Download or read book Numerical Investigation of Turbulent Particle Transport and Deposition in a Complex Passage written by Hong Loan Thi Dinh and published by . This book was released on 1999 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Investigation of Particle Deposition in a Turbulent Boundary Layer with Forced Turbulence in the External Flow written by Manoj Joishi and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deposition of particles on a wall plays a significant role in fluid-solid processes such as inclusions recovery from liquid steel in ladle furnace, that controls inclusion cleanliness upstream from solidification. The aim of this work is to study the turbulent deposition and capture of particles on a wall, in a situation where turbulence in the boundary layer originates both from wall shear and from agitation in the external flow. In a ladle furnace, such an agitation would result from bubble injection. A framework for simulations at mesoscopic scale in which particles are represented as points but the turbulence is fully resolved has been developped using an in-house solver, where a Lattice Boltzmann Method (LBM) solves flow dynamics and linear isotropic forcing generates artificial turbulence. Lagrangian Particle Tracking (LPT) is used to achieve one way coupling between particle motions and turbulent flow. These numerical methods were applied to Direct Numerical simulation (DNS) of a fully developed turbulent boundary layer in which particles smaller than the Kolmogorov length scale are introduced. The deposition mechanisms in aerosol conditions have been analyzed and quantified into a statistical law for deposition velocity in terms of Stokes number, and validated against data from the literature. Such simulations have provided a better understanding of deposition and capture mechanisms, depending on the turbulent flow in a wall boundary layer and on particle physical properties. Also, preliminary simulations in hydrosol conditions that match actual ladle operation have shown that the framework developed in this work can be applied to investigate inclusion behavior in secondary steel-making although statistical analysis in this work focused on aerosols.
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:
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.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Numerical Investigation of Particle Deposition on a Square Cylinder Placed in a Channel Flow written by Daniel J. Brandon and published by . This book was released on 1999 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Particle Adhesion written by Rijmai and published by CRC Press. This book was released on 1996-03-18 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, there has been an upsurge of interest in using techniques drawn from probability to tackle problems in analysis. These applications arise in subjects such as potential theory, harmonic analysis, singular integrals, and the study of analytic functions. This book presents a modern survey of these methods at the level of a beginning Ph.D. student. Highlights of this book include the construction of the Martin boundary, probabilistic proofs of the boundary Harnack principle, Dahlberg's theorem, a probabilistic proof of Riesz' theorem on the Hilbert transform, and Makarov's theorems on the support of harmonic measure. The author assumes that a reader has some background in basic real analysis, but the book includes proofs of all the results from probability theory and advanced analysis required. Each chapter concludes with exercises ranging from the routine to the difficult. In addition, there are included discussions of open problems and further avenues of research.
Download or read book Numerical Investigation of Particle laden Thermally Driven Turbulent Flows in Enclosure written by Riccardo Puragliesi and published by . This book was released on 2010 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Investigation of the Turbulence Mass Transport During the Mixing of a Stable Stratification with a Free Jet written by Armin Zirkel and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Investigation of the Influence of Particle Particle and Particle Wall Collisions in Turbulent Wall Bounded Flows at High Mass Loadings written by Michael Alletto and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Investigation of Particle fluid Interaction System Based on Discrete Element Method written by Hao Zhang and published by . This book was released on 2015 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on the numerical investigation of the particle-fluid systems based on the Discrete Element Method (DEM). The whole thesis consists of three parts, in each part we have coupled the DEM with different schemes/solvers on the fluid phase. In the first part, we have coupled DEM with Direct Numerical Simulation (DNS) to study the particle-laden turbulent flow. The effect of collisions on the particle behavior in fully developed turbulent flow in a straight square duct was numerically investigated. Three sizes of particles were considered with diameters equal to 50 μm, 100 μm and 500 μm. Firstly, the particle transportation by turbulent flow was studied in the absence of the gravitational effect. Then, the particle deposition was studied under the effect of the wall-normal gravity force in which the influence of collisions on the particle resuspension rate and the final stage of particle distribution on the duct floor were discussed, respectively. In the second part, we have coupled DEM with Lattice Boltzmann Method (LBM) to study the particle sedimentation in Newtonian laminar flow. A novel combined LBM-IBM-DEM scheme was presented with its application to model the sedimentation of two dimensional circular particles in incompressible Newtonian flows. Case studies of single sphere settling in a cavity, and two particles settling in a channel were carried out, the velocity characteristics of the particle during settling and near the bottom were examined. At last, a numerical example of sedimentation involving 504 particles was finally presented to demonstrate the capability of the combined scheme. Furthermore, a Particulate Immersed Boundary Method (PIBM) for simulating the fluid-particle multiphase flow was presented and assessed in both two and three-dimensional applications. Compared with the conventional IBM, dozens of times speedup in two-dimensional simulation and hundreds of times in three-dimensional simulation can be expected under the same particle and mesh number. Numerical simulations of particle sedimentation in the Newtonian flows were conducted based on a combined LBM - PIBM - DEM showing that the PIBM could capture the feature of the particulate flows in fluid and was indeed a promising scheme for the solution of the fluid-particle interaction problems. In the last part, we have coupled DEM with averaged Navier-Stokes equations (NS) to study the particle transportation and wear process on the pipe wall. A case of pneumatic conveying was utilized to demonstrate the capability of the coupling model. The concrete pumping process was then simulated, where the hydraulic pressure and velocity distribution of the fluid phase were obtained. The frequency of the particles impacting on the bended pipe was monitored, a new time average collision intensity model based on impact force was proposed to investigate the wear process of the elbow. The location of maximum erosive wear damage in elbow was predicted. Furthermore, the influences of slurry velocity, bend orientation and angle of elbow on the puncture point location were discussed.
