed an improvement in the LBM-cellular automata (LBM-CA) probabilistic method. In the current model, the fluid flow utilizes the D3Q19 LBM lattice model, while the particles movement employs the D3Q27 one. The particle numbers are defined at the same regular LBM (fluid) nodes, and the transport of particles from one node to its neighbouring nodes are determined in accordance with the particle bulk density and velocity by considering all the external forces. The previous CA models distribute particles at each time step without considering the local particles number and velocity at each node. The present model overcomes the deficiencies of the previous LBM-CA models and, therefore, can better capture the dynamic interaction between particles and the surrounding turbulent flow field. Despite increasing popularity of the LBM-MRT model in simulating complex multiphase fluid flows, this approach is still expensive in term of memory size and computational time required to perform 3D simulations. To improve the throughput of simulations, a single GeForce GTX TITAN X GPU is used in the present work. The CUDA parallel programming platform and the CuRAND library are utilized to form an efficient LBM-MRT-CA algorithm. The LBM-MRT fluid (i.e. no particles) model results were compared with two benchmark test cases ones. The first case is a turbulent free square jet, and the second one is a circular turbulent impinging jet for L/D=2 at Reynolds number equals to 25,000, where L is the nozzle-to-surface distance and D is the jet diameter. The LBM-CA simulation methodology was first validated against a benchmark test case involving particle deposition on a square cylinder confined in a duct. The flow was unsteady and laminar at Re=200 (Re is the Reynolds number), and simulations were conducted for different Stokes numbers. The GPU code was then used to simulate the particle transport and deposition in a turbulent impinging jet at Re=10,000. The effect of changing Stokes number on the particle deposition profile was studied at different L/D ratios, i.e. L/D=2, 4, and 6. The current model was finally used to simulate the particle impaction pattern from a circular jet for L/D=0.5, where the effect of changing Stokes and Reynolds numbers on the particle transport and deposition was examined. The present LBM-CA solutions agree well with other results available in the open literature. For comparative studies, another in-house serial CPU code was also developed, coupling LBM with the classical Lagrangian particle dispersion model. Agreement between results obtained with LBM-CA and LBM-Lagrangian models and the experimental data for the impinging jet case of L/D=0.5 is generally good, and the present LBM-CA approach on GPU achieves a speedup ratio of about 150 against the serial code running on a single CPU. Another new model was proposed to incorporate the solid particle phase effect (i.e. two-way coupling) on the fluid flow. The LMB-Lagrangian approach was used in this model to track solid particles in the computational domain. The solid particle phase was considered as a porous medium moving in the computational domain. The impact of the porous medium (i.e. the solid particle phase) on the fluid flow characteristics (e.g. fluid velocity) is a function of the particle phase volume fraction and velocity in the LBM. Particle-particle collision (i.e. four-way coupling) was also considered in this model by utilizing the discrete element method (DEM). This approach can numerically capture the multi-particle collision behaviours in dense particle suspension problems. This model data were compared with the numerical study ones for a single bubble injected in a fluidized bed, and the results of the bubble diameters at different injection velocity were in good agreement.
Book Synopsis Numerical modeling and simulation of particulate fouling on structured heat transfer surfaces using multiphase Eulerian-Lagrangian LES by : Robert Kasper
Download or read book Numerical modeling and simulation of particulate fouling on structured heat transfer surfaces using multiphase Eulerian-Lagrangian LES written by Robert Kasper and published by Cuvillier Verlag. This book was released on 2021-04-30 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: Durch die gezielte Strukturierung von wärmeübertragenden Oberflächen, wie beispielsweise durch Dellen oder Rippen, kann die örtliche Turbulenz und damit die thermische Durchmischung gesteigert werden. Dies kann die Effizienz von Wärmeübertragern oder Bauteilkühlsystemen erheblich erhöhen. Derartige Oberflächenstrukturrierungen begünstigen jedoch das Partikelfouling, daher die Ablagerung suspendierter Partikel, wie z.B. Sand, Schlamm oder Korrosionsprodukte. Gegenstand dieser Arbeit ist die Entwicklung eines universellen, numerischen CFD-Verfahrens zur Vorhersage des partikulären Foulings auf strukturierten Oberflächen, speziell Dellenoberflächen. Das entwickelte Verfahren basiert auf einer Kombination des Lagrangian-Particle-Trackings zur Beschreibung der dispersen Phase (Foulingpartikel), sowie räumlich und zeitlich aufgelöster Large-Eddy Simulation für die Berechnung der kontinuierlichen Phasen (Trägerfluid). Dieses Vorgehen ermöglicht nicht nur die Auswertung der infolge der Partikelablagerungen verminderten thermo-hydraulischen Effizienz, sondern auch die Untersuchung der Wechselwirkungen zwischen turbulenten Strömungsstrukturen und dem partikulärem Fouling. Dadurch kann gezeigt werden, dass die Verwendung von sphärischen Dellen als Oberflächenstrukturen nicht nur aus thermo-hydraulischer Sicht die optimale Wahl darstellt, sondern auch eine substantielle Verminderung des Partikelfoulings begünstigt. The application of structured heat transfer surfaces, such as dimples or ribs, increase the local turbulence and thus thermal mixing. This can improve the efficiency of heat exchangers or cooling systems significantly. However, structured surfaces are known to promote particulate fouling, hence the unwanted accumulation and deposition of suspended particles (e.g., silt, sludge or iron oxide). The scope of this work is the development of a universal numerical CFD method for the prediction of particulate fouling, especially on dimpled surfaces. The proposed approach is based on a combination of the Lagrangian point-particle tracking for the description of the disperse phase (fouling particles), and spatially and temporally resolved large-eddy simulations for the calculation of the continuous phase (carrier fluid). This approach allows not only the evaluation of the reduced thermo-hydraulic efficiency due to particle deposition, but also the investigation of the interaction between turbulent flow structures and the particulate fouling. It can be shown that the usage of spherical dimples as surface structures is not only the optimal choice from a thermo-hydraulic point of view, but also favors a substantial reduction of particulate fouling.
Book Synopsis Preprints for the ... Symposium on Turbulence by :
Download or read book Preprints for the ... Symposium on Turbulence written by and published by . This book was released on 1992 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis On the Full Lagrangian Approach and Thermophoretic Deposition in Gas-particle Flows by : David Patrick Healy
Download or read book On the Full Lagrangian Approach and Thermophoretic Deposition in Gas-particle Flows written by David Patrick Healy and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical and experimental studies of particle deposition in turbulent pipe flow have been carried out for over forty years, but some of the most important transport mechanisms are still not well understood. The first part of this thesis is concerned with the calculation of particle density when using Lagrangian methods to predict inertial particle transport in two-dimensional laminar fluid flows. Traditionally, Lagrangian calculations involve integrating the particle equations of motion along particle pathlines, and the particle density is obtained by applying a statistical averaging procedure to those pathlines which intersect a particular computational grid cell. Unfortunately, extremely large numbers of particles are required to reduce the statistical errors to acceptable levels, and this makes the method computationally expensive. Recently, the Full Lagrangian approach has been developed, which allows the direct calculation of the particle density along particle pathlines. This method had previously been applied only to simple analytical flow fields. The application of the method to CFD generated fluid velocity fields was shown to be possible, and the results obtained using the Full Lagrangian approach were compared to those from a traditional Lagrangian approach. It was found that better quality solutions could be obtained with the use of far fewer particle pathlines. An analysis of the manner in which the Full Lagrangian approach deals with particles whose paths cross each other (and the resulting discontinuity in particle density) was also undertaken, and this illustrates the sophistication of the method. The second part of the thesis comprises an experimental and theoretical study of the deposition of small particles in turbulent flows by thermophoresis. Thermophoresis is the phenomenon whereby small particles suspended in a gas in which there exists a temperature gradient experience a force in the direction opposite from that of the temperature gradient. Previous researchers have attempted to impose a radial temperature difference in pipe flow experiments, but have not yet succeeded in attaining a constant thermophoretic force along the length of the pipe. This limits the accuracy and usefulness of the data for the validation of theoretical expressions for the thermophoretic fluxes. An experimental rig has been designed to achieve a constant thermophoretic force. This was done by using an annular geometry with a cold inner wall and hot outer wall. The particle size was varied and the deposition flux was measured for turbulent flow with three temperature differences. The deposition fluxes for small particles were found to be independent of dimensionless particle size, with each increase in temperature difference resulting in an increase in magnitude of the flux. Evidence of a thermophoresis-turbulence coupling was found for intermediate-sized particles, and large particles were not influenced by thermophoresis. A theory of particle deposition, developed for the case of turbulent pipe flow, was modified to study flow in a turbulent annulus, so that theoretical expressions for the thermophoretic fluxes could be included and compared with the experimental results. Agreement with experimental data was quite good, but some deficiencies in a widely used theoretical expression for the thermophoretic flux were exposed. An alternative expression was used, which gave much better agreement with the experimental data, and the mechanisms behind the thermophoresis-turbulence coupling were also investigated. The validation of this expression for the thermophoretic force will allow its inclusion in numerical studies of particle deposition in more complex geometries.
