Water-based Alumina Research Articles

Computational analysis of water-based silver, copper, and alumina hybrid nanoparticles over a stretchable sheet embedded in a porous medium with thermophoretic particle deposition effects

Computational analysis of water-based silver, copper, and alumina hybrid nanoparticles over a stretchable sheet embedded in a porous medium with thermophoretic particle deposition effects

A sensitivity analysis on thermal conductivity of Al2O3-H2O nanofluid: A case based on molecular dynamics and support vector regression method

The current study examines the sensitivity study of the thermal conductivity of water-based alumina nanofluids with variations in concentration, sphericity, and temperature. Thermal conductivity data of alumina nanofluids were obtained by simulation using the non-equilibrium molecular dynamics method with the parameters of nanoparticle volume fraction (1.24–6.2%), particle sphericity (0.6975–1.0), and temperature (290–360 K). Volume fraction and temperature have been discovered to have a major effect on the thermal conductivity of nanofluids, but sphericity should also be taken into consideration. Further, for parameter sensitivity analysis, a support vector machine regression model of thermal conductivity versus parameters was created with a coefficient of determination up to 0.98. The findings show that an Al2O3-H2O nanofluid's thermal conductivity increases with temperature and volume fraction while decreasing with sphericity. Temperature, sphericity, and volume fraction are the variables that are most sensitive to modification, according to a sensitivity analysis. A change in thermal conductivity of up to 4 % can occasionally be brought on by temperature differences of merely 1 %. The use of spherical particles makes it possible for the thermal conductivity of the nanofluid to be more stable, and the sensitive volume fraction region that can cause thermal conductivity to fluctuate across a large range is between 2.5 % and 5.5 %.

Laminar Natural Convection of Water-Based Alumina Nanofluids in a Square Enclosure

Steady-state, laminar, natural convection of water-based alumina nanofluids in a square enclosure with partial heating from the bottom and symmetrical cooling from the sides has been investigated based on numerical simulations. The effects of Rayleigh number, normalized heat source length and nanoparticle volume fraction on the heat transfer behavior have been investigated. An increase in Rayleigh number, for given values of normalized heat source length and nanoparticle volume fraction, leads to an increase in Nusselt number. For a given set of values of Rayleigh number based on base-fluid properties and normalized heat source length, the Nusselt number does not vary significantly with increasing nanoparticle volume fraction because the strengthening viscous effects with increasing volume fraction for water-based alumina nanofluids counteracts the enhanced thermal diffusion in nanofluids. However, when effective Rayleigh number is based on nanofluid properties, Nusselt number decreases with increasing nanoparticle volume fraction. For a given set of values of Rayleigh number and nanoparticle volume fraction, the Nusselt number increases with increasing normalized heat source length due to the strengthening of advective transport. A correlation for mean Nusselt number is proposed which adequately captures qualitative and quantitative behavior obtained from the simulations across the considered parameter range.

MHD Stagnation Point of Blasius Flow for Micropolar Hybrid Nanofluid toward a Vertical Surface with Stability Analysis

This study investigates the magnetohydrodynamics of a micropolar fluid consisting of a hybrid nanofluid with mixed convection effects. By using the dimensionless set of variables, the resulting equations of ordinary differential equations are solved numerically using the bvp4c solver in MATLAB. In the present work, the water-based alumina–copper hybrid nanofluid is analytically modeled with modified thermophysical properties. The study reveals that the highest critical value of opposing flow is the hybrid nanofluid (ϕ1 = ϕ2 = 2%). By comparing the hybrid nanofluid with Cu–water nanofluid (ϕ1= 0%, ϕ2= 1%) as well as water (ϕ1= 0%, ϕ2= 0%), hybrid nanoparticle volume fraction enhances the dynamic viscosity performance and surface shear stress. In addition, the augmentation of the nanoparticle volume fraction and magnetic field parameter will increase the physical quantities Rex1/2 Cf, Rex Mx, and Rex−1/2 Nux. The result from the stability inquiry discloses that the first solution is more physically stable and trustworthy. It is proven that magnetohydrodynamics could contribute to controlling the fluid flow in a system, i.e., engineering operations and the medical field. In addition, this theoretical research can be a benchmark for experimental research.

Significance of nanoparticle radius and inter-particle spacing toward the radiative water-based alumina nanofluid flow over a rotating disk

Abstract The study of nanofluid flow over a rotating disk has significant importance because of its enormous range of implementations, including cancer treatments, chemotherapy, nanomedicines, fermentation sciences, selective drug delivery, food sciences, biosensors, biomedicines, and electronics. Due to these applications of nanofluid, the present problem investigates the magnetohydrodynamic flow of nanofluid with nonlinear thermal radiation and viscous dissipation. In this analysis, the aluminum oxide nanoparticles are mixed with water. Furthermore, the mechanism for inter-particle spacing and radius of aluminum oxide nanoparticles on the dynamics of the two-dimensional flow of nanofluid are investigated. The present problem is modeled in the form of partial differential equations (PDEs), and these PDEs are converted into ordinary differential equations with the help of suitable similarity transformations. The analytical solution to the current modeled problem has been obtained by using the homotopy analysis technique. The main purpose of the present research work is to analyze the behavior of the velocity and temperature of the nanofluid for small and large radius of the aluminum oxide nanoparticles and inter-particle spacing. Also, the role of heat transport is computed for linear and nonlinear thermal radiation cases. The major findings and principal results of this investigation are concluded that the primary velocity of nanoliquid is augmented due to the intensification in suction parameter for both the small and larger radius of aluminum oxide nanoparticles. Furthermore, it is perceived that the heat rate transfer is larger when the Eckert number and nanoparticle volume fraction are higher for both nonlinear and linear thermal radiation cases.

Stability Analysis of Buoyancy Magneto Flow of Hybrid Nanofluid through a Stretchable/Shrinkable Vertical Sheet Induced by a Micropolar Fluid Subject to Nonlinear Heat Sink/Source

The utilization of hybrid nanofluids (HNs) to boost heat transfer is a promising area of study, and thus, numerous scientists, researchers, and academics have voiced their admiration and interest in this area. One of the main functions of nanofluids is their dynamic role in cooling small electrical devices such as microchips and associated gadgets. The major goal of this study is to perform an analysis of the buoyancy flow of a shrinking/stretching sheet, whilst considering the fascinating and practical uses of hybrid nanofluids. The influence of a nonlinear heat source/sink induced by a micropolar fluid is also inspected. Water-based alumina and copper nanoparticles are utilized to calculate the fine points of the fluid flow and the features of heat transfer. The governing equations are framed with acceptable assumptions and the required similarity transformations are used to turn the set of partial differential equations into ordinary differential equations. The bvp4c technique is used to solve the simplified equations. Dual solutions are presented for certain values of stretching/shrinking parameters as well as the mixed convective parameter. In addition, the shear stress coefficient in the first-branch solution (FBS) escalates and decelerates for the second-branch solution (SBS) with the superior impact of the magnetic parameter, the mass transpiration parameter, and the solid nanoparticles volume fraction, while the contrary behavior is seen in both (FB and SB) solutions for the larger values of the material parameter.

Impact of Irregular Heat Sink/Source on the Wall Jet Flow and Heat Transfer in a Porous Medium Induced by a Nanofluid with Slip and Buoyancy Effects

In many industries, extremely high-performance cooling is a crucial requirement. However, the fundamental challenge to developing energy-efficient heat transfer fluids required for cooling is insufficient thermal conductivity. In this case, the utilization of nanofluid is effective to overcome these challenges. The current study aims to examine the two-dimensional (2D) stretching wall jet heat transfer fluid flow induced by a water-based alumina nanofluid embedded in a porous medium with buoyancy force. In addition, irregular heat sink/source and slip effects are assessed. The leading partial differential equations are changed into ordinary differential equations by incorporating similarity variables, then these equations are computationally or numerically worked out via the boundary-value problem of fourth-order (bvp4c) technique. The pertinent factors influencing the symmetry of the hydrothermal performance including friction factor, velocity, and temperature profiles, are illustrated using tables and graphs. The symmetrical outcomes reveal that the velocity declines in the presence of nanoparticles, whereas the temperature uplifts both assisting and opposing flows. Moreover, the friction factor augments due to porosity while the heat transfer rate declines.

Features of Radiative Mixed Convective Heat Transfer on the Slip Flow of Nanofluid Past a Stretching Bended Sheet with Activation Energy and Binary Reaction

The current exploration aims to inspect the features of thermal radiation on the buoyancy or mixed convective fluid flow induced by nanofluid through a stretching permeable bended sheet. The impact of activation energy and binary reaction along with slip migration is taken into account to discuss the fine points of water-based alumina nanoparticle flow. The structure of the curved sheet is assumed to be stretchable and the bended texture is coiled within a circular section with radius Rb. The similarity technique is utilized to reduce the leading partial differential equations into ordinary differential equations. These reduced equations are then deciphered numerically by employing the bvp4c method. The outcomes of the model were constructed in the form of several figures and bar graphs for the case of opposing and assisting flows with varying distinct embedded control parameters. The results display that the velocity field curves escalate with a higher radius of curvature parameter while temperature and concentration profiles shrink. More precisely, the outcomes show that the temperature distribution profile increases with the increase in nanoparticle’s volume fraction as well as thermal radiation parameter. Meanwhile, the concentration and velocity fields are decelerated with higher impacts of nanoparticle volume fraction. In addition, the heat and mass transfer rates were significantly improved for the higher value of the radiation and Schmidt number. On the other hand, the growing values of the velocity slip factor decrease the shear stress. Furthermore, the results are compared with the previous results in the limiting cases and observed a tremendous harmony.

Enabling water-based processing of graphene/alumina composites using an infiltration approach with amphiphilic triblock copolymers

Enabling the direct infiltration of freeze-cast graphene structures with water-based ceramic suspensions, otherwise prevented by graphene’s intrinsic hydrophobic behaviour, can lead to the production of hierarchical graphene/ceramic composites in a cost-effective and replicable manner. In this study, the addition of a triblock copolymer (PF127) in the formulation of water-based alumina slurries was used to allow the integration with reduced graphene oxide (rGO) scaffolds combining freeze-casting, wet chemistry processing and Spark Plasma Sintering. Wettability and infiltration tests were performed to optimise the composition of the ceramic suspension, leading to the preservation of alignment in embedded rGO scaffolds and maintaining channel widths of 5–15▒μm upon sintering at 1500∘ C.

Spectral Simulation on the Flow Patterns and Thermal Control of Radiative Nanofluid Spraying on an Inclined Revolving Disk Considering the Effect of Nanoparticle Diameter and Solid–Liquid Interfacial Layer

Abstract The current work enlightens the flow pattern and thermal scenario of a nanofluid spraying on an inclined permeable rotating disk. The whirling disk is assumed to revolve with the angular speed Ω. The water-based alumina (Al2O3) nanofluid is considered as a functioning liquid. The nanofluid spraying is treated to be magnetically influenced and thermally radiative. The perception of the nanoparticles' diameter and solid–liquid interfacial layer is incorporated precisely at the nanolevel to observe the thermal variations of the nanofluidic motion. How the magnetic effect, permeability, and nanolayer affect nanofluidic transportation is revealed in detail. The leading flow equations are altered nondimensional using apposite similarity translation, and the spectral quasi-linearization method (SQLM) is instigated to tackle those multi-ordered nonlinear equations. Various three-dimensional figures, graphs, and tables are described to detect and analyze the hydrothermal variations. The linear regression slope technique is addressed to extract the reduction or enhancement rate of heat transference. Also, the probable error is estimated statistically to assure that hydrothermal characteristic is correlated with physical parameters. The consequences indicate enhanced heat transport for nanolayers, but reduced heat transmission for nanoparticles' diameter. Thermal profile intensifies for thickness parameter and impermeable surface, whereas decreases for nanoparticles' diameter.

