Effect Of Particle Properties Research Articles

The effect of particle properties and solids concentration on the yield stress behaviour of drilling fluid filter cakes

Filter cakes made from model water-based drilling fluids were tested to determine cake properties such as porosity, thickness and yield stress. The effects of drilling fluid particle concentration, size distribution and shape on the properties of the resulting cakes were investigated. A hole punch tester was used to find the shear stress of the cakes, obtaining a yield stress from the measured peak force. The cake yield stress increased with increasing barite solids content in the fluid from 16.5 kPa at 3.1 vol% to 65.6 kPa at 24.8 vol%. A similar trend was observed for cakes made from calcium carbonate. Furthermore, the calcium carbonate cakes were thicker and stronger than the barite equivalents, with yield stresses increasing by between 29% and 56%. The addition of calcium carbonate particles to the existing barite network did not affect the cake thickness appreciably but gave cakes of lower porosity and higher yield stress.

Statistical Study of the Effect of Particle Properties on the Particle Penetration in the Idealized Trachea

The particulate matter (PM) is one of the harmful pollutants that causing an impact on human health. To study the significance of those small particle properties, the research had been conducted using three-dimensional computational fluid dynamics with the Eulerian-Lagrangian approach. The trajectories of the particles were tracked and recorded. The effect of particle diameter, particle density, and particle sphericity on the escaped particle percentage was investigated and characterized using the statistical analysis of variance. The results showed that the particle diameter, particle density, their interaction, and the quadratic effect of the particle diameter played important roles in the penetration of those injected particles.

The distribution of bed density in an air dense medium fluidized bed with single and binary mixtures of Geldart B and/or D particles

The distribution of bed density in an Air Dense Medium Fluidized Bed (ADMFB) with single and binary mixtures of solid particles was investigated for dry coal beneficiation. The effects of particle properties, superficial gas velocity, and mixture composition on the axial distribution of fluidized bed density were examined. A lower density region at the bottom of the fluidized bed with single particles has been observed, whereas the bed density at the upper part remains almost consistent. The increasing excess gas velocity does not change this trend although decreasing the overall bed density, however the binary mixtures of solid particles can be used to balance this non-uniform density distribution. A new equation has been derived to predict the bed density distribution, considering particle properties and fluidization characteristics. This correlation successfully accounts for the estimation of density distribution in ADMFB involving both single and binary mixtures of Geldart B and/or D particles.

Effects of Particle Properties on the Settling and Rise Velocities of Microplastics in Freshwater under Laboratory Conditions.

Microplastic (MP) contaminates terrestrial, aquatic, and atmospheric environments. Although the number of river sampling studies with regard to MP concentrations is increasing, comprehension of the predominant transport processes of MP in the watercourse is still very limited. In order to gain a better process understanding, around 500 physical experiments were conducted to shed more light on the effects of particle shape, size and density on the rise and settling velocities of MP. The determined velocities ranged between 0.39 cm/s for polyamide fibers (settling) and 31.4 cm/s for expanded polystyrene pellets (rise). Subsequently, the determined velocities were compared with formulas from sediment transport and, as there were large differences between theoretically and experimentally determined velocities, own formulas were developed to describe settling and rise velocities of MP particles with a large variety of shapes, sizes and densities. This study shows that MP differs significantly from sediment in its behavior and that a transfer of common sediment transport formulas should be treated with caution. Furthermore, the established formulas can now be used in numerical simulations to describe the settling and rising of MP more precisely.

Flow of granular materials in a bladed mixer: Effect of particle properties and process parameters on impeller torque and power consumption

The torque and power needed to drive an impeller are important quantities that can indicate flow behavior and can be used to control processes, especially mixing and granulation in the pharmaceutical industry. In this study, experiments were conducted on monodisperse spherical glass beads flowing in a cylindrical bladed mixer agitated by an impeller. The impeller torque was measured using a rotating platform and a data recording device, and the power draw for the motor driving the impeller was measured using a power meter. The effect of various impeller blade designs and material properties on the torque and power were investigated as a function of the impeller blade rotation rate. It was found that the torque exerted on a granular bed and the power consumption were a strong function of the impeller blade configuration, the position of the blades in a deep granular bed, the fill height of the glass beads, and the size and friction coefficient of the particles. It was observed that the time-averaged torque and power consumption for different particle sizes qualitatively scaled with particle diameter. A scale-up relationship for a deep granular bed was developed: the time-averaged torque and average adjusted power consumption scaled with square of the material fill height.

