Sedimentation Of Solid Particles Research Articles

γ-Aminobutyric Acid (GABA)-enriched Hemp Milk by Solid-state Co-fermentation and Germination Bioprocesses.

This study introduces the concept of developing a functional hemp drink enriched with γ-Aminobutyric acid (GABA) to enhance its nutritional value and functional properties utilizing Solid-State (SSF) co-Fermentation by Lactobacillus casei and Bacillus subtilis and germination bioprocesses. Bioprocesses may offer an alternative solution to challenges in hemp milk, such as product instability and the use of additives. Notably, the hemp milk produced through the germination for three days or co-fermentation processes yielded the highest GABA content of 79.84 and 102.45mg/100 mL, respectively, compared to the untreated milk. These bioactive milk samples exhibited higher zeta potential and soluble protein content and also reduced solid particle sedimentation and droplet sizes (D4,3 and D3,2) compared to the untreated milk. Furthermore, the peptide, total phenolic content, and antioxidant activity of the produced GABA-enriched kinds of milk surpassed those of the untreated milk. Overall, the SSF and germination processes present a promising alternative for producing stable milk analogs with enhanced health-boosting properties.

Physical Stability of Lotus Seed and Lily Bulb Beverage: The Effects of Homogenisation on Particle Size Distribution, Microstructure, Rheological Behaviour, and Sensory Properties.

The lotus seed and lily bulb beverage (LLB) has a problem with solid particle sedimentation. To address this issue, LLB was homogenised twice at different pressures (0~100 MPa) using a homogeniser. This study aims to investigate the changes in the particle size distribution (PSD), microstructure, rheological behaviour, sedimentation index (IS), turbidity, physicochemical properties, and sensory quality of LLBs after homogenisation treatments. The results regarding PSD and microstructure showed that the suspended particles were decomposed at high pressure with increasing homogenisation pressure, forming small particles of cellular material, cell wall fragments, fibre fractions, and polymers. The LLB showed shear-thinning behaviour and weak gelation characteristics (G' > G″) and rheological properties. Among all homogenisation pressures, the 60 MPa sample showed the lowest sedimentation rate and the highest turbidity. When the pressure was increased from 0 to 100 MPa, the total soluble solid (TSS) content showed an upward trend, while the ascorbic acid content (AAC) gradually decreased. The highest sensory evaluation was observed in the 60 MPa sample in terms of overall acceptability.

Numerical simulations of the sedimentation of soft particles in confined Newtonian liquids

The gravitational sedimentation of solid particles in liquids is important in several applications, many of which involve soft particles (e.g., microplastics, microgels, and biological cells). However, there is still little knowledge on the sedimentation of deformable beads. In this work, we employ fully three-dimensional finite-element numerical simulations to investigate the sedimentation of an initially spherical elastic bead in a Newtonian liquid contained inside a square-cross section vessel. In particular, we carry out a wide parametric analysis to understand the effects of inertia, particle deformability, and geometrical confinement on the particle sedimentation dynamics and settling velocity. In addition, the sedimentation of a particle in a Newtonian liquid close to a vertical wall is studied. When the particle sediments at the center of the vessel, the settling velocity increases at increasing inertia and decreases at increasing confinement and deformability. However, at intermediate inertia, the settling velocity passes through a minimum and then rises as the particle gets softer. Correspondingly, the equilibrium deformed shape of the particle shows the appearance of a concavity at the rear. When the sedimentation occurs close to a vertical wall, the closer the particle to the solid surface, the slower its sedimentation. On the other hand, the hydrodynamic interaction between the particle and the wall makes the particle move away from the wall.