Enhanced heat transfer efficiency of PTSC using hydromagnetic cross nanofluid: A hydrogen energy application

Nowadays, the foremost thermal source from the sun is solar energy. The current study deals with the enhanced heat transfer of Parabolic Trough Solar Collector (PTSC) using thermic radiation, space-dependent heat source, and nanotechnological energy. For this, we considered water-based graphene oxide (GO) and alumina alloy (AA7075) mixtures flow through PTSC fitted inside the solar wings of aircraft (Fig. 1). A theoretical Maxwell nano model is adopted by incorporating the thermic radiation and space-dependent heat source/sink effects in the energy equation. The pressure drop caused by the fluid-solid interactions is evaluated by introducing the Darcy-Forchheimer condition. The modeled problem is resolved numerically by applying suitable similarities. The impact of various physical constraints on flow and thermal fields are estimated for water-GO and water-GO-AA7075 fluids and found that water-GO-AA7075 hybrid nanoliquid effectively enhances the thermal performance of PTSC in the presence of thermic heat. Darcy-Forchheimer parameter effectively regulates the momentum and energy fields of hybrid nanoliquid.

The Effect of Navier Slip and Skin Friction on Nanofluid Flow in a Porous Pipe

The flow of nanofluids through a porous medium is considered the optimum method for convective heat transfer. In this study, nanofluid flow in a porous pipe with Navier slip is investigated. Two water-based nanofluids, Copper (Cu) and alumina (Al2O3), were considered. The governing equation is presented and non-dimensionalization has been done for momentum and energy equations, initial and boundary conditions, skin friction, and Nusselt number. The governing system was simplified to ordinary differential equations, which were numerically solved and a mathematical model of nanofluid flow was formulated. The results, with regard to variations in various parameters such as temperature, velocity, skin friction, and Nusselt number, are presented graphically and discussed. It was found that the velocity during the flow decreases with the increase of the Navier slip.

Quadratic Convective Nanofluid Flow at a Three-Dimensional Stagnation Point with the g-Jitter Effect

The nonlinear density variation with temperature happens in many thermal applications like solar collectors, energy production, heat exchangers, and combustions, and it gives a significant impact on heat transfer and fluid flows. Thus, a nonlinear convective of an unsteady stagnation point flow under the influence of gravity modulation in the presence of water-based nanoparticles alumina (Al2O3) is studied here. Suitable variables are utilized to reduce the highly coupled nonlinear governing equations into a system of dimensionless simple partial differential equations. The Keller-box method is then applied to solve the consequent governing equations. Velocity and temperature profiles for various values of pertinent parameters are displayed graphically and discussed. The results indicate that the quadratic convection has enhanced the fluid flow and heat transport. Furthermore, the nonlinear convection parameter and the nanoparticles volume fractions have delivered a positive effect on the skin friction and the rate of heat transfer.

Shear thinning molecular dynamics simulation of binder solution for 3D printing alumina

To simulate and analyze the effects of binder on the shear thinning ability of water-based alumina ceramic pastes for 3D printing, the single chain molecular weight of binders was set as 1825 (±20), the polymerization degree of the binder molecules containing polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyacrylamide (PAM) and carboxymethyl cellulose (CMC) was then set as 41, 41, 26 and 8 respectively via Materials Studio software (MS). The solutions consisting of 10 binder molecules and 1000 H2O molecules were built as the objects to carry out the all-atom molecular dynamics simulation. The mechanism of solution shear thinning was elucidated by analyzing the parameter of shear viscosity, molecular orientation configuration, radius of gyration distribution, diffusion coefficient and hydrogen bonding. Results show that the solution viscosity decreased by 17.828 mPa s (CMC), 16.551 mPa s (PAM), 6.744 mPa s (PVA), and 2.642 mPa s (PEG) respectively, when the shear rate was in range of 0.001–0.01 ps-1, all exhibiting good shear thinning ability. The order of shear-thinning ability was: CMC > PAM > PVA > PEG. The radius of gyration distribution range of unit chain length was 0.1504 Å (CMC), 0.1035 Å (PAM), 0.0758 Å (PVA), and 0.0618 Å (PEG), indicating that the shear-thinning ability was related with the radius of gyration distribution. As the shear rate increased, the diffusion coefficient of molecules was increased significantly. Besides, the straight-chain or directionally aligned molecules moved easily, and molecules with branched chains or ring structure moved slowly, which directly affect the shear thinning ability of binders. The average weakening degree of hydrogen bonding at 0.01 ps-1 compared with steady state was 7.9% (PVA), −4.1% (PEG), 44.6% (PAM) and 47.6% (CMC). The weakening of hydrogen bonding plays an important role in improving the shear thinning ability.

