Fraction Of Nanoparticles Research Articles

Application of central composite design (CCD)-response surface methodology (RSM) for optimization of heat transfer in dusty nanofluid flow with velocity slip

Background and Purpose The consequence of thermal radiation is scrutinized on the heat transport of Nano-diamond/silicon oil and silver/silicon oil nanofluids through a stretching endless plate. The single phase (Tiwari and Das) model is employed for nanofluid. The major objective of this study is to optimize the RSM-based Central composite design modeling to optimization of the heat transfer in dusty Oldroyd-B nanofluid across stretching surface. Additionally the velocity slip effect is considered. The dust particle phase is also taken into account. The significance of viscous dissipation, joule heating, inclined magnetic field with convective condition is investigated. Methodology The partial differential equations are developed under consideration, then transform to ODE’s by utilizing similarity tools. The transformed model of ODE’s is tackled numerically via bvp4c MATLAB tool with shooting algorithm. The effect of magnetic parameter, fluid interaction parameter, nanoparticle volume fraction, slip parameter and temperature interaction parameter on velocity field and temperature distribution of fluid phase and dust phase is investigated. Furthermore the Nusselt number on the wall is observed for interactive parameters of mass concentration of dust particles, fluid particles interaction parameter for velocity and unsteady parameters utilizing the face-centered Central Composite design (CCD) of the Response Surface Methodology (RSM). Additionally, Analysis of Variance (ANOVA) algorithm and 3D plots are utilized to examine the consequence of experimental design parameters via the response. The recommended model significance has been analyzed in conditions of correlation coefficient ( R 2 ), mean square error (MSE), root means square error (RMSE), prediction standard error to acknowledge the most excellent strong. Results The difference between the Predicted R2 of 0.9467 and the Adjusted R2 of 0.9867 is less than 0.2, which is assumed to be a reasonable concurrence. Furthermore results of the current analysis indicate that velocity gradient for nanofluid is diminishes for larger fluid particle interaction parameter for velocity, while the dust phase velocity is improved. The increment in Temperature gradients is observed via increasing values of the nanoparticle fraction and temperature base fluid particle interaction parameter. From the results it is concluded that skin friction coefficient is reduced with larger magnetic parameter for both mono nanofluids. Furthermore the heat transfer rate is increased by increasing the thermal radiation parameter for both mono nanofluids. It is concluded that silver/silicon oil nanofluid play a higher role in heat transportation as compare to Nano-diamond/silicon oil.

Exploiting and Enhancing the Heat Transport Rate of MoS2-Ag/EO Hybrid Nanofluid Flow via a Stretching Cylinder using Extended Yamada-Ota and Xue Models.

The current model offers valuable insights for materials science, heat exchangers, renewable energy production, nanotechnology, manufacturing, medicinal treatments, and environmental engineering. The findings of this study have the potential to improve material design, increase heat transfer efficiency across various systems, enhance energy conversion processes, and drive advancements in nanotechnology, medicinal treatments, and engineering design. The goal of the current research is to analyze the effects of thermal radiation and the volume fraction of nanoparticles in MoS2-Ag/engine oil-based hybrid nanofluid flow passing through a cylinder. After performing a substantial similarity transformation, the nonlinear dimensionless framework is recast as ODEs. The Yamada-Ota and Xue models are then applied to the dimensionless equation setup, which is numerically solved using the BVP4C approach. The resulting velocity and temperature fields, corresponding to various parameters, are examined and compared across both models. This investigation demonstrates a significant variation in heat transfer rates between the Yamada-Ota and Xue models, with the former having a larger impact. The velocity and temperature fields decrease as the magnetic field parameter increases in both nanofluids. However, as the magnetic field parameter values grow, the velocity fields in the two nanofluids behave differently. The Yamada-Ota and Xue models are used to determine the behavior of the hybrid nanofluid flow over a nonlinear extended cylinder. In all situations, the velocity and temperature fields exhibit superior decay characteristics.