Role of Lorentz force and nanoparticles morphology on the dynamics of ternary hybrid nanofluid flow subject to porous disks and gyrotactic microorganisms

This article explains the significance of Lorentz force and nanoparticle morphology on the dynamics of ternary hybrid nanofluid through porous disks. The gyrotactic microorganisms are investigated to avoid possible sedimentation of solid particles and maintain fluid stability. A 3-dimensional flow problem in the presence of two different types of tri-hybrids nanofluid nanomaterials (Metallic and Nonmetallic Oxides) is used here. By eliminating the pressure term, the governing partial differential equations are transformed into a high-order nonlinear system of differential equations. This system is subsequently utilized to construct the boundary layer model, and these equations are solved numerically using a shooting technique based on the Runge–Kutta method, with the assistance of MATLAB software. The comparison and validation results are in good agreement through a numerical approach. Different-shaped nanoparticles have a significant influence on motile microorganisms. Shear stress near porous surfaces was significantly reduced due to an increase in nanoparticle size. The addition of all types of nanoparticles improved the thermal performance. Many desirable results for engineering purposes are observed under suitable conditions of simultaneous effect of magnetohydrodynamics (MHD) with microorganisms.

On the detection of nanoparticle cloud migration by a resonant photonic surface signal towards sedimentation velocity measurements

Migration and sedimentation of solid particles in a liquid are physical phenomena involving accumulation of soft matter or decantation of fragmented matter. A thorough understanding together with relevant measurements are prerequisites regarding many fields, including medicine, galenic pharmacology, food processing, and the cosmetics industry. In this paper, we investigate the feasibility of monitoring and detecting the migration of a nanoparticle cloud with a resonant light probe. For this purpose, hybrid silicon/silica/UV210 organic integrated photonic racetrack resonators were patterned by thin film processes to be used as sensors measuring the outcome of the impact of a cloud of nanoparticles, the dynamic migration plus sedimentation phenomenon of the nanoparticle cloud in water. A broadband superluminescent diode has been used for the excitation. Then, the spectral characteristics of the resonant guided modes have been analyzed, considering the observed changes while tracking the free spectral range of the transduced comb spectra as a function of time. The way to operate can be summarized as follows: Solutions based on spherical silica nanoparticles of fixed size are prepared and subjected to rheological measurements to obtain their respective viscosities. Next, a millimeter tank filled with water is conveniently placed on the active surface of the sensing chip, prior to the addition of one of the previously mentioned solutions. The series of spectra are acquired during the whole migration sequence and the transduced optical signal is then directly processed and treated by a specific code operated in real time by way of Lagrange interpolation polynomials. Collected data are then compared to a simple theoretical model describing the sedimentation of a spherical particle in water (Stokes' law). Eventually, the implementation of the device in a characterization platform and the development of a specific protocol allows a global treatment, whose description is followed by discussions on measurements and data. Consequently, after the impact of the drop containing the nanoparticles, the monitoring of a first phase regarding their fast cloud migration into the global study volume (with flow of matter plus vortex) eventually followed by their slow sedimentation, can be detected using such a resonant light probe. The overall duration of the first phase associated with sedimentation velocities is in the order of a few tens of µm/min for particles with submicron diameters (several hundreds of nanometers); a first attempt of comparison of this first phase with the results of the classic Stokes model would give a convergence of the values reaching between 9 and 19% for the sedimentation rates.

Regulation of oil well cement paste properties by nanoclay: Rheology, suspension stability and hydration process

Enhanced grid reconstruction ability of oil well cement paste has been confirmed as a promising solution to inhibit particle sedimentation caused by the uncontrolled rheological property at high temperatures. The effect of nanoclay dispersions of Bentonite and Laponite on the rheological property, suspension stability and hydration process of the cement pastes was examined. The nanoclay dispersions (especially Laponite) enhanced the dynamic reversible gel structure and improved its reconstruction ability. The addition of nanoclay effectively inhibited the sedimentation of solid particles at high temperatures due to form a gel structure by polymer admixtures, nanoclay and cement colloidal particles. Moreover, the nanoclay facilitated the cement hydration and enhanced the mechanical property for the nucleation and filler effect. Accordingly, the nanoclay can enhance thixotropy and suspension stability of the early cement paste and increase the mechanical strength of hardened cement stones, which contributes to improving the sealing integrity of cement sheath.

Limiting Conditions for Droplet Fragmentation of Stabilized Suspension Fuels

The main barrier to the wide use of composite liquid fuels in the energy sector is the significant sedimentation of solid particles during fuel storage and transportation. As a result, the composition of fuel slurries changes quite fast and considerably when yet another portion of fuel is pumped from a storage tank. Stabilizing additives are one of the possible solutions to this problem. The technology of primary and secondary slurry fuel atomization is generally considered promising for obtaining a spray of small fragments (droplets and particles). This way, droplets of liquid components and solid particles can be produced with a size of less than 10 μm. A fuel aerosol with particles and droplets this small burns out rapidly. The most effective secondary droplet atomization technology is based on their microexplosive breakup in combustion chambers by superheating the water in the fuel to exceed its nucleation (boiling) point. As part of this research, we studied the impact of the main stabilizing additives to slurry fuels on droplet breakup behavior: heating time until breakup, breakup delay and duration, and the number, size, and velocities of secondary fragments. Soy lecithin and sodium lignosulfonate were used as stabilizers. The main components of the fuel slurries were water, rapeseed oil, diesel fuel, coal processing waste (filter cake), coking bituminous coal, soy lecithin, and sodium lignosulfonate. Droplets were heated at an ambient gas temperature ranging from 450 to 1050 K until the breakup conditions were achieved. Mathematical expressions were obtained for the relationship between input parameters and the key characteristics of the process. Principal differences and overall patterns of droplet breakup were established for slurries with and without stabilizing additives.

A new mathematical model of continuous gravitational separation with coalescence of liquid-liquid emulsions

A model for a continuous gravitational separation process of a liquid-liquid dispersion is presented, which is formulated as a population balance equation (PBE) that describes the coalescence and the hindered polydisperse sedimentation of droplets. This is important because this separation process is critical in the operation of many industries as discussed later. This study is based on previous findings by Garcia and Betancourt (2019) where a formulation for a batch process was presented. This analysis shows the improvements and differences between the model presented in this study and the formulation by Garcia and Betancourt (2019). The modeling framework comes from the Kynch’s theory that has been employed to model solid particle sedimentation processes; however, in this case the principles are applied to an organic phase-aqueous phase liquid mixture. For the numerical solution of the model, the PBE is discretized in terms of droplet volume. Since the population balance model is subject to mass loss due to droplet coalescence, we propose a formula to compute the source term of the largest droplet class. Model validation used experimental data from literature for a continuous process. Numerical results explored the variation of parameters such as feed flowrate, feed oil volume fraction and the standard deviation of the initial and feed droplet volumes.

Improving the Homogenization of the Liquid-Solid Mixture Using a Tandem of Impellers in a Baffled Industrial Reactor

The paper explores a tandem configuration of three-blade impellers in a stirred reactor. The working fluid is a liquid-solid mixture and the stirring mechanism fitted with the two impellers must prevent the sedimentation of solid particles while homogenously dispersing them in the bulk liquid. The present numerical investigation, performed with the expert software Ansys® Fluent, Release 16, employs the Eulerian multiphase model along with the RNG k–ε turbulence model to simulate the free-surface liquid–solid flows in the baffled stirred reactor. A sliding mesh approach is used to model the impellers rotation. The tandem configuration is clearly superior to a single impeller, while the existing electrical motor that drives the stirring mechanism still provides the necessary power.

Clogging Model for Coarse and Fine Filtering Cloths of Filtering Cylindrical Elements, Preventing Sedimentation of Mechanical Impurities in Their Gap

In this paper we propose a method for preventing sedimentation of solid particles in the lower part of the gap between filtering cylindrical elements of coarse and fine purification by increasing the size of the meshes and total thickness of the first downstream gas flow layers of the fine filtering element in excess of the maximum diameter of solid particles. Experimental corroboration for the proposed method showed absence of solid particles’ sedimentation in the lower part of the gap between filtering cylindrical elements of coarse and fine purification and clogging of their meshes. As a result of the experiments, we found that the maximum sedimentation of mechanical impurities inside the first screens of the fine filtering cloth is achieved when their meshes’ size and screens’ thickness are, respectively, equal to three and two and a half maximum diameters of a solid particle. We developed a mathematical model that describes the clogging dynamics of filtering elements, where pressure losses in the first section with constant mesh sizes of all screens and in the second section with a sequential decrease in mesh sizes have different clogging rates and therefore are calculated separately from each other. The clogging process at each section of the multilayer filter cloth is represented as a successive decrease in the effective screening area of the screen meshes. The mathematical model makes it possible to prevent the sedimentation of mechanical impurities in the gap between gas filter elements of coarse and fine purification and allows to analytically determine the clogging degree at any time of operation, depending on the pressure losses’ values.

Association between gastric content fluidity and pars oesophageal ulcers in nursery pigs: a cross-sectional study of high-risk Danish herds using commercial feed

BackgroundThe objective of this cross-sectional study was to assess the within-herd prevalence of pars oesophageal ulcers (POU) in high-risk Danish herds using commercial diets. Furthermore, we aimed to estimate the association between gastric content fluidity and POU using a generalised additive model (GAM). The study included 200 clinically healthy nursery pigs randomly selected from ten farms (20 pigs from each farm). The 10 farms were selected based on a suspected high prevalence of gastric ulcers. Post-mortem gastric ulcer assessment was based on macroscopic lesions, and gastric content fluidity was assessed based on the solid particle sedimentation percentage (solid phase).ResultsWe observed an overall prevalence of 35.5% for POU in nursery pigs. Within-herd prevalence varied considerably among farms, with values ranging from 0% in Farm 1 to 84% in Farm 4. Our model showed strong associations between POU and gastric content fluidity (P < 0.001), as well as between POU and farm of origin (P < 0.001). In addition, we observed that the risk of POU decreased non-linearly as the gastric content solid phase percentage increased, i.e. as the gastric content became more solid.ConclusionWe have demonstrated that pars oesophageal ulcers are present in Danish herds with nursery pigs fed commercial diets. Furthermore, we have established that gastric content fluidity is strongly associated with POU in nursery pigs. Even so, we cannot conclude that gastric content fluidity is solely responsible for POU. Future research should look into the association between pars oesophageal ulcers and both farm management activities and individual pig factors.

Numerical Simulation of the Solid Particle Sedimentation and Bed Formation Behaviors Using a Hybrid Method

In the safety analysis of sodium-cooled fast reactors, numerical simulations of various thermal-hydraulic phenomena with multicomponent and multiphase flows in core disruptive accidents (CDAs) are regarded as particularly difficult. In the material relocation phase of CDAs, core debris settle down on a core support structure and/or an in-vessel retention device and form a debris bed. The bed’s shape is crucial for the subsequent relocation of the molten core and heat removal capability as well as re-criticality. In this study, a hybrid numerical simulation method, coupling the multi-fluid model of the three-dimensional fast reactor safety analysis code SIMMER-IV with the discrete element method (DEM), was applied to analyze the sedimentation and bed formation behaviors of core debris. Three-dimensional simulations were performed and compared with results obtained in a series of particle sedimentation experiments. The present simulation predicts the sedimentation behavior of mixed particles with different properties as well as homogeneous particles. The simulation results on bed shapes and particle distribution in the bed agree well with experimental measurements. They demonstrate the practicality of the present hybrid method to solid particle sedimentation and bed formation behaviors of mixed as well as homogeneous particles.

Numerical validation and investigation for the sedimentation of solid particles in liquid pool using the CFD-DEM coupling algorithm

In this study, the applicability of the Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) coupling algorithm to the sedimentation of solid particles in a liquid pool was performed. This phenomenon is important because it is related with the issue of ex-vessel debris coolability during a severe accident. The numerical model was validated by comparing with the experiment of scaled condition. A total of eight experimental cases with particle densities of 3600, 6000, and 7800 kg/m3; nozzle inlet diameters of 20, 30, and 40 mm; and the particle diameters of 2, 4, and 6 mm were considered. The analysis focused on the characteristics of particle falling (particle falling time, and average particle velocity) and that of particle bed formation (maximum bed height, bed height distribution, dimple area, and dimple volume). The numerical results showed good agreements with the experimental data, while the deviation was shown for the case for a large ratio of the nozzle inlet diameter to the particle diameter due to the overestimation of particle momentum. The result indicated that consideration for fluid flow and three-dimensional analysis should be considered in numerical simulation for the better prediction of the debris particle sedimentation. Therefore, the CFD-DEM algorithm, which can simulate the local phenomenon of particle sedimentation, can be considered as a good method to reduce the uncertainty in the cooling of ex-vessel debris bed.

