Concentrations Of Al2O3 Nanoparticles Research Articles

Thermal management of Li-ion batteries in electric vehicles by nanofluid-filled loop heat pipes

An analytical model is developed to determine the thermal performance of a Loop Heat Pipe filled (LHP) with copper oxide–water and alumina–water nanofluids for battery thermal management in electric vehicles. The thermal performances of the LHP are predicted for different heat loads and nanoparticle concentrations. It is demonstrated that for fast charging operation corresponding to a heat load of 150 W, the LHP ensures evaporator temperatures of less than 60 °C for a heat sink temperature of 40 °C. The heat transport capacity of the LHP is enhanced and the evaporator temperature is deceased by augmenting the nanoparticle concentration. The water–CuO nanofluid-filled LHP performs better than the water–Al2O3 nanofluid-filled one. The addition of the nanoparticles increases the LHP total pressure drop and the driving capillary pressure. The capillary limit of the water–CuO nanofluid-filled LHP is hardly affected by CuO nanoparticle concentration until 6% beyond which the capillary limit starts decreasing. For the water–Al2O3 nanofluid-filled LHP, the capillary limit decreases when Al2O3 nanoparticle concentration increases. Beyond 6% Al2O3 nanoparticle concentration, the capillary limit of the Al2O3-filled LHP becomes lower than the water-filled one.

Study the Optical and Morphological Properties of (PMMA/PS/Al2O3) Nanocomposites Before and After Exposed to Argon Plasma

This study aimed to investigate the alterations in the structural and optical properties of Poly-methyl-methacrylate (PMMA) and Polystyrene (PS) through the utilization of different weight percentages of Aluminum oxide (Al2O3) nanoparticles (2%, 4%, 6%, and 8%) by weight. The optical microscope images indicate that the distribution of nanoparticles in the blend was uniform, resulting in a continuous network within the polymer matrix. The field emission scanning electron microscope revealed that there was a connection between the interface that connects the polymer matrix and the additive. The optical properties before and after the exposure to Ar plasma exhibited that the absorbance, absorption coefficient, refractive index, extinction coefficient, dielectric constant (real, imaginary) and optical conductivity of (PMMA/PS/Al2O3) nanocomposites increased with the increasing of the concentrations of the Al2O3. The transmittance and the energy gap for indirect transition (allowed, forbidden) decreased with the increasing concentrations of Al2O3 nanoparticles. The optical properties after irradiation are seen to have high values compared with those before the irradiation which is attributed to the increased charge carriers and the occurrence of some bonds breaking. Finally, the results indicated that the (PMMA/PS/ Al2O3) nanostructures can be considered as promising materials for optoelectronics nanodevices.

Effective utilization of waste plastic derived fuel in CI engine using multi objective optimization through RSM

This study provides the prediction that plastic pyrolysis oil (PPO) is equivalent to petroleum diesel in CI engines. The four input parameters have been considered to enhance performance and reduced emissions. The input parameters of engine trials, like fuel blend (PPO and diesel), compression ratio, nanoparticle concentration, and injection timing, were studied with the response surface methodology (RSM) using the central composite rotating design (CCRD) matrix. The main goal is to identify the ideal values of input parameters that will provide the highest achievable brake thermal efficiency (BTE), the lowest possible brake-specific fuel consumption (BSFC), and the lowest possible emission like carbon monoxide (CO), unburnt hydrocarbons (HC) and nitrogen oxides (NOx). The optimal engine output responses for BTE, BSFC, in-cylinder pressure, heat release rate (HRR), and ignition delay, respectively. Along witha composite desirability of 0.89 under optimum operating conditions. After the regression analysis, 16.56% PPO blend ratio, 53.53 ppm Al2O3 nanoparticle concentration, 18.06 compression ratio, and 20.95 °bTDC injection timing were received the optimized engine settings. Optimal engine input parameters were validated through actual engine trials and compared with optimized responses and found satisfactory and acceptable errors (less than 5%). The current study establishes vital input parameters providing the best engine performance, combustion characteristics, and lower emissions during engine trials. So current investigation declared PPO with Al2O3 nanoparticles is potential fuel for the CI engine.

Computational investigation of the influencing parameters on the melting of phase change material in a square enclosure with built in fin and Al2O3 nanoparticles

Recent advances in renewable energy resources set the interesting research development in the thermal energy storage concepts. The thermal energy storage system (TES) stores the thermal energy in the form of sensible or latent heat or by chemical exothermic and endothermic reactions. In this work, a numerical analysis is implemented to study the effect of Grashof number (Gr), simultaneous incorporation of longitudinal fin, and nanoparticles addition on the transfer of heat and rate of melting of phase change material (PCM). The variation in the position of the fin (0.25H, 0.5H, and 0.75H), length of the fin (0.25L, 0.5L, and 0.75L) relative to the height and length of the container respectively, and different concentrations of Al2O3 nanoparticles (0%, 1%, 3%, and 5%) were studied. The high temperature heat source is given to the left side of the wall, and the low temperature sink condition is applied to the right side. The analysis is carried out for three Gr (5000, 13000, and 20000). It is noted that the time of melting is reduced with longer lengths of the fin and Gr. Also, the melt fraction increases with the position and volume fraction of the nanoparticles up to a certain limit after it reduces. The fin’s optimum length and position were selected as 0.5H and 0.75L with 4.99% and 2.03% more liquid fraction than the other positions. Also the favourable nanoparticles concentration is adopted as 3% Al2O3 with an increase of 5.04%, 4% and 2.56% of melt fraction more than the pure PCM, PCM + (1% Al2O3) / (5% Al2O3) respectively.

Investigation of Superhydrophobic and Anticorrosive Epoxy Films with Al2O3 Nanoparticles on Different Surfaces.

In this study, superhydrophobic epoxy coatings were prepared on different surfaces by utilizing hydrophobized aluminum oxide (Al2O3) nanoparticles. The dispersions containing epoxy and inorganic nanoparticles with different contents were coated on glass, galvanized steel, and skin-passed galvanized steel substrates by the dip coating method. The contact angles of the obtained surfaces were measured via a contact angle meter device, and the surface morphologies were analyzed by utilizing scanning electron microscopy (SEM). The corrosion resistance was performed in the corrosion cabinet. The surfaces showed superhydrophobic properties with high contact angles greater than 150° and self-cleaning properties. SEM images indicated that the surface roughness increased as the concentration increased by the incorporation of Al2O3 nanoparticles into epoxy surfaces. The increase in surface roughness was supported by atomic force microscopy analysis on glass surfaces. It was determined that the corrosion resistance of the galvanized and skin-passed galvanized surfaces increased with the increase of Al2O3 nanoparticle concentration. It has been shown that red rust formation on skin-passed galvanized surfaces was reduced, although they have low corrosion resistance due to roughening on their surfaces.

Melting performance of nano-enhanced phase change materials in a triple-tube heat exchanger with zigzag-shaped tubes

This study aims at evaluating the melting behavior of nano-enhanced phase change materials (NePCM) inside a triple-tube heat exchanger with a zigzag-shape channel configuration. To assess the performance of the proposed geometry, a zigzag tube with different angles and heights is numerically simulated and the results are compared with the conventional triple-tube heat exchanger. Cu, CuO, Al2O3 and Ag nanoparticles with various concentrations are used to improve the thermal conductivity of NePCMs. The main finding of this research is a significant improvement in the melting performance of a triple-tube heat exchanger by employing a middle zigzag tube. The zigzag configuration with a 67.5° angle and 15 mm height is found as the optimum case with a great potential to (i) reduce the melting time from 4654 s in the case of a straight tube to just 827 s and (ii) increase the heat retrieval rate from just ∼47 W in case of a straight tube to ∼185 W. Among the type of nanoparticles analyzed in this research, Al2O3 has the highest melting performance with ∼14 % increase in the melting rate and heat charge rate at 4 % concentration. Increasing the concentration of Al2O3 nanoparticles from 2 % to 6 % improves the heat charge rate by ∼2.3 %.

The effect of Cu coated Al2O3 particle content and densification methods on the microstructure and mechanical properties of Al matrix composites

In the study, aluminum-based nanocomposites were reinforced with different concentrations of Al2O3 nanoparticles ranging from 0 to 15 wt. %. The Al2O3 nanoparticles were coated by nano Ag and nano Cu by the electroless chemical composition to improve the wettability between the matrix and the reinforcement phase. The influence of the suggested deformation technique and the concentrations of Al2O3 nanoparticles on the microstructure, density, and mechanical properties in terms of hardness and compressive strength of the hot extruded Al/Al2O3 nanocomposites was studied. Results revealed that, as the concentration of nano Al2O3 particles increases, the mechanical properties were improved. XRD, FE-SEM equipped with EDX, and elemental mapping indicates a near-uniform distribution of reinforcement nanoparticles in the matrix. The relative density of the formed nanocomposite recorded a slight decreases than the extruded pure Al. Owing to the presence of the Al2O3 nanoparticles, the Al-15 wt. % Al2O3 hot extruded composite achieves a hardness of 136 and 132 measured on the cross and longitudinal sections, respectively, illustrating an improvement of around 109% over the extruded pure Al. The hot extruded Al/Al2O3 nanocomposites with 5, 10, and 15 wt. % content revealed compressive strength of 564, 579, and 763 MPa, respectively, with an enhancement of 97, 102, and 166% over those of the extruded pure Al.

INFLUENCE OF AL2O3 NANO ADDITIVES ON THE VISCOSITY AND THERMAL CONDUCTIVITY OF DOUBLE DISTILLED WATER

The nano fluid consist of Al2O3 nanoparticles was dissolved by double distilled water (DDW) in three concentrations, 0.5% wt, 1%wt, and 1.5%wt of nanomaterials. The effect of adding nano materials on the viscosity and thermal conductivity was calculated experimentally at room temperature. Some mathematical models were used to calculate the viscosity and the thermal conductivity and compare it with the experimental work. The results showed that viscosity and thermal conductivity increased with increasing concentration of Al2O3 nanoparticles, and there is a great convergence between the theoretical and measured viscosity and thermal conductivity. The SEM images showed that there is homogeneity in the distribution of the nano fluid at 1%wt., and some agglomerations were detected at a concentration 1.5%. The EDS spectrum showed that the percentage of aluminum increased gradually with increasing the Al2O3 concentration. The X-Ray diffraction indicated slight increase in the intensity of diffraction with increasing the Al2O3 concentration.

Efficient direct numerical simulation of gas absorption in falling films using a combined high-throughput/high-performance approach

Direct Numerical Simulation (DNS) of liquid–gas mass transfer processes in falling film can model the transfer effect enhancement accurately, but requires huge computational effort. To improve the computational efficiency, we propose a hybrid parallel strategy combining high-throughput computing on the top level and high-performance unit simulations with different interface capture strategies on the bottom level. We investigate the CO2 absorption in methanol with different concentrations of Al2O3 nanoparticles using the proposed computation strategy to demonstrate its performance and assess the intensification mass transfer effect. Moreover, the Structural Similarity Index Measure (SSIM) is utilized in the case of oxygen absorption in water film to compare local gas concentration profiles obtained by the proposed approach, those obtained by the reduced modeling approach and the experimental data generated by a planar laser induced luminescence method under similar conditions. The results show that DNS model matches better the experimental data with high computational accuracy and efficiency.

Enhancing Heat Transfer Inside a Double Pipe Heat Exchanger Using Al2O3 Nanofluid, Experimental Investigation Under Turbulent Flow Conditions

The aim of the present research is to enhance the convective heat transfer coefficient inside the tube of the double pipe under turbulent flow conditions, this is carried out by mixing the water with aluminium oxide (Al2O3) nanoparticles. In this study, the effects of Al2O3 nanofluid with different volume concentrations of 0.05% to 0.4%, mass flow rates of nanofluid inside the tube, mass flow rates of the water flow through the annulus, and inlet temperature inside the tube on the Nusselt number were investigated. The analysis of experiential results revealed that use Al2O3 nanofluids leads to a significant enhancement of the convective heat transfer coefficient. The convective heat transfer coefficients reached maximum values at 0.1% of the volume concentrations of Al2O3 nanoparticles and then decreased as the increase of the volume concentrations from 0.1 to 0.4%. The Nusselt number increases as the Reynolds numbers of both the flows inside the tube and through the annulus increase. The fiction factor increases as the volume concentrations of nanoparticles increases. Empirical correlations are presented describing the Nusslet number and friction factor of the Al2O3 nanofluid flow through the tube of the double pipe heat exchangers, and concealing the affecting parameters in such process.

Tribological Performance of Different Concentrations of Al2O3 Nanofluids on Minimum Quantity Lubrication Milling

Nanofluid minimum quantity lubrication (NMQL) is a green processing technology. Cottonseed oil is suitable as base oil because of excellent lubrication performance, low freezing temperature, and high yield. Al2O3 nanoparticles improve not only the heat transfer capacity but also the lubrication performance. The physical and chemical properties of nanofluid change when Al2O3 nanoparticles are added. However, the effects of the concentration of nanofluid on lubrication performance remain unknown. Furthermore, the mechanisms of interaction between Al2O3 nanoparticles and cottonseed oil are unclear. In this research, nanofluid is prepared by adding different mass concentrations of Al2O3 nanoparticles (0, 0.2%, 0.5%, 1%, 1.5%, and 2% wt) to cottonseed oil during minimum quantity lubrication (MQL) milling 45 steel. The tribological properties of nanofluid with different concentrations at the tool/workpiece interface are studied through macro-evaluation parameters (milling force, specific energy) and micro-evaluation parameters (surface roughness, micro morphology, contact angle). The result show that the specific energy is at the minimum (114 J/mm3), and the roughness value is the lowest (1.63 μm) when the concentration is 0.5 wt%. The surfaces of the chip and workpiece are the smoothest, and the contact angle is the lowest, indicating that the tribological properties are the best under 0.5 wt%. This research investigates the intercoupling mechanisms of Al2O3 nanoparticles and cottonseed base oil, and acquires the optimal Al2O3 nanofluid concentration to receive satisfactory tribological properties.

Study on High-Speed Machining of 2219 Aluminum Utilizing Nanoparticle-Enhanced Minimum Quantity Lubrication (MQL) Technique

High-speed machining processes are significantly affected by the accumulation of heat generated by friction in the cutting zone, leading to reduced tool life and poor quality of the machined product. The use of cutting fluids helps to draw the heat out of the area, owing to their cooling and lubricating properties. However, conventional cutting fluid usage leads to considerable damage to human health and the environment, in addition to increasing overall manufacturing costs. In recent years, minimum quantity lubrication (MQL) has been used as an alternative lubricating strategy, as it significantly reduces cutting fluid consumption and eliminates coolant treatment/disposal needs, thereby reducing operational costs. In this study, we investigated microstructural surface finishing and heat generation during the high-speed cutting process of 2219 aluminum alloy using an MQL nanofluid. 2219 aluminum alloy offers an enhanced strength-to-weight ratio and high fracture toughness and is commonly used in a wide range of aerospace and other high-temperature applications. However, there is no relevant literature on MQL-based high-speed machining of these materials. In this study, we examined flood coolant and five different MQL nanofluids made by synthesizing 0.2% to 2% concentrations of Al2O3 nanoparticles into ultra-food-grade mineral oil. The study results reveal the chemistry between the MQL of choice and the corresponding surface finishing, showing that the MQL nanofluid with a 0.5% concentration of nanoparticles achieved the most optimal machining result. Furthermore, increasing the nanoparticle concentration does result in any further improvement in the machining result. We also found that adding a 0.5% concentration of nanoparticles to the coolant helped to reduce the temperature at the workpiece–tool interface, obtaining a good surface finish.

MHD-hybrid nanofluidic model on rotating plate with impact of thermal slip and heat absorption: a solution predictive neuro-computing approach

The main objective of this research is to design a numerical computational solver-based two-layers structure of Levenberg–Marquardt backpropagation neural networks, i.e. LMB-NNs for the analyses of the heat transfer phenomenon and velocities structure in the MHD incompressible hybrid nanofluidic flow (MHD-IHNF) model with thermal slip and heat absorption/generation over the rotating plate through varying involved parameters, including velocity slip parameter, thermal slip parameter, concentration of Al2O3 nanoparticles, heat generation parameter, Prandtl number, Hartman number, and thermophoresis for sundry scenarios. The MHD-IHNF model is mathematically formulated as a system of PDEs that are converted in the desired system of ODEs by means of suitable transformation. The data-sets are constructed by explicit Runge–Kutta numerical technique that is exploited as a target data-set for the learning of LMP-NNs based on the process of validation, training, and testing to determine the solution of MHD-IHNF model for sundry physical scenarios. The validation, convergence, stability, and verification of LMP-NNs for solution predictive strength of the MHD-IHNF problem are certified in terms of achieved accuracy, regression index measurements, and analysis of error histogram illustrations.

Математична модель тепломасообміну в каналі з нанорідиною при його нерівномірному нагріві концентрованим тепловим потоком

This work is aimed at determining the expediency of using a nanofliud (a special suspension with nanoparticles) as a heat transfer agent for a parabolic trough solar plant. Adding nanoparticles to a base heat transfer agent intensifies convective heat exchange inside the channel, thus increasing the total heat efficiency of the receiver system. A refined nonlinear 3D mathematical model was developed to study heat-and-mass transfer in the receiver system of a parabolic trough solar plant that consist of a concentrator and a tube heat receiver with a nanofluid. In the mathematical model, the values of the nonuniform heat flux on the tube heat receiver surface are found by approximating numerical data obtained by the Monte Carlo method. This simplifies the classical coupled deterministic-statistical mathematical model and allows one to obtain a purely deterministic model solved by the finite volume method. The model also accounts for the thermal conductivity of the heat receiver wall, the actual ambient conditions, and the heat loss from the heat receiver surface. A numerical algorithm was developed to conduct numerical parametric studies on determining the temperature fields of Syltherm800/Al2O3 nanofluid heat transfer agent. This nanofluid is prepared from the traditional heat transfer agent of parabolic trough solar plants – Syltherm800 silicone oil – by adding aluminum oxide nanoparticles thereto. The numerical studies were conducted both for pure Syltherm800 oil and for Syltherm800/Al2O3 nanofluid with an Al2O3 nanoparticle concentration of 3, 5, and 8 per cent. This study is the first to find that the use of a nanofluid as a heat transfer agent for a parabolic trough solar plant produces a positive effect only in the case of the laminar flow of a nanofluid heat transfer agent with a high nanoparticle concentration. A verification of the obtained numerical data showed that they are in satisfactory agreement with experimental ones.

Mechanical and Thermal Properties of Aluminum Matrix Composites Reinforced by In Situ Al2O3 Nanoparticles Fabricated via Direct Chemical Reaction in Molten Salts

The development of novel methods for industrial production of metal-matrix composites with improved properties is extremely important. An aluminum matrix reinforced by “in situ” α-Al2O3 nanoparticles was fabricated via direct chemical reaction between molten aluminum and rutile TiO2 nanopowder under the layer of molten salts at 700–800 °C in air atmosphere. Morphology, size, and distribution of the in situ particles, as well as the microstructure and mechanical properties of the composites were investigated by XRD, SEM, Raman spectra, and hardness and tensile tests. Synthesized aluminum–alumina composites with Al2O3 concentration up to 19 wt.% had a characteristic metallic luster, their surfaces were smooth without any cracks and porosity. The obtained results indicate that the “in situ” particles were mainly cube-shaped on the nanometer scale and uniform matrix distribution. The concentration of Al2O3 nanoparticles depended on the exposure time and initial precursor concentration, rather than on the synthesis temperature. The influence of the structure of the studied materials on their ultimate strength, yield strength, and plasticity under static loads was established. It is shown that under static uniaxial tension, the cast aluminum composites containing aluminum oxide nanoparticles demonstrated significantly increased tensile strength, yield strength, and ductility. The microhardness and tensile strength of the composite material were by 20–30% higher than those of the metallic aluminum. The related elongation increased three times after the addition of nano-α Al2O3 into the aluminum matrix. Composite materials of the Al-Al2O3 system could be easily rolled into thin and ductile foils and wires. They could be re-melted for the repeated application.

Machining feasibility and Sustainability study associated with air pressure, air flow rate, and nanoparticle concentration in Nanofluid minimum quantity lubrication-assisted hard milling process of 60Si2Mn steel

In recent years, more efficient hard machining processes have notably increased in demand for higher productivity but environmental friendliness. High hardness and strength as well as the enormous amount of cutting temperature are still the biggest obstacles. Nanofluid minimum quantity lubrication (NFMQL)–assisted hard machining has become a feasible and promising solution to overcome these problems. The work presents the experimental study on the effects of air pressure (5, 6, and 7 bar), air flow rate (150, 200, and 250 L/min), and Al2O3 nanoparticle concentration (0.5, 1.0, and 1.5%) on minimum quantity lubrication (MQL) hard milling process of 60Si2Mn (50÷52HRC) using vegetable oil as the based fluid. Box–Behnken experimental design and ANOVA analysis were employed to investigate the influences and interaction effects of input parameters on cutting forces, surface roughness, and surface microstructure. This study will be used for selecting the optimum air pressure, air flow rate, and Al2O3 nanoparticle concentration for efficient cooling lubrication performance of MQL in sustainable hard machining. The obtained results show that the optimal values for air pressure and nanoparticle concentration. For Q = 200 L/min, the optimal p is 6.0 bar and the optimal nanoparticle concentration (NC) is 0.9%. For Q = 250 L/min, the optimal p is 5.2 bar, and the optimal NC is 1.2%. Furthermore, using air flow rate Q = 250 L/min gives better results than Q = 200 L/min, but the selection will be depended on the specific equipment conditions.

Experimental investigation of increasing heat transfers inside a double pipe heat exchanger by using Al2O3 nanofluid

The aim of the present study is to investigation of increasing of the heat transfer coefficient inside the double tube. This is done by mixing water with aluminum oxide nanoparticles (Al2O3), the study was carried out experimentally. In this study, the effects of nanofluids at different volume concentrations from 0.05% to 0.4%, different mass flow rates of the nanofluids inside the tube, and different mass flow rates of the water flow through the annulus were tested. Experiments done with different nanoparticles and without nanoparticles under the same operating conditions. The experiment was designed, and built in the laboratory according to the international specifications and standards of the tubular exchanger manufacturers association (TEMA). By collecting and analyzing the results of the experiments, it was found that the nanoparticles have a significant improvement in the heat transfer coefficient inside the double tube. The heat transfer coefficient inside the tube increases with the increase the Reynolds number of the tube flow. The maximum value of the Nusselt number is when the volume concentration of Al2O3 nanoparticles is 0.1%.

Experimental investigation of a two-phase closed thermosyphon with Al2O3/R134a nanorefrigerant

Nanorefrigerants are mixtures of refrigerant and nanoparticles, which enhance the heat transfer in both air-conditioning and refrigeration systems. In the present work, the nanorefrigerant Al2O3/R134a is applied in a two-phase closed thermosyphon in order to investigate its thermal performance. More specifically, the influence of the Al2O3/R134a on the thermal resistance and heat transfer coefficient for various heat inputs in a two-phase closed thermosyphon were investigated experimentally. The two-phase closed thermosyphon was tested by varying the concentration of Al2O3 nanoparticles from 0.5% up to 1.5% by weight basis in the usual refrigerant R134a. The results of the experimental investigations indicate that there is a significant enhancement in heat transfer by 93.2% when the nanoparticle concentration of 1.0% was used in R134a when compared to the thermosyphon tested with pure R134a. The nanorefrigerant in thermosyphon has reduced its thermal resistance significantly by 59%. The heat transfer coefficient obtained for nanorefrigerants in two-phase closed thermosyphon is validated by Cooper correlation. It is inferred from the study that the depositions of nanoparticles in the thermosyphon enhance heat transfer. A new correlation to predict the rate of heat transfer is also proposed for employing the nanorefrigerants in a two-phase closed thermosyphon. The predicted correlation, heat transfer coefficient and thermal resistance are optimized by using Grey Relation analysis by computing the grade between the minimum and maximum values obtained from the experimental results.

