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Multiphase Flow and Granular Mechanics
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Multiphase Flow and Granular Mechanics

A special issue of Fluids (ISSN 2311-5521). This special issue belongs to the section "Flow of Multi-Phase Fluids and Granular Materials".

Deadline for manuscript submissions: closed (30 June 2024) | Viewed by 14980

Special Issue Editor

Dr. Hua Tan

E-Mail Website
Guest Editor
School of Engineering and Computer Science, Washington State University-Vancouver, Vancouver, WA 98686, USA
Interests: computational fluid dynamics (CFD); finite element analysis (FEA); multiphase flows; porous media flow; microfluidics; additive manufacturing; manufacturing process for fiber reinforced polymer (FRP) composites
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Multiphase flow and granular mechanics are two fascinating and interdisciplinary research areas with wide-ranging applications for engineering, physics, and environmental science. Multiphase flows occur when two or more phases, such as a gas–liquid, liquid–liquid, or solid–liquid, are present in a system. Granular mechanics, on the other hand, deal with the behavior of granular materials, such as sand, rocks, and powders. These two research areas share many well-known features and challenges, such as complex interfaces, phase transitions, and nonlinear behavior, making them crucial topics for interdisciplinary research.

This Special Issue aims to bring together original research articles, review papers, and perspectives focusing on recent advances and applications of multiphase flow and granular mechanics. This Special Issue also provides a platform for researchers to share their latest findings, exchange ideas, and identify future directions for research in these exciting and rapidly evolving fields.

Topics of interest include, but are not limited to:

  • The fundamentals of multiphase flow and granular mechanics;
  • Experimental and numerical methods to study multiphase flows and granular materials;
  • Modeling and the simulation of complex multiphase systems;
  • Transport phenomena in a multiphase flow and granular media;
  • Rheology and mechanical properties of granular materials;
  • Granular–fluid interactions in natural and engineered systems;
  • Applications in energy, environmental, and biomedical engineering.

Dr. Hua Tan
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Fluids is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • multiphase flow
  • granular mechanics
  • numerical methods
  • fluid–particle interactions
  • experimental techniques

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Published Papers (11 papers)

