Download or read book Particle particle Interactions in Concentrated Colloidal Suspensions in the Presence of Natural Organic Matter written by Peter James Harbour and published by . This book was released on 2002 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Particle Clusters in Flows of Concentrated Suspensions written by Alan L. Graham and published by . This book was released on 1980 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flow of Particulate Suspensions Through Constrictions written by Somnath Mondal and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle-laden flows occur in a variety of natural and industrial situations. As particulate suspensions flow through a medium, particles are often retained at constrictions such as pore throats, outlets or orifices. This occurs not only with oversized particles, but also with particles smaller than the constriction. For instance, jams are caused by the formation of particle bridges/arches when several particles attempt to flow through a constriction simultaneously. In many instances the success of an operation depends on our ability to either ensure or stop the flow of particles in the flow stream. Managing the flow of sand into wellbores during hydrocarbon production from poorly consolidated sandstone reservoirs, also referred to as sand control, is one such application in the oil and gas industry. This dissertation presents a multi-pronged effort at modeling the flow of granular suspensions of different concentrations, and through pore openings of different shapes, with two main objectives: (1) predicting the mass and size-distribution of the particles that are produced before jamming, and (2) investigating the underlying factors that influence the onset and stability of particle arches. Since, the dominant interactions and retention mechanisms are concentration dependent, we divided particulate suspensions into three groups based on the volumetric particle concentration ([phi]). High-concentration suspension flows ([phi]>~50%) are dominated by particle-particle interactions. We modeled polydisperse sand packs flowing through screens with rectangular and woven-square openings using 3D discrete element method (DEM). Simulations were validated against experimental data for a wide range of screen opening and sand size distributions. From the experiments and DEM simulations, a new scaling relation is identified, in which the number of different sized particles produced before retention follows a power-law correlation with the particle-to-outlet size ratio. This correlation is explained with a simple probabilistic model of bridging in polydisperse systems and a particle-size dependent jamming probability calculated from experimental data. A new method is presented to estimate the mass and size distribution of the produced solids through screens. The method uses the entire particle size distribution (PSD) of the formation sand, is validated with experimental data and numerical simulations, and provides more quantitative and accurate predictions of screen performance compared to past methods. It is also found that the stability of particle arches is compromised when adjacent outlets are less than three particle diameters away from each other. Low-concentration suspension flows ([phi]

Download or read book Rheology of Non spherical Particle Suspensions written by Francisco Chinesta and published by Elsevier. This book was released on 2015-10-06 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a review of the current understanding of the behavior of non-spherical particle suspensions providing experimental results, rheological models and numerical modeling. In recent years, new models have been developed for suspension rheology and as a result applications for nanocomposites have increased. The authors tackle issues within experimental, model and numerical simulations of the behavior of particle suspensions. Applications of non-spherical particle suspension rheology are widespread and can be found in organic matrix composites, nanocomposites, biocomposites, fiber-filled fresh concrete flow, blood and biologic fluids. - Understand how to model and predict the final microstructure and properties of particle suspensions - Explores nano, micro, meso and macro scales - Rheology, thermomechanical and electromagnetic physics are discussed

Download or read book Suspensions of Colloidal Particles and Aggregates written by Frank Babick and published by Springer. This book was released on 2016-04-04 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the properties of particles in colloidal suspensions. It has a focus on particle aggregates and the dependency of their physical behaviour on morphological parameters. For this purpose, relevant theories and methodological tools are reviewed and applied to selected examples. The book is divided into four main chapters. The first of them introduces important measurement techniques for the determination of particle size and interfacial properties in colloidal suspensions. A further chapter is devoted to the physico-chemical properties of colloidal particles—highlighting the interfacial phenomena and the corresponding interactions between particles. The book’s central chapter examines the structure-property relations of colloidal aggregates. This comprises concepts to quantify size and structure of aggregates, models and numerical tools for calculating the (light) scattering and hydrodynamic properties of aggregates, and a discussion on van-der-Waals and double layer interactions between aggregates. It is illustrated how such knowledge may significantly enhance the characterisation of colloidal suspensions. The final part of the book refers to the information, ideas and concepts already presented in order to address technical aspects of the preparation of colloidal suspensions—in particular the performance of relevant dispersion techniques and the stability of colloidal suspensions.

