Effect Of Particle Shape Research Articles

Coupled Effects of Particle Shape and Grain-Scale Deformability on Repose Angle of Sand–Rubber Granule Mixture

Coupled Effects of Particle Shape and Grain-Scale Deformability on Repose Angle of Sand–Rubber Granule Mixture

Digital image analysis of gas bypassing and mixing in gas‐fluidized bed: Effect of particle shape

AbstractThe study investigates effect of particle shape on gas bypassing and mixing of gas‐fluidized Geldart A particles. A shallow fluidized bed (FB), configured at benchscale, was used with digital image analysis (DIA) for the investigation. The extent of scatter of tracer particles throughout the bed was assessed from DIA images of defluidized powder. A novel method employing Jupyter notebook software, was used to directly determine Mixing Index from digital images. Remarkably, platelet‐shaped China clay powder displayed the best mixing characteristics (Mixing Index: 0.79) with no significant bypassing. Angular shaped Quartz displayed moderate mixing (Mixing Index: 0.67), but high bypassing (Bypassing Index: 0.75). Contrary to conventional assumptions, spherical‐shaped diatomite exhibited poor mixing (Mixing Index: 0.61) with the highest bypassing (Bypassing Index: 0.82). Platelet particles performed well even with fines removal. Most likely, particle shape significantly influenced the number of available particle contact points, tracer migration, and traceronparticle binding.

Solidification process modeling for energy storage by means of galerkin method utilizing nano-sized additives

In this study, a numerical method for modeling the freezing process inside a storage enclosure equipped with ψ-shaped fins has been scrutinized. The container features both square and sinusoidal walls, with ψ-shaped fins enhancing the thermal conduction within the system. Alumina nanoparticles, in both blade and cylindrical forms, have been dispersed in the water to investigate the effect of particle shape on the freezing process. The shape factor (m) is considered in the calculation of conductivity to capture the impact of different nanoparticle geometries. Additionally, a single-phase model is used for the nanomaterial formulation, with nanoparticle concentrations (φ) kept below 0.04 to ensure accurate representation. The results reveal that increasing (m) leads to a reduction in solidification time by approximately 7 %. When nanoparticles are dispersed in water, the time required for complete freezing decreases from 275.57 s to 201.95 s, representing a significant improvement. This demonstrates that the presence of nanoparticles can accelerate the freezing process by about 26.71 %. By incorporating ψ-shaped fins and optimizing nanoparticle characteristics, the study provides valuable insights into enhancing thermal conduction and reducing freezing times.

Human Mastication Analysis-A DEM Based Numerical Approach.

Mastication is an essential and preliminary step of the digestion process involving fragmentation and mixing of food. Controlled muscle movement of jaws with teeth executes crushing, leading towards fragmentation of food particles. Understanding various parameters involved with the process is essential to solve any biomedical complication in the area of interest. However, exploring and analyzing such process flow through an experimental route is challenging and inefficient. Computational techniques such as discrete element numerical modeling can effectively address such problems. The current work employs the Discrete Element Method (DEM) as a numerical modeling technique to simulate the human mastication process. Tavares and Ab-T10 breakage models coupled with Gaudin Schumann and Incomplete Beta fragment distribution models have been implemented to analyze the fragmental distribution of food particles. The effect of particle shape (spherical, polyhedron, and faceted cylinder), size (aspect ratio), and orientation (vertical and horizontal) on breakage and fragment distribution is analyzed. To account for the elastic-plastic behavior and moisture content in food particles, modifications has been made in breakage models by incorporating numerical softening factor and adhesion force. The study demonstrates how numerical modeling techniques can be utilized to analyze the mastication process involving multiple process parameters.

Flotation Performance of Coal: Investigating the Synergistic Effects of Particle Size and Shape, and the Influence of Geometric Elements

Flotation Performance of Coal: Investigating the Synergistic Effects of Particle Size and Shape, and the Influence of Geometric Elements

Experimental evaluation of the effect of pullout velocity on the behavior of multi-plate anchors

The determination of the pullout capacity of anchors has been a key point of offshore and onshore applications, considering factors such as the shape, size, penetration velocities, and pull-out velocities of the anchors. Multi-plate expandable anchors can be considered as an alternative that exhibits higher capacity compared to single plate anchors. While previous studies have demonstrated the influence of penetration velocity, there is a lack of research investigating the pullout capacity of multi-plate expandable anchors. In the present study, experimental tests were conducted to investigate the effect of various pull-out velocities. Different soil relative densities and the distance between anchors were examined in the laboratory tests. The study also employed two analytical methods—constant control volume and movement control volume—to investigate the results of pull-out velocity. In addition, the Discrete Element Method (DEM) was used to analyze the effect of particle shape on the results. In the experimental tests, the findings suggest that increasing the pull-out velocity from 10 to 30 mm/min improved the pullout capacity of anchors and the optimal distance between plate anchors was determined to be 1B. The DEM findings showed that the sharp-cornered shape had good agreement with experimental results.

The interplay among particle packing, binder, and strength: amelioration of ultra-high performance concrete with nanomaterials, a hope or hype?

A Middling quality of concrete exacerbates deterioration that tarnishes structural integrity and leads to dilapidated infrastructures. The significant intent of this work is to develop sustainable Ultra-High-Performance Concrete (UHPC) using nanosilica and nano clay. The factors, such as particle size, shape, and particle packing effect plays a key role in development of eco-friendly UHPC. Elkem Materials Mixture Analyser (EMMA), based on Modified Andreasen and Andersen particle packing theory is employed for mix optimization to attain dense packing with low binder content. UHPC is amalgamated with cement, silica fume, nanosilica, and nano clay in various combinations. The mix combination includes control mix (A0), B1–B3 that holds 1–3% nano silica, and C1–C3 yields 1–3% nano clay. It is inferred, B3 (3% nanosilica) exhibits the highest compressive strength of 118 MPa due to its size, quasi spherical shape, and homogenous dispersion. Consequently, C2 (2% nanoclay) manifest 18 and 33% enhancement in splitting tensile and modulus of rupture due to due to layered shape of nano clay that acts as reinforcement, inhibits cracks, and improves strength Microstructural analysis confirms the formation of additional hydration products with less voids. Thus, synergy of particle size, shape, and packing effect results in sustainable UHPC.

Effect of the particle shape on the shear mechanical behavior of coral sand

Abstract Coral sand particles exhibit a wide range of shapes, which can be divided into four shapes, e.g., blocky, dendritic and rodlike, flaky, and shell debris. The particle shape of these mixtures is defined by the sphericity, concavity, aspect ratio, flatness and overall regularity, which ranges from 0 to 1. The effect of particle shape on the strength, crushing characteristics, and critical state parameter is systematically investigated through a series of triaxial drainage shear tests under different confining pressures. And the relationship between critical state parameters and mechanical parameters is established. The test results demonstrate the existence of an evident strain-hardening phenomenon in the stress–strain curve of coral sand, accompanied by a strain-softening phenomenon when the bias stress reaches its peak value. The sample is initially subjected to shear shrinkage, followed by shear expansion. The volumetric deformation of the coral sand decreased with increasing peripheral pressure. The particles are transformed from rough irregular shapes to smooth spheres as evidenced by an increase in the shape parameter. The greater the degree of irregularity in the shape of the particles, the more pronounced the resulting change in size reduction. In addition, the critical state parameter was found to be influenced by the shape of the coral sand particles and the mode of particle accumulation. The overall shear resistance of coral sand particles was found to depend on particle rearrangement in addition to particle surface roughness and interparticle friction. It is proposed that the general regularity critical state parameter equation relates the particle shape of coral sand to its critical state mechanical properties, which is of great importance to the practical application and research of coral sand in engineering, and provides an effective means of predicting mechanical properties granular materials.

Effects of Particle Size and Shape on the Texture Property of a Solid-Liquid Dispersion System With Gel Particles.

Food texture is one of the most important factors for assessing the quality and acceptability of food. However, the study of food texture has been delayed compared with other factors, such as flavor and taste, due to the difficulty of quantitative analysis related to real physiological senses. Furthermore, the numerical and systematic evaluation of the texture property of dispersion systems, in which solid particles are dispersed in a liquid medium, is very difficult, despite most foods being in a solid-liquid dispersion state during mastication in the human mouth. In this study, the texture property of a solid-liquid dispersion system with spherical and cubic gel particles of agar and konjac was examined to evaluate the physical behavior of food during mastication using the back extrusion method. The yield stress of the system strongly depended on the size and shape of the particles, the mixing ratio of particles of different sizes and shapes, and the concentration of components in the particles. The proposed index, reflecting the size, shape, and number of particles and the yield stress of a single particle, expressed well the measured yield stress of the entire dispersion system. However, the adhesiveness and recoverability showed relatively little dependence on particle size. The findings obtained in this study will contribute to elucidating the texture property of various foods and to the development of new and novel food products and cuisines, thereby benefiting food science and industry.

Assessing the effect of size and shape factors on the devolatilization of biomass particles by coupling a rapid-solving thermal-thick model

In CFD modeling, while the isothermal assumption has conventionally been coupled for updating particle temperature, its applicability diminishes when dealing with thermally thick particles. A thermal-thick discrete phase model (DPM) is developed to simulate pyrolysis of biomass particle group at high heating rates and temperatures, with particles tracked in a Lagrangian scheme. The effects of particle size and shape on the volatile release and heating history are investigated. For spherical particles with a diameter of 9.6mm, the temperature difference between the surface and center (∆T) does not disappear even up to 50seconds. In the particle size range spanning from 200 μm to 9.6mm, the duration required for a complete volatile release extends from 1.5 to 40s. For cylindrical particles, in contrast to the particles with an aspect ratio (AR, ratio of particle length to diameter) of 1, the devolatilization time of particles with an AR of 15 can be shortened by more than 50%. In addition, both the particle shape and size can significantly influence the volatile distribution within the reactor. This work contributes to understanding both the particle size and shape impact on heat and mass transfer during biomass pyrolysis at high heating rates.

Effect of particle shape on the void space in granular materials: implications for the properties of granular filters

Effect of particle shape on the void space in granular materials: implications for the properties of granular filters

The angle of repose and base stress distribution of granular piles: An experimental investigation

The angle of repose and characteristics of the base stress distribution underneath granular piles serve as essential indicators in understanding the mechanical and packing properties of particle system. One counterintuitive phenomenon is that there is an evident dip of the base stress beneath the pile apex that might have implications in the design of granular pile facilities. The repose angle and stress dip are influenced by many categories of factors and exhibit different variations. Based on the localized source method, particle packing experiments were conducted to investigate the effects of funnel height, particle size, particle shape, and packing method on the repose angle and the vertical stress distribution of granular piles. The experimental results show that the repose angle of piles of irregular particle shape and higher funnel height is much larger, but there is a decreasing trend of repose angle with increasing particle sizes. The natural packing angles before and after the critical collapse of granular pile exhibits periodic variation. On the other hand, the stress dip phenomenon occurred in all granular piles constructed by localized procedure. An increase in funnel height and a middle particle size mitigate the stress dip to some extent, whereas irregular particle shape exacerbates it. Comparison of the results from different packing methods reveals that larger repose angle and more pronounced stress dip are observed in confined packing piles compared to that in free packing piles. Considering a growth rate of less than 5 %, the average vertical stress under the sand silo reaches saturation state. Moreover, the pressure on the silo wall increases with the height of silo pile but remains somewhat lower than predicted by the Ketchum equation and current design values.

Particle-resolved computational modeling of hydrogen-based direct reduction of iron ore pellets in a fixed bed. Part II: Influence of the pellet sizes and shapes

Full-fledged computational modeling of Direct Reduction reactors encompasses single-pellets models and the step-wise scaling up to industrial-scale reactors. This study delves into the particle-resolved computational modeling of hydrogen-based direct reduction of 0.5 kg iron ore fixed-beds, as a scale-bridging step and focusing on the influence of pellet sizes and shapes. To investigate the effect of particle sizes, two beds with particles sized 10.0–12.5 and 12.5–16.0 mm were characterized and numerically reconstructed using the discrete element method. While to assess the effect of particle shapes, a third numerical bed was generated directly upon a high-resolution CT-scan of a real bed. Through reactive CFD simulations, we investigated the reduction process in these three beds using hydrogen as the reducing gas. Our findings reveal that the bed structure significantly impacts the reduction efficiency and overall conversion degree. This study emphasizes the importance of accurate bed reconstruction and provides critical insights for optimizing the hydrogen-based direct reduction process in industrial applications.

