Modeling of solid-liquid flow inside conical diverging sections using computational fluid dynamics approach
TL;DR: In this paper, the authors used the computational fluid dynamics approach to simulate coal water slurry through conical diverging sections and found the 0.3-m long diverging section to be the optimum design for best pressure recovery, maximum volumetric efficiency and lowest head-loss.
About: This article is published in International Journal of Mechanical Sciences.The article was published on 2020-11-15. It has received 7 citations till now. The article focuses on the topics: Pressure drop & Flow separation.
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01 Sep 2021
TL;DR: This review paper discusses the potential and the challenges of the CFD approach, underlying the essential interplay between CFD simulations and experiments, and discussing the main sources of uncertainty of CFD models, and evaluating existing models based on their interpretative or predictive capacity.
Abstract: Slurry pipe transport has directed the efforts of researchers for decades, not only for the practical impact of this problem, but also for the challenges in understanding and modelling the complex phenomena involved. The increase in computer power and the diffusion of multipurpose codes based on Computational Fluid Dynamics (CFD) have opened up the opportunity to gather information on slurry pipe flows at the local level, in contrast with the traditional approaches of simplified theoretical modelling which are mainly based on a macroscopic description of the flow. This review paper discusses the potential of CFD for simulating slurry pipe flows. A comprehensive description of the modelling methods will be presented, followed by an overview of significant publications on the topic. However, the main focus will be the assessment of the potential and the challenges of the CFD approach, underlying the essential interplay between CFD simulations and experiments, discussing the main sources of uncertainty of CFD models, and evaluating existing models based on their interpretative or predictive capacity. This work aims at providing a solid ground for students, academics, and professional engineers dealing with slurry pipe transport, but it will also provide a methodological approach that goes beyond the specific application.
18 citations
TL;DR: Wang et al. as discussed by the authors proposed a novel numerical method for grouting in flowing water based on the Euler-Euler framework: two-fluid tracking (TFT) method.
11 citations
TL;DR: In this paper, the authors proposed the introduction of a twisted pipe section of a suitable length and geometry, that produces enough turbulence in the flow, sufficient for the re-dispersion of the already settled particles and check their further deposition.
3 citations
2 citations
TL;DR: In this article , the authors investigated the flow of coal water suspension through a converging section, diverging section and a bend using computational fluid dynamics approach and found that the headloss across the entire test section is found to be minimum for the case where the angle of convergence/divergence is fixed at 1° each.
Abstract: The design and choice of pipe fittings in such systems plays an important role as far as headloss and flow separation are factors of concern. This study aims to investigate the flow of coal water suspension through a converging section, diverging section and a bend using computational fluid dynamics approach. The modelling and simulation are carried out on geometries consisting of both converging and diverging sections of variable angles along with a bend of R/d ratio of 2. The computational fluid dynamics simulation results are in good agreement with the experimental data, with an average percentage error of 1.96%. 1° angle of divergence and 7° angle of convergence are optimum designs for the lowest local headloss. However, the headloss across the entire test section is found to be minimum for the case where the angle of convergence/divergence is fixed at 1° each. The specific energy consumption gives a practical idea about the minimum energy required for the transportation of solids through some distance, which is an all-time minimum for the suspension containing 60% solids by mass. The study presents a detailed investigation into the local as well as global flow characteristics of the coal water suspension through a test section.
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References
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TL;DR: In this paper, a new method to model the effect of the solid boundaries on the rest of the flowfield in large-eddy simulations is proposed, where the filtered Navier-Stokes equations are solved up to the first computational point from there to the wall, a simplified set of equations is solved, and an estimate of the instantaneous wall shear stress required to impose boundary conditions is obtained.
Abstract: A new method to model the effect of the solid boundaries on the rest of the flowfield in large-eddy simulations is proposed The filtered Navier-Stokes equations are solved up to the first computational point From there to the wall, a simplified set of equations is solved, and an estimate of the instantaneous wall shear stress required to impose boundary conditions is obtained Computations performed for the plane channel, square duct, and the rotating channel flow cases gave improved results compared with existing models The additional computing time required by the model is on the order of 10-15% of the overall computing time The mean flow quantities and low-order statistics, which are of primary interest in engineering calculations, are in very good agreement with the reference data available in the literature
356 citations
07 Jan 1991
336 citations
TL;DR: In this paper, a review of the numerical studies performed in this area including conventional numerical methods as well as the new Lattice Boltzmann Method (LBM) is presented.