Conservative mathematical model and numerical simulation of batch gravity settling with coalescence of liquid-liquid dispersions

Population balance equations (PBE) provide a suitable a framework for dealing with drop breakage and coalescence. In addition, modeling of the solid particle sedimentation process based on Kynch’s theory has been successfully used and validated in mineral processing and wastewater treatment. In this work, we present a model that merges the coalescence process with hindered polydisperse sedimentation. The PBE model is projected onto a partial differential equation (PDE) system by discretizing the droplet volume. Because there is loss of mass in the system when the daughter droplets are greater than the larger species considered for the numerical solution, two terms that produce the conservation of the mass or total volume of the dispersed phase are incorporated into the PDE system. The resulting PDE system is split into two systems: homogeneous PDEs and ordinary differential equations (ODEs). The homogeneous PDEs and the ODEs are discretized using a first-order central differencing scheme and the second-order, two-stage Runge-Kutta method, respectively. The model predicts the vertical variation of the composition of the dispersed phase layer that forms at the top or bottom of the gravity settler. The proposed model was calibrated and validated through an experiment with an oil and water system. In particular, simulations illustrate the effects of: the continuity of the dispersion (oil-in-water and water-in-oil) and the standard deviation of the initial droplet volumes on phase separation quality, as well as the influence of the coalescence frequency on the average droplet volume.

Experimental investigation on effects of solid concentration, chemical additives, and shear rate on the rheological properties of bottom ash (BA) slurry

ABSTRACT An experimental analysis is done for understanding the effect of various parameters like shear rate, solid concentration, and particle size on rheological behavior of bottom ash slurry. The coarser-sized bottom ash slurry has the settling characteristics and that leads to sedimentation of solid particles during the flow of slurry in the pipeline. This effect results in high pressure drop and also the sedimentation bed needs more power for flow in pipeline. In the current study, rheological behavior of bottom ash slurry is experimentally analyzed with and without addition of chemical additives. Cetyl Trimethyl Ammonium Bromide (CTAB) with Sodium Salicylate (NaSal) is used as chemical additives with a range 0.1%–1.0% by mass of total slurry sample. It is observed that all the BA slurry samples at 30% and 40% solid mass concentration shows non-Newtonian nature and follows Herschel-Bulkley model with shear thickening behaviors. It is also observed from the experimental result that the rheological properties of BA slurry are very much affected by shear rate. Combined effect of various range of BA solid mass concentration, shear rate, and dosages of chemical additives were investigated and get encouraging results.

Characteristics and origin of suspended matter in a small reservoir in Poland

The study involved qualitative and quantitative analysis of suspended sediment and its origin in a small reservoir located in Blizne, Podkarpackie Region (SE Poland), and was conducted during summer 2017. Results showed a linear negative correlation between the suspended sediment in a water column and its organic matter content. There was also a clear relationship between the suspended sediment content and the rate of sedimentation of solid particles suspended in the water column. The research showed that the TOC-to-OM conversion factor commonly applied to bottom sediments does not apply to sediments suspended in the water column. It was also observed that the organic matter prevailing in entrapped sediment was of autochthonous origin. Its share was greatest and the content of total phosphorus highest when retention period increased. The increase in phosphorus content co-occurred with the decreasing TOC:TN ratio, and with a decrease in the sedimentation rate. Analysis has thus shown that the composition and specific nature of suspended sediment in this reservoir affects the rate of deposition of matter and can determine the siltation processes.

Study Investigates Formation Damage Induced by Water Reinjection in Unconsolidated Sands

