Volume Percentage Of Particles Research Articles

Numerical analysis of a helically corrugated tube using a novel combination of W/EG-based non-Newtonian hybrid nanofluid

In this study, the second law analysis of a non-Newtonian hybrid TiO2-SiO2 nanofluid based on water/ethylene glycol has been carried out. The influence of the corrugation-height ratio (e/dh) and volume fraction (φ) on the rates of entropy creation and exergy destruction are investigated using a helically corrugated tube. The model is simulated using ANSYS FLUENT 19.0 with the corrugated wall kept at a constant heat flux of 25 kW/m2 and a range of hybrid nanofluid volume flow rates from 15 to 25 lpm. As the corrugation height and particle volume percentage increases, the HCT's rates of entropy generation and exergy destruction decrease. Additionally, as the volume flow rate of the hybrid nanofluid increases within the abovementioned range, the Bejan number and entropy generation number also decrease. For volume fraction of 5%, the Bejan number decreases to 0.873 at 25 lpm. The total irreversibility is reduced by adding corrugation and employing hybrid nanofluids. Also, working with the combination of corrugation and hybrid nanofluid leads to a notable increase in exergetic efficiency, reaching a maximum value of 82.8%.

Enhancing Heat Transfer in Compact Automotive Engines using Hybrid Nano Coolants

This research aimed to compare the performance of a reduced-scale automotive radiator using single nano coolant (CNC and CuO) and its hybrid nano coolant (CNC and CuO nanoparticles) to enhance heat transmission. Three ratios of 70:30, 80:20, and 90:10 of hybrid nano coolants was tested. UV Vis stability characterization of the nanofluids showed that all samples were highly stable for up to 30 days. A modest concentration (0.01 vol per cent) of the hybrid nano coolant was shown to efficiently increase the heat transfer rate of a reduced-size automobile radiator, demonstrating that the heat transfer behaviour of the nano coolant was reliant on the particle volume percentage. The results show the potential use of hybrid nano coolants in increasing heat transfer efficiency, decreasing cooling system size by up to 71 percent, and thus lowering fuel consumption; these benefits have significant implications for developing more efficient cooling systems in various industrial applications. The experimental findings showed that 80:20 exhibited a significant amount of improvement in thermal properties. The consistency of the low volume concentration of hybrid nano coolants throughout the experiment is further evidence of their promise as a practical substitute for conventional cooling media in the compact size of an automotive engine cooling system.

Melting behavior and migration characteristics of microencapsulated phase change material particles in galinstan flow and application in minichannel heat sink

Mini/microchannel cooling performance can be improved with microencapsulated phase change material (MPCM) slurry as coolant by utilizing latent heat absorption capacity of MPCM. Compared with existing water, using liquid metal (LM) as basefluid can combine the advantages of high apparent heat capacity of MPCM particles and high thermal conductivity of LM. Thus, the prepared MPCM-LM slurry is proposed as coolant for minichannel heat sink. The melting of particles near the bottom enhances heat transfer performance of two-phase MPCM-LM slurry, but migration and aggregation cause the increase of pressure drop. Furthermore, the two-phase model is adopted to investigate the melting behavior and migration characteristics of MPCM particles in galinstan flow and the effect of particle volume percent on minichannel cooling performance. The results show that particles present boundary-to-center melting behavior in MPCM-galinstan slurry, resulting in the larger reduction degree in bulk mean temperature compared to MPCM-water slurry. Different from uniform distribution for small-diameter particles, the large-diameter particles migrate upward, leading to top-aggregation distribution and up-down asymmetry of velocity profile. Finally, the increase of particle volume percent significantly reduces heat capacity thermal resistance of heat sink, and maximum reduction is 59.02% for MPCM-galinstan slurry with φ s = 20% compared to pure galinstan.