Rheological behavior of water-ash mixtures from Sakurajima and Ontake volcanoes: implications for lahar flow dynamics

Lahars represent one of the most serious volcanic hazards, potentially causing severe damage to the surrounding environment, not only immediately after eruption but also later due to rainfall or snowfall. The flow of a lahar is governed by volcanic topography and its rheological behavior, which is controlled by its volume, microscale properties, and the concentration of particles. However, the effects of particle properties on the rheology of lahars are poorly understood. In this study, viscosity measurements were performed on water-ash mixtures from Sakurajima and Ontake volcanoes. Samples from Sakurajima show strong and simple shear thinning, whereas those from Ontake show viscosity fluctuations and a transition between shear thinning and shear thickening. Particle analysis of the volcanic ash together with a theoretical analysis suggests that the rheological difference between the two types of suspension can be explained by variations in particle size distribution and shape. In particular, to induce the complex rheology of the Ontake samples, coexistence of two particle size groups may be required since two independent behaviors, one of which follows the streamline (Stokes number St << 1, inertial number I < 0.001) and the other shows a complicated motion (St ~ 1, I ~ 0.001), compete against each other. The variations in the spatial distribution of polydisperse particles, and the time dependence of this feature which generates apparent rheological changes, indicate that processes related to microscale particle heterogeneities are important in understanding the flow dynamics of lahars and natural polydisperse granular-fluid mixtures in general.

Effect of particle properties on the energy-size reduction of coal in the ball-and-race mill

Breakage behaviors and energy consumed characteristics of coal are directly influenced by properties, such as particle size, ash content or density. It is essential to model these effects and conduct quantitative evaluation. In this study, samples of 4 particle sizes × 4 ash contents were ground in a Hardgrove mill for 9 energy levels, respectively. Breakage rate of particles in the top size and t10 were determined and effects of coal properties on two parameters were also discussed. Though the relation between consumed energies and t10 of each sample can be described by classical breakage model, experimental data of all samples were scatter. In this case, particle size and ash content were modelled into breakage equation in exponential term, namely t10 = A × (1 − e−b∙x∙Ecs/eYa). This modified model gave good fitting results to experimental data. Introduce of coal properties into energy-size reduction model helps to compare grinding energy efficiency of various coals. Confidence analyses of repeat experiments demonstrated the repeatability of test results and indicated the reliability of new breakage model.

Effect of Particle Properties and Dispersion Medium on the Particulate Feeling of Foods

Effect of Particle Properties and Dispersion Medium on the Particulate Feeling of Foods

Effects of Particle Properties on Agglomerate Formation of Fine Particles in Vibrating Fluidized Bed

Effects of Particle Properties on Agglomerate Formation of Fine Particles in Vibrating Fluidized Bed

Measurement of solid mass flow rate by a non-intrusive microwave method

The methods of accurate measurement on the real-time solid mass flow rate are very limited, especially for non-intrusive measuring approaches. This paper presents a non-intrusive measurement system on solid mass flow rate. The measuring principle is based on microwave attenuation theory and microwave Doppler Effect. A series of experiments have been carried out to test the microwave measurement method. The effects of particle properties in terms of size and relative permittivity on the measuring results have been carefully discussed. The correlations between the output signal and the solid mass flow rate have been investigated. The experiment results show that the size and material of the measured solids can significantly influence the reflected microwave signal. To improve the measurement accuracy, the correlation related on the functions of particle diameter and permittivity is proposed for the solid mass flow rate. Furthermore, the experiments under the unsteady flow condition confirm that this method is promising to be applied in the actual industrial processes.

Gravitational discharge of fine dry powders with asperities from a conical hopper

The effects of particle properties, especially the surface roughness and particle type, on the gravity discharge rate and flow behavior of fine dry powders from a conical hopper are studied in detail. The van der Waals force is considered to dominate the discharge of small particles, while the empty annulus effect dominates the discharge of large particles. To predict the van der Waals force between two rough spherical particles, a model based on Rumpf theory is adopted. The effect of surface roughness can be reflected by Bond number Bog which is correlated with discharge rate. By modifying the powder bed porosity and Beverloo constant, the discharge rates of fine dry powders can be well predicted by an empirical correlation. Finally, not only the ratio of hopper outlet size to particle size D0/dp but also the Bond number Bog is found to be an important indicator to determine the powder flowability. © 2017 American Institute of Chemical Engineers AIChE J, 64: 427–436, 2018

A numerical framework for the direct simulation of dense particulate flow under explosive dispersal

