Download or read book Experiments and Simulations of Particle laden Turbulent Shear Flows written by Stefan Horender and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Investigation of Particle laden Turbulent Flow in Free Shear Turbulent Combustion written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Explicit numerical mixed phase simulations are described which couple random gasdynamic motions to inertiallly interactive gas borne particles. Theses simulations are numerical experiments intended to provide data for investigating the interaction between a developing turbulent free shear layer and gas borne solid particles it entrains. The simulations predict most probable distributions of dispersed phase trajectories, standard deviations, and gas phase mixing dynamics which include the concomitant back-influences of the particle phase on the carrier gas flow. Data for refinement of the computational scheme and physical verification are provided by experiment. The experimental evidence is developed in a splitter plate divided, two-channel free shear mixing combustion tube. A variety of particle concentrations and particle size distributions are admitted into non-combusting or combusting flows with selected heat release levels. The computations, in turn, provide guidance on design and selection of new experiments.
Download or read book Modeling Approaches and Computational Methods for Particle laden Turbulent Flows written by Shankar Subramaniam and published by Academic Press. This book was released on 2022-10-20 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modelling Approaches and Computational Methods for Particle-laden Turbulent Flows introduces the principal phenomena observed in applications where turbulence in particle-laden flow is encountered while also analyzing the main methods for analyzing numerically. The book takes a practical approach, providing advice on how to select and apply the correct model or tool by drawing on the latest research. Sections provide scales of particle-laden turbulence and the principal analytical frameworks and computational approaches used to simulate particles in turbulent flow. Each chapter opens with a section on fundamental concepts and theory before describing the applications of the modelling approach or numerical method. Featuring explanations of key concepts, definitions, and fundamental physics and equations, as well as recent research advances and detailed simulation methods, this book is the ideal starting point for students new to this subject, as well as an essential reference for experienced researchers. - Provides a comprehensive introduction to the phenomena of particle laden turbulent flow - Explains a wide range of numerical methods, including Eulerian-Eulerian, Eulerian-Lagrange, and volume-filtered computation - Describes a wide range of innovative applications of these models
Download or read book CFD simulations of particle laden flows Particle transport and separation written by David Schellander and published by Anchor Academic Publishing (aap_verlag). This book was released on 2014-02-01 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study presents the basic models for discrete and continuous particle laden flow simulation. An overview of the two main approaches, the Lagrangian discrete particle model and the Eulerian granular phase model is given. Moreover these two approaches are combined to a hybrid model to use the benefits of the discrete and continuous description. This safes computational time and increase the efficiency of particle laden flow simulations. Furthermore the models are extended to poly-disperse particles including a simple agglomeration model based on a population balance equation. Finally the usability of the models is shown at a pneumatic particle transport system including particle strand building and the separation of particles using an industrial cyclone.
Download or read book Computational Investigation Of The Dynamics Of Inertial Particles In Homogeneous Turbulent Shear Flow written by Parvez Sam Sukheswalla and published by . This book was released on 2015 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle-laden turbulent shear flows are ubiquitous in environmental and industrial flow-systems, and their analysis is thus of prime importance. In this work, we study the motion of a dilute suspension of particles in a non-stationary homogeneous turbulent shear flow (HTSF), subject to varying levels of imposed mean-shear, gravity, and inertia. We use direct numerical simulations (DNS) of the fluid velocity field (coupled with Lagrangian particle tracking), to assess the influence of flow-anisotropy and gravity on the motion of the particles. We first discuss numerical challenges encountered while performing DNS of HTSF at higher Reynolds numbers. The presence of sharp velocity gradients in the HTSF flow field is found to cause premature loss of resolution at the small scales, leading to shortened simulation-times. To counter this, the existing pseudo-spectral DNS setup is augmented with a Weighted Essentially Non-Oscillatory (WENO) scheme, enabling numerically-stable HTSF simulations at higher Reynolds numbers. We then consider the motion of individual particles as they interact with the anisotropic topology of the turbulence. In contrast to isotropic turbulence, particles are found to collect within vortex layers, regions where strong vorticity and strain are coupled with low streamline curvature. Shear-induced anisotropy in the turbulence also leads to reduced gravitational settling speeds for intermediate-inertia particles, though stronger gravity overcomes this effect. Particle velocity variances are found to be highly anisotropic at stronger shear, while gravity now tends to diminish this effect by limiting the interaction-time between particles and turbulence. Shear and gravity acting together cause particle acceleration variances to exceed those of the underlying fluid, corroborating findings from past turbulent boundary layer experiments. Analytical expressions are derived for the mean velocities and accelerations of the particles, and are in agreement with the DNS results. Finally, we analyze the relative velocities and clustering characteristics of particle pairs, and find that stronger shear and gravity suppress path-history effects for particles with stronger inertia. Shear-induced anisotropy in pair-statistics is affected by both inertia and gravity, with stronger gravity seen to oppose the action of shear. Changes in the relative-velocity anisotropy are correlated to the trends shown by single-particle velocity variances. Particle collision rates increase with stronger shear, and are found to scale in proportion to the underlying turbulence timescales.