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Research

24 pages, 5293 KiB  
Article
Computational Fluid Dynamics Study on Bottom-Hole Multiphase Flow Fields Formed by Polycrystalline Diamond Compact Drill Bits in Foam Drilling
by Lihong Wei and Jaime Honra
Fluids 2024, 9(9), 211; https://doi.org/10.3390/fluids9090211 - 10 Sep 2024
Viewed by 659
Abstract
High-temperature geothermal wells frequently employ foam drilling fluids and Polycrystalline Diamond Compact (PDC) drill bits. Understanding the bottom-hole flow field of PDC drill bits in foam drilling is essential for accurately analyzing their hydraulic structure design. Based on computational fluid dynamics (CFD) and [...] Read more.
High-temperature geothermal wells frequently employ foam drilling fluids and Polycrystalline Diamond Compact (PDC) drill bits. Understanding the bottom-hole flow field of PDC drill bits in foam drilling is essential for accurately analyzing their hydraulic structure design. Based on computational fluid dynamics (CFD) and multiphase flow theory, this paper establishes a numerical simulation technique for gas-liquid-solid multiphase flow in foam drilling with PDC drill bits, combined with a qualitative and quantitative hydraulic structure evaluation method. This method is applied to simulate the bottom-hole flow field of a six-blade PDC drill bit. The results show that the flow velocity of the air phase in foam drilling fluid is generally higher than that of the water phase. Some blades’ cutting teeth exhibit poor cleaning and cooling effects, with individual cutting teeth showing signs of erosion damage and cuttings cross-flow between channels. To address these issues, optimizing the nozzle spray angle and channel design is necessary to improve hydraulic energy distribution, enhance drilling efficiency, and extend drill bit life. This study provides new ideas and methods for developing geothermal drilling technology in the numerical simulation of a gas-liquid-solid three-phase flow field. Additionally, the combined qualitative and quantitative evaluation method offers new insights and approaches for research and practice in drilling engineering. Full article
(This article belongs to the Special Issue Multiphase Flow and Granular Mechanics)
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20 pages, 3535 KiB  
Article
Stability or Instability of a Static Liquid Bridge Appearing in Shaped Crystal Growth from Melt via the Pulling-Down Method
by Andreea V. Cojocaru and Stefan Balint
Fluids 2024, 9(8), 176; https://doi.org/10.3390/fluids9080176 - 31 Jul 2024
Viewed by 655
Abstract
This study presents sufficient conditions for the stability or instability of the static liquid bridge appearing in crystal growth from the melt of micro-fibers, thin plates, and hollow micro-tubes of predetermined sizes using the pulling-down method. The case in which the contact angle [...] Read more.
This study presents sufficient conditions for the stability or instability of the static liquid bridge appearing in crystal growth from the melt of micro-fibers, thin plates, and hollow micro-tubes of predetermined sizes using the pulling-down method. The case in which the contact angle and the growth angle verify the inequality αc>π/2−αg is considered. Experimentally, only stable static liquid bridges can be created; unstable static liquid bridges exist just in theory, because in reality they collapse. The results of this study are significant for shaped crystal growth from melted materials, with given macroscopic dimensions, and using specific equipment. This is because the obtained inequalities represent limits for what can and cannot be achieved experimentally. Full article
(This article belongs to the Special Issue Multiphase Flow and Granular Mechanics)
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16 pages, 2368 KiB  
Article
Slow Translation of a Composite Sphere in an Eccentric Spherical Cavity
by Yi C. Chen and Huan J. Keh
Fluids 2024, 9(7), 154; https://doi.org/10.3390/fluids9070154 - 28 Jun 2024
Cited by 1 | Viewed by 638
Abstract
This semi-analytical study is presented examining the quasi-steady creeping flow caused by a soft (composite) spherical particle, which is a hard (impermeable) sphere core covered by a porous (permeable) layer, translating in an incompressible Newtonian fluid within a non-concentric spherical cavity along the [...] Read more.
This semi-analytical study is presented examining the quasi-steady creeping flow caused by a soft (composite) spherical particle, which is a hard (impermeable) sphere core covered by a porous (permeable) layer, translating in an incompressible Newtonian fluid within a non-concentric spherical cavity along the line joining their centers. To solve the Brinkman and Stokes equations for the flow fields inside and outside the porous layer, respectively, general solutions are constructed in two spherical coordinate systems attached to the particle and cavity individually. The boundary conditions at the cavity wall and particle surface are fulfilled through a collocation method. Numerical results of the normalized drag force exerted by the fluid on the particle are obtained for numerous values of the ratios of core-to-particle radii, particle-to-cavity radii, the distance between the centers to the radius difference of the particle and cavity, and the particle radius to porous layer permeation length. For the translation of a soft sphere within a concentric cavity or near a small-curvature cavity wall, our drag results agree with solutions available in the literature. The cavity effect on the drag force of a translating soft sphere is monotonically increasing functions of the ratios of core-to-particle radii and the particle radius to porous layer permeation length. While the drag force generally rises with an increase in the ratio of particle-to-cavity radii, a weak minimum (surprisingly, smaller than that for an unconfined soft sphere) may occur for the case of low ratios of core-to-particle radii and of the particle radius to permeation length. This drag force generally increases with an increase in the eccentricity of the particle position, but in the case of low ratios of core-to-particle radii and particle radius to permeation length, the drag force may decrease slightly with increasing eccentricity. Full article