Predicting and optimizing the thermal-hydraulic, natural circulation, and neutronics parameters in the NuScale nuclear reactor using nanofluid as a coolant via machine learning methods through GA, PSO and HPSOGA algorithms

This investigation studies the optimization of water-based alumina nanofluid to advance heat transfer and safety performance of the NuScale natural circulation reactor. First, comprehensive CFD and neutronic simulation is employed to design a reactor core using nanofluid coolant (0.001–10% volume fractions and 10–90 nm particle sizes). Consequently, the outlined results prove a sufficient enhancement of safety and heat transfer parameters by applying nanofluid coolant. Next, a developed Artificial Neural Network (ANN), utilizing the obtained data, predicts the thermal–hydraulic and neutronic parameters of the NuScale reactor core with Al2O3/Water nanofluid. Achieving the optimal vol% and size of nanoparticles by implementing Genetic Algorithms (GA), Particle Swarm Optimization (PSO), and Hybridized PSO-GA, based on the developed ANN results, are the main goals of this work. These optimization algorithms, which have a significant ability to attain the best solutions, also determine the optimal values of natural circulation parameters (Vmax/Vavg, Vout-Vin, and pressure drop), heat transfer coefficient, MDNBR, RPPF, and excess reactivity, for obtained vol% and size. The validation results demonstrate the efficiency of the developed ANN and these three evolutionary computation algorithms for optimization. The differences between the outcomes of implemented algorithms, focusing on how each works and affects optimal solutions in problem space, are also described. Finally, this paper compares the results of optimal design with conventional NuScale, which uses water coolant. This comparison indicates the potential of the proposed nanofluid coolant to increase thermal and safety performance.

Ceramic Molding Based on 3D Printing Technology

3D printing technology can also be described as an increase in the manufacture of materials. In the forming process, no traditional machine tools, fixtures and cutting tools are required. Parts models of arbitrary complex shapes can be manufactured quickly and accurately. In the experimental process, small printers are modified in the extrusion part and printed with water-based alumina slurry as ink. The water-based oxide slurry is mainly water medium and contains only a small amount of organic binder. The influence of pH value, solid content, plasticizer, binder, lubricant and dispersant on the fluidity of slurry is studied. The results show that the slurry has the best stability when the amount of dispersant is 0.4 wt%, plasticizer is 1.0 wt%, lubricant is 4.0 wt%, binder is 1.0 wt%.

Study on the flow and heat dissipation of water-based alumina nanofluids in microchannels

In this paper, the flow and heat dissipation performance of 0.1–0.5 vol per cent of Al2O3 -water nanofluid through serpentine micro-channel was experimentally studied in the Reynolds range 124–1000. By analyzing the experimental results of nanofluid flow and heat dissipation: In the experiment, the Nusselt number of nanofluids is 1.12–1.66 times that of deionized water, which indicates that Al2O3 -water nanofluids have significant heat transfer enhancement effect. Nanofluid flow resistance is 1.02–1.80 times that of deionized water, this indicates that Al2O3 -water nanofluid has the disadvantage of increasing energy consumption. From a comprehensive performance point of view: all the nanofluids used in the experiment have enhanced heat transfer factors more significant than one, and the enhanced heat transfer effect is better than that of deionized water, this suggests that Al2O3 -water nanofluid has the drawback of rising energy consumption. All the nanofluids used in the experiment have enhanced heat transfer factors more significant than one, and the enhanced heat transfer effect is better than that of deionized water. Nano-fluids, with a volume fraction of 0.4%, have an average increased heat transfer factor of 1.4, which is the best overall performance.

