Solid Particles In Fluid Research Articles

Hydrodynamic Impact of Dusty Fluid-Suspended Solid Particles in a Single-Walled Corrugated Channel for Water-Curing Infrastructure Networks

Infrastructure engineering is impacted by solid particles in fluids, and engineering components are influenced by fluid flow methods. This work explores the effects of dusty fluids with suspended solid particles in a single-walled corrugated channel using electromagnetic hydrodynamics. Potential, continuity, and momentum equations were employed to study the periodic sinusoidal waves in the corrugations of two wavy walls using the perturbation method. We assessed the impact of corrugation on velocity for EMHD fluid flow using mathematical computation, concentrating on the analytical velocity solutions. The analysis of velocity profiles through graphs reveals that corrugation affects fluid and particle velocity behavior, with small amplitude reducing wave effects and dusty particles boosting velocity. The proposed model uses mathematical induction to solve engineering problems using corrugated wall conditions for fluid control during curing stages. It may be valuable for sanitation networks, rainwater drainage networks, and irrigation systems. In the end, a thorough examination of the obtained results and information from past papers demonstrated a high level of agreement. Additionally, its use in the curing of water will offer alternative methods of managing the flowing fluid than mechanical pressure.

Experimental investigation on inter-particle settling dynamics of multiple spherical particles released side by side at intermediate Reynolds numbers

The settling of solid particles in fluid constitutes a fundamental and crucial aspect with applications spanning various natural phenomena and engineering processes, including sediment transport and wastewater treatments. This paper delves into an experimental investigation aimed at comprehending the settling dynamics and self-organization of multiple spherical particles settling side by side at intermediate Reynolds numbers. The study employs an electromagnetic release device, previously developed for controlled settling of particles under gravity, ensuring simultaneous release with zero initial rotation and velocity. This research captures settling trajectories and provides insight into the flow fields surrounding particles by utilizing particle tracking and particle image velocimetry. The experiments systematically investigate the influence of the settling patterns, the flow fields, the velocities of particles, and their dependence on Reynolds number Re (Re = 52–258), the number of particles n (n = 3–8), as well as the initial spacing between particles l0* (l0* = 0–2). The results consistently reveal a left–right symmetry about the centerline in settling patterns, flow fields, and particle rotations across all values of n, l0*, and Re. The final settling pattern exhibits distinct shapes dependent on l0*: a “V” or “M” shape for l0* < 0.2, a “concave-downward” shape for 0.2 < l0* < 2, and a “straight-line” shape for l0* ≥ 2. The lateral spread of particles increases with time, particularly pronounced with smaller l0* and larger Re, attributed to strong repulsive forces between neighboring particles. Correspondingly, the maximum of horizontal velocities reduces from outside to inside and increases with decreasing l0* and increasing Re. The inner vortices are smaller than the outer vortices, which causes the lateral spread. The vertical spread increases with n but remains insensitive to Re. The average terminal settling velocities for all particles in the array are consistently smaller than those for single particles, as a portion of kinetic energy contributes to horizontal motions.

Introducing an efficient capped fluidized bed and quantifying its flow and heat transfer performance

Fluid-solid particle beds have a very wide range of industrial applications but there are few publications relating to a general method to quantify solid particle bed performance for a comparative efficiency study. The conventional approach of characterizing bed efficiency involves bubble sizes, bubble frequency, byproduct quantity for bed reactors, and pressure drop for minimum fluidization. However, different solid particle beds have different states with varying flow rates, which makes the comparative study more difficult to achieve. In this work, a common approach to measure solid particle bed efficiency in terms of heat transfer is presented. The two cases considered here are 1) When work is done by the particles such as in a catalytic reactor, and 2) When work is done on the particles such as in cooling/drying of particles. In addition to the packed bed and fluidized bed, a solid particle bed called a capped fluidized bed is introduced. The Eulerian–Lagrangian method, also known as CFD-DEM simulation, is adopted for this analysis. Numerical simulations show potentially significant advantages of capped beds over packed and fluidized beds under certain fluidization states. Capped fluidized bed pressure drop is comparatively lower than that for a packed bed and similar to a fluidized bed, which allows it to operate at a wider range of flow states. Current fluidized bed performance is limited by the entrainment and possible loss of particles at high flow rates. However, the capped fluidized bed restricts the particles from leaving the bed and thus permits higher flow rate operation. Further experimental research is required to more completely characterize this type of solid particle bed.

Development of Particle Resolved - Subgrid Corrected Simulations: Hydrodynamic force calculation and flow sub-resolution corrections

Particle Resolved - Direct Numerical Simulation (PR-DNS) of fluid–solid particles is conducted to study hydrodynamic interactions at the interface between phases. An original distinction is proposed between Particle Resolved Simulation (PRS) and Particle Resolved - Direct Numerical Simulation (PR-DNS). In PR-DNS, velocity gradients and pressure are fully resolved, which required several dozens of meshes in the diameter of the particles (40 in Stokes configuration), whereas for PRS, with grid resolution of 10 meshes per diameter, the gradients are only partly resolved, resulting in a sub-resolution of hydrodynamic forces exerted by the fluid to the interface of solid particles. The very high computational cost, associated to PR-DNS, limits its application to academic cases, even though, it was originally developed to study the collective physical effects of a fluid–particle assembly. It explains why numerous simulations with a grid resolution of only a dozen meshes in the particle’s diameter – typically between 10 and 16 – referred to here as PRS, can be found in the literature. In these cases, the velocity gradients and pressure are not accurately computed, inducing an error in the hydrodynamic forces exerted by the fluid to the interface of particles. This paper aims to clarify the hydrodynamic interactions at this scale for a single particle settling in an infinite medium under Stokes configuration. For this purpose, an original method, designed for solid particles, is proposed to compute hydrodynamic forces. A mesh-dependent correlation is then built to numerically correct the partially resolved hydrodynamic forces obtained with PRS, in what we call Particle Resolved - Subgrid Corrected Simulations (PR-SCS). Finally, the correction is assessed for various Reynolds numbers and density ratios under the Stokes assumption.

Crystallization and refluidization in very-narrow fluidized beds

Fluidization of solid particles by an ascending fluid is frequent in industry because of the high rates of mass and heat transfers achieved. However, in some cases, blockages occur and hinder the correct functioning of the fluidized bed. In this paper, we investigate the crystallization (defluidization) and refluidization that take place in very-narrow solid–liquid fluidized beds under steady flow conditions. For that, we carried out experiments where either monodisperse or bidisperse beds were immersed in water flows whose velocities were above those necessary for fluidization, and the ratio between the tube and grain diameters was smaller than 6. For monodisperse beds consisting of regular spheres, we observed that crystallization and refluidization alternate successively along time, which we quantify in terms of macroscopic structures and agitation of individual grains. We found the characteristic times for crystallization and propose a new macroscopic parameter quantifying the degree of bed agitation. The bidisperse beds consisted of less regular spheres placed on the bottom of a layer of regular spheres (the latter was identical to the monodisperse beds tested). We measured the changes that macroscopic structures and agitation of grains undergo and show that the higher agitation in the bottom-layer hinders crystallization of the top layer. Our results bring new insights into the dynamics of very-narrow beds, in addition to proposing a way of mitigating defluidization.

A particle-resolved heat-particle-fluid coupling model by DEM-IMB-LBM

Multifield coupling is frequently encountered and also an active area of research in geotechnical engineering. In this work, a particle-resolved direct numerical simulation (PR-DNS) technique is extended to simulate particle-fluid interaction problems involving heat transfer at the grain level. In this extended technique, an immersed moving boundary (IMB) scheme is used to couple the discrete element method (DEM) and lattice Boltzmann method (LBM), while a recently proposed Dirichlet-type thermal boundary condition is also adapted to account for heat transfer between fluid phase and solid particles. The resulting DEM-IBM-LBM model is robust to simulate moving curved boundaries with constant temperature in thermal flows. To facilitate the understanding and implementation of this coupled model for non-isothermal problems, a complete list is given for the conversion of relevant physical variables to lattice units. Then, benchmark tests, including a single-particle sedimentation and a two-particle drafting-kissing-tumbling (DKT) simulation with heat transfer, are carried out to validate the accuracy of our coupled technique. To further investigate the role of heat transfer in particle-laden flows, two multiple-particle problems with heat transfer are performed. Numerical examples demonstrate that the proposed coupling model is a promising high-resolution approach for simulating the heat-particle-fluid coupling at the grain level.

Study of the Interaction between Fluid Flow and Solid Particle with Smoothed Particle Hydrodynamics Method

This study shows the interaction between the solid particles with water flow occurring caused by the piping erosion phenomenon. This modelling study was executed by using Smoothed Particle Hydrodynamics (SPH) as a numerical approach with the DualSPHysics platform. The water flow is assumed as laminar flow with a low Reynolds number of 100 and 200. The solid particle is modelled as a circular-shaped particle with a fixed position. The result evaluated in this research is the coefficient of hydrodynamics force on the solid particle. In the case of interaction between one circular-shaped solid particle against the water flow, it is found that by increasing the size of volume control, the output will have higher accuracy. The accuracy of this model is also improved by elongating the maximum time simulation to ensure that the SPH particle has spread evenly throughout the volume control. In the case of interaction between two solid particles against water flow at different distances, it is found that increasing the distance between the two particles reduce the force, drag coefficient, and lift coefficient of each particle. Furthermore, the increase of distance between the two particles makes vortices form in a single dominant frequency and it affects the strouhal number.

Interactions between solid–fluid particles during thermosolutal convection of a rotating cylinder in a cavity

The ISPH method is adopted to simulate the diffusion of solid particles through a nanofluid flow during the dual rotation of two circular cylinders inside a cavity. Half of the solid particles are carrying and the others carry . The novelty of this work is in simulating the dual rotation of circular cylinders with the dispersion of solid particles below the influences of Soret-Dufour numbers. The major outcomes revealed that the interactions between solid particles and nanofluid flow are enhanced according to an increase in Soret/Dufour numbers. Increasing the Hartmann number declines the interaction process between solid particles and nanofluid flow. The radius of a circular cylinder is working well in changing the transport of heat/mass within a cavity due to the variations in the total number of solid particles. The values of Nusselt and Sherwood numbers are influenced by physical factors.

Performance analysis of a 2D numerical model in estimating minimum fluidization velocity for fluidized beds

The minimum fluidization velocity of a fluid–solid particle fluidized bed is the primary focus of this paper. The computationally economic Eulerian Granular model has been used to analyze fluidization for both gas–solid particle and liquid-solid particle fluidized beds. The conventional approach of finding minimum fluidization velocity (umf) is either with a pressure drop across the particle bed or the change in bed height. However, these parameters are often unstable and cannot be used to generalize the degree of fluidization accurately. In this paper, the dominant factor of unstable pressure drop estimation in the 2D Two-Fluid Model (TFM) and a key non-dimensional Euler number has been investigated in determining minimum fluidization velocity for different quasi-2D fluidized beds for different bed sizes, particle sizes, and particle numbers. Averaging assumptions and limitations of these numerical models are discussed in detail for four different fluidized bed cases. A comparative study of the drag model shows little to no influence in unstable pressure drop estimation near fluidization velocity, and all drag models perform similarly. It is observed that particle-particle collision is not the dominant reason for unstable pressure drop near minimum fluidization. Instead, wall effects on the particle bed including frictional losses and wall-particle collision play a key role in unstable pressure drop calculation for the quasi-2D fluidized beds. Pressure drop characteristics alone do not suffice to obtain minimum fluidization velocity with 2D TFM using existing models. Thus, a different approach has been proposed to investigate minimum fluidization involving the Euler number, which has shown promising performance in determining minimum fluidization velocity and characterizing fluidization with 2D TFM. Results show consistency in Euler number characteristics for all different fluidized bed cases considered in this paper. This can revitalize computationally economic 2D Eulerian simulations, increase the range of possible applications, and provide guidance to the future development of computationally efficient and more accurate numerical models, and empirical correlations for minimum fluidization velocity.

A coupled discrete element material point method for fluid–solid–particle interactions with large deformations

Fluid–solid–particle systems such as water–soil–rock mixtures are very common in many natural processes and engineering applications. However, modelling these complex interactions is still very challenging due to their multi-scale nature. Here, we present a hybrid model that combines the advantages of the two-phase (solid and liquid) Material Point Method (MPM) on handling continuum materials with large deformations and the capability of the Discrete Element Method (DEM) on simulating the mechanical behaviours of rigid particles. Moreover, in our model, the DEM has the ability to deal with non-spherical particles. A new collision detection approach is presented in detail, and a unified DEM style contact force model is proposed to couple MPM with DEM by considering momentum exchanges between particles and continuum phases. The proposed model is validated by several numerical benchmarks, including (1) flows around a cylinder, (2) a block sliding on an inclined plane, (3) projectile impacts a granular medium, and (4) sphere impacts and penetrates into wet granular material. The results match well with analytical solutions and experimental observations, demonstrating this model’s capability to efficiently solve complex fluid–solid–particle interactions with large deformations. Finally, an example of column collapse is simulated to show future potential applications of the proposed method.

Filter Cake Removal during the Cementing and Completion Stages in CO2 Storage Wells: Current Developments, Challenges, and Prospects

Carbon capture and storage (CCS) technology has become one of the most cost‐effective and promising ways to achieve global climate change mitigation goals. The CO2 storage capacity in depleted oil and gas reservoirs is currently the safest and most economical option. The long‐term sealing of the cement–formation interface in CO2 storage wells (CSW) is essential to avoid CO2 leakage. The filter cake easily affects the interfacial sealing ability, which is a thin impermeable layer formed by drilling fluid residue or solid particles remaining on the borehole wall due to permeable formation. Filter cake removal is essential for favorable cementation and production efficiency. This study highlights the current developments and the main challenges for oil‐ and water‐based mud filter cake removal during the cementing and completion process. Moreover, research ideas and recommendations for various types of filter cake removal are proposed to provide a reference for future work. This information helps deepen understanding with respect to the different filter cake removal options available in the CCS industry and provides a knowledge base that can facilitate the improvement of the cementing quality and production efficiency of existing systems to combat battle CSW safety and production efficiency problems.

An efficient and generalized solid boundary condition for SPH: Applications to multi-phase flow and fluid–structure interaction

In this paper, we generalize the solid boundary condition where a one-sided Riemann solver is introduced to determine the fluid–solid interaction for weakly compressible smoothed particle hydrodynamics (SPH) presented in Zhang et al. (2017) to model multi-phase flows with large density ratio and multi-phase fluid–structure interaction (FSI) in multi-resolution scenario. Compared with the boundary condition proposed by Adami et al. (2012) where solid is discretized by dummy particles whose physical quantities are extrapolated from surrounding fluid particles, the present method is very simple and efficient as extra extrapolation is avoided by constructing a one-sided Riemann problem for each interacting fluid–solid particle pair. This feature makes its extension to multi-phase flow and FSI straightforward. Furthermore, we adopt a penalty method in multi-resolution discretization to prevent particle penetration in violent multi-phase simulation. A set of examples involving multi-phase flows with high density ratio and complex interface, and multi-phase FSI are studied to demonstrate the accuracy, robustness and versatility of the present method. The validations presented herein and those reported by Zhang et al. (2017) where free-surface flows exhibiting violent events such as impact and breaking are studied indicate that the present method provides a unified approach for addressing the solid, i.e., rigid and flexible, boundary condition in multi-physics SPH applications.

Two-phase experimental and numerical studies on scouring at the toe of vertical seawall

This paper presents experimental and numerical modeling of scouring erosion at the toe due to wave impact on a highly reflective vertical seawall. For the experimental study, new experiments and analyses are provided in the light of advanced measurement techniques. They show the complex nature of the triple wave–structure–sediment interactions with their non-linearities, asymmetries, and hysteresis. For the numerical study, a two-dimensional x/z two-phase Eulerian model is introduced using a new fluid–solid particle interaction. The numerical model is also based on a projection technique, σ-transformation, and a second-order hybrid finite-difference and finite-volume method. A good agreement is obtained between the numerical and experimental results. Both models show that the wave run-up or down on vertical wall conducts to the formation of ascending or impinging vertical jets, which leads to the seawall scour.

Simulations of effects of fiber rigidity on wet press

A previously developed lattice-Boltzmann lattice-spring method is applied to simulate a wet press process. In simulations, multi-individual flexible fibers are settled on a wire screen by the force of gravity, and a fiber network is formed on the top surface of the wire screen. Next, the coordinates and velocities of fluid and fiber solid particles are copied to a computer press simulator composed of two perforated plates. A pressure pulse is imposed at the fluid contact line of the two press plates. Water is squeezed out of the fiber network by the pressure. During simulations, fiber rigidity, fiber concentrations, and pressure pulses are varied and their effects on water removal and re-wet phenomena are systematically studied.

Numerical study on the momentum and heat transfer of porous spheroids under laminar flow

This study focuses on the combined effect of particle shape and porosity on the momentum and heat transfer of granular matter under laminar flow. Particle-resolved direct numerical simulations (PR-DNS) are carried out at different working conditions. Numerical results show that both the particle shape (via the aspect ratio, Ar, of the spheroid) and porosity play important roles in affecting the drag coefficient (Cd) and average Nusselt number (Nu). The influence of particle shape on Cd and Nu is regardless of the particle porosity. It is found that the Cd decreases with the increase of Ar for a given Reynolds number (Re). The Nu decreases with the increase of Ar under high Reynolds number (100<Re<200), but increases first and then decreases under low Reynolds number (20<Re<100). The influence of particle porosity also highly depends on Re.Under high Reynolds number (100<Re<200), the strong influence of particle porosity on Cd and Nu is mainly caused by the increase of convectional capability of the fluid with Re which can flow into the pore structure easier. On the contrary, the effect of the particle porosity can be almost ignored under low Reynolds number (20<Re<100). Finally, superior to previously available correlations of Cd and Nu for non-spherical solid particles in fluids, the effect of the porosity is considered and novel correlations are established. The high predictive accuracy strongly demonstrates their capability.

Shear Jamming and Fragility of Suspensions in a Continuum Model with Elastic Constraints.

Under an applied traction, highly concentrated suspensions of solid particles in fluids can turn from a state in which they flow to a state in which they counteract the traction as an elastic solid: a shear-jammed state. Remarkably, the suspension can turn back to the flowing state simply by inverting the traction. A tensorial model is presented and tested in paradigmatic cases. We show that, to reproduce the phenomenology of shear jamming in generic geometries, it is necessary to link this effect to the elastic response supported by the suspension microstructure rather than to a divergence of the viscosity.

Intensifying Mass and Heat Transfer using a High-g Stator-Rotor Vortex Chamber

Vortex reactors take advantage of the synergy between enhanced heat and mass transfer rates and multifunctional phenomena at different temporal and spatial scales. Proof-of-concept experiments with our novel and innovative STAtor-Rotor VOrtex Chamber (STARVOC) confirm its advantageous features for the sustainable production of chemicals and fuels. STARVOC is a high-g contactor that uses carrier flow (gas or liquid) tangential injection to drive a rotor attached to low-friction bearings. The vortex chamber inside the rotor contains a secondary phase or phases, such as a solids bed, a liquid layer, or a suspension. Carrier fluid passes through the perforated rotor wall and contacts a densely and uniformly distributed secondary phase with enhanced slip velocities. Experiments focused on pressure profiles, rotor angular velocity, and solids azimuthal velocity. With air as the carrier fluid and different solid particle beds as the secondary phase, STARVOC reached bed azimuthal velocities up to four-fold compared to those reached in Gas-Solid Vortex Units with fully static geometry. These results show its potential to improve interfacial heat and mass transfer rates and take advantage of flow energy and angular momentum. Due to its process intensification capabilities, STARVOC is a promising alternative for the state-of-the-art chemical industry.