Squeeze infiltration processing and characterization of silicon reinforced composites

Thermal management components such as heat sink and heat spreaders used in electronic systems require materials with low CTE, low density and high thermal conductivity. The present work aims to fabricate a low-cost Si particle reinforced-A356 composite as thermal base plate for thermal management applications. The composites were prepared using squeeze infiltration technique where 30–70%Si preforms are used for reinforcement. The composite with high Si content in Al matrix possesses low density, low coefficient of thermal expansion (CTE) and good thermal conductivity. The density for the 70Si composite is 2.39 gm/cc (density of Al: 2.7 gm/cc) and CTE at room temperature is 10.5 × 10−6 K−1 (CTE of Al: 23 ×10−6 K−1). The increase in Si particle volume percentage in 356 Aluminum alloy matrix has decreased the CTE and density significantly. Effect of the silicon particles on the thermal and mechanical properties are evaluated and optimized. The theoretical and the experimental properties obtained are in close comparison shows the high integrity of the squeeze infiltrated Al-Si composites. The performance of the composite was studied through simulation using ANSYS workbench.

Fractal expression of soil particle-size distribution at the basin scale

Abstract Soil structure at the basin scale affects the superficial moisture content, heat, salinity balance, and ecological balance of groundwater system. To study the soil particle size fractal characteristics at the basin scale, 188 groups of soil samples were collected over a distance of 258 km in the Ziya River basin of the North China Plain. Particle volume percent was measured using a laser particle size analyzer, and then analyzed by applying the fractal theory to reveal the spatial distribution of soil particle size and soil voids. The results showed that: (1) From the Taihang Mountain piedmont to the coastal area, soil particle-size volume percentages varied in a small range, with the fractal dimension D showing an overall decreasing trend; (2) D showed a significant spatial variation, ranging from 0.13 to 2.188. It was jointly determined by particle uniformity and particle size range; (3) When D ≤ 1, the characteristic fractal size was 30 μm in the basin. When 1 < D ≤ 1.5, the characteristic fractal size was 20 μm and D a was 1.37, and when D > 1.5, the two parameters were 10 μm and 1.77, respectively. The research results indicated that D can effectively quantify the characteristics of soil structure at a large scale.

Hydrodynamic Characteristics Effect of Foam Control in a Three-Phase Fluidized Bed Column

The present work was devoted to study the effect of operating parameters (e.g., superficial gas and liquid velocities, size of solid particles, volume percentage of particles loaded in column and type of particles) on foams, and to investigate the process of foam suppression.
 The experimental apparatus was operated in continuous mode for the two phases (i.e. air and a solution of aqueous anionic surfactant). Sands which were considered as hydrophilic behavior particles were used as solid phase. A specific surface treatment was performed on hydrophilic sands particles to transfer it into hydrophobic one. These two versions of sands were used in the experimental setup respectively to study their effect on suppression of foams. The average gas holdup for the entire column was measured by means of the local gas holdup which was computed from the pressure difference in each segment of the column. Local solid concentration along the column was measured experimentally by analyzing the samples of mixture drawn from the sampling ports. From the present work it was found that: Flow regimes of multiphase system could be easily determined by utilizing local gas holdup profile measured by pressure drop transducer method. The transition from the homogenous to heterogeneous regime was advanced, from ug=4 to 2cm/s with increasing solid concentration from 10 to 20%v and decreasing average particle diameter from dp=(0.8) to (0.25) mm.
 When a mixture of water/surfactant was employed in the bubble column, foam could be present depending on the input operating parameters. The fluid mechanism of foam suppression with hydrophilic particles was enhanced by a direct attack on the foam by hydrophobic particles (i.e. hydrophobic particles were more effective in retaining liquid–destroying foam than the hydrophilic particles). It was found that hydrophobic particles of 0.25 mm average diameter and 10%v loading in the reactor could reduce foaminess fraction from 0.85 to 0.15 if the liquid velocity was 0.3 cm/s. The foaminess fraction could be reduced to 0.0 if the liquid velocity increased to 0.4 cm/s. The results of this study may have abroad applications in petroleum and petrochemical industries where liquid hydrocarbons are processed.

Shear Mode Damper Testing Using Flake Shape Based Magnetorheological Fluids

Use of anisotropic iron particles in the magnetorheological (MR) fluid having a high yield stress is a challenge as it increases the viscosity of the fluid in off-state. In this clause, a novel flake shaped iron powder based MR fluid with high yield stress is synthesized and used in shear mode MR damper (SMMD). MR damper design is optimized using fluid properties and Bingham model. Damping performance of newly synthesized MR fluid damper is at par with the available friction based damper used in front loaded washing machine. The unique feature of this design is minimal volume of the fluid (1.5 ml) required to achieve damping force of 50N. Effect of different volume percentage of particles in MR fluid is evaluated in terms of damping force. Effect of testing parameters like displacement and frequency of excitation on damping force was evaluated. Effect of settling of particle on damper performance is discussed in this work. It shows that the flakes shaped-based MR fluid show better stability against gravity. The smaller quantity of present flake shaped-based MR fluid will reduce the cost of shear mode damper.

Flexible Piezoelectric 0–3 PZT-PDMS Thin Film for Tactile Sensing

In this paper, Lead Zirconate-Titanate (PZT)/Poly-dimethylsiloxane (PDMS) based composite is fabricated and characterized for its potential application as a flexible piezoelectric material. Thin films of the composite are prepared by dispersing different volume percentage of PZT particles in cross-linked PDMS matrix. Corona poling of the films is performed to increase the piezoelectric charge constant. X-ray diffraction results indicate that poling aligns the randomly oriented ferroelectric domains in the PZT particles along the poling axis. Piezoelectric voltage response and piezoelectric charge constant values before and after the poling show the improvement in piezoelectricity due to poling. The piezoelectric charge constant, d33 and magnitude of relative permittivity of the films increase and flexibility of the films decrease with the increase of PZT particle volume percentage in the composite. Results show that for 28 v% PZT composite poled film a d33 of 78.33 pC/N was achieved with a Young’s modulus of around 10 MPa and magnitude of relative permittivity of 10. The film demonstrates effectiveness for tactile sensing by generating charges across the film proportional to the finger pressure applied on them. The easy fabrication process makes the composite a promising candidate to build flexible low cost tactile sensing devices.

Numerical investigation of thermal pulsating alumina/water nanofluid flow over three different cross-sectional channel

Purpose The purpose of this study is to investigate the pulsating flow in a three-dimensional channel. Channel flow is laminar and turbulent. After validation, the effect of different channel cross-sectional geometries (circular, hexagonal and triangular) with the pulsating flow are investigated. For this purpose, the alumina nanofluid was considered as a working fluid with different volume percentages (0 per cent [pure water], 3 per cent and 5 per cent). Design/methodology/approach In this study, the pulsatile flow was investigated in a three-dimensional channel. Channel flow is laminar and turbulent. Findings The results show that the fluid temperature decreases by increasing the volume percentage of particles of Al2O3; this is because of the fact that the input energy through the wall boundary is a constant value and indicates that with increasing the volume percentage, the fluid can save more energy at a constant temperature. And by adding Al2O3 nanofluid, thermal performance improves in channels, but it should be considered that the use of nanofluid causes a pressure drop in the channel. Originality/value Alumina/water nanofluid with the pulsating flow was investigated and compared in three different cross-sectional channel geometries (circular, hexagonal and triangular). The effect of different volume percentages (0 per cent [pure water], 3 per cent and 5 per cent) of Al2O3 nanofluid on temperature, velocity and pressure are studied.

Properties–microstructure relationship in Al–Fe in situ composite produced by friction stir processing

Effects of Fe particle volume percent (from 0 to 5%) and changing the tool rotation direction in each pass were studied on the microstructure evolution and mechanical properties of the in situ Al/intermetallic composites produced by three passes friction stir processing (FSP) with ∼10 µm Fe particles. Optical and scanning electron microscopes were used for the investigation of the composite homogeneity, formation of Al–Fe intermetallic compounds, and fracture surfaces. Tensile and microhardness tests were also carried out to evaluate the mechanical properties of the composites. Solid-state reactions between the aluminum matrix and Fe particles led to in situ formation of Al3Fe and Al5Fe2 intermetallics in the composite. Changing the tool rotation direction in each pass reduced asymmetrical distribution of the reinforcing particles and resulted in better dispersion of Fe particles. Increase in the particle volume percent refined the composite average grain size from ∼35 μm in the sample processed without particles to ∼6 μm in the composite included 5 vol.% of the Fe particles. Zener limiting grain size relationship was used to estimate the volume fraction of the sub-micron particles in the composites. Enhancement of the reinforcing particle volume percent (to 5%) increased ultimate tensile strength and yield strength of the composite up to ∼60% and ∼95%, respectively, due to finer grain structure as well as the higher load-bearing capacity of the Fe and intermetallic reinforcing particles compared to the aluminum matrix. Contributions of the Hall–Petch effect and the other strengthening mechanisms in the yield strength of the composites were also investigated.

Experimental Analysis on Thermophysical Properties of Al<sub>2</sub>O<sub>3</sub>/CuO Hybrid Nano Fluid with its Effects on Flat Plate Solar Collector

Hybrid nanofluid is the new generation of heat transfer fluid for various heat transfer applications where transport characteristics are substantially higher than the base liquid. The study presents an experimental investigation of rheological and thermophysical properties of Al2O3/ CuO hybrid nanoparticles suspended in 25:75 (by weight) ethylene glycol and water mixture. This manuscript presents experimental work of thermophysical properties of Al2O3/CuO/water/ethylene glycol hybrid nanofluids and its effect on thermal efficiency of flat plate solar collector. Nanofluids of particle volume percentage of 0.5%, 1%, 1.5% and 2% were tested. Results show that thermal conductivity, viscosity and density increases with nanoparticles concentration. The efficiency of the collector was improved by 45% by increasing the nanoparticle weight fraction.

Turning of aluminum metal matrix composites: influence of the reinforcement and the cutting condition on the surface layer of the workpiece

Aluminum metal matrix composites (Al-MMCs) are difficult to machine. The reinforcement of aluminum using ceramic particles accelerates tool wear. Moreover, demanded machining accuracies or properties of the surface layer are difficult to achieve. In the present study, the effect of silicon carbide reinforcement particles on the surface layer of the workpiece was investigated using multiple cutting conditions for dry turning. Three differently reinforced Al-MMCs regarding the volume percentage (17% and 30%) and the particle size (0.6 µm and 3 µm) and their non-reinforced matrix were considered as the workpiece materials. The reinforcement and the cutting condition affect the results of turning. A greater particle volume percent improves the surface roughness and decreases the tensile stress in the surface. The smaller particle size caused a lower tensile stress in the surface. A general effect of the particle size on the workpiece roughness can not be concluded. The most important cutting parameter for the surface layer of the workpiece is the feed. Greater feeds decrease the tensile stress in the surface, but deteriorate the surface quality.

Effect of dispersants on the kinetics of asphaltene settling using turbidity measurement method

ABSTRACTOrganic deposition especially asphaltenes in reservoirs, wells, and equipment has a detrimental effect on petroleum economy. Generally, for chemically control of asphaltene precipitation using dispersants and inhibitors of precipitation or solvents of asphaltene is very common. Although asphaltene in crude oil is stable under specific conditions, but there is no assurance that the system will be stable and asphaltenes could be remaining in suspension state. In this study, the kinetic effects of three dispersants on stabilization of asphaltene aggregates were investigated by turbidity measurement method. Turbidity measurement showed as the dispersant strength rises, the turbidity of unstable sample containing dispersant less declines versus time. In order to carry out further studies on dispersants, the effect of dispersant on asphaltene particle size distribution was investigated. The results of asphaltene particle size distribution measurements showed that adding dispersant cause to decrease the volume percent of particles with medium diameter.

Mathematical Model for Assessing Wort Filtration Performance Based on Granularity Analysis

A laboratory filtration system equipped with a 0.80 μm nitrocellulose membrane for wort filtration and a 0.45 μm mixed cellulose ester microporous membrane for beer filtration was used for this study. The critical granularity distributions of wort and beer before and after filtration were determined by the Beckman Coulter Multisizer 3 counter and particle size analyzer. Using Matlab 7.0 software, a mathematical model of the wort filtration performance and granularity relationship was established, which is applicable for predicting and improving the wort filtration performance. The granularity distribution and percentages of particle numbers and volumes of the wort before and after filtration had great impact on the wort filtration performance. The percentages of particle numbers and particle volumes were used to characterize the wort filtration performance based on a mathematical model. The correlation between real and predicted wort filtration performance values was very close. R2, the relative error of real value and prediction value on wort filtration performance, was defined as (predicted value – real value)/real value. When we used the particle number percentage, a relative variation R2 was between 1.67 and 3.01%. When we used the particle volume percentage, the relative variation R2 was between 2.89 and 3.87%.

Nonlinear vibration and instability of rotating piezoelectric nanocomposite sandwich cylindrical shells containing axially flowing and rotating fluid–particle mixture

Axially flowing and rotating fluid‐particle mixture‐induced vibration and instability of a sandwich cylindrical shell are the main contribution of this work. The sandwich structure is made from a functionally graded carbon nanotube‐reinforced composite (CNTRC) cylindrical shell integrated with piezoelectric sensor and actuator layers. In this regard, the perturbation velocity potential is introduced and the pressure exerted by a fluid is obtained by the linearized Bernoulli formula. The actuator layer is subjected to an applied voltage in thickness direction which operates in control of vibration and stability. Based on Mindlin shell theory, the motion equations are derived and solved by the differential quadrature method (DQM). A detailed parametric study is conducted to elucidate the influences of the vibrational modes, distribution type and volume fractions of single‐walled carbon nanotubes (SWCNTs), boundary conditions, volume percent of particles and applied voltage on the vibration and instability of the structure. Results indicate that the system becomes unstable in the form of flutter in the cases of angular rotation of the shell or fluid as well as axial flow and angular rotation of the fluid while in the case of the rotating shell containing a corotating fluid, the loss of stability does not occur. POLYM. COMPOS., 38:E577–E596, 2017. © 2016 Society of Plastics Engineers

Effects of AlB2 Particles and Zinc on the Absorbed Impact Energy of Gravity Cast Aluminum Matrix Composites

The effect of different amounts of boron, in the form of AlB2 particles, as well as zinc concentration in a gravity cast Al-B-Zn composite, was studied and related to the absorbed energy upon fracture during Charpy impact experiments. In addition, the authors correlated the composite Brinell hardness with the quantitative assessment of brittle and ductile fracture areas of the Charpy fractured specimens and found that increasing AlB2 particle concentration resulted in a reduction of absorbed impact energy. Although larger zinc levels produced somewhat similar results, the AlB2 effect was prevalent. The energy absorption upon impact reached a maximum when no particles were present; conversely, the lowest amount of absorbed energy corresponded to a composite with a composition of 15 wt.% Zn and 8% in volume of AlB2, i.e., the highest concentration of AlB2 and zinc studied. Raising the amount of AlB2 as well as zinc, as expected, resulted in higher Brinell hardness. A statistical analysis allowed studying of the particle size distribution, whereas values for crack tip opening displacement were subsequently calculated for the range of particle sizes found and the corresponding AlB2 particle volume percent. Higher porosity values were measured for larger AlB2 volume percent. Finally, analyses of fracture surfaces corroborated that brittle fracture was favored in composites with higher amounts of AlB2 and zinc.

Preparation of SiC Nano-particulates Reinforced Aluminum Matrix Nanocomposites by High Intensity Ultrasonic Cavitation Process

The present investigation attempts to evaluate the effect of high intensity ultrasonic cavitation on dispersing the SiC nanoparticles in aluminum 6061 melt. Aluminum melt with various volume percentages of SiC nanoparticles was ultrasonically processed by dipping the ultrasonic horn into the melt. SEM and EDS study with elemental mapping validates the uniform distribution of SiC nanoparticles in the Al matrix. Compared to the un-reinforced alloy matrix and conventional composites, the mechanical properties of the nanocomposites, including tensile strength and hardness improved quite significantly as the particle volume percentage increased. The nanocomposites show better ductile properties as compared to the conventional composites. To understand the effect of ultrasonic vibrations on processing the nanocomposites, the nanocomposite was processed at three amplitudes and the results are presented. Ultrasonic cavitation based fabrication process proved as a better alternative to the conventional stir casting route to disperse the nano ceramic particles in molten alloys.

Production of Cu–Sn–graphite–SiC composite coatings by electrodeposition

Cu–Sn composites incorporated with graphite and/or SiC particles were produced by electrodeposition technique. The effect of particle concentration in the plating bath and current density on tin content and volume percentage of particles in the coatings has been investigated. Structure, morphology, micro hardness and wear properties of the coatings have been studied. The results showed that particles cause an increase of tin content in the plated Cu–Sn. Graphite and silicon carbide particles had different effects on coating hardness; 7.8vol.% graphite decreased the hardness of Cu–Sn layer from 231Hv to 172Hv whereas, 5.1vol.% SiC raised the hardness to 316Hv. Moreover, friction coefficient of pure bronze (77Cu–23Sn) layer, Cu–Sn — 3.4vol.% SiC and bronze — 6vol.% graphite composite coatings have been obtained 0.73, 0.53 and 0.25, respectively. While, Cu–Sn coating including overall 7vol.% both graphite & SiC particles had friction coefficients of 0.34. However, the presence of both particles in the deposited layer led to lower weight loss within wearing test.

Physicochemical Characterization of Particulate Emissions from a Compression Ignition Engine: The Influence of Biodiesel Feedstock

This study undertook a physicochemical characterization of particle emissions from a single compression ignition engine operated at one test mode with 3 biodiesel fuels made from 3 different feedstocks (i.e., soy, tallow, and canola) at 4 different blend percentages (20%, 40%, 60%, and 80%) to gain insights into their particle-related health effects. Particle physical properties were inferred by measuring particle number size distributions both with and without heating within a thermodenuder (TD) and also by measuring particulate matter (PM) emission factors with an aerodynamic diameter less than 10 μm (PM(10)). The chemical properties of particulates were investigated by measuring particle and vapor phase Polycyclic Aromatic Hydrocarbons (PAHs) and also Reactive Oxygen Species (ROS) concentrations. The particle number size distributions showed strong dependency on feedstock and blend percentage with some fuel types showing increased particle number emissions, while others showed particle number reductions. In addition, the median particle diameter decreased as the blend percentage was increased. Particle and vapor phase PAHs were generally reduced with biodiesel, with the results being relatively independent of the blend percentage. The ROS concentrations increased monotonically with biodiesel blend percentage but did not exhibit strong feedstock variability. Furthermore, the ROS concentrations correlated quite well with the organic volume percentage of particles - a quantity which increased with increasing blend percentage. At higher blend percentages, the particle surface area was significantly reduced, but the particles were internally mixed with a greater organic volume percentage (containing ROS) which has implications for using surface area as a regulatory metric for diesel particulate matter (DPM) emissions.

Characterization of particle dispersion and volume fraction in alumina-filled epoxy nanocomposites using photo-stimulated luminescence spectroscopy

A novel method is presented to validate the dispersion of α-alumina nanoparticles within a polymer matrix, as well as to create a calibration for filler particle volume fraction identification. Using photo-stimulated luminescence spectroscopy (PSLS), spectral information from α-alumina-filled epoxy nanocomposites consisting of varying volume fraction quantities of alumina nanoparticles was collected and analyzed. Surface contour maps of each nanocomposite were created by comparing integrated intensity data from the R1 curve of α-alumina throughout each specimen. These maps show satisfactory dispersion of alumina in the 5 and 25% volume fraction composites, whereas agglomerations were detected in various regions of the 38% nanocomposite, establishing the capability of this method to characterize photo-luminescent particle dispersion. This new approach also provides high spatial resolution, which can be used to determine the exact locations of voids, inclusions and/or agglomerations, while also predicting the volume percentage of photo-luminescent particle content within a specimen, lending itself as a quality control method in the manufacturing of these composites. Photo-stimulated luminescence spectra (PSLS) emission from alumina-filled epoxy nanocomposites consisting of varying volume fractions of alumina nanoparticles was collected and analyzed to characterize dispersion within the sample through intensity maps. The measurements are based on integrated intensity data from the R1 curve of α-alumina throughout each specimen. This novel method has potential as a quality control method to determine the location of voids, inclusions and/or agglomerations, while in addition predicting the volume percentage of particles within a specimen.