250 citations
Book•
18 Jan 2011
TL;DR: In this article, the authors present a detailed analysis of flow properties in a pipe with respect to the Euler's Equation and the Bernoulli Equation along a streamline.
Abstract: CHAPTER 1 INTRODUCTION. 1.1 Note to Students. 1.2 Scope of Fluid Mechanics. 1.3 Definition of a Fluid. 1.4 Basic Equations. 1.5 Methods of Analysis. 1.6 Dimensions and Units. 1.7 Analysis of Experimental Error. 1.8 Summary. Problems. CHAPTER 2 FUNDAMENTAL CONCEPTS. 2.1 Fluid as a Continuum. 2.2 Velocity Field. 2.3 Stress Field. 2.4 Viscosity. 2.5 Surface Tension. 2.6 Description and Classification of Fluid Motions. 2.7 Summary and Useful Equations. References. Problems. CHAPTER 3 FLUID STATICS. 3.1 The Basic Equation of Fluid Statics. 3.2 The Standard Atmosphere. 3.3 Pressure Variation in a Static Fluid. 3.4 Hydraulic Systems. 3.5 Hydrostatic Force on Submerged Surfaces. 3.6 Buoyancy and Stability. 3.7 Fluids in Rigid-Body Motion (on the Web). 3.8 Summary and Useful Equations. References. Problems. CHAPTER 4 BASIC EQUATIONS IN INTEGRAL FORM FOR A CONTROL VOLUME. 4.1 Basic Laws for a System. 4.2 Relation of System Derivatives to the Control Volume Formulation. 4.3 Conservation of Mass. 4.4 Momentum Equation for Inertial Control Volume. 4.5 Momentum Equation for Control Volume with Rectilinear Acceleration. 4.6 Momentum Equation for Control Volume with Arbitrary Acceleration (on the Web). 4.7 The Angular-Momentum Principle. 4.8 The First Law of Thermodynamics. 4.9 The Second Law of Thermodynamics. 4.10 Summary and Useful Equations. Problems. CHAPTER 5 INTRODUCTION TO DIFFERENTIAL ANALYSIS OF FLUID MOTION. 5.1 Conservation of Mass. 5.2 Stream Function for Two-Dimensional Incompressible Flow. 5.3 Motion of a Fluid Particle (Kinematics). 5.4 Momentum Equation. 5.5 Introduction to Computational Fluid Dynamics. 5.6 Summary and Useful Equations. References. Problems. CHAPTER 6 INCOMPRESSIBLE INVISCID FLOW. 6.1 Momentum Equation for Frictionless Flow: Euler's Equation. 6.2 Euler's Equations in Streamline Coordinates. 6.3 Bernoulli Equation-Integration of Euler's Equation Along a Streamline for Steady Flow. 6.4 The Bernoulli Equation Interpreted as an Energy Equation. 6.5 Energy Grade Line and Hydraulic Grade Line. 6.6 Unsteady Bernoulli Equation: Integration of Euler's Equation Along a Streamline (on the Web). 6.7 Irrotational Flow. 6.8 Summary and Useful Equations. References. Problems. CHAPTER 7 DIMENSIONAL ANALYSIS AND SIMILITUDE. 7.1 Nondimensionalizing the Basic Differential Equations. 7.2 Nature of Dimensional Analysis. 7.3 Buckingham Pi Theorem . 7.4 Determining the PI Groups. 7.5 Significant Dimensionless Groups in Fluid Mechanics. 7.6 Flow Similarity and Model Studies. 7.7 Summary and Useful Equations. References. Problems. CHAPTER 8 INTERNAL INCOMPRESSIBLE VISCOUS FLOW. 8.1 Introduction. PART A. FULLY DEVELOPED LAMINAR FLOW. 8.2 Fully Developed Laminar Flow between Infinite Parallel Plates. 8.3 Fully Developed Laminar Flow in a Pipe. PART B. FLOW IN PIPES AND DUCTS. 