Discrete modelling of debris flows for evaluating impacts on structures

Lahars (volcanic debris flows) are natural phenomena that can generate severe damage and wreak havoc in densely populated urban areas. The evaluation of the forces and pressures generated by these mass flows on constructions (e.g., buildings, bridges and other infrastructure) is crucial for civil protection, assessment of physical vulnerability and risk management. The current tools developed to model the spread of flows at large scale in densely populated urban areas remain inaccurate in the evaluation of mechanical efforts. Here, we developed a discrete numerical model for evaluating debris-flow (DF) impact forces at the local scale of one structure (pillar or column) like a building, a bridge and other infrastructure. In this model, the large-sized solid particles that damage infrastructures and edifices are explicitly modelled using Distinct Element Method (DEM). We considered the fluid and fine-grained solid particles not only in the frame of the pressure exerted on structures, but also through their effects on the movement of particles, i.e. buoyancy and drag. The fluid velocity field and the fluid free surface obtained from Computational Fluid Dynamics (CFD) calculation based on Navier–Stokes equations are imported in the DEM simulation. This model is able to reproduce a range of magnitudes of DFs in terms of volumes, velocities and flow heights. Finally, the model provides insights on impact forces generated by particles on structures and on hydrostatic and/or dynamic pressure due to the combined effect of fluid and solid phases. The model provides results consistent with existing empirical models.

Topology optimization on fuel tank rib structures for fuel sloshing suppression based on hybrid fluid–solid SPH simulation

In this paper, we propose a topology optimization method for aircraft fuel tank structural design to reduce the fuel sloshing effect, which is beneficial for aircraft fuel gauge accuracy and flight safety. The method is applied to optimize the hole layouts in the tank rib to reduce fuel sloshing time, increase stiffness, and guarantee lightweight requirements. Specifically, we introduce a hybrid fluid–solid particle based simulator by modeling the impact and elastic forces between fluid (fuel) and solid (ribs, tank wall), to analysis violent fuel sloshing inside the complicated internal tanks, caused by large angle maneuvers and accelerations of an aircraft. Meanwhile, an effective optimizer is built for the rib design, in which the explicitly controlled hole layouts are projected onto the modeled solid particles, such that the process of finite element meshing and remeshing is no longer needed during each optimization iteration. In this way, our proposed method is able to work with complicated aircraft fuel tanks under violent fuel sloshing conditions. We then use a real aircraft wing tank as design case to validate the proposed framework. The result shows that by the generated layout of rib holes, the fuel sloshing time is shortened by 46%, the maximal fuel gauge error is reduced by 14%, and the maximal center of gravity (CG) shift is reduced by 0.15 m.

Formation damage mechanism of a sandstone reservoir based on micro-computed tomography

Formation damage caused by well drilling, completion, oil testing, oil recovery, and stimulation seriously affects oil and gas production, the evaluation of which plays an important role in the process of oilfield development. Thus, it is necessary to study formation damage mechanism from micro scale. In this study, two sets of displacement experiments were conducted using two sandstone samples and two chemical reagents. Each set was divided into three processes: first formation water injection, reverse chemical reagents injection and second formation water injection. According to the results of displacement experiments, the permeability changes of two sandstone samples were analyzed and the formation damage rates of different experimental processes were calculated respectively. In addition, we analyzed the formation damage of the two samples from the macroscopic aspect according to the changes of inlet pressure curves. We compared the pore structure changes of sandstone samples at different experiment processes by computed tomography (CT) images, and found the particle migration phenomenon. Based on the core sensitive regions observed by CT images, the pore network models of the sensitive regions were extracted to quantitatively characterize the change of pore structure parameters (pore radius, throat radius, coordination number and tortuosity). Finally, we designed a two-dimensional microscopic seepage channel model according to the real core structure. The flow rule of solid particles in fluid was simulated by finite element method, and the reason of reservoir clogging was analyzed. Through this study, we found that the injection of chemical reagents increased the inlet pressure and led to the decrease of core permeabilities. There was a negative correlation between the export rate of particle migration and matrix deformation degree. Cited as : Wang, Z., Li, H., Lan, X., Wang, K., Yang, Y., Lisitsa, V. Formation damage mechanism of a sandstone reservoir based on micro-computed tomography. Advances in Geo-Energy Research, 2021, 5(1): 25-38, doi: 10.46690/ager.2021.01.04