Download or read book Particle deposition in turbulent flow a review of existing models written by A. Husain and published by . This book was released on 1982 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Particle Deposition from Turbulent Flow written by and published by . This book was released on 2002 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report reviews published experimental and theoretical investigations of particle deposition from turbulent flows and considers the applicability of this body of work to the specific case of particle deposition from flows in the ducts of heating, ventilating and air conditioning (HVAC) systems. Particle deposition can detrimentally affect the performance of HVAC systems and it influences the exposure of building occupants to a variety of air pollutants. The first section of this report describes the types of HVAC systems under consideration and discusses the components, materials and operating parameters commonly found in these systems. The second section reviews published experimental investigations of particle deposition rates from turbulent flows and considers the ramifications of the experimental evidence with respect to HVAC ducts. The third section considers the structure of turbulent airflows in ventilation ducts with a particular emphasis on turbulence investigations that have been used as a basis for particle deposition models. The final section reviews published literature on predicting particle deposition rates from turbulent flows.

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 A Review of Dispersion Modelling and Particle Trajectories in Atmospheric Flows written by Jai Singh Sachdev and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric and turbulence modelling, boundary layer parameterization, and current dispersion modelling techniques are reviewed. Dispersion models for atmospheric flow conditions include the K-Diffusion model, Gaussian Plume model, and Lagrangian particle tracking techniques (Gaussian Puff model), and their applications in CALPUFF (a commercial software package) are described. Studies of Gaussian Plume and Puff models in stable, neutrally stable, and unstable boundary layers show that the puff method reproduces acceptable plume model results in simple flow cases. The influence drag and gravity forces have on the motion of pollutant particles are investigated by means of derivation and analysis of the equations of translational motion. Incorporation of the drag and gravity forces into the Gaussian Puff dispersion model shows that the effect these forces have on the growth of a pollutant plume depends on the magnitude and frequency of the turbulent flow-field fluctuations. The Gaussian Puff model is flexible in that it can be applied in complex flow conditions; however, the assumption of the Gaussian distribution of pollutants does not account for particle deposition.

Download or read book Particle Deposition in Turbulent Flow written by David Daniel McCoy and published by . This book was released on 1975 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Modeling Turbulent Dispersion and Deposition of Airborne Particles in High Temperature Pipe Flows written by Pritheesh Gnanaselvam and published by . This book was released on 2020 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: The simulations and experiments outlined are designed to explore the effect of existing turbulent dispersion models in predicting particle deposition characteristics at higher temperatures. The continuous phase solution was obtained from using a Reynolds-Averaged Navier Stokes (RANS) turbulence model and the turbulent dispersion was modeled using a Continuous Random Walk (CRW) model. Euler-Maruyama scheme was implemented to solve the non-dimensional Langevin equation to model the stochastic nature of the equation appropriately. Previous studies have shown that the particle deposition characteristics depend greatly on the time step of integration. With the Euler-Maruyama scheme, the CFD results were shown to be less sensitive to the time step of integration and with decrease in time step more stable results were obtained. Direct comparison with the Discrete Random Walk (DRW) model shows that DRW fails to predict flow fluctuations seen by particles in the diffusion-impaction regime. Previous studies of this phenomenon were all performed at ambient conditions. The CRW model was shown to predict impact velocities reasonably well, when the chosen time step of integrations is such that the stochastic and damping term are comparable in magnitude. Presented here are pipe-flow experiments conducted in the High Temperature Deposition Facility (HTDF) with a mean jet velocity of 150 m/s – 200 m/s with exit centerline temperature of 1525K to assess the capability of CRW in predicting particle deposition characteristics at high temperatures. The flow temperature was chosen in such a way that the temperature inside the pipe at any point is higher than the melting point of dust used, so that an `all stick’ condition can be used to model particle-wall interactions. The derivation and the effect of the drift correction and the stochastic terms in the normalized Langevin equation were discussed in detail. Simulations were performed trying to reproduce experimental results with and without injection line. The CFD model without injection line was shown to follow the predicted pipe deposition based on the effective drift correction, whereas the CFD model with injection line did not show significant change in pipe deposition results with velocity. CFD results using the OSU-CRW model posited that the model is more appropriate for turbulent pipe flows in the fully developed region.

Download or read book Particle Deposition from Turbulent Flow in a Pipe written by Pushkar Tandon and published by . This book was released on 1997 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiphase Flow Handbook Second Edition written by Efstathios Michaelides and published by CRC Press. This book was released on 2016-10-26 with total page 1559 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Multiphase Flow Handbook, Second Edition is a thoroughly updated and reorganized revision of the late Clayton Crowe’s work, and provides a detailed look at the basic concepts and the wide range of applications in this important area of thermal/fluids engineering. Revised by the new editors, Efstathios E. (Stathis) Michaelides and John D. Schwarzkopf, the new Second Edition begins with two chapters covering fundamental concepts and methods that pertain to all the types and applications of multiphase flow. The remaining chapters cover the applications and engineering systems that are relevant to all the types of multiphase flow and heat transfer. The twenty-one chapters and several sections of the book include the basic science as well as the contemporary engineering and technological applications of multiphase flow in a comprehensive way that is easy to follow and be understood. The editors created a common set of nomenclature that is used throughout the book, allowing readers to easily compare fundamental theory with currently developing concepts and applications. With contributed chapters from sixty-two leading experts around the world, the Multiphase Flow Handbook, Second Edition is an essential reference for all researchers, academics and engineers working with complex thermal and fluid systems.

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 Deposition of Particles in a Turbulent Pipe Flow written by Bennie Mols and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Particle Deposition from Turbulent Flow in a Divergent Channel written by Wai-Ting Huang and published by . This book was released on 1997 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Stochastic Methods for Predicting Particle Dispersion in Turbulent Flows written by Kyle Paul Sala and published by . This book was released on 2013 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current research seeks to develop a computational model that accurately describes particle dispersion in turbulent flow. Current particle dispersion models do not accurately predict the small-scale clumping of particles in turbulent flow that occurs due to interaction with turbulent eddies. A new stochastic vortex structure (SVS) model was developed and compared with current stochastic Lagrangian models (SLM) for turbulent flows. To examine what characteristics of the fluid flow field that lead to dispersion of particles, a number of non trivial measures were used. A discrete-element model is used to transport particle locations for cases with and without adhesive forces. Direct numerical simulations (DNS) are used as a baseline for comparison between the two models. Initial results show that the SVS model matches the spatial structure of the flow field of DNS reasonably well, while the SLMs do not. Investigation of particle collision rate suggest that while SVS matches the large length scales of flow, it omits the smaller scales of the flow.

Download or read book Particle Deposition from Turbulent Flows written by Angus David Leeming and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: