Decreasing Particle Diameter Research Articles

Experimental investigation of heat transfer from elliptic tubes heat exchanger immersed in a fluidized bed

In this work, heat transfer, wall-to-bed, characteristics from elliptic tubes heat exchangers, both inline and staggered tubes arrangements, were studied experimentally. Bundles of twenty tubes of the same total surface area of 0.015 m2 and a length of 200 mm are immersed in a bed of granulated charcoal of different grain sizes, 2, 4 and 6 mm. Air was used as a fluidizing fluid. One of these tubes which was made of copper, instrumented, electrically heated and positioned in the middle of tube bundle, while the others are wooden dummy to be influenced only by the presence of the neighbouring tubes. Measurements are reported in the range of fluidization number within range of 1 to1.4. The results showed that, the local Nusselt number around the elliptic heated tube is about uniform with its maximum value at the tube sides and minimum at the stagnation and rear points of the tube. In addition, the average Nusselt number increases with the increase of the fluidization number and with the decrease in particle diameter. Heat transfer characteristics were found to improve in staggered tube bundle if compared with the inline tube arrangements. The present results of pressure drop and average Nusselt numbers were validated with a numerical model of the same conditions for the case of particle diameter of 2 mm. Good qualitative and quantitative agreements have been achieved between experimental and numerical data. Finally, correlation equations for the average heat transfer in terms of Nu, fluidization number and tube to particle diameter ratio are deduced.

Improved thermal and oxidation stabilities of pickering high internal phase emulsions stabilized using glycated pea protein isolate with glycation extent

The development of food grade high internal phase emulsions (HIPEs) stabilized by plant protein-based particles has attracted widespread attention due to their potential applications in food, cosmetic, and biomedical fields. This work reported that glycation with glucose progressively improved the emulsification efficiency of pea protein isolate (PPI) in a glycation extent manner. The physicochemical and structural properties of glycated PPI (gPPI) products with different glycation extent of 0%–36.69% were characterized. The glycation with increasing glycation extent led to a decrease in particle diameter ranging from 157.53 nm to 115.77 nm, while the three-phase contact angle remarkably increased from 54.85° to 79.62°. In addition to emulsification efficiency, glycation progressively facilitated protein adsorption at the interface and defined interfacial structure. The improved thermal and oxidation stability of gPPI by increasing glycation extent was largely attributed to enhanced conformation flexibility that also facilitated formation of bridged emulsions. These findings are important for developing PPI-based Pickering stabilizers for HIPEs and improving insight on modified emulsifying properties of gPPI via glycation extent.

Impact of Atomization Pressure on the Particle Size of Nickel-Based Superalloy Powders by Numerical Simulation.

Vacuum induction melting gas atomization (VIGA) has evolved as an important production technique of superalloy powders used in additive manufacturing. However, the development of powder preparation techniques is limited because the crushing process of gas-atomized metal melt is difficult to characterize by conventional experimental methods. Herein, we report the application of computational fluid dynamics to simulate the breaking behavior of droplets in the process of preparing nickel-based superalloy powders by VIGA, as well as the results on the effect of gas pressure on the atomization process and powder particle size distribution of metal melt. In the process of primary atomization, the crushing morphology of superalloy melt shows an alternate transformation of umbrella shapes and inverted mushroom cloud shapes, and with the increase in atomization pressure, the disorder of the two-phase flow field increases, which is conducive to sufficient breakage of the melt. Most importantly, in the process of secondary atomization and with the increasing atomization pressure, the particle size distribution becomes narrower, the median particle diameter and average particle size decrease, and the decreasing trend of the particle size increases gradually. The simulation results are compliant with the performed nickel-based superalloy powder preparation tests. This study provides insight into the production and process optimization of superalloy powder prepared by the VIGA method.