Computational micropolar model of hybrid nanofluid flow across a wedge

Non-Newtonian flow from wedges is a vital problem in coatings, polymer processing etc. Hence the main aim is to investigate the convective boundary layer flow of micropolar hybrid nanofluid (MHN)from a wedge. It is assumed that the wedge surface is isothermal. The Eringen model is employed to define micropolar fluid. Nanoscale Tiwari–Das formulations are used to study the specific effects of nanoparticles and volume fractions. The dimensionless boundary value problem arises by suitable coordinate transformations as a system of nonlinearly coupled ordinary differential equations. The so-called Falkner Skan flow case is resolved. Dimensionless, transformed, coupled momentum, microrotation, boundary layer equations are resolved using the numerical scheme MATLAB bvp4c. The parameteric investigations are performed on hybrid nanofluids using water as the basis liquid and varying volume fractions from 0 to 8%. Affirmation with previous work is done. The consequence of Eringen micropolar parameter, Hartree pressure gradient parameter, nanoparticle volume fraction, Eckert number, heat absorption (sink) parameter, on the flow and physical characteristics are visualized graphically and in tables. With rising material factor and volume fraction of nanoparticle, temperature is markedly enhanced. Increases in volume fraction dampen angular velocity close to the wedge surface, while farther from the wall, the opposite effect is seen. Temperature and thermal boundary layer thickness are both greatly enhanced by increasing Eckert number. With an increase in the volume proportion of nanoparticles, velocity decreases. Heat generation raises temperatures while a heat sink lowers them. The pressure gradient parameter increases skin friction while decreasing Nusselt number. Nusselt number for hybrid nanofluid is higher than for nanofluid.

Magnetic hybrid micelles with controllable structures via interfacial instability-induced confined Co-assembly

Co-assembly of amphiphilic block copolymers (BCPs) and nanoparticles (NPs) is an encouraging route to produce shape-tunable functional hybrid micelles, which can integrate the excellent water stability of BCPs and the versatile functionalities of NPs. In this paper, we present an facile method to prepare magnetic hybrid micelles through confined co-assembly of polystyrene grafted Fe3O4@PS NPs and PS-b-poly(ethylene oxide) (PS-b-PEO) induced by interfacial instability of emulsion droplets. The morphology of hybrid micelles can be regulated by varying the surfactant concentration, weight fraction of Fe3O4 NPs, and block ratio of PS-b-PEO. The distribution of NPs inside the micelles is determined by the ratio (d/L) of the NP diameter (d) to the thickness of PS domain of the micelles (L). When 0.49 ≤ d/L < 0.76, the NPs locate within the cylindrical micelles. When d/L ≥ 0.76, the NPs selectively locate in the spherical micelles. More interestingly, the size-selective loading of NPs in the micelles can be achieved, even mixture of NPs different in size is applied. Moreover, these magnetic hybrid micelles show good biocompatibility and morphology-dependent magnetic resonance responsiveness, which may find potential applications in magnetic resonance imaging.

High-temperature tensile properties of Cu-modified AlSi10Mg alloy fabricated by selective laser melting

In this study, an AlSi10Cu4Mg alloy was prepared by selective laser melting (SLM) using a mixture of pre-alloyed AlSi10Mg and elemental Cu powders, followed by aging at 180 ℃ for 2 h. The high-temperature tensile properties of both the SLMed and SLM-aged samples were tested in the temperature range of 200–400 ℃, and the microstructure changes during deformation were compared. At the temperature of 200 ℃, the SLMed sample exhibits outstanding tensile properties with an ultimate tensile strength (UTS) of 327±2 MPa and an elongation (EL) of 25.5±0.5 %. This is mainly related to the strain hardening that caused by the accumulation of anomalous dislocations near the high-volume fraction of Si nano-particles within the grains. For the SLM-aged sample, the aging treatment is found to further increase the strength, yielding a UTS of 381±3 MPa. The metastable transition of the Al2Cu phase indirectly promotes the precipitation of the nano-sized Si phase during the aging process. As the testing temperature increases, the strength increment of the SLM-aged sample gradually diminishes, while the elongation increment increases. Due to the limited intrinsic thermal stability of Si nano-particles and θ′ phase, the coarsening of the precipitates can weaken the strengthening effect. The dynamic recrystallization process can be accelerated by the aging treatment, thereby helping to improve the elongation.

Amplifying thermal performance of solar flat plate collector by Al2O3/ Cu/MWCNT/SiO2 mono and hybrid nanofluid

Flat plate collectors (FPCs) have garnered widespread usage in applications such as water heating, space heating, and various thermal systems, presenting an eco-friendly and sustainable approach to harnessing solar energy. However, the thermal performance of FPCs has been adversely affected by the improper selection of Heat Transfer Fluids (HTFs). The purpose of the work is to explore and demonstrate the potential advancements in solar flat plate collector (FPC) technology through the use of nanofluids to Enhance Energy Conversion, Explore Synergistic Effects, Contribute to Sustainable Energy Solutions and Address Technological Challenges. That is to optimize the thermal performance of FPCs by incorporating standalone and hybrid nanoparticles into the base fluid to augment their thermal properties. This approach explores new possibilities for synergistic effects and enhanced thermal properties, offering a novel contribution to the field of nanofluid research. The standalone and hybrid nanofluids encompass nanoparticles such as Al2O3, Cu, multi-walled carbon nanotubes (MWCNT), and SiO2 at a concentration of 0.5 wt%. In the preparation of hybrid nanofluids, equal volume fractions (25 % each) of Al2O3, Cu, MWCNT, and SiO2 nanoparticles were employed. The investigation includes the evaluation of thermal performance parameters, namely heat gain, heat loss coefficients, and thermal efficiency of FPCs, comparing these values with those of water. Hybrid nanofluids exhibit significantly improved thermal performance compared to both plain water and monodisperse nanofluids. Employing hybrid nanofluids yields results that indicate a peak outlet temperature of approximately 83.2 °C, a higher heat gains of 2385 W, a reduced heat loss coefficient of 25.5 W/m2K, and a peak thermal efficiency of 70.4 %. The use of hybrid nanofluids, as opposed to monodisperse nanofluids, offers superior thermal performance for flat plate collector-based solar heating systems.

Peristaltic flow under the effects of tilted magnetic field: enhancing heat transfer using graphene nanoparticles

ABSTRACT This study investigates the consequences of inclined magnetic field and thermal radiation on peristaltic transportation of nanofluid through a porous media. The nanoliquid is composed of graphene nanoparticles and water. Viscous dissipation, mixed convection, thermal radiation, Joule heating and gravity effects are also considered. Mathematical modeling is carried out under small Reynolds number and large wavelength approximations. Resulting system of equations is numerically solved through built-in command NDSolve through Mathematica. The purpose of this research is to investigate the impact of volume fraction of nanoparticles, phase difference, inclination angle of the applied magnetic field, geometry parameters, Hartmann, Darcy and Brinkman numbers on axial velocity, temperature profile, heat transfer rates at the boundaries, pressure gradient, and pressure rise per wavelength. Outcomes of this study reveal that the addition of graphene nanoparticles enhances heat transfer performance. Velocity profile reduces and temperature increases for greater Hartmann number. Moreover, higher values of Hartmann number enhance heat transfer performance and peristaltic pumping. The enhancement of Darcy number increases velocity, temperature, and pressure while decreasing the peristaltic pumping. Variation in thermal radiation parameter reduces the temperature profile. The rate of pumping and pressure gradient decreases on increasing Froude number.

Thermal Transportation in Heat Generating and Chemically Reacting MHD Maxwell Hybrid Nanofluid Flow Past Inclined Stretching Porous Sheet in Porous Medium with Solar Radiation Effects

The emerging concept of hybrid nanofluids has grabbed the attention of researchers and scientists due to improved thermal performance because of their remarkable thermal conductivities. These fluids have enormous applications in engineering and industrial sectors. Therefore, the present research study examines thermal and mass transportation in hybrid nanofluid past an inclined linearly stretching sheet using the Maxwell fluid model. In the current problem, the hybrid nanofluid is engineered by suspending a mixture of aluminum oxide Al2O3 and copper Cu nanoparticles in ethylene glycol. The fluid flow is generated due to the linear stretching of the sheet and the sheet is kept inclined at the angle ζ=π/6 embedded in porous medium. The current proposed model also includes the Lorentz force, solar radiation, heat generation, linear chemical reactions, and permeability of the plate effects. Here, in the current simulation, the cylindrical shape of the nanoparticles is considered, as this shape has proven to be excellent for the thermal performance of the nanomaterials. The governing equations transformed into ordinary differential equations are solved using MATLAB bvp4c solver. The velocity field declines with increasing magnetic field parameter, Maxwell fluid parameter, volume fractions of nanoparticles, and porosity parameter but increases with growing suction parameter. The temperature drops with increasing magnetic field force and suction parameter values but increases with increasing radiation parameter and volume fraction values. The concentration profile increases with increasing magnetic field parameters, porosity parameters, and volume fractions but reduces with increasing chemical reaction parameters and suction parameters. It has been noted that the purpose of the inclusion of thermal radiation is to augment the temperature that is serving the purpose in the current work. The addition of Lorentz force slows down the speed of the fluid and raises the boundary layer thickness, which is visible in the current study. It has been concluded that, when heat generation parameters increase, the temperature field increases correspondingly for both nanofluids and hybrid nanofluids. The increase in the volume fraction of the nanoparticles is used to enhance the thermal performance of the hybrid nanofluid, which is evident in the current results. The current results are validated by comparing them with published ones.

Effect of Silica and Alumina Nanoparticles Addition on the Dielectric and Rheological Properties of Shea Oil Methyl Ester

Study’s Excerpt/Novelty This study introduces a novel green nanofluid by incorporating shea methyl ester (SME) with surface-modified Al2O3 and SiO2 nanoparticles, addressing the environmental concerns associated with mineral-based transformer oils. The research highlights that SiO2 nanoparticles significantly enhance the dielectric properties of the base oil while minimally impacting its viscosity, suggesting improved insulation performance. This innovative approach offers a sustainable alternative with superior electrical characteristics, potentially transforming the application of transformer oils in the industry. Full Abstract The increasing environmental and utility concerns of mineral-based transformer oils have impelled research into alternative insulation liquids. This study developed a green nanofluid using a two-step approach, incorporating shea methyl ester (SME) derived from shea butter oil and surface-modified Al2O3 and SiO2 nanoparticles. The dynamic viscosity at 25 °C and dielectric properties of the developed nanofluid were investigated in the frequency range of 0.1–15 kHz. Adding nanoparticles into the SME noticeably increased the oil's viscosity, with SiO2 nanoparticles having the least effect on the base liquid's viscosity. The addition of 0.6 wt% of Al2O3 nanoparticles increased the dielectric loss of the SME at all frequencies (0.1–15 kHz), while the addition of 0.6 wt% SiO2 filler nanoparticles reduced the loss of the base oil at frequencies beyond 4 kHz indicative of an improved electrical property. Adding Al2O3 and SiO2 to the base SME oil obtained higher relative permittivity values. This study successfully developed an SME and single nanoparticle-based nanofluid, incorporating a 0.6 wt% weight fraction of surface-modified Al2O3 and SiO2 nanoparticles. The addition of these nanoparticles increased the dynamic viscosity of the base methyl ester oil, with approximately 43% and 36% increases, respectively. The nanofluid developed by incorporating SiO2 nanoparticles showed promising dielectric performance for its application as an insulation liquid.