Formation Damage Induced by Water-Based Alumina Nanofluids during Enhanced Oil Recovery: Influence of Postflush Salinity.

Injecting nanofluids (NFs) has been proven to be a potential method to enhance oil recovery. Stranded oil is produced by wettability alteration where nanoparticles form a wedge film on pore wall surfaces, which is thought to shrink the pore space of the reservoir. Furthermore, ensuring the stability of the injected NF during the application is a major challenge. A low permeability reservoir and salinity of water make the response of NF injection to the formation damage more difficult. This article, therefore, studied the formation damage induced by the injection of alumina nanofluids (Al-NFs) in a relatively low permeability (7.1 mD) sandstone core. The salinity of the postflush water was also considered to mitigate the destructive impact. Al-NF was formulated by dispersing alumina nanoparticles (Al-NPs) in an aqueous solution of sodium dodecylbenzene sulfonate (SDBS) at its critical micelle concentration (CMC, 0.1 wt %). The formation damage, inherent to Al-NF injection, was evaluated by core-flooding tests. The assays consisted of the injection of 1 PV Al-NF (0.05 wt %) at the trail of which postflush at different salinities was flooded. The study found that the salinity of the postflush has an effect on the formation damage and oil recovery factor (RF). A chase water with a salinity concentration of 3 wt % sodium chloride (NaCl) produced an RF of 8.7% compared to a base case of water-flooding with a pressure drop of up to 13 MPa across the core (70 mm in length). These results pertained to the deposition of Al-NPs at the injection end. However, lowering the postflush salinity to 1 wt % NaCl mitigated the formation damage as evidenced by the decrease in pressure (35%) and an increase in RF to 17.2%.

Effects of eluted metal ions on the properties of ceramic slurry and slip-casted green bodies

ABSTRACT The characteristics of ceramics produced by wet forming are determined by the particle dispersion in the utilized slurry, obtained by mixing ceramic powder and a solvent. Evaluation and control of the particle dispersion is thus important. In the case of ceramic powder containing a sintering aid, metal ions may be eluted from the particles during preparation of the aqueous slurry. It remains unclear, however, how the metal ions affect the particle dispersion and the green body characteristics. Hence, in the present study, Mg2+ or Al3+ ions were added to common water-based alumina slurries, and their effects on the slurry and green body characteristics were investigated. It was found that the presence of about 10 mM of metal ions caused agglomeration of the slurry particles and decreased the green body packing fraction. The effects were particularly significant for small amounts of the added dispersant. When the dispersant dosage exceeded a certain level, the added metal ions produced no observable change in the slurry or green body characteristics. In addition, higher-valence metal ions were found to decrease the maximum green body packing fraction and increase the dispersant dosage required to reach the maximum packing fraction.

Viscous and Ohmic Heating Effects on MHD Flow of Nanofluid Past a Porous Stretching Sheet with Thermal Radiation and Heat Generation/Absorption: Copper-Alumina Water

The important focus of this work is to numerically examine the viscous dissipation and Ohmic heating effects on hydromagnetic flow of nanofluid over a porous stretching sheet with thermal radiation and heat generation/absorption filled with water-based copper and alumina nanofluids. Heat transfer features are investigated through convective conditions. Consider steady, nonlinear, two-dimensional of an incompressible, viscous and electrically conducting fluid past a porous stretching sheet in the presence variable magnetic field. To obtain meaningful results, we have taken thermal radiation in the heat transfer procedure. Governing nonlinear partial differential equation and they are transformed into an ordinary differential equation by using similarity transformation and the numerical solution is obtained by using Nachtsheim-Swigert shooting iteration scheme together with a fourth order Runge-Kutta integration method. Numerical results are obtained for the velocity and the temperature in the boundary layer region is studied in elaborate. Quantities of engineering interest such as skin friction coefficient and nusselt number are also obtained numerically and are tabulated.