The effect of instantaneous particle distributions on the gas-phase temperature in an unsteady particle-laden jet heated with high-flux radiation

Detailed simultaneous planar measurements of particle number density and gas-phase temperature were performed in radiatively heated particle-laden jet with average particle volumetric loadings in the range 0.625−−1.4×10−3, which is within the transition region between the two- and four-way coupling regimes, to evaluate the correlation between the local particle volume fraction and temperature for inertial particles with a series of diameter distributions and radiative heating powers. Utilising novel optical measurement and image processing techniques, together with Voronoi analysis, regions of high instantaneous particle number density and localised regions of high/low gas-phase temperatures were identified. The results show that the particle volume fraction measured within the identified ‘hot regions’ was more than 1.5 times greater than the mean value for each case, while within the ‘cold regions’ the particle volume fraction was typically less than the mean. Similarly, the temperature around individual particles was found to increase with an increase in the local particle volume fraction, while the variation in local gas temperature in the vicinity of particles increases with a decrease in particle diameter. Furthermore, the temperature surrounding particles that were determined to be within closely spaced cluster regions (which form in the present measurements due to the random distribution of particles in the flow) was found to be greater than that around particles outside of clusters, even for the same local particle volume fraction (measured in a radius of 0.1 times the jet pipe diameter around each particle). The particle distributions were found to closely match a random Poisson distribution, consistent with the high particle Stokes numbers (86 ≤SkD≤ 514), and are not affected by the presence of radiative heating, implying that any flow phenomena induced by thermal gradients in the flow negligibly influence the particles in the near field of the jet for the conditions investigated here.

Synthesis of TiO<sub>2</sub> from TiOSO<sub>4</sub> Solution with Sonochemical Method

TiO2 is a semiconductor that possesses superior chemical and physical properties, widely used in various fields. In this research, the synthesis of TiO2 particles was carried out by the sonochemical method. Synthesis begins by mixing the precursor TiOSO4 in H2O with a ratio of the solvent volume (v/v) H2O/TiOSO4 20-80. TiO2 particles through sonochemically reduced for 15-75 minutes. Changes in particle diameter during the synthesis process are calculated by particle size analyzer. The results of the particle size analyzer showed that the increase in the solvent volume ratio causes the average diameter of TiO2 particles to increase with a heterogeneous size distribution. Conversely, the increasing time on sonochemical processing causes a very significant decrease in the average particle diameter. The best parameter in the sonochemical method was the lowest solvent volume ratio, 20, and the sonochemical time process of 75 minutes generated a single anatase phase 338 nm with a spherical shape.

Assessment of a Nigerian chalcopyrite ore dissolution in sulfuric acid medium

ABSTRACT. This paper presents a study of dissolution kinetics of a Nigerian chalcopyrite ore in sulfuric acid lixiviant. The effects of acid concentration, temperature and particle diameter on the dissolution rates of chalcopyrite ore have been examined. The dissolution rates are significantly influenced by increase in temperature, hydrogen ion concentration [H+], and decrease in particle diameter. The experimental data for the dissolution rate have been analyzed with the shrinking core model which shows the rate controlling step for the dissolution of chalcopyrite ore occurs via surface chemical solution. With 4 M H2SO4 solution, about 91.6% of 10 g/L chalcopyrite ore at 80 oC was dissolved within 120 min using -90+75 µm particle diameter. The reaction order with respect to hydrogen ion concentration was found to be 0.57 with correlation coefficient 0.968. The calculated activation energy, (Ea) value of 44.9 kJ/mol for the dissolution process was established. However, the SEM morphology of the residues from leaching process showed that about 8.4% of the initial solid material contained admixtures of Fukuchilite (Cu0.42Fe0.58S2), and elemental sulphur (So) and are formed around the shrinking core of the unreacted material.
 
 KEY WORDS: Chalcopyrite, Sulfuric acid, Dissolution kinetics
 
 Bull. Chem. Soc. Ethiop. 2022, 36(1), 187-196. 
 DOI: https://dx.doi.org/10.4314/bcse.v36i1.15

Modeling Sand Particulate Flows Through Angled Apertures and Surfaces in Concentrated Solar-Thermal Power Receivers

Abstract Concentrated solar-thermal power towers are increasingly migrating toward sand-based particle receiver designs to improve thermal efficiency and reach temperatures above 1000 °C for air Brayton power cycles and supercritical CO2 power cycles. However, utilizing sand affords complexities in modeling particle flow characteristics due to variable geometric shape, size, and composition. Thus, the objective of this study is to model the particle flow characteristics of sand through variable angled chevron shapes and receiver hoppers to help formulate robust modeling for flow dynamics. Treating the chevrons as an array of apertures, a novel method of calculating sand particle mass flowrate across angled apertures and surfaces is developed. Employing high-speed photography and particle imaging velocimetry techniques, our results incorporate the impact of effective angles upon velocity, residence time, and breakage profiles of falling sand particles. This study determines that a Beverloo equation incorporating effective angles for velocity and aperture size effectively predicts mass flowrate through chevrons, which can serve as a reference for future particulate flow modeling in this field. Furthermore, increasing hopper and chevron tip angles resulted in a more significant decrease in particle diameter and curtain opacity after sand flow trials.