Download or read book A Structural Theory for Concentrated Suspensions in Polymeric Liquids written by John M. Wiest and published by . This book was released on 1986 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transient Dynamics of Concentrated Particulate Suspensions Under Shear written by Endao Han and published by Springer Nature. This book was released on 2020-03-09 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis demonstrates the first use of high-speed ultrasound imaging to non-invasively probe how the interior of a dense suspension responds to impact. Suspensions of small solid particles in a simple liquid can generate a rich set of dynamic phenomena that are of fundamental scientific interest because they do not conform to the typical behavior expected of either solids or liquids. Most remarkable is the highly counter-intuitive ability of concentrated suspensions to strongly thicken and even solidify when sheared or impacted. The understanding of the mechanism driving this solidification is, however, still limited, especially for the important transient stage while the response develops as a function of time. In this thesis, high-speed ultrasound imaging is introduced to track, for the first time, the transition from the flowing to the solidified state and directly observe the shock-like shear fronts that accompany this transition. A model is developed that agrees quantitatively with the experimental measurements. The combination of imaging techniques, experimental design, and modeling in this thesis represents a major breakthrough for the understanding of the dynamic response of dense suspensions, with important implications for a wide range of applications ranging from the handling of slurries to additive manufacturing.

Download or read book Microstructure and Momentum Transport in Concentrated Suspensions written by and published by . This book was released on 1996 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper reviews several coupled theoretical and experimental investigations of the effect of microstructure on momentum transport in concentrated suspensions. An expression to predict the apparent suspension viscosity of mixtures of rods and spheres is developed and verified with falling-ball viscometry experiments. The effects of suspension-scale slip (relative to the bulk continuum) are studied with a sensitive spinning-ball rheometer, and the results are explained with a novel theoretical method. The first noninvasive, nuclear magnetic resonance imaging measurements of the evolution of velocity and concentration profiles in pressure-driven entrance flows of initially well mixed suspensions in a circular conduit are described, as well as more complex two-dimensional flows with recirculation, e.g. flow in a journal bearing. These data in nonhomogeneous flows and complementary three-dimensional video imaging of individual tracer particles in homogeneous flows are providing much needed information on the effects of flow on particle interactions and effective theological properties at the macroscale.

Download or read book Transport Processes in Bubbles Drops and Particles written by Daniel DeKee and published by CRC Press. This book was released on 2002-06-14 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Fluid Dynamics of Active Suspensions written by Barath Ezhilan and published by . This book was released on 2016 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is devoted to understanding the effect of inter-particle interactions, external fields and confinement in active suspensions. Active suspensions, such as a bath of swimming micro-organisms, have microstructural elements which are motile and exert active stresses on the suspending fluid. The internally generated stresses in active suspensions lead to an intrinsic coupling between the swimmer configurations and the immersing fluid. The first theme of the thesis focuses on hydrodynamically driven self-organization in active suspensions. We first study the dynamics of concentrated active suspensions in a 3D periodic domain using a coupled Smoluchowski-Stokes kinetic model and discover novel instabilities for both rear-actuated (pusher) and front-actuated (puller) swimmers, characterized by giant number density fluctuations, due to the coupled effects of hydrodynamic and steric interactions. Next, we incorporate chemotactic run-and-tumble effects in the kinetic model to study the dynamics in thin films of aerotactic bacteria. A transition to chaotic dynamics beyond a critical film thickness is reported, in agreement with experiments, and shown to be a consequence of the coupling between aerotactic response of bacteria and hydrodynamic disturbance flows. The second theme focuses on the sole interplay between motility and confinement in dilute suspensions, ignoring the effect of inter-particle interactions. First, we investigate the dynamics of a confined suspension of Brownian swimmers using a simple kinetic model by prescribing a no-flux condition on the probability distribution function of particle configurations and explain several peculiar dynamics reported in experiments, viz., wall accumulation, as well as upstream swimming, centerline depletion and shear-trapping when a pressure-driven flow is imposed. Next, we calculate the swim pressure of non-Brownian run-and-tumble spherical swimmers using a kinetic model based on coupled bulk/surface probability density functions. The third theme focuses on the effect of confinement on active self-organization. We discover a symmetry-breaking phase-transition to a spontaneous flowing state with net fluid pumping beyond a critical concentration in a strongly confined channel. The framework for studying confined active suspensions is also extended to explore geometric control of active self-organization in circular and other complex domains.

Download or read book Flow of Particles in Suspensions written by U. Schaflinger and published by Springer. This book was released on 2014-05-04 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a broad overview of the issues related to the flow of particles in suspensions. Chapters cover the newest research in advanced theoretical approaches and recent experimental techniques. Topics include macroscopic transport properties, the mechanics of capsules and cells, hydrodynamic diffusion and phase separation.