(This article belongs to the Special Issue Multiphase Flow and Granular Mechanics)
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21 pages, 12980 KiB  
Article
Effects of Inlet Velocity Profile on the Bubble Dynamics in a Fluidized Bed Partially Filled with Geldart B Particles
by Rohit Kanchi and Prashant Singh
Fluids 2024, 9(7), 149; https://doi.org/10.3390/fluids9070149 - 22 Jun 2024
Viewed by 730
Abstract
In this study, a two-dimensional computational domain featuring gas and solid phases is computationally studied for Geldart-B-type particles. In addition to the baseline case of a uniform gas-phase injection velocity, three different inlet velocity profiles were simulated, and their effects on the fluidized [...] Read more.
In this study, a two-dimensional computational domain featuring gas and solid phases is computationally studied for Geldart-B-type particles. In addition to the baseline case of a uniform gas-phase injection velocity, three different inlet velocity profiles were simulated, and their effects on the fluidized bed hydrodynamics and bubble dynamics have been studied. An in-house computer program was developed to track the bubbles and determine the temporal evolution of their size and position prior to their breakup. This program also provides information on the location of bubble coalescence and breakup. The gas-solid interactions were simulated using a Two-Fluid Model (TFM) with Gidaspow’s drag model. The results reveal that the bed hydrodynamics feature a counter-rotating vortex pair for the solid phase, and bubble dynamics, such as coalescence and breakup, can be correlated with the vortices’ outer periphery and the local gradients in the vorticity. Full article
(This article belongs to the Special Issue Multiphase Flow and Granular Mechanics)
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22 pages, 36248 KiB  
Article
Physical and Numerical Experimentation of Water Droplet Collision on a Wall: A Comparison between PLIC and HRIC Schemes for the VOF Transport Equation with High-Speed Imaging
by Bruno Silva de Lima, Martin Sommerfeld and Francisco José de Souza
Fluids 2024, 9(5), 117; https://doi.org/10.3390/fluids9050117 - 16 May 2024
Viewed by 830
Abstract
Liquid films are often found in engineering applications with thicknesses ranging from micrometer scales to large scales with a wide range of applications. To optimize such systems, researchers have dedicated themselves to the development of new techniques. To further contribute to this development, [...] Read more.
Liquid films are often found in engineering applications with thicknesses ranging from micrometer scales to large scales with a wide range of applications. To optimize such systems, researchers have dedicated themselves to the development of new techniques. To further contribute to this development, the objective of this work is to present the results of the collision of water droplets on a wall by means of experimentation and numerical simulations. For physical experimentation, an injector is used to generate a chain of water droplets that collide with the opposite wall, forming a liquid film. Images of the droplets were obtained using two high-speed recording cameras. The results for different droplet sizes and impact angles are presented and the relationship between the momentum parameter and non-dimensional pool size was established. Modeling such processes is a common challenge in engineering, with different techniques having their advantages and limitations. The simulations in this work were run using the volume of fluid method, which consists of solving a transport equation for the volume fraction of each considered fluid. A correlation was found between the surface tension to momentum transport ratio, Scd, and the non-dimensional pool size for different droplet sizes and impact angles. Regions where partial depositions were most likely to occur were found via physical experiments. Full article
(This article belongs to the Special Issue Multiphase Flow and Granular Mechanics)
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18 pages, 4768 KiB  
Article
Characteristics of a Particle’s Incipient Motion from a Rough Wall in Shear Flow of Herschel–Bulkley Fluid
by Alexander Seryakov, Yaroslav Ignatenko and Oleg B. Bocharov
Fluids 2024, 9(3), 65; https://doi.org/10.3390/fluids9030065 - 5 Mar 2024
Viewed by 1388
Abstract
A numerical simulation of the Herschel–Bulkley laminar steady state shear flow around a stationary particle located on a sedimentation layer was carried out. The surface of the sedimentation layer was formed by hemispheres of the same radius as the particle. The drag force, [...] Read more.
A numerical simulation of the Herschel–Bulkley laminar steady state shear flow around a stationary particle located on a sedimentation layer was carried out. The surface of the sedimentation layer was formed by hemispheres of the same radius as the particle. The drag force, lift force, and torque values were obtained in the following ranges: shear Reynolds numbers for a particle ReSH=2–200, corresponding to laminar flow; power law index n=0.6–1.0; and Bingham number Bn=0–10. A significant difference in the forces and torque acting on a particle in shear flow in comparison to the case of a smooth wall is shown. It is shown that the drag coefficient is on average 6% higher compared to a smooth wall for a Newtonian fluid but decreases with the increase in non-Newtonian properties. At the edge values of n=0.6 and Bn=10, the drag is on average 25% lower compared to the smooth wall. For a Newtonian fluid, the lift coefficient is on average 30% higher compared to a smooth wall. It also decreases with the increase in non-Newtonian properties of the fluid, but at the edge values of n=0.6 and Bn=10, it is on average only 3% lower compared to the smooth wall. Approximation functions for the drag, lift force, and torque coefficient are constructed. A reduction in the drag force and lifting force leads to an increase in critical stresses (Shields number) on the wall on average by 10% for incipient motion (rolling) and by 12% for particle detachment from the sedimentation bed. Full article
