Flow Of Solid Particles Research Articles

The effect of ultrasonic treatment of a cured monolayer formed by three-dimensional printing from a prepreg reinforced with continuous carbon fiber on the resistance to the flow of solid particles

—The effect of ultrasonic processing at resonant frequencies of 22 and 44 kHz of a monolayer formed by three-dimensional printing from prepregs reinforced with continuous carbon fiber on the resistance to the flow of solid particles by imitating it by jet-abrasive treatment is investigated. The increment of the weight of both control and experimental samples in comparison with the initial state was established. It is shown that the force effect of ultrasound in rational modes contributes to a decrease in weight gain by 31.4% when processed at a frequency of 22 kHz and by 9% when processed at a frequency of 44 kHz. The decrease in weight increment is determined by an increase in the density of the monolayer structure after ultrasonic exposure, which leads to an increase in surface hardness in units of Schor-D by 13.5% at a frequency of 22 kHz and by 10% at a frequency of 44 kHz.

Coupled Modeling of Computational Fluid Dynamics and Granular Mechanics of Sand Production in Multiple Fluid Flow

Summary Sand production is a significant issue in oil and gas fields with poorly consolidated formations, often involving the multiphase flow of reservoir fluids and solid particles. The multiscale mechanisms of sand production, particularly fluid flow and particle movement, remain poorly understood. This study investigates these mechanisms using a coupled computational fluid dynamics and discrete element method (CFD-DEM) modeling approach. Single and multiple fluid flows of water and heavy oil were simulated with increasing fluid injection velocities, leading to different sand production patterns. The simulation results were compared with experimental results from a large cylindrical specimen of weak artificial sandstone under similar loading conditions. The multiphase conditions created various localized flow and deformation patterns that influenced both fluid and solid production, resulting in shorter transient sand production periods. Microstructures and phenomena such as fingering and water coning were observed, associated with a critical flow rate below which oil displacement was uniform and no water breakthrough occurred. Higher fluid injection velocities and fluid viscosities resulted in greater drag forces, leading to progressive damage zones and explaining the occurrence of single or multiple staged sand production events. The evolution of the microscopic granular structure was visualized under the effect of transient sand production.

Extending the CFD-DEM coupling algorithm to accurately predict the particle separation in a two-phase air–solid particle flow through an aerofall AG mill

Extending the CFD-DEM coupling algorithm to accurately predict the particle separation in a two-phase air–solid particle flow through an aerofall AG mill

Simultaneous measurement of velocity field of liquid–solid particle flow in pipelines and analysis of flow characteristics

The liquid–solid particle flow within a horizontal pipeline is a typical particle-laden flow. The interplay between loaded particles and carrier phase engenders significant complexities in the dynamic behavior of such flows. We investigated the dynamics of a liquid–solid particle flow featuring dilute, slightly buoyant, hundred-micron-sized spherical particles fully suspended in the turbulent flow in a pipe, where Re is 7038. Cases with solid volume fractions of 0, 2.67 × 10-4, 5.33 × 10-4, 8.00 × 10-4, 1.07 × 10-3 and 1.33 × 10-3 were considered in this study. Experimental measurement techniques were utilized to acquire images of particles in the two-phase flow across the entire flow field via optical field feedback. Particle image velocimetry (PIV) and particle tracking velocimetry (PTV) were employed to simultaneously obtain liquid-phase velocity fields and particle trajectories. This approach allowed for a comprehensive depiction of the velocity field of each phase. Subsequently, a detailed explanation and analysis of the flow characteristics of the liquid–solid particle flow were provided based on the distribution of macroscopic velocity fields, the microscopic vorticity field, particle velocity vectors, and velocity slip. As a result, it was found that with the addition of solid particles and an increase in volume concentration, the drag effect of the solid phase and the trend of accumulation near the lower wall caused a decrease in the liquid phase velocity profile and deformation of the parabolic shape. In the liquid–solid particle flow with a volume concentration of 1.33 × 10-3, compared to the single-liquid phase flow, the standard deviation of velocity in the central region increased from 0.0097 m/s to 0.0159 m/s, and in the near-wall region, it increased from 0.0257 m/s to 0.0347 m/s, representing increases of 1.54 times and 1.26 times respectively. The proportion of medium vortices increased from 17 % to 30 %, nearly doubling. This study actively explores the concurrent measurement and flow characteristics of liquid–solid particle flow.