In this paper, we present a Cartesian grid-based numerical framework for the direct simulation of dense particulate flow under explosive dispersal. This numerical framework is established through the integration of the following numerical techniques: (1) operator splitting for partitioned fluid–solid interaction in the time domain, (2) the second-order SSP Runge–Kutta method and third-order WENO scheme for temporal and spatial discretization of governing equations, (3) the front-tracking method for evolving phase interfaces, (4) a field function proposed for low-memory-cost multimaterial mesh generation and fast collision detection, (5) an immersed boundary method developed for treating arbitrarily irregular and changing boundaries, and (6) a deterministic multibody contact and collision model. Employing the developed framework, this paper further studies particle jet formation under explosive dispersal by considering the effects of particle properties, particulate payload morphologies, and burster pressures. By the simulation of the dispersal processes of dense particle systems driven by pressurized gas, in which the driver pressure reaches $$1.01325\times 10^{10}\,\,\mathrm {Pa}$$ ( $$10^5$$ times the ambient pressure) and particles are impulsively accelerated from stationary to a speed that is more than $$12000\,\,\mathrm {m/s}$$ within $$15\,\,\mathrm {\upmu s}$$ , it is demonstrated that the presented framework is able to effectively resolve coupled shock–shock, shock–particle, and particle–particle interactions in complex fluid–solid systems with shocked flow conditions, arbitrarily irregular particle shapes, and realistic multibody collisions.

An experiment investigation into the effect of particle properties on natural gas hydrate sediments#br#

An experiment investigation into the effect of particle properties on natural gas hydrate sediments#br#

Analysis of Minor Component Segregation in Ternary Powder Mixtures

In many powder handling operations, inhomogeneity in powder mixtures caused by segregation could have significant adverse impact on the quality as well as economics of the production. Segregation of a minor component of a highly active substance could have serious deleterious effects, an example is the segregation of enzyme granules in detergent powders. In this study, the effects of particle properties and bulk cohesion on the segregation tendency of minor component are analysed. The minor component is made sticky while not adversely affecting the flowability of samples. The segregation extent is evaluated using image processing of the photographic records taken from the front face of the heap after the pouring process. The optimum average sieve cut size of components for which segregation could be reduced is reported. It is also shown that the extent of segregation is significantly reduced by applying a thin layer of liquid to the surfaces of minor component, promoting an ordered mixture.

The effect of particle properties on the depth profile of buoyant plastics in the ocean.

Most studies on buoyant microplastics in the marine environment rely on sea surface sampling. Consequently, microplastic amounts can be underestimated, as turbulence leads to vertical mixing. Models that correct for vertical mixing are based on limited data. In this study we report measurements of the depth profile of buoyant microplastics in the North Atlantic subtropical gyre, from 0 to 5 m depth. Microplastics were separated into size classes (0.5–1.5 and 1.5–5.0 mm) and types (‘fragments’ and ‘lines’), and associated with a sea state. Microplastic concentrations decreased exponentially with depth, with both sea state and particle properties affecting the steepness of the decrease. Concentrations approached zero within 5 m depth, indicating that most buoyant microplastics are present on or near the surface. Plastic rise velocities were also measured, and were found to differ significantly for different sizes and shapes. Our results suggest that (1) surface samplers such as manta trawls underestimate total buoyant microplastic amounts by a factor of 1.04–30.0 and (2) estimations of depth-integrated buoyant plastic concentrations should be done across different particle sizes and types. Our findings can assist with improving buoyant ocean plastic vertical mixing models, mass balance exercises, impact assessments and mitigation strategies.

Experimental and CFD study of particle deposition on the outer surface of vortex finder of a cyclone separator

Based on the industrial background of carbonaceous deposition in secondary cyclone separators of FCC units, this paper focuses on particle deposition pattern and investigation of factors on deposition on the outer surface of vortex finder of secondary cyclone. Particle deposition experiments were carried out with a 500mm-diameter cyclone in a cold-model pilot test platform. Deposition patterns were obtained under different inlet gas velocities, particle concentrations and experimental materials etc. Furthermore, discrete phase model (DPM) was applied to obtain particles distribution in the annular space and the effect of particle properties and operational conditions on mass of deposited particles was also investigated. In addition, Gas shielding method was preliminarily explored to avoid particle deposition. The results will provide experimental evidence for analyzing the deposition process and help to further understand the deposition mechanism.