(This article belongs to the Special Issue Multiphase Flow and Granular Mechanics)
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28 pages, 5176 KiB  
Article
A Computational Study of the Influence of Drag Models and Heat Transfer Correlations on the Simulations of Reactive Polydisperse Flows in Bubbling Fluidized Beds
by Manuel Ernani Cruz, Gabriel Lisbôa Verissimo, Filipe Leite Brandão and Albino José Kalab Leiroz
Fluids 2023, 8(11), 290; https://doi.org/10.3390/fluids8110290 - 28 Oct 2023
Viewed by 1795
Abstract
In this work, the influence of gas–solid drag and heat transfer coefficient models on the prediction capacity of the Euler–Euler approach to simulate reactive bubbling fluidized bed flows is studied. Three different cases are considered, a non-reactive bidisperse bubbling fluidized bed flow (Case [...] Read more.
In this work, the influence of gas–solid drag and heat transfer coefficient models on the prediction capacity of the Euler–Euler approach to simulate reactive bubbling fluidized bed flows is studied. Three different cases are considered, a non-reactive bidisperse bubbling fluidized bed flow (Case 1), and two reactive polydisperse flows in bubbling fluidized beds, one for biomass gasification (Case 2), and the other for biomass pyrolysis (Case 3). The Gidaspow, Syamlal–O’Brien, and BVK gas–solid drag models and the Gunn, Ranz–Marshall, and Li–Mason gas–solid heat transfer correlations are investigated. A Eulerian multiphase approach in a two-dimensional Cartesian domain is employed for the simulations. Computational results for the three cases are compared with experimental data from the literature. The results obtained here contribute to a better understanding of the impacts of such closure models on the prediction ability of the Euler–Euler approach to simulate reactive flows. The results indicate that, for the simulation of reactive flows in bubbling fluidized bed reactors, the kinetic modeling of the reactions has a global effect, which superposes with the influence of the drag and heat transfer coefficient models. Nevertheless, local parameters can be noticeably affected by the choice of the interface closure models. Finally, this work also identifies the models that lead to the best results for the cases analyzed here, and thus proposes the use of such selected models for gasification and pyrolysis processes occurring in bubbling fluidized bed reactors. Full article
(This article belongs to the Special Issue Multiphase Flow and Granular Mechanics)
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14 pages, 4325 KiB  
Article
Settling Flow Details in the Flash Smelting Furnace—A CFD-DEM Simulation Study
by Jani-Petteri Jylhä and Ari Jokilaakso
Fluids 2023, 8(10), 283; https://doi.org/10.3390/fluids8100283 - 23 Oct 2023
Cited by 1 | Viewed by 1746
Abstract
The flash smelting furnace has previously been simulated using computational fluid dynamics (CFD). A new approach is to combine CFD and the discrete element method (DEM) for more detailed simulations of the different phenomena that occur as copper matte droplets settle through a [...] Read more.
The flash smelting furnace has previously been simulated using computational fluid dynamics (CFD). A new approach is to combine CFD and the discrete element method (DEM) for more detailed simulations of the different phenomena that occur as copper matte droplets settle through a slag layer. One of the most important phenomena found is the formation of a channeling flow which carries matte droplets faster through the slag. However, such phenomena cannot be directly observed in the flash smelting furnace settler due to the extreme temperatures of the opaque molten slag inside the furnace, therefore alternative methods are required for validating the phenomenon. In this work, the simulated channeling flow is validated with a sphere–oil model. The phenomenon was similar in all of the studied cases, although in the experimental setup the spheres settled faster in the oil model than in the simulations. The differences were most likely caused by the cohesion of the spheres and slight differences in the properties provided by the manufacturer and real properties for the oil and the spheres, and by the fact that simulation ignores surface tension and changing air–oil and water–oil interfaces. Full article
(This article belongs to the Special Issue Multiphase Flow and Granular Mechanics)
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21 pages, 8974 KiB  
Article
Analysis of Core Annular Flow Behavior of Water-Lubricated Heavy Crude Oil Transport
by Salim Al Jadidi, Shivananda Moolya and Anbalagan Satheesh
Fluids 2023, 8(10), 267; https://doi.org/10.3390/fluids8100267 - 28 Sep 2023
Cited by 2 | Viewed by 1997
Abstract
A possible method for fluid transportation of heavy oil through horizontal pipes is core annular flow (CAF), which is water-lubricated. In this study, a large eddy simulation (LES) and a sub-grid-scale (SGS) model are used to examine CAF. The behavior of heavy oil [...] Read more.