Synthesis and Characterization UV-Curable Waterborne Polyurethane Acrylate/Al2O3 Nanocomposite Coatings Derived from Jatropha Oil Polyol

A new UV-curable waterborne polyurethane acrylate/alumina (UV-WPUA/Al2O3) coatings were successfully developed. The waterborne polyurethane acrylate (WPUA) dispersion was synthesized by reacting jatropha oil polyol (JOL) with isophorone diisocyanate (IPDI), 2,2-dimethylol propionic acid (DMPA), and 2-hydroxyethyl methacrylate (HEMA) via in-situ and anionic self-emulsifying methods. The WPUA/Al2O3 dispersion was formulated by various sonicating concentrations of alumina nanoparticles (0.3, 0.6, 0.9, and 1.2 wt%) into WPUA dispersion. The UV-WPUA/Al2O3 coatings were obtained with 75 wt% oligomers, 25 wt% monomer trimethylolpropane triacrylate (TMPTA), and 3 wt% of a commercial photoinitiator (benzhophenol) for UV-curing were used. The effect of Al2O3 nanoparticles on WPUA coatings was analyzed by FTIR, surface morphology, and coating performance properties such as pendulum hardness, pencil hardness, scratch resistance, and adhesion test. FTIR revealed the formation of JOL, neat UV-WPUA, and UV-WPUA/Al2O3 coatings, respectively. FESEM/EDX demonstrated that Al2O3 nanoparticles at the lower loading (up to 0.6 wt%) were well-dispersed correlated with contact angle (CA). The hardness property can reach 63.4% at the lower concentration of the Al2O3 addition 0.6 wt%. The adhesive strength, scratch hardness, and scratch resistance were greatly improved to 5B, 5H, and 2N, respectively. The preparation method offered in this study is an effective and convenient approach to producing UV-WPUA/Al2O3 coatings. The enhancement of the properties with the lesser concentration of Al2O3 nanoparticles (≤ 0.6 wt%) addition in this study shows a new promising potential as surface coating application for several major industrial areas, such as marine, transportation, and biomedical field with major economic and environmental benefits.

Flow and heat transfer characteristics of a nanofluid as the coolant in a typical MTR core

Abstract The purpose of this work was to perform a thermal–hydraulic numerical analysis of a nanofluid as the coolant in a typical MTR (material testing reactor) core. Numerical simulation was carried out for turbulent flow of water based nanofluid of different concentrations of Al2O3 nanoparticles through a sub-channel of a typical MTR core subjected to cosine shape heat flux at various values of Reynolds number using the Ansys-Fluent computer code. The optimum performance of the studied nanofluid as a coolant in MTR core was determined by the determination of the conditions under which the total entropy generation due to both heat transfer and fluid flow had a minimum value. The results showed that this condition was at Re = 4.8 × 104. The studied range of Reynolds number (Re) and particle concentration (ϕ) were 2.5 × 104 ≤ Re ≤ 5.6 × 104 and 0% ≤ ϕ ≤ 9% respectively. Results for local and average heat transfer and flow characteristics were presented. For the studied range of Reynolds number and particle concentration, four new correlations were developed. Two correlations relating Nusselt number and friction coefficient with the parameters Re and ϕ whereas the other two correlations were one relating Nusselt number with Reynolds and Prandtl numbers and the other relating the friction coefficient with Reynolds number.