Titanium-Enriched Slag Prepared by Atmospheric Hydrochloric Acid Leaching of Mechanically Activated Vanadium Titanomagnetite Concentrates.

The titanium-enriched slag was obtained via atmospheric hydrochloric acid leaching of mechanically activated vanadium titanomagnetite concentrates (VTMCs). Under the influence of mechanical activation, specific physicochemical changes were observed via X-ray diffractometry, scanning electron microscopy, and granulometric laser diffraction analysis. Experimental findings revealed that the mechanical activation of VTMCs resulted in a decrease in the median volume particle diameter (d50) and an increase in the specific surface area (SA) with an increased milling time. The results of the leaching experiment revealed that the mechanical activation treatment favors the extraction of iron (Fe) and titanium dioxide (TiO2) from the VTMCs. The Fe and TiO2 extractions from the mechanically activated sample after 10 h compared with the unactivated sample were increased by 12.82% and 4.73%, respectively. The presence of the ilmenite phase in the titanium-enriched slag was confirmed by X-ray diffractometry and EDS patterns, and the content of the TiO2 in the enriched slag can get as high as 43.75%.

CFD simulation of laminar free convection flows of nanofluids in a cubical enclosure

Understanding the physics behind heat transfer within an enclosure especially in the natural convection domain has many important applications. The heat transfer performance of nanofluids inside a cubical enclosure with an internal heat source fixed on the side-wall of the enclosure will be investigated under natural convection flow condition in this paper. A three-dimensional two-phase mixture model will be developed and validated for this investigation. Computational fluid dynamic (CFD) simulations will be undergone using an in-house solver developed on simplified marker and cell (SMAC) algorithm within a collocated grid by finite difference method. The time dependent flow and characteristics of heat transfer for nanofluids will be investigated with pure water as the base fluid dispersed with different nanoparticles. In addition, parametric studies will also be performed by varying the particle volume concentrations (0%≤Φ ≤ 3%), particle diameters (25 nm ≤ Dp ≤ 50 nm) and Grashof numbers (103 ≤ Gr ≤ 106). The particle volume concentration when increased in a nanofluid gives more affinity to heat absorption. Velocity increase of particles leads to the efficient mixing of nanofluid and so an increase in Grashof number also leads to heat transfer enhancement. Decrease in particle diameter is the final parameter which shows a heat transfer increase.

Mathematical Model of Airflow and Solid Particles Transport in The Human Nasal Cavity

As part of the mathematical model of the human respiratory system, a submodel is considered for the study of the non-steady airflow with solid particles (suspended particulate matter (PM) / dust particles) and the deposition of particles of various sizes in the human nasal cavity. It is assumed that the nasal cavity is divided by the bone-cartilaginous septum into two symmetrical (relative to the nasal septum) parts; the average geometry of the right part of the human nasal cavity is considered. The inhaled air is considered as a multiphase mixture of homogeneous single-component gas and solid dust particles. The Eulerian-Lagrangian approach to modeling the motion of a multiphase mixture is used: a viscous liquid model is used to describe the motion of the carrier gas phase; the carried phase (dust particles) is modeled as separate inclusions of various sizes. The process of heating the inhaled air due to its contact with the walls is also taken into account. The features of the unsteady flow of a multiphase air mixture with dust particles were obtained using Ansys CFX for several scenarios. It has been noted that when studying the airflow in the nasal cavity, it is necessary to take into account the presence of turbulence, for which it is proposed to use the k-ω model. The velocity fields of inhaled air in the nasal cavity have been obtained; presented temperature distributions in the nasal cavity at different time points; made estimates of air heating at different temperatures of inhaled air; gave estimates of the proportion of deposited particles in the nasal cavity depending on the particle size for real machine-building production; presented trajectories of movement of suspended particles. Thus, it is shown that more than 99.7 % of particles with a diameter of more than 10 microns deposit in the human nasal cavity; as the particle diameter and mass decrease, the proportion of deposited particles decreases. Suspended particles with a size of less than 2.5 microns almost do not deposit in the nasal cavity. They can penetrate deeper into the lower airways and lungs of a person with the inhaled air and, having fibrogenic and toxic effect, can cause diseases. The results obtained are in good agreement with the results of individual studies performed by other scientists. Further development of the model involves studying airflow in the human lungs and modeling the formation of diseases caused by the harmful effects of environmental factors (including dust particles) entering the human body by inhalation.