Investigations of the effects of particle properties on the wear resistance of the particle reinforced composites using a novel wear model

A wear model is developed based on the discrete lattice spring–mass approach to study the effects of particle volume fraction, size, and stiffness on the wear resistance of particle reinforced composites. To study these effects, we have considered three volume fractions (10%, 20% and 30%), two sizes ([Formula: see text] and [Formula: see text] sites), and two different stiffness of particles embedded in the matrix in a regular pattern. In this model, we have discretized the composite system ([Formula: see text] sites) into the lumped masses connected with interaction spring elements in two dimensions. The interaction elements are assumed as linear elastic and ideal plastic under applied forces. Each mass is connected to its first and second nearest neighbors by springs. The matrix and particles sites are differentiated by choosing the different stiffness values. The counter surface is simulated as a rigid body that moves on the composite material at a constant sliding speed along the horizontal direction. The governing equations are formed by equating the spring force between the pair of sites given by Hooke’s law plus external contact forces and the force due to the motion of the site given by the equation of motion. The equations are solved for the plastic strain accumulated in the springs using an explicit time stepping procedure based on a finite difference form of the above equations. If the total strain accumulated in the spring elements connected to a lump mass site exceeds the failure strain, the springs are considered to be broken, and the mass site is removed or worn away from the lattice and accounts as a wear loss. The model predicts that (i) increasing volume fraction, reducing particle size and increasing particle stiffness enhance the wear resistance of the particle reinforced composites, (ii) the particle stiffness is the most significant factor affecting the wear resistance of the composites, and (iii) the wear resistance reduced above the critical volume fraction ([Formula: see text]), and [Formula: see text] increases with increasing particle size. Finally, we have qualitatively compared the model results with our previously published experimental results to prove the effectiveness of the model to analysis the complex wear systems.

The effect of particle properties on the heat transfer characteristics of a liquid–solid fluidized bed heat exchanger

The dominant parameters of a liquid–solid fluidized bed heat exchanger are studied both numerically and experimentally. The numerical simulations have been validated using a laboratory scale fluidized bed heat exchanger filled with stainless steel spherical particles as the particulate medium. In addition, the effect of particle properties such as the particle density, specific heat, thermal conductivity and size on the heat transfer characteristics of the fluidized bed heat exchanger have been studied using the strong tool of computational fluid dynamics. The results show that the heat transfer rate can be maximized for an optimum particle size. Moreover, the study on different materials has been conducted comparing stainless steel, aluminum and copper as the particulate phase. The obtained results of different particle properties are discussed considering the hydrodynamics and heat transfer aspects of changing the particle properties.

The effects of particle properties, void fraction, and surface tension on the trickle-bubbly flow regime transition in trickle bed reactors

The hydrodynamics of trickle bed reactors operating near the trickle-bubbly flow regime transition have not been fully characterized in the literature. In this work, an air–water system is used to investigate the effects of particle size, particle shape, void fraction, and surface tension on the trickle-bubbly flow regime transition in trickle bed reactors. The flow regime transition is detected based on standard deviation of pressure drop with confirmation by visual observation. For all cases, the liquid superficial velocity required for the trickle-bubbly transition was found to be relatively independent of the gas superficial velocity (vG=4–40mm/s). Literature models, defined for the trickle-pulse transition, are unable to predict this trend when extrapolated to low gas superficial velocities (vG⩽40mm/s). To address this gap, a correlation is proposed based on the experimental data gathered in this work.

Cratering of a particle bed by a subsonic turbulent jet: Effect of particle shape, size and density

The effect of particle properties on scour hole or crater formation, which occurs when a localized jet impinges on a bed of particles, is explored. Individual particle properties, such as particle density, size, and shape, are isolated and a parametric study is performed demonstrating the transient and steady crater growth for several particles. By keeping the particle diameter constant and changing the particle shape, this work shows that the effects of shape are significant. Uniform non-spherical (e.g. cylinders) and irregular frit shaped (e.g. crushed glass) particles are investigated. Non-spherical particles generally have higher friction, and the resulting decrease in recirculation rate of particles along the crater walls generally produces a narrower but deeper crater relative to spheres of the same size. A modification to the densimetric Froude number, which scales the steady crater depth to jet and particle properties is developed that accounts for particle shape. A new description of particle size called the erosion diameter is introduced, which is the average of the longest dimension a particle will align in a shear flow with its orthogonal, and results in the best scaling. The short-term crater depth grows faster for larger particles, which is counter to the long-term growth, and is explained by the early behavior being dominated by the number of particles that can be eroded. The transient crater depth growth is fit by an arctangent fitting function, which predicts the steady crater depth, and is compared to the logarithmic growth function that is generally used for early crater growth. For very large spherical particles, a high velocity is necessary for cratering and a newly identified particle–particle based cratering mechanism dominates. Additionally, cohesion reduces the crater depth and width and the steady crater depth does not scale with non-cohesive particles, but a further modification to the densimetric Froude number to account for cohesion is proposed.