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.
Download or read book Turbulent Shear Flows 5 written by Franz Durst and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first four symposia in the series on turbulent shear flows have been held alternately in the United States and Europe with the first and third being held at universities in eastern and western States, respectively. Continuing this pattern, the Fifth Symposium on Turbulent Shear Flows was held at Cornell University, Ithaca, New York, in August 1985. The meeting brought together more than 250 participants from around the world to present the results of new research on turbulent shear flows. It also provided a forum for lively discussions on the implications (practical or academic) of some of the papers. Nearly 100 formal papers and about 20 shorter communications in open forums were presented. In all the areas covered, the meeting helped to underline the vitality of current research into turbulent shear flows whether in experimental, theoretical or numerical studies. The present volume contains 25 of the original symposium presentations. All have been further reviewed and edited and several have been considerably extended since their first presentation. The editors believe that the selection provides papers of archival value that, at the same time, give a representative statement of current research in the four areas covered by this book: - Homogeneous and Simple Flows - Free Flows - Wall Flows - Reacting Flows Each of these sections begins with an introductory article by a distinguished worker in the field.
Download or read book Computational Fluid Dynamics for the Petrochemical Process Industry written by R.V.A. Oliemans and published by Springer. This book was released on 2012-11-05 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second of the 1989 conferences in the Shell Conference Series, held from 10 to 12 December in the Netherlands and organized by Koninklijke/Shell-Laboratorium, Amsterdam, was on "Computational Fluid Dynamics for Petrochemical Process Equip ment". The objective was to generate a shared perspective on the subject with respect to its role in the design of equipment involving complex flows. The conference was attended by scientists from four Shell laboratories and experts from universities in the USA, France, Great Britain, Germany and The Netherlands. R. V. A. Oliemans, G. Ooms and T. M. M. Verheggen formed the organizing committee. Complexities in fluid flow may arise from equipment geometry and/or the fluids themselves, which can be mUlti-component, single-phase or multiphase. Pressure and temperature gradients and any reactivity of components in the flow stream can be additional factors. Four themes were addressed: turbulent reacting and non-reacting flow, dispersed multiphase flow, separated two-phase flow and fluid flow simulation tools. The capabilities and limitations of a sequence of turbulence flow models, from the relatively simple k-£ model to direct numerical simulation and large eddy turbulence flow models, were considered for a range of petrochemical process equipment. Flow stability aspects and the potential of cellular automata for the simulation of industrial flows also received attention. The papers published in this special issue of Applied Scientific Research provide a fair representation of the Computational Fluid Dynamics topics discussed in the context of their application to petrochemical process equipment.
Download or read book Symposium on Turbulent Shear Flows written by and published by . This book was released on with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hybrid Particle Laden Flow Modelling written by David Schellander and published by GRIN Verlag. This book was released on 2013-09-20 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doctoral Thesis / Dissertation from the year 2013 in the subject Engineering - Mechanical Engineering, grade: 1, University of Linz (Department on Particulate Flow Modelling), language: English, abstract: The numerical hybrid model EUgran+, which is an Eulerian-Eulerian granular phase model extended with models from the Eulerian-Lagrangian model for dense rapid particulate flows, is modified to account for poly-dispersed particle diameter distributions. These modifications include the implementation of I) a new poly-dispersed drag law and of II) new particle boundary conditions distinguishing between sliding and non-sliding particle-wall collisions and III) a new implementation of the population balance equation in the agglomeration model using the Eulerian-Lagrangian approach, referred to as Bus-stop model. Further, the applicability of the EUgran+ model is extended to cover dilute to dense poly-disperse particulate flows. Furthermore, this provides an improvement in the numerical simulation of dust separation and the formation of particle strands in industrial scale cyclones. In this PHD thesis, the EUgran+Poly model is validated at 3 specific cases with different mass loadings: I) poly-dispersed particle conveying in a square pipe with a 90 degree bend at low mass loading (L = 0:00206); II) a particle conveying case in a rectangular pipe with a double-loop at high mass loading (L = 1:5); III) in a vertical pipe the implementation of the agglomeration model is validated. To show the applicability of the presented models a simulation of an industrial cyclone in experimental scale is presented. The validation and application shows that considering a poly-disperse Eulerian-Eulerian granular phase improves the accordance of the simulation results with measurements significantly. Finally, the hybrid model is a good compromise for a computational efficient simulation of particulate transport and separation with different mass loading regimes.