Investigation of the Photothermal Performance of the Composite Scaffold Containing Light-Heat-Sensitive Nanomaterial SiO2@Fe3O4

The objective of this investigation was to fabricate a photothermally responsive composite bone scaffold aimed at facilitating bone tissue regeneration and remedying bone defects via mild thermal stimulation. The photothermal-sensitive nanomaterial SiO2 coated Fe3O4 (SiO2@Fe3O4), synthesized through the hydrolysis–condensation process of tetraethyl orthosilicate (TEOS), displayed a uniform distribution of SiO2 coating, effectively preventing the aggregation of Fe3O4 particles within the scaffold matrix. The composite scaffold containing 5% mass fraction of photothermal-sensitive nanoparticles exhibited evenly dispersed microstructural porosity, a compressive strength of 5.722 MPa, and a water contact angle of 58.3°, satisfying the mechanical property requisites of cancellous bone while demonstrating notable hydrophilic characteristics. Upon exposure to near-infrared light at ambient temperature, the 5% composite scaffold underwent a temperature elevation of 3–6 °C within 40–45 s, attaining a temperature range (40–43 °C) conducive to fostering osteogenic differentiation. Experimental findings validated that the SiO2@Fe3O4/polyvinyl alcohol (PVA)/hydroxyapatite (HA)/polycaprolactone (PCL)/β-tricalcium phosphate (β-TCP) bone scaffold showcased outstanding mechanical and photothermal attributes, thereby presenting a pioneering avenue for advancing bone tissue cell proliferation and addressing bone defect rehabilitation.

The effect of MgO nanoparticle on PVA/PEG-based membranes for potential application in wound healing

The interest in wound dressings increased ten years ago. Wound care practitioners can now use interactive/bioactive dressings and tissue-engineered skin substitutes. Several bandages can heal burns, but none can treat all chronic wounds. This study formulates a composite material from 70% polyvinyl alcohol (PVA) and 30% polyethylene glycol (PEG) with 0.2, 0.4, and 0.6 wt% magnesium oxide nanoparticles. This study aims to create a biodegradable wound dressing. A Fourier Transform Infrared (FTIR) study shows that PVA, PEG, and MgO create hydrogen bonding interactions. Hydrophilic characteristics are shown by the polymeric blend’s 56.289° contact angle. MgO also lowers the contact angle, making the film more hydrophilic. Hydrophilicity improves film biocompatibility, live cell adhesion, wound healing, and wound dressing degradability. Differential Scanning Calorimeter (DSC) findings suggest the PVA/PEG combination melted at 53.16 °C. However, adding different weight fractions of MgO nanoparticles increased the nanocomposite’s melting temperature (Tm). These nanoparticles improve the film’s thermal stability, increasing Tm. In addition, MgO nanoparticles in the polymer blend increased tensile strength and elastic modulus. This is due to the blend’s strong adherence to the reinforcing phase and MgO nanoparticles’ ceramic material which has a great mechanical strength. The combination of 70% PVA + 30% PEG exhibited good antibacterial spatially at 0.2% MgO, according to antibacterial test results.

Evaluation of Heat Transfer and Fluid Dynamics across a Backward Facing Step for Mobile Cooling Applications Utilizing CNT Nanofluid in Laminar Conditions

In a variety of engineering applications, the efficacy of heat dissipation in mobile cooling systems is greatly influenced by the Backward Facing Step. Its significance in optimizing cooling solutions for mobile devices is highlighted by the fact that its design and fluid dynamics are crucial in minimizing skin friction and improving passive heat transfer. In this paper, we present a verification of an advanced numerical model for heat transfer and fluid flow through a Backward Facing Step, used in mobile cooling. The objective of this study is to explore fluid separation, a method enhancing passive heat transfer and reducing skin friction. ANSYS/FLUENT software has been used to solve the backward facing step in a horizontal duct filled with pure water. Carbon nanotube (CNT) dispresed into the base fluid at different volume fractions of 0.2%, 0.65%, and 1%. This study focused on laminar flow conditions ranging from Reynolds numbers 200 to 900. In order to reduce the computation time and ensuring the accuracy and reliability of numerical simulations, a grid independence study has been conducted. The findings revealed a substantial rise in the average Nusselt number and heat transfer coefficient with increased Reynolds number and volume fraction of nanoparticles. Specifically, the nanofluid (CNT/water) exhibited the highest average Nusselt number and heat transfer coefficient with volume fractions 1%. Furthermore, the research showed a decrease in the skin friction factor as both Reynolds number increased and nanoparticles’ volume fraction decreased. The increments of nanoparticles' concentrations lead to increase viscosity, promotes agglomeration, alters flow behaviour by inducing turbulence, and enhances heat transfer. These factors collectively contribute to higher skin friction due to increased resistance to fluid flow and disrupted streamline patterns

Analytical Investigation of Magnetohydrodynamic Hybrid Nanofluid Flow Over a Permeable Shrinking Sheet

The flow and heat transfer of Cu-Al2O3/water hybrid nanofluid over a shrinking sheet were investigated taking account of the magnetic field, suction, variable heat sink, and thermal radiation. At first, the governing equations were completely changed into ordinary differential equations (ODEs) with proper transformations. The novelty of this investigation is that the ODEs were analytically solved and the dual characteristics of flow properties and heat transfer were graphically presented. Results revealed that an increase in the volume fraction of Cu nanoparticles (φ2), magnetic parameter (M), and suction parameter (S) caused an increase in the local skin friction coefficient (Rex1/2Cf), local Nusselt number (Rex-1/2Nux) and region of the existence of dual solutions. With the increase of φ2, M, and S, fluid velocity increased and temperature decreased. Contrary to this, the converse was observed for increasing the volume fraction of Al2O3 nanoparticles (φ1). These findings indicated that with proper tuning of these parameters, the cooling rate of a shrinking sheet could be controlled and the possible working conditions of a system might be increased.

The Lattice Boltzmann Simulation of Free Convection Heat Transfer of a Carbon-Nanotube Nanofluid in a Triangular Cavity with a Solar Heater

In this paper, the flow and free convection heat transfer of a multi-walled carbon nanotube/water nanofluid in a triangular cavity with a solar heater is studied using the lattice Boltzmann method. The side walls of the cavity are cold and the bottom wall is partially heated by a solar heater, which have a non-uniform temperature distribution. It is assumed that the heating energy is provided by an absorber that is directly exposed to sunlight. Because of the limited variations of density, the Boussinesq approximation is used, which causes the coupling of hydrodynamic and thermal fields. For velocity and temperature distribution functions, a lattice Boltzmann model with two dimensions and nine directions is adopted. The effect of parameters, such as the Rayleigh number, the volume fraction of nanoparticles, and the position of solar heater, on the flow and heat fields is studied. The results show that, for all Rayleigh numbers studied, the Nusselt number increases as nanoparticles volume fraction increases. The addition of 4% nanoparticles causes the average Nusselt number to increase about 11% at low (Ra = 103) and moderate (Ra = 104) Rayleigh numbers and 217% at the high Rayleigh number (Ra = 105). Furthermore, it is shown that for a fixed Rayleigh number, heat transfer can be optimized by adjusting solar heater’s position. This study can provide a useful insight for utilizing solar heaters with non-uniform temperature distribution in triangular cavities.