Download or read book Particle interactions in fluid suspensions written by Andrew Roy Parker and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Particle Interactions in Suspension Flows written by and published by . This book was released on 1969 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Suspension Concentrates written by Tharwat F. Tadros and published by Walter de Gruyter GmbH & Co KG. This book was released on 2017-02-20 with total page 401 pages. Available in PDF, EPUB and Kindle. Book excerpt: Suspension Concentrates is a survey into the theory of the formulation and stabilization of suspensions, elaborating on the breaking of aggregates and agglomerates and the role of dispersing agents on flocculation and electrostatic and steric stabilization. Practical analysis by rheology is discussed. Suspension Concentrates is ideal for research scientists and Ph.D. students investigating chemistry, chemical engineering and colloidal science.

Download or read book Theory and Applications of Colloidal Suspension Rheology written by Norman J. Wagner and published by Cambridge University Press. This book was released on 2021-04-15 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Essential text on the practical application and theory of colloidal suspension rheology, written by an international coalition of experts.

Download or read book Colloidal Interactions in Field directed Self assembly written by Pushkar P. Lele and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis discusses: (1) the fabrication of an experimental tool, namely holographic optical tweezers for simultaneously manipulating spatial locations of multiple particles, (2) development of a framework for interpreting hydrodynamic interactions between multiple particles close to a no-slip surface and comparisons of experimental data with predictive modeling results (Stokesian dynamics simulations) (3) investigations of colloidal particle interactions under external AC fields and the intriguing spontaneous pattern formations in the suspension and, (4) the use of an unconventional assemble-stretch technique for creating novel 2D and 3D crystalline arrays of anisotropically shaped particles, from spherical particle templates. By blinking holographic optical traps, we investigate the hydrodynamic interactions in multi-particle ensembles, influenced by a no-slip surface. The measurements are carried out by screening out electrostatic interactions in the suspension. We observe that with increasing proximity with the surface, the effect of particle-particle hydrodynamic interactions on the short-time self-diffusivities is screened. We use the Stokeslet representation of particles and combine it with the method of images to understand the correlated motion of particles within the ensembles. Analysis of the resultant ensemble eigen-modes reveals that even in dilute suspensions, the effective diffusivities decay as the inverse of the separations, over the range of particle-particle separations we experimented with. The relative modes exhibit dominant contributions from close neighboring particles and the collective modes incorporate long-range contributions from all particles in the ensemble. Our analysis also confirms that for larger number of particles in the ensemble, the contributions from particle-particle interactions increase and in concentrated suspensions they over-ride the strong hydrodynamic screening by the wall. We investigate the microstructure of polarizable particles in AC electric fields as a function of field strength and frequency and observe three key features: (1) The order-disorder transition as a function of field strength and frequency exhibits an ordered regime consisting of dipolar chains and crystals between two disordered regimes at low and high field strengths. While the transition to order at low field strengths is consistent with the polarization-induced interactions becoming larger than the thermal energy of the particles, the reentrant disordered regime at high field strengths is marked by large- scale rotating structures; (2) As mentioned, using blinking laser tweezers to characterize the interaction of particle pairs, we demonstrate that particle pair rotation opposite of alignment in the field direction is the microscopic phenomenon driving the observed suspension behavior. The pair particle rotation is observed to decrease with increasing frequency, thus requiring higher field strengths, in agreement with the frequency and field strength dependence of the second order-to-disorder transition; (3) The particle rotation is consistent with a mechanism based on the mutual polarization of particles, and is an effect of the phase lag between the polarization and the applied and mutually induced field. The connection we made between particle interactions and suspension microstructure answers a long-standing debate regarding the mechanism underlying the band structures in experiments employing parallel electrode geometries. Creating ordered crystalline structures from anisotropic particles is a fundamental challenge. To create such structures, either one can direct the assembly of particles from a random dispersion using external fields or, as we will show, they can be created from the controlled deformation of isotropic particle templates. Using an assemble-stretch technique we create 2D and 3D anisotropic particle assemblies from an initial template of close-packed spheres. This method enables the fabrication of anisotropic crystals from particles of any deformable material with a reasonable glass transition temperature, and thus, is a key advantage of the technique. Be- cause the aspect ratios of the particles in the deformed crystal depends solely on the applied mechanical strain, the method offers good control over particle aspect ratios, and can be used to create assemblies from different particle sizes. As long as the original template can be fabricated with long range order, the stretched anisotropic structures will also be ordered over large length scales. We demonstrate that it is also possible to simply align and stack 2D structures to create crystals in three dimensions. The assemble-and-stretch approach shows great promise for ultimately creating structures with complete photonic bandgaps. (Abstract shortened by UMI.).

Download or read book Colloidal Suspension Rheology written by Jan Mewis and published by Cambridge University Press. This book was released on 2012 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented in an accessible and introductory manner, this is the first book devoted to the comprehensive study of colloidal suspensions.