Download or read book Mean Value and Correlation Problems connected with the Motion of Small Particles suspended in a turbulent fluid written by Tchen Chan-Mou and published by Springer. This book was released on 2013-11-21 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Shear Flows I written by F. Durst and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present book contains papers that have been selected from contributions to the First International Symposium on Turbulent Shear Flows which was held from the 18th to 20th April 1977 at The Pennsylvania State University, University Park, Pennsylvania, USA. Attend ees from close to 20 countries presented over 100 contributions at this meeting in which many aspects of the current activities in turbulence research were covered. Five topics received particular attention at the Symposium: Free Flows Wall Flows Recirculating Flows Developments in Reynolds Stress Closures New Directions in Modeling This is also reflected in the five chapters of this book with contributions from research workers from different countries. Each chapter covers the most valuable contributions of the conference to the particular chapter topic. Of course, there were many additional good con tributions to each subject at the meeting but the limitation imposed on the length of this volume required that a selection be made. The realization of the First International Symposium on Turbulent Shear Flows was p- sible by the general support of: U. S. Army Research Office U. S. Navy Research Office Continuing Education Center of The Pennsylvania State University The conference organization was carried out by the organizing committee consisting of: F. Durst, Universitat Karlsruhe, Karlsruhe, Fed. Rep. of Germany V. W. Goldschmidt, Purdue University, West Lafayette, Ind. , USA B. E. Launder, University of California, Davis, Calif. , USA F. W. Schmidt, Pennsylvania State University, University Park, Penna.
Download or read book Turbulent Particle Laden Gas Flows written by Aleksei Y. Varaksin and published by Springer Science & Business Media. This book was released on 2007-07-05 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents results of experimental and theoretical studies of "gas-solid particles" turbulent two-phase flows. It analyzes the characteristics of heterogeneous flows in channels (pipes), as well as those in the vicinity of the critical points of bodies subjected to flow and in the boundary layer developing on their surface. Coverage also treats in detail problems of physical simulation of turbulent gas flows which carry solid particles.
Download or read book Experimental Investigation on the Turbulence of Particle laden Liquid Flows in a Vertical Pipe Loop written by Rouholluh Shokri and published by . This book was released on 2016 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: The turbulent motion of particles and their interactions with the turbulence of the carrier phase make a complex system. Hence understanding the physics and consequently developing a well-stablished model becomes very difficult. With insufficient computational power to numerically resolve all the scales of these kinds of flows using Direct Numerical Simulation (DNS), experimental investigations still remain the sole source of information for these systems, especially at high Reynolds numbers. Lack of comprehensive experimental data for solid-liquid flows as well as limitation of the existing experimental data to low Reynolds numbers are the motivations for this investigation. The main goal of this research is to experimentally investigate solid-liquid turbulent flows in a vertical pipe and provide some insight into these flows, especially for an extended range of Reynolds numbers. To fulfil the abovementioned goal, a 50.6 mm vertical pipe loop was constructed and dilute mixtures of water and glass beads were used. The glass bead diameters were 0.5, 1 and 2 mm and the volumetric concentration ranged from 0.05 to 1.6% depending on the particle size. The experiments were performed at three Reynolds numbers: 52 000, 100 000, and 320 000 which are referred to here as low, medium and high Re. A combined technique of Particle Image/Tracking velocimetry (PIV/PTV) was employed to perform the measurements. The measured and reported flow parameters are: mean axial velocity profiles of the solid and liquid phases, particle distribution over the cross section of the pipe (concentration profile), particle-particle interaction index, axial and radial fluctuating velocity profiles of both phases, and shear Reynolds stress and its correlation for both phases. The relatively wide range of different parameters tested here provided interesting and novel experimental results. The results showed that the turbulent motions of the fluid and particles and their interactions varied drastically as Re increased. Moreover, the behavior of the particles and their impact on the fluid can be very different in the axial and radial directions. The results proved that the well-known criteria for axial turbulence modulation of the carrier phase could not perform well at high Reynolds numbers and their performance was much poorer for the radial direction modulation. The new data sets provided by the present study offer valuable insight into the processes or phenomena heavily influenced by turbulence, such as pipe wear rate, oil sand lump ablation, and pressure loss/energy consumption. In addition, these data sets can be utilised to evaluate and improve the existing correlations and models for particulate turbulent flows. In addition, a quantitative analysis of the particle and carrier phase turbulence modulation was conducted. Particle turbulence intensities in present study were combined with other experimental data from the literature to propose a novel empirical correlation was proposed for axial particle turbulence in solid-liquid flows. Moreover, a novel empirical criterion/correlation was proposed to classify the carrier phase turbulence attenuation/augmentation phenomenon for both gas-solid and liquid-solid flows by employing a wide range of data from the present study and from the literature. Two major improvements of the proposed criterion/correlation are the prediction of the onset and the magnitude of the carrier phase turbulence augmentation. These new empirical correlations will assist the researchers in this field to effectively design and coordinate their experimental or numerical efforts.