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 189513, “An Experimental Investigation of Formation Damage Induced by Produced-Water Reinjection in Unconsolidated Sands,” by Jalel Ochi and Rezki Oughanem, Total, prepared for the 2018 SPE International Conference and Exhibition on Formation Damage Control, Lafayette, Louisiana, USA, 7–9 February. The paper has not been peer reviewed. In recent years, many studies have focused on investigating formation damage caused by produced-water reinjection (PWRI). Nevertheless, many questions about this subject remain unanswered, particularly with respect to the occurrence of this phenomenon in unconsolidated sands. This paper describes a coreflooding program performed with sandpacks at different permeabilities, water qualities, and injection conditions. Introduction The authors performed a complete experimental laboratory study using suspensions containing solid particles, mono-sized oil droplets, or both. Several coreflooding experiments using highly permeable sandpacks were performed over a long duration, during which significant volumes, sometimes reaching 100 L, have been injected. Also, permeability evolution has been monitored along three sections of each sandpack in order to better understand the dynamic of associated formation damage. A schematic of the experimental setup used to carry out the coreflooding experiments is shown in Fig. 1. The suspensions containing solid particles or oil droplets were previously prepared in a 70-L reservoir tank. The tank is made from glass to facilitate suspension stirring and to prevent the aggregation of solid particles within it. The tank’s volume allows an injection over days and nights without interruption. The injection of suspension is ensured by a pump equipped with two low-diameter section pistons to ensure a proper injection of suspension without sedimentation of solid particles. Experimental Results Injection of Emulsions With Only Oil Droplets. In investigating the permeability decline generated by the injection of an emulsion with 100 mg/L of oil and 2-µm mean droplet size, the authors found that the formation damage generated by the deposition of oil droplets took place over the entire length of the sandpack. Also, results showed that oil deposition took place first at the entry section, followed by the second and third sections. The oil-deposition dynamic suggests the propagation as a front. Indeed, the oil droplets deposit along the first section until the permeability decline reaches a minimum. Once the permeability decline is stabilized within the first section, the same phenomenon is reproduced successively in the second and then third sections. These results indicate that the permeability reduction of sandpacks depends on the droplet size rather than on oil concentration even if the kinetics of the permeability decline depend on the oil concentration. For the same mean droplet size of 2 µm, the permeability decreases more slowly for an emulsion of 50 than for 200 mg/L, for example. However, whatever the oil concentration, the final permeability decline stabilizes at the same level of approximately 74% of the virgin permeability (26% of permeability loss).

Simulation of Solid Particle Sedimentation by Using Moving Particle Semi-implicit Method

Simulation of Solid Particle Sedimentation by Using Moving Particle Semi-implicit Method

A Simplified Model Applied to the Barite Sag and Fluid Flow in Drilling Muds: Simulation and Experimental Results

In this work, a study on the modeling of sedimentation and transport of barite particles in drilling fluids was developed. The goal of this study was to evaluate the feasibility of using a simplified two-phase model based on conservation equations to describe the sedimentation of particulate material in drilling fluids. The model was evaluated in three different case studies, where the transport and the sedimentation of solid particles in a carrying fluid were simulated. The simulation results included a two-dimensional flow of liquid in the absence of particles; the axial flow of fluid and particles to investigate the existence of the slip velocity; and the one-dimensional particle settling in drilling fluids. The resulting model used to predict the barite sag is based on the conservation equations and uses the Eulerian approach to take into account the two-phase flow. The model was able to predict the barite sedimentation as well as the formation and properties of the bed of particles. Moreover, the proposed model can be used to evaluate the influence of the particle size, the liquid viscosity, and the solids concentration on the sedimentation process of particles in drilling fluids. Experimental work was also conducted in order to estimate the parameters of the proposed model related to the solid-solid force interaction due to solid particles, and the contribution of the pressure gradient. The results were analyzed by using the one-way ANOVA test for a 95% confidence level, and showed significant reproducibility. Therefore, despite to the simplicity of the proposed model, it could be used as a first approach to the modeling of the barite sag in drilling fluids.

Modelling and Simulation of Solid Particle Sedimentation in an Incompressible Newtonian Fluid

We present in this paper a method that simulates the motion of rigid particles in a Newtonian fluid. This method is based on a variational formulation throughout the fluid/solid domain, with constraints on the unknown and on the test functions. The rigid motion of the particle is enforced by penalizing the strain tensor on the rigid domain for canceling the deformation rate in the volume occupied by the particle. The time discretization is performed by using the characteristics method. We developed a code from FreeFem++ that simulates Stokes flows or Navier–Stokes flows (low Reynolds number). A simulation of an elliptical rigid particle sedimentation in a Newtonian fluid has shown the importance of this approach.