Download or read book Numerical Simulation of Solid Particle Transport in Atmospheric Boundary layer Over Obstacles written by Gang Huang and published by . This book was released on 2015 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transport of solid particles inside a laboratory-scale turbulent boundary-layer is studied by numerical simulations, to obtain a better understanding of the mechanisms associated with wind erosion of soil. The presence of one or several Gaussian hills allows a study of the topographic effects on the transport, deposition and re-emission of solid particles. The carrier fluid motion is resolved in a Large Eddy Simulation (LES). Wall models are implemented to better account for the effects of turbulent flow near the terrain. Particle trajectories are calculated using a Lagrangian tracking. Take-off and rebound models are developed in order to take into account particle emissions and impacts at the wall. In the first part, the flow over transversal Gaussian hills is simulated and validated by comparison with different experiments. According to Oke [1988], the flow inside an urban canopy can be schematically characterised into different flow regimes depending on the relative localisation of the obstacles at the ground. This concept is applied to the case of sand dunes, assimilated to 2D hills in this study. The focus is on the recirculation zone (RZ) on the lee side, which has the characteristic of increasing the residence time and the interaction fluid/particle in general, particle trapping and deposition in particular. The variations of RZ with different hill geometries and Reynolds numbers are examined. A study on the roughness sublayer is conducted in order to determine the roughness effects due to the layer of solid particles on the wall. The second part of the work is devoted to the simulation of solid particle transport over the Gaussian hills. The objective is to improve the modelling of particle take-off, rebound and the two-way coupling between the fluid and the particle. A first work of validation is conducted by using the complete model of solid particle transport developed in this thesis. In particular, the evolution of particle emission flux predicted by the take-off model is in accordance with classical saltation models and experiments from the literature. Over the Gaussian hills, analysis of particle transport is conducted using concentration and mean velocity fields. Two mappings are realised. The first indicates the intensity of the local and instantaneous flow structures that arguably regulate the re-entrainment of particles trapped inside the RZ. The second shows the accumulation of particles on the wall. These results highlight zones prone to wind erosion and particle deposition around the hills. Last but not least, the fluxes of particle trapping and deposition inside the RZ are quantified and compared to the incoming flux from upstream. These fluxes, albeit relatively weak in comparison to the incoming one, contribute potentially to dune migrations and desertification.
Download or read book Numerical Investigations of Particle containing Turbulent Open Channel Flows written by Yu Pan and published by . This book was released on 1995 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Particle Image Velocimetry written by Markus Raffel and published by Springer Science & Business Media. This book was released on 2007-08-09 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This immensely practical guide to PIV provides a condensed, yet exhaustive guide to most of the information needed for experiments employing the technique. This second edition has updated chapters on the principles and extra information on microscopic, high-speed and three component measurements as well as a description of advanced evaluation techniques. What’s more, the huge increase in the range of possible applications has been taken into account as the chapter describing these applications of the PIV technique has been expanded.
Download or read book Annual Report written by National Sea Grant College Program (U.S.) and published by . This book was released on 1989 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1968 with total page 1016 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards written by and published by . This book was released on 2006 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theses on any subject submitted by the academic libraries in the UK and Ireland.