Hydromagnetic Thermosolutal Instability of an Oldroyd Nanofluid in a Porous Medium

The onset of double-diffusive convection of an Oldroyd nanofluid fluid saturated in a porous medium, heated and soluted from below, is examined both analytically and numerically under the linear stability analysis in the presence of a horizontal magnetic field and physically realistic boundary condition on the volume fraction of nanoparticles. The resulting eigenvalue problem is solved numerically by employing Galerkin method. We recover the important works of Umavathi and Prathap Kumar (J. C. Umavathi and J. Prathap Kumar, J. Heat Transfer 139, 012401 (2017)), Jaimala et al. (R. Jaimala, Singh, and V. K. Tyagi, Int. J. Heat Mass Transfer 111, 451 (2017); Jaimala, R. Singh, and V. K. Tyagi, Int. J. Heat Mass Transfer 125, 290 (2018)) and Kuznetsov and Nield (A. V. Kuznetsov and D. A. Nield, International Journal of Thermal Sciences 77, 126 (2014)) as special cases. The important findings include: (i) the independence of thermal Rayleigh-Darcy number for stationary convection upon relaxation and retardation parameters, (ii) the parameters Rn, Rs, Le, NA and λ1 (absent in case of stationary convection) enhance both the stationary and oscillatory convections and the parameter Q, ε and λ2 (absent in case of stationary convection) delay the occurrence of both convections, (iii) instability first sets in as oscillatory convection and (iv) a number of sufficient conditions for the existence and also for the non-existence of oscillatory convection are obtained analytically but only stated (without proof).

Investigation of partial charging of enhanced ice storage systems

AbstractPartial storage strategy can save energy and reduce emissions. In this study, analysis of the partial melting process of ice inserted with nanoparticles inside a square enclosure is investigated for thermal energy storage. The lattice Boltzmann method is for melting and heat transfer in the storage unit. The validation demonstrates strong concurrence between the current findings and the experimental data documented in the literature. The analysis is performed for various Rayleigh numbers, nanoparticle volume fractions, and their effect on melting time and energy storage. Two types of nanoparticles are tested that is, copper and alumina. The outcomes indicate that the Rayleigh number and volume fraction of nanoparticles have a significant impact on the phase change process. The nanoparticles addition leads to homogenous and hence expedited melting process including the final stage of the ice melting process which is very slow without nanoparticles. Furthermore, copper nanoparticles are slightly more effective than alumina. Moreover, using 6% copper nanoparticles can reduce the melting time by up to 12.4%.

Numerical analysis of the flow dynamics in Maxwell hybrid nanofluid flow with gyrotactic microorganisms over a permeable stretching surface with convective and zero-mass flux conditions: A comparative analysis

This study observes the 2-D flow of a Maxwell hybrid nanofluid flow on a permeable stretching surface containing Cu and CuO nanoparticles and gyrotactic microorganisms. The thermal convective and zero-mass flux constraints are adopted by incorporating a hot working fluid with a heat transfer coefficient and zero mass flow at the permeable sheet’s surface to investigate the heat transfer rate. This study is designed to present a comparative analysis of the nanofluid (Cu–water) as well as hybrid nanofluid (Cu–CuO/water) flows on a stretching sheet. Examining activation energy in water-based hybrid nanofluid flow offers important insights into the kinetics of chemical reactions, which in turn helps to optimize the features of the nanofluid and build more effective systems that use nanofluids for a variety of applications. The problem formulated initially is converted to dimension-free notation using appropriate variables for finding the numerical solution by incorporating the bvp4c MATLAB function. From the obtained results, it is found that the higher magnetic and porosity factors have declined the velocity profiles. Also, in the absence of porous media and magnetic field effects, the velocity distribution is highly affected when compared with the existence of these effects. It is observed that the velocity profiles of both nanofluids are dominant for Newtonian fluid in comparison to non-Newtonian fluid. Also, the thermal profiles of both nanofluids are dominant for non-Newtonian fluid in comparison to Newtonian fluid. The friction force of hybrid nanofluid is significantly influenced by the magnetic factor, porosity factor, and volume fractions of the solid nanoparticles when compared to nanofluid.