Evaluation of array capacitive sensor for local concentration measurement of gas–solid particles flow by coupled fields based on CFD-DEM

An array capacitive sensor adopting two excitation modes is designed for measuring local particle concentration in gas–solid two-phase flow. Considering the difficulty in obtaining instantaneous flow parameters under dynamic experiments, a 3D dynamic simulation model coupling gas–solid two-phase fluid and electrostatic fields is proposed to quantitatively evaluate the sensor performance. In the coupling model, Computational Fluid Dynamics and Discrete Element Method are applied to establish two-phase fluid field for particle micro-distribution. The method of defining particle shape and position is used to set permittivity distribution in electrostatic field for coupling gas–solid fluid field and electrostatic field of array capacitive sensor. Using the method of reconstructed image and data fitting, the performance of two excitation modes are evaluated under a typical dynamic flow with structure of stratified flow. Experimental result validates the simulation conclusions and proves the effectiveness of the coupling simulation model for evaluating capacitive sensors in gas–solid flow systems.

A COMPUTATIONAL STUDY FOR AIR-€“SOLID PARTICLES FLOW PATTERNS IN RIB-ROUGHENED FLUIDIZED BED VESSELS

This paper includes analysis of the flow of air and solid particles in fluidized bed units using a computational fluid dynamics (CFD) technique. The CFD simulations are carried out with three geometries, one plane vessel and the other two with ribs of square and triangle shape. The results are obtained in terms of velocity, volume fraction distribution, and bed expansion. The effect of other parameters, such as coefficient of restitution, initial bed height, and particle diameter, is also examined. When the particle diameter is large, airflow in an upward direction increases the solid bed height but the flow is almost steady. In the case of small-sized particles, the velocity field and volume fraction profiles for both phases vary with time. In certain regions within the bed, the air becomes concentrated and takes the form of a bubble. The results also show that in fluidized bed units, the unsteady behavior is usually enhanced when ribs are used. The comparison in terms of root mean square values indicates that velocity variation is ~50% more when triangular ribs are used The overall results show that placement of triangle-shaped ribs can be favorable for enhancing momentum and related processes/phenomena in the fluidized bed devices.

Studying the interaction process of a solid particles flow with the hydraulic classifier flowing part

The paper provides a theoretical description of the solid particles movement process along with the horizontal flow of slurry within the hydraulic classifier flow part. Three modes of movement of solid particles are described: deceleration relative to the slurry flow at a constant speed or its increase, acceleration relative to the slurry flow at a decrease in its speed, with the speed of the slurry flow. The complex equation of solid particles motion in a horizontal co-flow of liquid. A graphic description of the process is given. A laboratory installation was developed to study the interaction of the hydraulic classifier flow part with the slurry flow. Experimental studies were carried out and quantitative process parameters were determined during the movement of rolled quartz solid particles in the size range < 1.8 mm and < 0.2 mm. For the first time in crisis economic conditions, in order to confirm the reliability of previously obtained analytical dependencies to determine the rational parameters of hydraulic disintegrators and determine the operational characteristics of equipment, full-scale experimental studies of the JPD 300-120 suction dredger equipped with an innovative ejector soil suction head with a jet disintegrator system were carried out.