A possible method for fluid transportation of heavy oil through horizontal pipes is core annular flow (CAF), which is water-lubricated. In this study, a large eddy simulation (LES) and a sub-grid-scale (SGS) model are used to examine CAF. The behavior of heavy oil flow through turbulent CAF in horizontal pipes is numerically investigated. The Smagorinsky model is utilized to capture small-scale unstable turbulent flows. The transient flow of oil and water is first separated under the behavior of the core fluid. Two different conditions of the horizontal pipes, one with sudden expansion and the other with sudden contraction, are considered in the geometry to investigate the effects of different velocities of oil and water on the velocity distribution, pressure drop, and volume fraction. The model was created to predict the losses that occur due to fouling and wall friction. According to the model, increasing water flow can reduce fouling. Additionally, the water phase had an impact on the CAF’s behavior and pressure drop. Also, the increased stability in the CAF reduces the pressure drop to a level that is comparable to water flow. This study demonstrated that a very viscous fluid may be conveyed efficiently utilizing the CAF method. Full article
(This article belongs to the Special Issue Multiphase Flow and Granular Mechanics)
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21 pages, 5656 KiB  
Article
Rapid Hydrate Formation Conditions Prediction in Acid Gas Streams
by Anna Samnioti, Eirini Maria Kanakaki, Sofianos Panagiotis Fotias and Vassilis Gaganis
Fluids 2023, 8(8), 226; https://doi.org/10.3390/fluids8080226 - 5 Aug 2023
Cited by 3 | Viewed by 2081
Abstract
Sour gas in hydrocarbon reservoirs contains significant amounts of H2S and smaller amounts of CO2. To minimize operational costs, meet air emission standards and increase oil recovery, operators revert to acid gas (re-)injection into the reservoir rather than treating [...] Read more.
Sour gas in hydrocarbon reservoirs contains significant amounts of H2S and smaller amounts of CO2. To minimize operational costs, meet air emission standards and increase oil recovery, operators revert to acid gas (re-)injection into the reservoir rather than treating H2S in Claus units. This process requires the pressurization of the acid gas, which, when combined with low-temperature conditions prevailing in subsurface pipelines, often leads to the formation of hydrates that can potentially block the fluid flow. Therefore, hydrates formation must be checked at each pipeline segment and for each timestep during a flow simulation, for any varying composition, pressure and temperature, leading to millions of calculations that become more intense when transience is considered. Such calculations are time-consuming as they incorporate the van der Walls–Platteeuw and Langmuir adsorption theory, combined with complex EoS models to account for the polarity of the fluid phases (water, inhibitors). The formation pressure is obtained by solving an iterative multiphase equilibrium problem, which takes a considerable amount of CPU time only to provide a binary answer (hydrates/no hydrates). To accelerate such calculations, a set of classifiers is developed to answer whether the prevailing conditions lie to the left (hydrates) or the right-hand (no hydrates) side of the P-T phase envelope. Results are provided in a fast, direct, non-iterative way, for any possible conditions. A set of hydrate formation “yes/no” points, generated offline using conventional approaches, are utilized for the classifier’s training. The model is applicable to any acid gas flow problem and for any prevailing conditions to eliminate the CPU time of multiphase equilibrium calculations. Full article
(This article belongs to the Special Issue Multiphase Flow and Granular Mechanics)
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14 pages, 4182 KiB  
Article
Supercritical Dynamics of an Oscillating Interface of Immiscible Liquids in Axisymmetric Hele-Shaw Cells
by Victor Kozlov, Stanislav Subbotin and Ivan Karpunin
Fluids 2023, 8(7), 204; https://doi.org/10.3390/fluids8070204 - 12 Jul 2023
Cited by 1 | Viewed by 1151
Abstract
The oscillation of the liquid interface in axisymmetric Hele-Shaw cells (conical and flat) is experimentally studied. The cuvettes, which are thin conical layers of constant thickness and flat radial Hele-Shaw cells, are filled with two immiscible liquids of similar densities and a large [...] Read more.
The oscillation of the liquid interface in axisymmetric Hele-Shaw cells (conical and flat) is experimentally studied. The cuvettes, which are thin conical layers of constant thickness and flat radial Hele-Shaw cells, are filled with two immiscible liquids of similar densities and a large contrast in viscosity. The axis of symmetry of the cell is oriented vertically; the interface without oscillations is axially symmetric. An oscillating pressure drop is set at the cell boundaries, due to which the interface performs radial oscillations in the form of an oscillating “tongue” of a low-viscosity liquid, periodically penetrating into a more viscous liquid. An increase in the oscillation amplitude leads to the development of a system of azimuthally periodic structures (fingers) at the interface. The fingers grow when the viscous liquid is forced out of the layer and reach their maximum in the phase of maximum displacement of the interface. In the reverse course, the structures decrease in size and, at a certain phase of oscillations, take the form of small pits directed toward the low-viscosity fluid. In a conical cell, a bifurcation of period doubling with an increase in amplitude is found; in a flat cell, it is absent. A slow azimuthal drift of finger structures is found. It is shown that the drift is associated with the inhomogeneity of the amplitude of fluid oscillations in different radial directions. The fingers move from the region of a larger to the region of a lower amplitude of the interface oscillations. Full article
(This article belongs to the Special Issue Multiphase Flow and Granular Mechanics)
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