Experimental Investigation of Heat Transfer From Elliptic Tube Immersed in a Fluidized Bed

Abstract Heat transfer characteristics around an elliptic heated tube immersed in fluidized bed were studied experimentally. Experiments were carried out under uniform heat flux condition, with air as a fluidizing gas and pulverized coal as a bed material of Geldart D. An elliptic tube was heated by using a cartridge heater of 16 mm outer diameter (OD) and 200 mm length. The heated tube had a total surface area of As ≈ 0.015 m2 and a length of 200 mm. The local as well as average heat transfer coefficients were calculated at different superficial air velocities, particle sizes of 2, 4, and 6 mm, and a static bed height of 250 mm. Various values of fluidization number, Usup/Umf, based on hydraulic diameter of the heated tube are utilized in the experiments which are ranged from 1 to 1.4. The results showed that the minimum fluidization velocity increased with the increase in bed particles diameter. The local Nusselt number was quasi-uniform and having a maximum value at the sides of the heated tube and minimum at the stagnation, θ = 0 deg, and top, θ = 180 deg, of the tube. The local and average Nusselt numbers increase with the increase of the fluidization velocity and decrease in particle diameter. A correlation equation for the average Nusselt number with the fluidization number and tube to particle diameter ratio is deduced.

The effect of particle size and volumetric loading on the gas temperature distributions in a particle-laden flow heated with high-flux radiation

The instantaneous, spatially resolved gas-phase temperature distribution within a particle-laden flow heated using high-flux radiation has been measured for a series of heating fluxes, particle volumetric loadings and particle diameters using two-colour laser induced fluorescence of toluene. The temperature of the gas downstream from the start of the heating region was found to increase with an increase in heat flux, an increase in particle loading and a decrease in particle diameter. Coherent regions of high and low temperature in the instantaneous flow associated with spatial variations in the particle distribution were identified for all particle diameters investigated. The time-averaged gas-phase temperature on the jet axis was found to increase approximately linearly with distance in the region downstream from the heating beam to the edge of the measurement region investigated, indicating near-constant convective heat transfer due to the large temperature difference between the gas and radiatively heated particles throughout this region. The axial gradient of gas-phase temperature with distance was also calculated using a simplified, one-dimensional heat transfer model. The difference between the model and measurements was, on average, less than 20%, with the magnitude of this difference found to increase with a decrease in particle diameter and an increase in particle loading.

One Pot Microwave Irradiation Synthesis of Spherical and Nanotube Titanates Incorporated Reduced Graphene for Efficient Hydrogen Production Photo-Electrocatalytically

Nanosphere and titanate nanotube (TNT) amalgamated with different graphene oxide (GO) ratios synthesized by one pot microwave irradiation route have presented excellent potential towards hydrogen production photoelectrochemically under solar irradiation. The hybrid nanospherical array of the 50TNT-50GO photocatalyst showed a current density equal 9.2 mA cm−2 at a bias of 0.20 V vs. RHE exceeding those of the nanotubes 30TNT-70GO (4.0 mA cm−2 at 0.38 V) and 10TNT-90GO (3.7 mA cm−2 at 0.4 V). The former electrode also exhibits small Tafel slope value (40 mV dec−1), decreased particle diameter (7 nm), decreased band gap (2.6 eV) and high rate of charges transfer. The hybrid structure elucidation carried out using TEM-SAED, XRD, N2 adsorption, UV–Vis, FTIR and PL techniques approved the interfacial interaction between TNT and GO(RGO) networks that was responsible for the high quantum yield, delay of charges recombination beside the increase in the pore volume.