8.4 Shear Stress Distribution in Fully Developed Pipe Flow. 8.5 Turbulent Velocity Profiles in Fully Developed Pipe Flow. 8.6 Energy Considerations in Pipe Flow. 8.7 Calculation of Head Loss. 8.8 Solution of Pipe Flow Problems. PART C. FLOW MEASUREMENT. 8.9 Direct Methods. 8.10 Restriction Flow Meters for Internal Flows. 8.11 Linear Flow Meters. 8.12 Traversing Methods. 8.13 Summary and Useful Equations. References. Problems. CHAPTER 9 EXTERNAL INCOMPRESSIBLE VISCOUS FLOW. PART A. BOUNDARY LAYERS. 9.1 The Boundary-Layer Concept. 9.2 Boundary-Layer Thicknesses. 9.3 Laminar Flat-Plate Boundary Layer: Exact Solution (on the Web). 9.4 Momentum Integral Equation. 9.5 Use of the Momentum Integral Equation for Flow with Zero Pressure Gradient. 9.6 Pressure Gradients in Boundary-Layer Flow. PART B. FLUID FLOW ABOUT IMMERSED BODIES. 9.7 Drag. 9.8 Lift. 9.9 Summary and Useful Equations. References. Problems. CHAPTER 10 FLUID MACHINERY. 10.1 Introduction and Classification of Fluid Machines. 10.2 Turbomachinery Analysis. 10.3 Pumps, Fans, and Blowers. 10.4 Positive Displacement Pumps. 10.5 Hydraulic Turbines. 10.6 Propellers and Wind-Power Machines. 10.7 Compressible Flow Turbomachines. 10.8 Summary and Useful Equations. References. Problems. CHAPTER 11 FLOW IN OPEN CHANNELS. 11.1 Basic Concepts and Definitions. 11.2 Energy Equation for Open-Channel Flows. 11.3 Localized Effect of Area Change (Frictionless Flow). 11.4 The Hydraulic Jump. 11.5 Steady Uniform Flow. 11.6 Flow with Gradually Varying Depth. 11.7 Discharge Measurement Using Weirs. 11.8 Summary and Useful Equations. References. Problems. CHAPTER 12 INTRODUCTION TO COMPRESSIBLE FLOW. 12.1 Review of Thermodynamics. 12.2 Propagation of Sound Waves. 12.3 Reference State: Local Isentropic Stagnation Properties. 12.4 Critical Conditions. 12.5 Summary and Useful Equations. References. Problems. CHAPTER 13 COMPRESSIBLE FLOW. 13.1 Basic Equations for One-Dimensional Compressible Flow. 13.2 Isentropic Flow of an Ideal Gas: Area Variation. 13.3 Normal Shocks. 13.4 Supersonic Channel Flow with Shocks. 13.5 Flow in a Constant-Area Duct with Friction. 13.6 Frictionless Flow in a Constant-Area Duct with Heat Exchange. 13.7 Oblique Shocks and Expansion Waves. 13.8 Summary and Useful Equations. References. Problems. APPENDIX A FLUID PROPERTY DATA. APPENDIX B EQUATIONS OF MOTION IN CYLINDRICAL COORDINATES. APPENDIX C VIDEOS FOR FLUID MECHANICS. APPENDIX D SELECTED PERFORMANCE CURVES FOR PUMPS AND FANS. APPENDIX E FLOW FUNCTIONS FOR COMPUTATION OF COMPRESSIBLE FLOW. APPENDIX F ANALYSIS OF EXPERIMENTAL UNCERTAINTY. APPENDIX G SI UNITS, PREFIXES, AND CONVERSION FACTORS. APPENDIX H A BRIEF REVIEW OF MICROSOFT EXCEL (ON THE WEB). Answers to Selected Problems. Index.
208 citations
TL;DR: In this paper, a physical model for the prediction of the pressure drop and flow patterns is presented for the hydraulic transport of coarse particles in horizontal tubes, which is compared with new experimental data and shows good agreement.
182 citations