scholarly journals Eulerian-Eulerian Simulation of Particle-Liquid Slurry Flow in Horizontal Pipe

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Titus Ntow Ofei ◽  
Aidil Yunus Ismail
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Radial Distribution ◽  
Pressure Loss ◽  
Particle Concentration ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Turbulence Models ◽  
Particle Volume ◽  
Horizontal Pipe

In this study, a computational fluid dynamics (CFD) simulation which adopts the inhomogeneous Eulerian-Eulerian two-fluid model in ANSYS CFX-15 was used to examine the influence of particle size (90 μm to 270 μm) and in situ particle volume fraction (10% to 40%) on the radial distribution of particle concentration and velocity and frictional pressure loss. The robustness of various turbulence models such as the k-epsilon (k-ε), k-omega (k-ω), SSG Reynolds stress, shear stress transport, and eddy viscosity transport was tested in predicting experimental data of particle concentration profiles. The k-epsilon model closely matched the experimental data better than the other turbulence models. Results showed a decrease in frictional pressure loss as particle size increased at constant particle volume fraction. Furthermore, for a constant particle volume fraction, the radial distribution of particle concentration increased with increasing particle size, where high concentration of particles occurred at the bottom of the pipe. Particles of size 90 μm were nearly buoyant especially for high particle volume fraction of 40%. The CFD study shows that knowledge of the variation of these parameters with pipe position is very crucial if the understanding of pipeline wear, particle attrition, or agglomeration is to be advanced.

Radiative Transfer With Dependent Scattering by Particles: Part 2—Experimental Investigation

1986 ◽  
Vol 108 (3) ◽  
pp. 614-618 ◽  
Author(s):  
Y. Yamada ◽  
J. D. Cartigny ◽  
C. L. Tien
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Small Particles ◽  
Particle Volume ◽  
Water Matrix ◽  
Test Cells ◽  
Radiative Scattering ◽  
Regime Map

Dependent radiative scattering by particles is experimentally investigated using plane-parallel cells containing latex spheres of 11, 2, and 0.08 μm diameter dispersed in an air or water matrix. The dependent scattering efficiencies and the bidirectional transmittance and reflectance were measured and compared with analytical results. The close-packed 2-μm spheres, which were expected to show dependent scattering from the previous criterion, gave results identical to independent scattering. Measured dependent scattering efficiencies of the small particles tested decrease with increasing particle volume fraction and were compared with those predicted by the theoretical investigation. The bidirectional transmittance and reflectance of dependent scattering were compared with those of independent scattering with the same number of spheres within the test cells. Several different patterns of dependent transmittance and reflectance appeared depending on the optical thickness. Finally, a newly proposed regime map bounding independent and dependent scattering is compared with the present and previous experimental data.

scholarly journals Improved Heat Transfer in Guar Gel Composites Reinforced with Randomly Distributed Glass Microspheres

2021 ◽  
Author(s):  
Ruifeng CAO ◽  
Taotao WANG ◽  
Yuxuan ZHANG ◽  
Hui WANG
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Particle Size ◽  
Composite Materials ◽  
Effective Thermal Conductivity ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Glass Microspheres ◽  
Particle Volume ◽  
Number Of Particles

Improved heat transfer in composites consisting of guar gel matrix and randomly distributed glass microspheres is extensively studied to predict the effective thermal conductivity of composites using the finite element method. In the study, the proper and probabilistic three-dimensional random distribution of microspheres in the continuous matrix is automatically generated by a simple and efficient random sequential adsorption algorithm which is developed by considering the correlation of three factors including particle size, number of particles, and particle volume fraction controlling the geometric configuration of random packing. Then the dependences of the effective thermal conductivity of composite materials on some important factors are investigated numerically, including the particle volume fraction, the particle spatial distribution, the number of particles, the nonuniformity of particle size, the particle dispersion morphology and the thermal conductivity contrast between particle and matrix. The related numerical results are compared with theoretical predictions and available experimental results to assess the validity of the numerical model. These results can provide good guidance for the design of advanced microsphere reinforced composite materials.

3D Micro-Structural Modeling of Vibration Characteristics of Smart Particle-Reinforced Metal-Matrix Composite Beams

2019 ◽  
Vol 19 (07) ◽  
pp. 1950078
Author(s):  
Recep Ekici ◽  
Vahdet Mesut Abaci ◽  
J. N. Reddy
Keyword(s):  
Particle Size ◽  
Metal Matrix Composite ◽  
Metal Matrix ◽  
Vibration Amplitude ◽  
Natural Frequencies ◽  
Particle Distribution ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Particle Volume ◽  
Random Particle

In this study, the effects of micro-structural parameters such as particle volume fraction, size and random distribution of Al 6061/SiC particulate metal-matrix composite (MMC) beams on free vibration response and the active vibration control are investigated. For this purpose, numerical particle-reinforced MMC (PRMMC) beam specimens were modeled with 3D finite elements, and the cubic-shaped reinforcing SiC particles were randomly distributed in Al 6061 metal matrix similar to an actual micro-structure. The particle size and especially volume fraction play an important role on the natural frequencies of the smart PRMMCs although they have no effect on the mode shapes. The random particle distribution has minor effect on the natural frequencies of the smart PRMMCs. With the increase of the feedback control gain, both the vibration amplitude and the suppression time are reduced reasonably. Increasing the particle volume fraction induces an important reduction in the damping time and the vibration amplitude for both the controlled and uncontrolled damped vibrations. Finally, increasing the particle size decreases the vibration suppression capacity and increases the vibration amplitude and time slightly. Random particle distribution had no obvious effect on the uncontrolled and controlled vibrations.

