Coupled CFD-DEM Modeling

Hamid Reza Norouzi holds a PhD from the University of Tehran in chemical engineering. His research interests are discrete element modeling, computational fluid dynamics and multiphase flows in chemical and pharmaceutical processes.Reza Zarghami is Head of the Pharmaceutical Engineering program and Assistant Professor at the School of Chemical Engineering at the University of Tehran. His research interests include pharmaceutical processing and manufacturing, powder technology, advanced fluid mechanics and CFD in chemical engineering, and he has published over 70 articles.Rahmat Sotudeh-Gharebagh is Director of Standard Research Institute, ISIRI, Tehran, Iran and a Professor of Chemical Engineering, at the University of Tehran. He founded the Pharmaceutical Engineering program there. His research interests include fluidization engineering, process modeling and simulation, chemical engineering education, pharmaceutical engineering and information technology. He has published three books, over 230 articles, and serves as editor-in-chief of Chemical Product and Process Modeling, and Journal of Industrial Technology Development.Navid Mostoufi is a Professor at the School of Chemical Engineering at the University of Tehran in Iran where he has taught for 14 years. His industry experience has included developing operator training simulators and feasibility studies for several companies. He is the author of more than 140 journal articles and 115 conference papers on process engineering and modeling, and is an editor for three journals including Chemical Product and Process Modeling where he is joint editor-in-chief with Professor Rahmat Sotudeh-Gharebagh.

• About the Authors xiPreface xiii1 Introduction 11.1 Multiphase Coupling 21.2 Modeling Approaches 21.3 Modeling with DEM 51.4 CFD‐DEM Modeling 71.5 Applications 101.6 Scope and Overall Plan 101.7 Online Content 12References 12Part I DEM 152 DEM Formulation 172.1 Hard‐Sphere 182.1.1 Equation of Motion 192.1.2 Collision Model 192.1.3 Interparticle Forces 222.2 Soft‐Sphere 242.2.1 Equations of Motion 252.3 Force‐Displacement Laws 272.3.1 Linear Viscoelastic Model 292.3.2 Nonlinear Viscoelastic Models 362.3.3 Comparison of Viscoelastic Force‐Displacement Models 452.3.4 Elastic Perfectly Plastic Models 492.4 Torque Expressions 562.4.1 Model A: Constant Torque Model 562.4.2 Model B: Viscous Model 572.4.3 Model C: Spring‐Dashpot Model 572.5 Boundary and Initial Conditions 582.5.1 Boundary Conditions 582.5.2 Initial Condition 60Nomenclature 60References 643 DEM Implementation 683.1 Computational View 683.2 Program Structure 713.3 Contact Search Algorithms 763.3.1 Definition of Problem 793.3.2 Cell‐Based Algorithms 803.3.3 Sort‐Based Algorithms 963.3.4 Tree‐Based Broad Search Algorithms 993.3.5 Fine Search for Spherical Particles 1033.4 Integration Methods 1033.4.1 Single‐Step Methods 1063.4.2 Multi‐Step Algorithms 1103.4.3 Predictor‐Corrector Methods 1123.4.4 Evaluation of Integration Methods 1143.5 Spring Stiffness 1193.5.1 Maximum Overlap 1223.5.2 Collision Time and Maximum Contact Force 1233.6 Wall Implementation 1233.6.1 Definition of Wall Elements 1253.6.2 Contact Detection 1283.6.3 Moving Wall 1363.7 Parallelization 1383.7.1 Distributed Memory Parallelization 1383.7.2 Shared‐Memory Parallelization 141Nomenclature 145References 1474 Non‐Spherical Particles 1524.1 Shape Representation 1534.2 Kinematics and Dynamics of a Rigid Body 1564.2.1 Euler Angles and Transformation Matrix 1574.2.2 Equations of Motion 1594.2.3 Quaternions for Rigid Body Dynamics 1634.3 Superellipsoids 1644.3.1 Contact Forces 1664.3.2 Effective Radius and Curvatures 1694.3.3 Torque Calculations 1734.3.4 Contact Detection 1744.4 Multi‐Sphere Method 178Nomenclature 184References 1865 DEM Applications to Granular Flows 1895.1 Packing of Particles 1895.1.1 Confined Packing 1895.1.2 Pile Formation 1925.1.3 Rigid and Flexible Fibers 1945.2 Flow in Hoppers 1965.2.1 Flow Patterns 1975.2.2 Segregation 1995.2.3 Discharge Rate 2015.3 Solid Mixing 2035.3.1 Mechanisms of Mixing and Segregation 2035.3.2 Mixing Index 2055.3.3 Rotating Drums 2095.3.4 Tumbling Blenders 2205.3.5 Shaft Batch Mixers 2235.3.6 Continuous Mixers 2295.4 Screw Conveying 2345.4.1 Simulation of Screw Conveyor 2375.4.2 Results of the Simulations 2385.4.3 Literature 2395.5 Film Coating 2415.5.1 Phenomenological Models 2435.5.2 Monte‐Carlo Method 244Nomenclature 247References 249Part II CFD‐DEM 2576 CFD‐DEM Formulation and Coupling 2596.1 Multiphase Coupling 2606.1.1 Coupling Strategies 2606.1.2 Types of Coupling 2626.1.3 Interphase Interactions 2656.2 Momentum Coupling 2676.2.1 Single Phase Flow of Fluids 2676.2.2 Fluid Resolution in CFD‐DEM 2746.2.3 Unresolved Surface CFD‐DEM 2756.2.4 Surface Force Decomposition 2876.3 Energy Coupling 3036.3.1 Governing Equations 3046.3.2 Rates of Heat Transfer for Particles 3086.3.3 Rates of Heat Transfer for Fluid 3166.3.4 Sequence of Calculations 3176.4 Mass Coupling 3196.4.1 Governing Equations 3196.4.2 Rates of Mass Transfer for Particles 3246.4.3 Rates of Change in Fluid 3296.4.4 Sequence of Calculations 329Nomenclature 329References 3357 CFD‐DEM Applications to Multiphase Flow 3417.1 Fluidization 3417.1.1 Macro‐Scale Phenomena 3427.1.2 Meso‐Scale Phenomena 3447.1.3 Micro‐Scale Phenomena 3457.2 Spouting 3477.3 Pneumatic Conveying 3557.3.1 Dilute Phase and Dense Phase Conveying 3567.3.2 Horizontal Conveying 3577.3.3 Vertical Conveying 3597.4 Non‐Isothermal Flows 3597.5 Reactive Flows 3627.6 Miscellaneous 364Nomenclature 365References 3668 Interparticle Forces and External Fields 3728.1 Governing Equations 3738.1.1 Sequence of Calculations 3758.2 Interparticle Forces 3768.2.1 van der Waals Force 3768.2.2 Liquid Bridge Force 3798.2.3 Electrostatic Force 3868.3 External Fields 3908.3.1 Electric Field 3908.3.2 Magnetic Field 3938.3.3 Vibration Field 3978.3.4 Acoustic Field 3988.4 Applications 399Nomenclature 404References 407Index 412