Book Synopsis Dispersion and Deposition of Heavy Particles in Turbulent Flows by : Chunyu Jin
Download or read book Dispersion and Deposition of Heavy Particles in Turbulent Flows written by Chunyu Jin and published by . This book was released on 2012 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Particulate Two-phase Flow by : M. C. Roco
Download or read book Particulate Two-phase Flow written by M. C. Roco and published by Butterworth-Heinemann. This book was released on 1993 with total page 1032 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a collection of 28 contributions on basic phenomena and advanced methods of investigation for particulate two-phase flow. Written by leading scientists in the field, this book covers new measurement methods, experimental results on particulate two-phase flow microstructure at low and large Reynolds numbers, micromechanical, probabilistic, and numerical simulations, as well as production of ultrafine particles via aerosols and colloids for materials with controlled microstructure. Each chapter is focused on the qualitative progress made in the field in the last several years and has an extensive review section and original results. This unique volume assembles information previously found only in journals and specialized publications. It is an invaluable reference for researchers and engineers from academia and industry.
Book Synopsis Particles in Turbulent Flows by : Leonid I. Zaichik
Download or read book Particles in Turbulent Flows written by Leonid I. Zaichik and published by John Wiley & Sons. This book was released on 2008-12-04 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The only work available to treat the theory of turbulent flow with suspended particles, this book also includes a section on simulation methods, comparing the model results obtained with the PDF method to those obtained with other techniques, such as DNS, LES and RANS. Written by experienced scientists with background in oil and gas processing, this book is applicable to a wide range of industries -- from the petrol industry and industrial chemistry to food and water processing.
Book Synopsis IUTAM Symposium on Computational Approaches to Multiphase Flow by : S. Balachandar
Download or read book IUTAM Symposium on Computational Approaches to Multiphase Flow written by S. Balachandar and published by Springer Science & Business Media. This book was released on 2007-01-28 with total page 443 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book provides a broad overview of the full spectrum of state-of-the-art computational activities in multiphase flow as presented by top practitioners in the field. It starts with well-established approaches and builds up to newer methods. These methods are illustrated with applications to a broad spectrum of problems involving particle dispersion and deposition, turbulence modulation, environmental flows, fluidized beds, bubbly flows, and many others.
Author :University of Illinois at Urbana-Champaign. Office of Engineering Publications Publisher : ISBN 13 : Total Pages :408 pages Book Rating :4.:/5 (31 download)
Book Synopsis The Summary of Engineering Research by : University of Illinois at Urbana-Champaign. Office of Engineering Publications
Download or read book The Summary of Engineering Research written by University of Illinois at Urbana-Champaign. Office of Engineering Publications and published by . This book was released on 1992 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 754 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Les Dem written by Orde and published by . This book was released on 2015-11-17 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les Dem is a breakthrough attempt to grapple at one time with Picasso's great painting - Les Demoiselles D'Avignon - a turning point in art history, with Cubism - the greatest historical shift in perspective since the Renaissance and with art studies. Orde uses this work as an example of how to look in depth at art, to develop ones appreciation for all art, and he does so in a long poetic work.
Download or read book Two-Phase Flow written by Cl Kleinstreuer and published by Routledge. This book was released on 2017-11-01 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: This graduate text provides a unified treatment of the fundamental principles of two-phase flow and shows how to apply the principles to a variety of homogeneous mixture as well as separated liquid-liquid, gas-solid, liquid-solid, and gas-liquid flow problems, which may be steady or transient, laminar or turbulent.Each chapter contains several sample problems, which illustrate the outlined theory and provide approaches to find simplified analytic descriptions of complex two-phase flow phenomena.This well-balanced introductory text will be suitable for advanced seniors and graduate students in mechanical, chemical, biomedical, nuclear, environmental and aerospace engineering, as well as in applied mathematics and the physical sciences. It will be a valuable reference for practicing engineers and scientists. A solutions manual is available to qualified instructors.
Book Synopsis Dissertation Abstracts International by :
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2000 with total page 846 pages. Available in PDF, EPUB and Kindle. Book excerpt:
