CFD modeling of the gas–particle flow behavior in spouted beds

Spouted bed systems have emerged as very efficient fluid-particle contactors and find many applications in the chemical and biochemical industry. Some important applications of spouted beds include coal combustion, biochemical reactions, drying of solids, drying of solutions and suspensions, granulation, blending, grinding, and particle coating. An extensive overview can be found in Mathur and Epstein[1]. The pattern of solid and gas flows in a spouted bed was numerically simulated using a CFD modeling technique. The Eulerian-Eulerian multifluid modeling approach was applied to predict gas-solid flow behavior. A commercially available, control-volume-based code FLUENT 6.1 was chosen to carry out the computer simulations. In order to reduce computational times and required system resources, the 2D axisymmetric segregated solver was chosen. The typical flow pattern of the spouted bed was obtained in the present calculation. The simulated velocity and voidage profiles presented a good agreement qualitative and quantitative with the experimental results obtained by He et al. [4].

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Research on the viscosity of stabilized emulsions in different pipe diameters using pressure drop and phase inversion

Experimental and Computational Multiphase Flow ◽

10.1007/s42757-020-0102-2 ◽

2021 ◽

Author(s):

Jose Plasencia ◽

Nathanael Inkson ◽

Ole Jørgen Nydal

Keyword(s):

Pressure Drop ◽

Salt Water ◽

Flow Behavior ◽

Turbulent Viscosity ◽

Relative Viscosity ◽

Cfd Modeling ◽

Water Fraction ◽

Water Fractions ◽

Oil Emulsions ◽

Mixture Velocity

AbstractThis paper reports experimental research on the flow behavior of oil-water surfactant stabilized emulsions in different pipe diameters along with theoretical and computational fluid dynamics (CFD) modeling of the relative viscosity and inversion properties. The pipe flow of emulsions was studied in turbulent and laminar conditions in four pipe diameters (16, 32, 60, and 90 mm) at different mixture velocities and increasing water fractions. Salt water (3.5% NaCl w/v, pH = 7.3) and a mineral oil premixed with a lipophilic surfactant (Exxsol D80 + 0.25% v/v of Span 80) were used as the test fluids. The formation of water-in-oil emulsions was observed from low water fractions up to the inversion point. After inversion, unstable water-in-oil in water multiple emulsions were observed under different flow regimes. These regimes depend on the mixture velocity and the local water fraction of the water-in-oil emulsion. The eddy turbulent viscosity calculated using an elliptic-blending k-ε model and the relative viscosity in combination act to explain the enhanced pressure drop observed in the experiments. The inversion process occurred at a constant water fraction (90%) and was triggered by an increase of mixture velocity. No drag reduction effect was detected for the water-in-oil emulsions obtained before inversion.

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Electrostatic effect on the flow behavior of a dilute gas/cohesive particle flow system

AIChE Journal ◽

10.1002/aic.690420610 ◽

1996 ◽

Vol 42 (6) ◽

pp. 1590-1599 ◽

Cited By ~ 23

Author(s):

Yu-Feng Zhang ◽

Yi Yang ◽

Hamid Arastoopour

Keyword(s):

Flow System ◽

Flow Behavior ◽

Particle Flow ◽

Dilute Gas ◽

Electrostatic Effect

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Shear Flow Analysis of Nanosize Particle Flow Behavior Using Kinetic Theory

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.277-279.939 ◽

2005 ◽

Vol 277-279 ◽

pp. 939-944

Author(s):

Hae Ryung Kim ◽

Jaihyun Seu ◽

Hamid Arastoopour

Keyword(s):