Disordered Spheres with Extensive Overlap in Projection: Image Simulation and Analysis

2011 ◽  
Vol 17 (6) ◽  
pp. 872-878 ◽  
Author(s):  
Christopher D. Chan ◽  
Michelle E. Seitz ◽  
Karen I. Winey
Keyword(s):  
Particle Size ◽  
Critical Thickness ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Spherical Particles ◽  
Specimen Thickness ◽  
Number Density ◽  
Particle Volume ◽  
Transmission Electron ◽  
Projection Image

AbstractThis article simulates highly overlapped projections of spherical particles that are distributed randomly in space. The size and number of the features in the projections are examined as well as how these features change with particle size and concentration. First, there are discernable features in projection even when particles overlap extensively, and the size of these discernable features is the expected size of an individual particle. Second, the number of features increases with specimen thickness at a rate of t0.543 when the specimen thickness is below a critical value and becomes independent of specimen thickness at higher thicknesses. A criterion is established for the critical thickness based on particle size and particle volume fraction. When the specimen thickness is known and smaller than the critical thickness, a single representative transmission electron microscopy (TEM) (or scanning TEM) image exhibiting extensive particle overlap can be used to determine the size and number density of the spherical particles.

Physical and mechanical properties of stir-casting processed AA2024/B4Cp composites

2014 ◽  
Vol 21 (4) ◽  
pp. 505-515 ◽  
Author(s):  
Aykut Canakci ◽  
Fazli Arslan ◽  
Temel Varol
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Tensile Strength ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Stir Casting ◽  
Particle Volume ◽  
Electron Microscopic ◽  
Particle Content ◽  
Casting Technique

AbstractIn this study, metal matrix composites of an aluminum alloy (AA2024) and B4C particles with volume fractions 3, 5, 7, and 10 vol% and with sizes 29 and 71 μm were produced using stir-casting technique. The effects of B4C particle content and size of boron carbide on the mechanical properties of the composites such as hardness, 0.2% yield strength, tensile strength, and fracture were investigated. Furthermore, the relation between particle content, microstructure, and particle distribution has been investigated. The hardness of the composites increased with increasing particle volume fraction and with decreasing particle size, although the tensile strength of the composites decreased with increasing particle volume fraction and with decreasing particle size. Scanning electron microscopic observations of the microstructures revealed that dispersion of the coarser sizes of B4C particles was more uniform while the finer particles led to agglomeration of the particles and porosity.

Dependence of Thermal Conductivity and Mechanical Rigidity of Particle-Laden Polymeric Thermal Interface Material on Particle Volume Fraction

2003 ◽  
Vol 125 (3) ◽  
pp. 386-391 ◽  
Author(s):  
Ravi S. Prasher ◽  
Paul Koning ◽  
James Shipley ◽  
Amit Devpura
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Mechanical Response ◽  
Volume Fraction ◽  
Effective Medium Theory ◽  
Particle Volume Fraction ◽  
Thermal Interface Material ◽  
Particle Volume ◽  
Thermal Interface ◽  
Medium Theory

This paper reports the measurement of the thermal conductivity of particle-laden polymeric thermal interface materials for three different particle volume fractions. The experimental data are further compared with the percolation model and effective medium theory. We then introduce a method of obtaining the contact resistance between the particles and the polymeric matrix by a combination of percolation modeling and experimental data. We also discuss the dependence of the mechanical response of these particle-laden polymers for different filler or particle loading. A novel mechanical length scale is defined to understand the mechanical response of these materials, and is correlated to the viscosity of these materials.

An Experimental Study on the Cuttings Transport in Inclined Slim-Hole Annulus

2012 ◽  
Author(s):  
Y. J. Kim ◽  
S. M. Han ◽  
N. S. Woo
Keyword(s):  
Particle Concentration ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Flow Characteristics ◽  
Directional Drilling ◽  
Cuttings Transport ◽  
Particle Volume ◽  
Two Phase ◽  
Solid Liquid ◽  
And Control

In directional drilling, it is difficult to adjust and control the cuttings, so it is very important to evaluate the flow characteristics of a drilling flow field. In this study, solid-liquid two-phase flow experiments have been carried out in non-Newtonian fluids for hole inclinations from vertical to 75 degrees, flow velocities from 0.33 m/s to 0.66 m/s, particle concentration from 4 to 16 %, and pipe rotations from 0 to 400 rpm. Pressure drop within the test section, and particle volume fraction are measured for the above test conditions. These quantities were influenced by particle concentration within the flow, pipe rotation, flow volume, and inclination of the annulus. Moreover, empirical correlations were developed for estimating friction coefficient and particle volume fraction inside annulus. The new correlations generated in this study are believed to be very practical and handy when they are used in the field. Therefore, this study can provide meaningful data for directional drillings.

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