Finite element simulation of the effect of particle shape and thermal residual stress on the tensile properties of NbCp/Fe composites

To optimize the microstructure and properties of NbCp/Fe composites, this study considered factors such as load transfer, plastic strain, matrix damage, and interface debonding. A two-dimensional finite element model was constructed using ABAQUS software. Random adsorption algorithm was used to realize the random distribution of particles within the representative volume element, and interface damage was described using a cohesive zone model. The effects of particle shape and thermal residual stress on the tensile properties of NbCp/Fe composites were investigated. The results show that circular particles uniformly distribute the stress during the tensile process, effectively enhancing the tensile properties of the composites. Conversely, triangular particles, with obvious sharp corners, reduce their tensile properties, particularly in the presence of thermal residual stresses, which further aggravates the stress concentration between the particles and the matrix. This leads to a decrease in the strength and toughness of the material.

Examination of particle motion in fluidized bed flotation columns: Effect of particle shape

The critical analysis of particle dynamics within the flow field is vital for the optimization and enhancement of new fluidized bed flotation columns. Prior research has centered on the kinetic properties of auxiliary fluidized particles (glass spheres) in these columns [1]. However, in real-world applications, these particles undergo wear and transform into irregular shapes. This investigation seeks to explore the motion characteristics of particles of various geometries in a three- phase gas-liquid-solid environment. By quantifying the velocities of particles with different shapes, we aim to improve the evaluation of their dispersion and collision behavior with the column walls. First, the particle concentration distribution within the fluidized zone is continuously monitored through pressure sensors at various axial positions, allowing us to examine the concentration patterns of particles from different shape categories under various operational conditions. Second, the motion dynamics of particles within the fluidization zone are studied using high-speed camera techniques. Particle velocities are determined by correlating tracer particle velocities with black markers for precise measurement. To evaluate the frequency of particle-wall collisions, a modified collision model is applied to ascertain collision rates and to investigate the influence of shape parameters on such interactions. Lastly, the normal and tangential restitution coefficients are measured based on the trajectories of particles before and after collisions with the walls.

Entropy optimization in multigrade motor oil based nanofluid: a spectral and sensitivity analysis with particle shape and dispersion effects

PurposeThis study aims to enhance heat transfer efficiency while minimizing friction factor and entropy generation in the flow of Nickel zinc ferrite (NiZnFe2O4) nanoparticles suspended in multigrade 20W-40 motor oil (as specified by the Society of Automotive Engineers). The investigation focuses on the effects of the melting process, nonspherical particle shapes, thermal dispersion and viscous dissipation on the nanofluid flow.Design/methodology/approachThe fundamental governing equations are transformed into a set of similarity equations using Lie group transformations. The resulting set of equations is numerically solved using the spectral local linearization method. Additionally, sensitivity analysis using response surface methodology (RSM) is conducted to evaluate the influence of key parameters on response function.FindingsHigher dispersion reduces entropy production. Needle-shaped particles significantly enhance heat transfer by 27.65% with melting and reduce entropy generation by 45.32%. Increasing the Darcy number results in a reduction of friction by 16.06%, lower entropy by 31.72% and an increase in heat transfer by 17.26%. The Nusselt number is highly sensitive to thermal dispersion across melting and varying volume fraction parameters.Originality/valueThis study addresses a significant research gap by exploring the combined effects of melting, particle shapes and thermal dispersion on nanofluid flow, which has not been thoroughly investigated before. The focus on practical applications such as fuel cells, material processing, biomedicine and various cooling systems underscores its relevance to sectors such as nuclear reactors, tumor treatments and manufacturing. The incorporation of RSM for friction factor analysis introduces a unique dimension to the research, offering novel insights into optimizing nanofluid performance under diverse conditions.

Exploring the influence of silicon oxide microchips shape on cellular uptake using imaging flow cytometry

Nano- and micro-carriers of therapeutic molecules offer numerous advantages for drug delivery, and the shape of these particles plays a vital role in their biodistribution and their interaction with cells. However, analysing how microparticles are taken up by cells presents methodological challenges. Qualitative methods like microscopy provide detailed imaging but are time-consuming, whereas quantitative methods such as flow cytometry enable high-throughput analysis but struggle to differentiate between internalised and surface-bound particles. Instead, imaging flow cytometry combines the best of both worlds, offering high-resolution imaging with the efficiency of flow cytometry, allowing for quantitative analysis at the single-cell level. This study focuses on fluorescently labelled silicon oxide microchips of various morphologies but related surface areas and volumes: rectangular cuboids and apex-truncated square pyramid microchips fabricated using photolithography techniques, offering a reliable basis for comparison with the more commonly studied spherical particles. Imaging flow cytometry was utilised to evaluate the effect of particle shape on cellular uptake using RAW 264.7 cells and revealed phagocytosis of particles with all shapes. Increasing the particle dose enhanced the uptake, while macrophage stimulation had minimal effect. Using a ratio particle:cell of 10:1 cuboids and spheres showed an uptake rate of approximately 50%, in terms of the percentage of cells with internalised particles, and the average number of particles taken up per cell ranging from about 1–1.5 particle/cell for all the different shapes. This study indicates how differently shaped micro-carriers offer insights into particle uptake variations, demonstrating the potential of non-spherical micro-carriers for precise drug delivery applications.Graphical

Numerical prediction on frictional characteristics of binary mixtures consisting of flexible cylindrical particles and rigid spheres

A Discrete Element Method (DEM) model for deformable cylindrical particles is established to investigate the Jenike shear process of binary mixtures consisting of flexible cylindrical particles and rigid spheres. The effects of the shape of flexible cylindrical particles and the proportion of cylindrical particles to spherical ones on the friction behavior of the mixture are discussed. Numerical results show that both the shear stress and internal friction angle increase with the aspect ratio (Ar) of the flexible cylindrical particles but decrease with the increase of the proportion of spherical particles. The role of Ar becomes slight when when the amount of spheres are much higher than the cylindrical particles (double or higher). For the mono-system containing flexible cylindrical particles of Ar=6 but without spheres, the strong interlocking packing structure leads to high shear stress and internal friction angle. It is indicated that the inclusion of rigid spheres disrupts the interlocking structure between flexible cylindrical particles and acts as a lubricant during the shear process. Based on the numerical results, a predictive correlation is established to predict the frictional characteristics of binary mixtures consisting of flexible cylindrical particles and rigid spheres considering the effect of particle shape and proportion. Furthermore, through a microscopic analysis of the numerical results, a deeper understanding of this phenomenon is gained. It is confirmed that the spherical particles can fill the voids between the flexible cylindrical particles, increasing the compactness of the mixture and promoting lubrication effects. The current research contributes to the better understanding of the mechanism of particle flow and is of paramount importance to improve the kinetic theories for complex granular flows.

Modeling a Flexible Membrane for Triaxial Tests with Coupled FDM–DEM: Considering Realistic Particle Shape Effects

Modeling a Flexible Membrane for Triaxial Tests with Coupled FDM–DEM: Considering Realistic Particle Shape Effects

Effect of Particle Shape on the Flow of an Hourglass.

The flow rate of a granulate out of a cylindrical container is studied as a function of particle shape for flat and elongated ellipsoids experimentally and numerically. We find a nonmonotonic dependence of the flow rate on the grain aspect ratio a/b. Starting from spheres the flow rate grows and has two maxima around the aspect ratios of a/b≈0.6 (lentil-like ellipsoids) and a/b≈1.5 (ricelike ellipsoids) reaching a flow rate increase of about 15% for lentils compared to spheres. For even more anisometric shapes (a/b=0.25 and a/b=4) the flow rate drops. Our results reveal two contributing factors to the nonmonotonic nature of the flow rate: both the packing fraction and the particle velocity through the orifice are nonmonotonic functions of the grain shape. Thus, particles with slightly nonspherical shapes not only form a better packing in the silo but also move faster through the orifice than spheres. We also show that the resistance of the granulate against shearing increases with aspect ratio for both elongated and flat particles; thus change in the effective friction of the granulate due to changing particle shape does not coincide with the trend in the flow rate.