Shear Flow ◽

Kinetic Theory ◽

Flow Behavior ◽

Flow Analysis ◽

Particle Diameter ◽

Particle Flow ◽

Particle Collision ◽

Simple Shear Flow ◽

Particle Force ◽

Nanosize Particle

Nanosize particle flow is significantly affected by inter-particle force. Due to the inter-particle force, the most significant characteristic of nanosize particle flow may become the formation of agglomerates or clusters which considerably affects the flow patterns. The formation of agglomerates or clusters results in a reduction in the number and an increase in the size of particles, both of which directly affect the frequency of inter-particle collisions and, in turn, the particle phase properties such as viscosity and pressure, as well as gas/particle drag force in gas/particle flow systems. In this present work, we focus our attention on the verification of nanosize particle flow behavior due to the formation of agglomerates or clusters under different fluctuation of flow and inelasticity of particle collision. By extending the application of the cohesive model using kinetic theory to nanosize particle flow system, we performed the homogeneous simple shear flow analysis using various fluctuation energy and restitution coefficient. The predicted flow properties, such as particle diameter growth, agreed well with the expected trends.

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CFD Modeling of Fluid Flow Behavior and Bath Surface Deformation in LD Converter

CFD Modeling and Simulation in Materials Processing ◽

10.1002/9781118364697.ch38 ◽

2012 ◽

pp. 319-326 ◽

Cited By ~ 2

Author(s):

T. K. Kundu ◽

Snehanshu Pal

Keyword(s):

Fluid Flow ◽

Surface Deformation ◽

Flow Behavior ◽

Cfd Modeling ◽

Bath Surface

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An Evaluation of Thermochemical Property Models for CaO-MnO-SiO2-Al2O3-MgO Slag

Journal for Manufacturing Science and Production ◽

10.1515/jmsp-2013-0003 ◽

2013 ◽

Vol 13 (4) ◽

pp. 251-262 ◽

Cited By ~ 1

Author(s):

J. Muller ◽

J.D. Steenkamp

Keyword(s):

Thermal Conductivity ◽

Heat Capacity ◽

Chemical Composition ◽

Flow Behavior ◽

Slag System ◽

Cfd Modeling ◽

Thermochemical Property ◽

Thermochemical Properties ◽

Weight Percentage ◽

Fixed Weight

AbstractThe modeling of thermochemical properties is important in studying the physical behavior of slag in the operation of pyrometallurgical smelters. To study the flow of slag through a submerged-arc furnace (SAF) tap-hole, knowledge of thermochemical properties such as viscosity, thermal conductivity, density and heat capacity are required. In literature various models exist for silicate slags that enable thermochemical properties to be predicted as functions of chemical composition and temperature. This paper reports on the application of models in the CaO-MnO-SiO2-Al2O3-MgO slag system to be used in future CFD modeling of slag tapped from SAFs producing high-carbon ferromanganese (HCFeMn) or silicomanganese (SiMn). FactSage 6.2 is used to estimate the phase composition of slags with varying chemical composition and temperature. The dependence of thermochemical property models on chemical composition and temperature is illustrated in the form of ternary diagrams showing the predicted property values as a function of basicity (chemical composition) and temperature. Slag compositions typical of HCFeMn and SiMn processes are used. Each thermochemical property is calculated at 1400, 1500 and 1600 °C at a fixed weight percentage ratio Al2O3/SiO2 of 0.57 and 6% MgO. Ternary phase diagrams (1400, 1500 and 1600 °C) and a ternary liquidus temperature diagram are also presented for the system. Since viscosity has the most significant influence on flow behavior, results from various viscosity models have been compared with measured data. Predictions for thermal conductivity, density, and heat capacity are also discussed.

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Computational Modeling and Experimental Investigation of Static Straight-Through Labyrinth Seals

Volume 5: Design, Analysis, Control and Diagnosis of Fluid Power Systems ◽

10.1115/imece2008-67847 ◽

2008 ◽

Cited By ~ 6

Author(s):

Alexandrina Untaroiu ◽

Christopher P. Goyne ◽

Costin D. Untaroiu ◽

Houston G. Wood ◽

Robert Rockwell ◽

...