Numerical simulation model of gas–liquid–solid flows with gas–liquid free surface and solid-particle flows

Gas–liquid–solid flow is an important phenomenon in large-scale industrial processes. The difficulties in numerical simulations of these processes lie in the problems of high calculation cost for a large-scale system, the simultaneous occurrence of dispersed and sedimented particle flows, and the coexistence of solid particles and a gas–liquid free surface. In this study, a numerical simulation model of gas–liquid–solid flows was developed based on the continuum description. The volume-of-fluid (VOF) method and granular flow model were coupled in the proposed model. As a result, the proposed model is applicable to gas–liquid–solid flows where a gas–liquid free surface and solid-particle flows coexist. In addition, the use of the granular flow model enabled simultaneous simulations of dispersed and sedimented particle flows. Based on the continuum description, the proposed model has the advantage of low calculation cost compared to the DEM-VOF method. Numerical simulations were conducted to verify the model for the submerged granular collapse, floated granular collapse, water entry, and oscillation on a free surface. The results of the numerical simulations using the proposed model were compared with the simulation results using the DEM-VOF method, experimental results or theoretical relationships. These comparisons indicate that the proposed model is reasonably applicable to the gas–liquid–solid flows. In addition, the limitations of the model were evident in the granular flow along a gas–liquid surface under the influence of capillary effects. Therefore, if the solid particles are small such that the capillary effect is not negligible, the capillary effect should be considered for more accurate numerical simulations.

Non-symmetric distributions of solids deposition for solid-water stratified flow in deviated tubing strings

Dynamic performance on solids flow with water in deviated tubing is essential for the reliability of pump and normal operation of horizontal and directional wells. Compared with coal-water flow in vertical tubing and sand-oil flow with high production in deviated tubing, solids deposition with water shows obvious non-symmetric distributions in deviated tubing from simulations and experiments. The mathematical model of two phase flow was developed under coupling conditions of deviated tubing, low flow rate and viscosity based on the kinetic theory of granular flow and first-order discrete scheme. The results show that solid-water stratified flow in deviated tubing can be divided into two zones of suspension bed and the moving bed throughout the flow field. The solid flowing velocity with water is negative and particles slide down at the bottom of moving bed zone. The process of solids flow with water in deviated tubing will produce pressure loss and consume the kinetic energy. The thickness of deposited layer and the flowing velocity of solids flow downward with water at the moving bed zone enhance with the decreased inlet flow rate and the increased particle size, tubing inside diameter (ID) and inclination angle. Solids are easier into suspension from the upper part of moving bed zone to suspension bed zone and more solid particles flow with water towards the tubing outlet with the increase of inlet flowing velocity. The decision is made to reduce the screen width, tubing ID and inclination angle to maintain to be greater than critical deposition velocity in order to prevent solids settling. And it provides the theoretical basis and technical reserves for solid control and offers an effective approach to enhance tubing cleaning in deviated strings.

ASSESSMENT OF WEIGHT OF SEDIMENT FORMATION DEPOSIT IN MUNICIPAL COLLECTOR SYSTEM (MCS)

The main purpose of this work is to provide calculations of annual weight of sediment formation deposit in Municipal Collector System (MCS). The article considers two-phases flow in the collector. The storm water collector is small culvert for storm water (rainwater) or for removing the river (creek, stream, flow) underground. The article defines the solid particles in flow as sand, clay, stones, silt, etc. It was found that in case of signif\icant flow rate, then all solid particles move in the pipe. If not, they settle to the bottom and sediment is formed. In this paper, total weight of sediment formation in Moscow collector system is calculated at average annual values. On this ground a consideration can be made that sediment deposit reduces efficiency of the system partially or completely.

Study of the hydraulic parameters of the flow of solid particles in the process of hydrotransport

The article presents the characteristics of transferring solids together with water in the process of hydrotransport at pumping stations, that is, the influence on the distribution of kinematic and dynamic parameters of the flow of hydraulic transport, the description of the pressure dispersed flows in the process of hydrotransport with high volume concentrations and a wide range of particle sizes and densities of solid particles that form mixtures.

Numerical Simulation of Gas-solid Jet Fire in Natural Gas Pipeline Leakage

Aiming at the problem that gas-solid two-phase jet flame formed by jet fire entrained by natural gas pipeline leakage is less studied, the gas-solid two-phase jet and pure gas-phase jet flame models formed by natural gas pipeline leakage are established by FLUENT software. The differences between the gas-solid two-phase jet and the pure gas-phase jet flame were comparatively studied, and the effect of different particle size on flame height, temperature and radiation of gas-solid jet was analyzed. The results indicate that the solid particles entering the flame will lead to a lower temperature compared to a gas-jet-only flame. The larger the mass flow of solid particles is, the lower the flame temperature of the gas-solid jet will be, and the corresponding flame height and radiation hazards are also reduced. The present study findings can be used for the purpose of studying gas-solid two-phase jet flame in leakage of natural gas pipelines.

