Particle Dispersion, Agglomeration and Deposition in Fully-coupled Turbulent Channel Flow Using Large Eddy Simulation and Discrete Element Method
Author: Mohammad Afkhami
Publisher:
Published: 2014
Total Pages: 0
ISBN-13:
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Author: Mohammad Afkhami
Publisher:
Published: 2014
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKAuthor: Chunyu Jin
Publisher:
Published: 2012
Total Pages: 244
ISBN-13:
DOWNLOAD EBOOKAuthor: M. Afkhami
Publisher: Elsevier Inc. Chapters
Published: 2013-06-10
Total Pages: 16
ISBN-13: 0128086408
DOWNLOAD EBOOKLarge eddy simulation and a discrete element method are applied to study the flow, particle dispersion and agglomeration in a horizontal channel. The particle-particle interaction model is based on the Hertz-Mindlin approach with Johnson-Kendall-Roberts cohesion to allow the simulation of Van der Waals forces in a dry air flow. The influence of different particle surface energies on agglomeration, and the impact of fluid turbulence, are investigated. The agglomeration rate is found to be strongly influenced by the particle surface energy, with most of the particle-particle interactions taking place at locations close to the channel walls, aided by the higher concentration of particles in these regions.
Author: Xiaojing Zheng
Publisher: Springer Nature
Published: 2024-01-02
Total Pages: 349
ISBN-13: 3031472586
DOWNLOAD EBOOKThis book presents the proceedings of the 'IUTAM Symposium on Turbulent Structure and Particles' held in 2023. It provides a comprehensive overview of the latest research and developments in the field of turbulent dispersed multiphase flows. The book features contributions from experts in academia and industry, covering a range of topics including droplet and pollutant dispersion, sand/dust storms, sediment transport in water or air flows, fluidized beds, bubbly flows and more. The content is a valuable reference for researchers, engineers, and students who are interested in understanding the complex behavior of multiphase flows in different natural and industrial environments.
Author: Orde
Publisher:
Published: 2015-11-17
Total Pages: 364
ISBN-13: 9781326476779
DOWNLOAD EBOOKLes 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.
Author: M. Elimelech
Publisher: Butterworth-Heinemann
Published: 2013-10-22
Total Pages: 458
ISBN-13: 1483161374
DOWNLOAD EBOOKParticle Deposition and Aggregation: Measurement, Modelling and Simulation describes how particle deposition and aggregation can be measured, modeled, and simulated in a systematic manner. It brings together the necessary disciplines of colloid and surface chemistry, hydrodynamics, experimental methods, and computational methods to present a unified approach to this problem. The book is divided into four parts. Part I presents the theoretical principles governing deposition and aggregation phenomena, including a discussion of the forces that exist between particles and the hydrodynamic factors that control the movement of the particles and suspending fluid. Part II introduces methods for modeling the processes, first at a simple level (e.g. single particle-surface, single particle-single particle interactions in model flow conditions) and then describes the simulation protocols and computation tools which may be employed to describe more complex (multiple-particle interaction) systems. Part III summarizes the experimental methods of quantifying aggregating and depositing systems and concludes with a comparison of experimental results with those predicted using simple theoretical predictions. Part IV is largely based on illustrative examples to demonstrate the application of simulation and modeling methods to particle filtration, aggregation, and transport processes. This book should be useful to graduates working in process and environmental engineering research or industrial development at a postgraduate level, and to scientists who wish to extend their knowledge into more realistic process conditions in which the fluid hydrodynamics and other complicating factors must be accommodated.
Author: Pritheesh Gnanaselvam
Publisher:
Published: 2020
Total Pages: 140
ISBN-13:
DOWNLOAD EBOOKThe 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.
Author: Jean-Pierre Minier
Publisher: Springer
Published: 2018-06-12
Total Pages: 261
ISBN-13: 9783319823850
DOWNLOAD EBOOKThe 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.
Author: Christoph Rettinger
Publisher:
Published: 2023
Total Pages: 0
ISBN-13: 9783843952736
DOWNLOAD EBOOKAuthor: Srinivas Praveen Mokkapati
Publisher:
Published: 2010
Total Pages:
ISBN-13:
DOWNLOAD EBOOKAttachment of particles to one another due to action of certain inter-particle forces is called as particle agglomeration. It has applications ranging from efficient capture of ultra-fine particles generated in coal-burning boilers to effective discharge of aerosol sprays. Aerosol sprays have their application in asthma relievers, coatings, cleaning agents, air fresheners, personal care products and insecticides. There are several factors that cause particle agglomeration and based on the application, agglomeration or de-agglomeration is desired. These various factors associated with agglomeration include van derWaals forces, capillary forces, electrostatic double-layer forces, effects of turbulence, gravity and brownian motion. It is therefore essential to understand the underlying agglomeration mechanisms involved. It is difficult to perform experiments to quantify certain effects of the inter-particle forces and hence we turn to numerical simulations as an alternative. Simulations can be performed using the various numerical simulation techniques such as molecular dynamics, discrete element method, dissipative particle dynamics or other probabilistic simulation techniques. The main objective of this thesis is to study the geometric characteristics of particle agglomerates using dissipative particle dynamics. In this thesis, agglomeration is simulated using the features of dissipative particle dynamics as the simulation technique. Forces of attraction from the literature are used to modify the form of the conservative force. Agglomeration is simulated and the characteristics of the result ing agglomerates are quantified. Simulations were performed on a sizeable number of particles and we observe agglomeration behavior. A study of the agglomerates resulting from the different types of attractive forces is performed to characterize them methodically. Also as a part of this thesis, a novel, dynamic particle simulation technique was developed by interfacing MATLAB and our computational C program.