Keyword(s):

Experimental Data ◽

Flow Behavior ◽

Optimization Techniques ◽

Bulk Flow ◽

Numerical Code ◽

Cfd Modeling ◽

Leakage Flow ◽

Dynamic Coefficients ◽

Seal Design ◽

Flow Parameters

To design highly efficient and stable turbomachines, engineers require accurate methods to model seal flows and calculate clearance-excitation forces generated by the eccentric position of the rotor. One of the most widely used methods to predict leakage flow and dynamic coefficients is the use of computer codes developed based on bulk flow theory. In recent years, computational fluid dynamics (CFD) modeling is increasingly being recognized as an accurate assessment tool for flow parameters and dynamic coefficients evaluation as compared to the bulk flow codes. This paper presents computational and experimental investigations that were carried out to calculate flow parameters in a stationary straight-through model labyrinth seal. The main objective of this study is to explore the capabilities of Ansys-CFX, a commercially available state of the art 3D numerical code, to accurately model compressible flow through the seals. The flow behavior is analyzed using CFD and the flow parameters calculated by CFD are validated against experimental data taken for the same seal configuration. The integrated values of leakage flow rates estimated from the computational results agree with the experimental data within 7.6%. This study serves as a benchmark case that supports further efforts in applying CFD analysis in conjunction with automatic design optimization techniques for seals used for compressible media. It was shown that optimization algorithms combined with CFD simulations have good potential for improving seal design.

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Particle flow behavior in models of branching vessels

Biorheology ◽

10.3233/bir-1985-22201 ◽

1985 ◽

Vol 22 (2) ◽

pp. 87-104 ◽

Cited By ~ 66

Author(s):

Takeshi Karino ◽

Harry L. Goldsmith

Keyword(s):

Flow Behavior ◽

Particle Flow

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Evaluation of Single-Phase CFD Applicability to Estimate Fluid Hot Spot Locations by Comparing Water DNB Data

12th International Conference on Nuclear Engineering, Volume 2 ◽

10.1115/icone12-49174 ◽

2004 ◽

Author(s):

Kazuo Ikeda ◽

Yasushi Makino ◽

Masaya Hoshi

Keyword(s):

Heat Generation ◽

Pressure Loss ◽

Single Phase ◽

Flow Behavior ◽

Cfd Modeling ◽

Spacer Grid ◽

Flow Measurements ◽

Fuel Rods ◽

Spacer Grids ◽

Grid Design

For development of PWR spacer grids, it is necessary to confirm mechanical strength and thermal-hydraulic characteristics. Mitsubishi has applied Computational Fluid Dynamics (CFD) to thermal-hydraulic design of spacer grids. To satisfy the requirement of high thermal performance spacer grid, the compatibility of low-pressure loss and high Critical Heat Flux (CHF) performance is necessary; therefore, parametric CFD analyses have been carried out for new spacer grid designs. Related to spacer grid design, i.e., strap structures and mixing vane, the parametric analyses have been carried out to estimate pressure-loss of each spacer grid. Moreover, thermal analyses, where heat generation from fuel rods was taken into account, have been carried out to evaluate coolant mixing capability, which is assumed to relate the CHF performance, by comparing fluid peak temperature of each grid design. In our previous study (ICONE11-36087), the rod type Laser Doppler Velocimetry (rod LDV) and Particle Imaging Velocimetry (PIV) technique were applied to cross-flow and axial flow measurements in rod gaps and sub-channels to obtain reference data for verification of CFD estimation. Estimated velocity fields at the downstream of the grid were quantitatively compared with the measurements. As a result, it was confirmed that the CFD modeling estimated flow behavior in the rod bundle appropriately. In this study, CFD under single-phase condition, which took into account heat generation from rods, was performed to simulate flow conditions of water DNB test with the same design grid of the previous study. The correlation between estimated enthalpy distribution around fuel rods by the CFD and the CHF rods in the DNB test was examined. This study was performed in collaboration with Westinghouse Electric Company and Mitsubishi Heavy Industries, Ltd.

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