Experimental Investigation of a Close-coupled Atomizer Using the Phase Doppler Measurement Technique

A common method for producing metal powders used for additive manufacturing is based on the atomization of a stream of molten metal by means of a high-pressure gas flow. In the present experimental study, the influence of the liquid mass flow rate on the atomization result has been investigated for a close-coupled atomizer operated with water and air as a substitute for molten metal and argon gas. The phase Doppler measurement technique has been employed to measure local particle size and velocity distributions within the spray. The results indicate that the liquid mass flow rate is a sensitive parameter in determining the mean particle size as well as the width of the particle size distribution. Its influence appears to be strongest in the center of the spray. Here, a decrease in the liquid mass flow rate has been found to lead to a significant decrease in the arithmetic mean particle diameter and a considerably narrower particle diameter distribution.

Numerical Prediction of Erosion Based on the Solid-Liquid Two-Phase Flow in a Double-Suction Centrifugal Pump

Due to the high sediment content in the Yellow River, the pump units in the pumping stations along the line are often eroded by sediment, causing the reduction of pump efficiency and structural damage. The purpose of this paper is to study the influence of particle diameter on the particle track, erosion distribution and erosion rate in a double-suction centrifugal pump in a pumping station of the Yellow River with a Lagrangian particle-tracking approach and a Tabakoff erosion model. The results show that the surface erosion of the impeller on both sides in the double-suction centrifugal pump has an asymmetric distribution, and the erosion rate on both sides is different. The particle diameter affects the moving trajectory of particles and has a significant effect on the erosion morphology and position in the impeller. With the increase of particle diameter, the velocity of the particles moving towards the pressure side of the blade inlet increases, resulting in punctate impact erosion. When the particle diameter decreases, sliding abrasion gradually forms on the pressure side of the blade outlet. The change rule of the solid particle volume fraction on the impeller wall is consistent with that of erosion distribution on the impeller wall. The larger the solid volume fraction is, the higher the wall erosion rate is.

Effect of Reduced Dimensionality on the Magnetic and Transport Properties of Ca Doped Colossal Magnetoresistive Nanoparticles

Magnetic and electrical measurements of different nanosize Ca doped colossal magnetoresistive La0.7Ca0.3MnO3 are reported. The nanoparticles are synthesized with the modified citrate rout at different temperatures. X-ray diffraction measurements revealed three dominant peaks 23.040, 40.5170 .47.170, 58.660 which confirms the perovskite-like structure. The average crystallite size the nanoparticles are found to be 20 to 32nm. All the synthesized nanoparticles exhibit ferromagnetic ordering close to the phase transition temperatures. The size dependent magnetic and electrical transport properties are explored at different fields and temperature. Saturation magnetization is found to decrease with decreasing particle diameter. It is found that the particle size can tune the trend of coercive field. Coercive field first increases from 78 to 210 Oe and then decreases to 174 Oe. The electrical transition temperature is found to be 158 K for 20nm particle. Oxygen deficiency in such system generally reduces Mn4+ to Mn3+ to keep the charge neutrality of the structure and hence it destroys the conduction path ways to mobile electrons, at least in long range, and thus insulating behavior becomes more prominent in the larger temperature range. The trend at lower temperature attribute to the coulomb blockade.

In vivo study of iron oxide-calcium phosphate composite nanoparticles for delivery to atherosclerosis

Atherosclerosis is a macrophage-related inflammatory disease that remains a leading cause of death worldwide. Magnetic iron oxide (IO) nanocrystals are clinically used as magnetic resonance imaging contrast agents and their application as a detection agent for macrophages in arterial lesions has been studied extensively. We recently fabricated heparin-modified calcium phosphate (CaP) nanoparticles loaded with a large number of IO nanocrystals via coprecipitation from a supersaturated CaP solution supplemented with heparin and ferucarbotran (IO nanocrystals coated with carboxydextran). In this study, we further increased the content of IO nanocrystals in the heparin-modified IO–CaP composite nanoparticles by increasing the ferucarbotran concentration in the supersaturated CaP solution. The increase in nanoparticle IO content caused a decrease in particle diameter without impairing its dispersibility; the nanoparticles remained dispersed in water for up to 2 h due to electrostatic repulsion between particles due to the surface modification with heparin. The nanoparticles were more effectively taken up by murine RAW264.7 macrophages compared to free ferucarbotran without showing significant cytotoxicity. A preliminary in vivo study showed that the nanoparticles injected intravenously into mice delivered more IO nanocrystals to macrophage-rich carotid arterial lesions than free ferucarbotran. Our nanoparticles have potential as a delivery agent of IO nanocrystals to macrophages in arterial lesions.