Cartographic technique for determining areas of soil contamination by heavy metals

ABSTRACT Soils are the interface of streams of matter and energy. In the modern world, they are constantly under man-made pressure, not least from pollution, so we need to monitor their status. If we know the points of impact, we can model the flows of solid particles and salts in solution, predict the trajectory of pollutants and, thereby, reduce the number of samples needed in a monitoring scheme. This is especially useful in areas of subdued relief where it is hard to see the zones of concentration. Sampling points may be selected according to accumulative surface curvature that separates shedding zones from the receiving zones where sampling should be concentrated. The cartographic model clearly indicates the zones of concentration and, so, minimises the chance of sampling the wrong places.

Influence of Lump Ore Ratio and Shapes on the Particle Flow Behavior Inside the Direct Reduction Shaft Furnace by Discrete Element Modeling Model

In recent years, with the attention given to hydrogen reduction‐related technologies, the parameter indicators of direct reduction in the shaft furnace have gained importance. Herein, the numerical simulation of the particle flow field in the shaft furnace is investigated with the help of discrete element method (DEM) model. In contrast to the subregional modeling and the single particle shape study of the previous studies, this study innovatively uses the real shape of the particles and the overall structure of the vertical furnace for modeling. The transient characteristics of solid particle flow under ten lump ore ratios and three shapes are considered. The results show that the mass fraction and the shape of lump ore have little effect on the particle falling speed, but have a significant effect on the particle segregation behavior. In addition, the void ratio responds to the permeability condition in the furnace, which is also influenced by the lump ore proportion and shape.

Experimental measurements of gas-particle flows in large-scale strippers

Measurements of gas–solid particle flow in a large-scale stripper unit are reported. The experiments target industrial (pilot) scale measurements of gas-particle flow that can be used to validate numerical methods for modeling multiphase flows, such as computational fluid dynamics coupled to the discrete element method (CFD-DEM). Specifically, experiments were performed with Geldart Group B (533 µm) glass beads in a stripper unit. In general, previous CFD-DEM validation datasets were performed in benchtop experimental systems and limited to O(105) particles. Here, the number of particles in the isolated section of the stripper is O(107) for all tests. Measurements are reported for a ∼2 m tall section of the ∼1 m diameter stripper. Radial mass flux profiles measured at five axial positions and three axial pressure drop measurements are reported for six operating conditions.

Evaluation on Micromixing of a Continuous Solid Particle Flow in In-Line HSMs by Experiments and Artificial Intelligence Approaches

Evaluation on Micromixing of a Continuous Solid Particle Flow in In-Line HSMs by Experiments and Artificial Intelligence Approaches

CFD Simulation and Experimental Results Validation of Slurry Erosion Wear using Slurry Pot Test Rig