Download or read book Particle Laden Inhomogeneous Elastic Turbulence written by Himani Garg and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laboratory experiments show that, even in very dilute solutions, the interaction of polymers with fluid flows can dramatically change the properties of turbulent flows or, if the flow is laminar, can trigger a new sort of irregular motion named “elastic turbulence”. Flows in such a dynamical regime are promising for enhancing mixing efficiency in microfluidic applications, which often involve the presence of suspended finite-size impurities, like small and heavy solid particles. The understanding of particle dispersion in high-Reynolds number flows of Newtonian, as well as non-Newtonian, fluids were addressed by previous investigations, and it is a subject of interest both at a fundamental level and for applications, e.g., environmental or industrial ones. However, the dynamics of particles in elastic turbulent flows are still quite unexplored.The present study aims at investigating the aggregation properties of pointlike material particles (heavier than the carrying fluid) in viscoelastic fluids in elastic turbulence conditions (i.e. in the limit of vanishing fluid inertia and large elasticity). We carry out extensive direct numerical simulations of the periodic Kolmogorov mean shear flow of two-dimensional dilute polymer solutions described by the Oldroyd-B model. Both the small- and large-scale features of the resulting inhomogeneous particle distribution are examined, focusing on their connection with the underlying flow structure. Our analysis reveals that particles are preferentially clustered in regions of instantaneously maximally stretched polymers. The intensity of such a phenomenon depends on the interplay, parametrized by the Stokes number, between the particle inertia and the typical time scale associated with the elastic turbulence flow, and is the largest for intermediate values of particle inertia.In particular, it is shown that the preferential concentration of inertial particle suspensions in such turbulent-like flows follow from the dissipative nature of their dynamics. We provide a quantitative characterization of this phenomenon (using correlation and Kaplan-Yorke dimension) that allows to relate it to the accumulation of particles in filamentary highly strained flow regions producing clusters of fractal dimension slightly above 1.At larger scales, particles are found to undergo turbophoretic-like segregation along the non-homogeneity direction of the flow. Indeed, our results indicate that the particle distribution is strongly related to the mean turbulent-like structures of the flow. As an effect of turbophoresis, average density profiles peak in the regions of lowest turbulent eddy diffusivity. The large-scale inhomogeneity of the particle distribution is interpreted in the framework of a model derived in the limit of small, but finite, particle inertia. The qualitative characteristics of different observables (such as root-mean-square deviation of the particle distribution, relative to the uniform one) are, to a good extent, independent of the flow elasticity. When increased, the latter is found, however, to slightly reduce the globally averaged degree of turbophoretic unmixing.
Download or read book Engineering Turbulence Modelling and Experiments 6 written by Wolfgang Rodi and published by Elsevier. This book was released on 2005-05-05 with total page 1011 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the world renowned ERCOFTAC (International Symposium on Engineering Turbulence Modelling and Measurements).The proceedings include papers dealing with the following areas of turbulence:·Eddy-viscosity and second-order RANS models ·Direct and large-eddy simulations and deductions for conventional modelling ·Measurement and visualization techniques, experimental studies ·Turbulence control ·Transition and effects of curvature, rotation and buoyancy on turbulence ·Aero-acoustics ·Heat and mass transfer and chemically reacting flows ·Compressible flows, shock phenomena ·Two-phase flows ·Applications in aerospace engineering, turbomachinery and reciprocating engines, industrial aerodynamics and wind engineering, and selected chemical engineering problems Turbulence remains one of the key issues in tackling engineering flow problems. These problems are solved more and more by CFD analysis, the reliability of which depends strongly on the performance of the turbulence models employed. Successful simulation of turbulence requires the understanding of the complex physical phenomena involved and suitable models for describing the turbulent momentum, heat and mass transfer. For the understanding of turbulence phenomena, experiments are indispensable, but they are equally important for providing data for the development and testing of turbulence models and hence for CFD software validation. As in other fields of Science, in the rapidly developing discipline of turbulence, swift progress can be achieved only by keeping up to date with recent advances all over the world and by exchanging ideas with colleagues active in related fields.