Fabrication and Characterisation of a Photo-Responsive, Injectable Nanosystem for Sustained Delivery of Macromolecules.

The demand for biodegradable sustained release carriers with minimally invasive and less frequent administration properties for therapeutic proteins and peptides has increased over the years. The purpose of achieving sustained minimally invasive and site-specific delivery of macromolecules led to the investigation of a photo-responsive delivery system. This research explored a biodegradable prolamin, zein, modified with an azo dye (DHAB) to synthesize photo-responsive azoprolamin (AZP) nanospheres loaded with Immunoglobulin G (IgG). AZP nanospheres were incorporated in a hyaluronic acid (HA) hydrogel to develop a novel injectable photo-responsive nanosystem (HA-NSP) as a potential approach for the treatment of chorio-retinal diseases such as age-related macular degeneration (AMD) and diabetic retinopathy. AZP nanospheres were prepared via coacervation technique, dispersed in HA hydrogel and characterised via infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Size and morphology were studied via scanning electron microscopy (SEM) and dynamic light scattering (DLS), UV spectroscopy for photo-responsiveness. Rheological properties and injectability were investigated, as well as cytotoxicity effect on HRPE cell lines. Particle size obtained was <200 nm and photo-responsiveness to UV = 365 nm by decreasing particle diameter to 94 nm was confirmed by DLS. Encapsulation efficiency of the optimised nanospheres was 85% and IgG was released over 32 days up to 60%. Injectability of HA-NSP was confirmed with maximum force 10 N required and shear-thinning behaviour observed in rheology studies. In vitro cell cytotoxicity effect of both NSPs and HA-NSP showed non-cytotoxicity with relative cell viability of ≥80%. A biocompatible, biodegradable injectable photo-responsive nanosystem for sustained release of macromolecular IgG was successfully developed.

A fluidized-bed reactor for enhanced mass transfer and increased performance in thermally regenerative batteries for low-grade waste heat recovery

A thermally regenerative battery with a fluidized-bed reactor design (TRB-FB) is developed to enhance mass transfer and promote battery performance. The results demonstrate that the fluidized-bed design induces highly efficient mass transfer and improves the battery performance considerably. Comparative tests show that the highest power density (11.6 W m−2), total charge (274.6 C), and energy density based on the anolyte volume (834.2 Wh m−3) are obtained with the TRB-FB. Moreover, reversibility testing over successive cycles reveals that the TRB-FB generates a relatively stable power output over 15 batch cycles. Although a decreased particle diameter induces better fluidization, highly efficient mass transfer, and improved performance, an exceedingly small particle diameter results in decreased fluidization and a significant dip in battery performance. The optimal particle diameter is determined to be 187.5 μm. In addition, increasing the stirring rate within a certain range further enhances mass transfer and promotes battery performance.

Numerical Assessment of Nanofluids in Recharging Microchannel: Thermo-Hydrodynamic and Entropy Generation Analysis

Abstract Three-dimensional numerical study is presented in this work that deals with thermo-hydrodynamic and entropy generation analysis of water-based nanofluids in recharging microchannel (RMC). Four different water-based nanofluids (Al2O3, CuO, SiO2, and ZnO) are considered with volume concentrations of 1–5% and nanoparticle diameters of 10–50 nm to understand their effect on thermo-hydrodynamic performance and entropy generation. Substrate bottom surface is subjected to a constant wall heat flux of 100 W/cm2 while coolant with Reynolds number range of 100–500 flows through the RMC. It is revealed that among all the nanofluids under investigation, water/Al2O3 provides enhanced thermal performance with higher effectiveness parameter (η), and it also shows reduced entropy generation. With increasing volume concentration of water/Al2O3 nanofluid, heat transfer coefficient increases, effectiveness parameter increases, and entropy generation reduces. Water/Al2O3 nanofluid with smaller nanoparticle diameter shows enhanced heat transfer coefficient and reduced entropy generation, whereas it shows decreased effectiveness parameter. This is attributed to increased pressure drop with decreasing particle diameter. This study suggests that an optimized combination of particle diameter and volume concentration should be chosen for using nanofluid-based coolants for high heat flux removal.