Erosion wear is a severe issue in different industrial applications results in economic costs and operational failure. In most of the industry pipelines are used to handle the slurry during industrial process, the slurry handling pipeline is failure due to erosion wear. The slurry pot test rig is developed and fabricated for investigating the erosion wear rate of different material and solid particles used in the slurry pipeline with various working conditions. The various influencing parameters such as solid particle flow velocity, impact angle, solid particle size, and concentration are responsible for the rate of material loss and erosion wear mechanisms. The present study is based on experimental work and its validation of results of slurry erosion wear for slurry handling pipeline using slurry pot test rig and CFD simulation. For experimentation, mild steel is used as pipeline material and coal bottom ash is used as solid particles for simulating slurry handling pipeline use in a thermal power plant. The experimentation is performed on the slurry pot test rig. The computational fluid dynamics (CFD) tool is used to predict and simulate the experimental results of the slurry pot test rig. The simulation results compared with experimental results and check the percentage of errors with both the results. The simulation results show a similar kind of trend for erosion wear behavior of mild steel as per the experimental results. Simulation results show the average error up to ± 21% variation with the experimental result. The simulation results give the position of erosion wear over the sample surface.&#x0D; HIGHLIGHTS&#x0D; &#x0D; Erosion wear is the major problem in slurry handling industries (thermal power plant, chemical industries, hyro-power plants, coal minis) and components (Pipelines, Centrifugal pumps, flow control valve, turbines etc.)&#x0D; Experimental worked conducted to find the erosion wear rate and material removal mechanism of pipeline material (MS) with simulating thermal power plant conditions. Similarly software simulation analysis performed for same conditions&#x0D; The experimental results give the exact value of erosion wear rate but it does not show the position of maximum wear over the sample surface. Therefore, the experimental results are used for finding the erosion wear rate i.e. value of the sample and simulation results are used for finding the position of maximum erosion wear over the target sample&#x0D; &#x0D; GRAPHICAL ABSTRACT

Numerical Simulation of Erosion Characteristics and Residual Life Prediction of Defective Pipelines Based on Extreme Learning Machine

Aiming to solve the problem that the residual life of defective elbows is difficult to predict and the prediction accuracy of a traditional extreme learning machine (ELM) is unsatisfactory, a genetic algorithm optimization neural network extreme learning machine method (GA-ELM) that can effectively predict erosion rate and residual life is proposed. In this method, the input weight and hidden layer node threshold of the hidden layer node is mapped to GA, and the input weight and threshold of the ELM network error is selected by GA, which improves the generalization performance of the ELM. Firstly, the effects of solid particle velocity, particle size, and mass flow rate on the erosion of elbow are studied, and the erosion rates under the conditions of point erosion defect, groove defect, and double groove erosion defect are calculated. On this basis, the optimized GA-ELM network model is used to predict the residual life of the pipelines and then compared with the traditional ELM network model. The results show that the maximum erosion rate of defect free elbow is linearly correlated with solid particle velocity, particle size, and mass flow rate; The maximum erosion rate of defective bend is higher than that of nondefective bends, and the maximum erosion rate of defective bend is linearly related to mass flow rate, but nonlinear to solid particle flow rate and particle size; the GA-ELM model can effectively predict the erosion residual life of a defective elbow. The prediction accuracy and generalization ability of the GA-ELM model are better than those of the traditional ELM model.

Continuous Solid Particle Flow in Microreactors for Efficient Chemical Conversion

Continuous Solid Particle Flow in Microreactors for Efficient Chemical Conversion

Inertial Self-Assembly Dynamics of Interacting Droplet Ensembles in Microfluidic Flows.

The multiphase flow of droplets is widespread and used for both biological and nonbiological applications alike. However, the ensemble interactions of such systems are inherently nonlinear and complex, compounded by interfacial effects, making it a difficult many-body problem. In comparison, the self-assembly dynamics of solid particles in flow have long been studied and exploited in the field of inertial microfluidics. Here, we report novel self-assembly dynamics of liquid drops in microfluidic channels that contrast starkly with the established paradigm of inertial microfluidics, which stipulates that higher inertia leads to better spatial ordering. Instead, we find that ordering can be negatively correlated with inertia, while Dean flow can achieve long-range spatial periodicity on length scales at least 3 orders of magnitude greater than the drop diameter. Experimentally, we decouple droplet generation from ordering, enabling independent and systematic variation of key parameters, especially in ranges practical to droplet microfluidics. We find the inertia-dependent emergence of preferred drop separations and show that surfactant effects can influence the longitudinal ordering of multidrop arrays. The dynamics we describe have immediate utility to droplet microfluidics, where the ability to order drops is key to the streamlined integration of on-chip incubation with deterministic drop manipulation downstream─two important functions for biological assays. To this end, we demonstrate the use of passive inertial drop self-assembly to combine a delay line with picoinjection. These results not only present a largely unexplored direction for inertial microfluidics but also show the practical benefit of its unification with the versatile field of droplet microfluidics.