Thermal analysis of hybrid nanoliquid contains iron-oxide (Fe3O4) and copper (Cu) nanoparticles in an enclosure

The major aim of this work is to analyze the thermophysical properties of hybrid nanoliquid inside a square lid driven enclosure under the effect of applied magnetic field and mixed convection. The Hybrid nanofluid is considered a suspension of Iron-oxide (Fe3O4) and Copper (Cu) nanoparticles into water. The cavity walls have varying properties such as top adiabatic wall is moving continuously while the lower wall is maintained at a high constant temperature, in addition, the vertical walls are kept at a low fixed temperature. The magnetic field is applied to the right vertical wall in a horizontal direction. Additionally, the effects of buoyancy forces caused by temperature gradients and shear forces caused by continuous lid motion are considered. The mathematical modelling of problem with all assumptions yields the nonlinear partial differential system. First this system is transferred into non-dimensional form and then transformed system is solved by using Galerkin finite element method (GFEM) along with Gaussian elimination method. Results for isotherms, streamlines and average Nusselt number are obtained versus Richardson number (0.1 ≤ Ri ≤ 15), Grashof number (10 ≤ Gr ≤ 10000), Hartmann number (0 ≤ Ha ≤ 100), volume fractions of solid nanoparticles (0.005 ≤ ϕ1 ≤ 0.02) and (0.005 ≤ ϕ2 ≤ 0.02). It is observed that the Richardson number and Grashof number have significant impacts on both flow velocity and temperature. In addition, concentration of hybrid nanoparticles improves the heat transfer performance. The obtained results may be crucial for thermal management in the cooling of electronics, heat exchangers, solar thermal collectors, industrial operations, medical equipment, HVAC systems, food processing, and renewable energy systems.

Entropy generation on the dynamics of volume fraction of nano-particles and coriolis force impacts on mixed convective nanofluid flow with significant magnetic effect

Recent advances in simulating entropy generation for dissipative cross-materials with a quartic auto catalyst are reported. Entropy generation can be used to generate entropy in any irreversible heat transfer process, which is important in thermal machines. This study examines the impact of entropy generation on the thermal transport and momentum of a continuous two-dimensional dusty fluid magnetohydrodynamic (MHD) migration across an inclined stretched sheet. We also conducted an entropy generation study to discuss the effects of viscous dissipation, the volume proportion of dust particles, and mixed convection. The two-phase models that address the fluid phase and the solid phase have been discussed. As part of the flow model’s innovation, the effect of raising particulate matter concentration on the dynamic behavior of the fluid is investigated. The described model transforms the prevailing partial differential equations (PDEs) for two phases into a nonlinearly associated, nondimensional set of equations by implementing appropriate similarity alterations. For graphical results, MATLAB programming incorporates the bvp4c mechanism. This study indicates how to examine the impact of appropriate factors on the dusty phase of fluid and the non-Newtonian fluid phase. Both the entropy generation ( E gen ) and the Bejan quantity (Be) are presented in relation to their associated dimensionless factors. Parametric research is used to evaluate the impact of different flow parameters on temperatures, entropy generation, and Bejan numbers. The heat transfer rate using several quadratic regression models, which provide more clarity in determining physical parameters crucial to engineering, is assessed. It is observed that the entropy ( E gen ) and Bejan number (Be) declines with the rising mass concentration ( β ν ) of dusty particles. Also demonstrated that for both cases, increasing the magnetic influence and dust volume fraction ( Φ D ) resulted in a decrease in velocity profiles at the same time as temperature increased.

The Role of Adsorption Phenomena in ac Conductivity Measurements of Dielectric Nanoparticle Suspensions

The authors of numerous measurements of conductivity for suspensions of nanoparticles of various types carried out in the last decade came to the general conclusion that the well-known Maxwell’s theory is not applicable to quantitative explanation of the properties of such systems. In the present work, we demonstrate that the Maxwell’s theory can be still applicable even for such systems, but the specifics of the standard ac measurements have to be correctly taken into account. Namely, the dependence of the capacitance of “metal–electrolyte” cuvette boundaries on nanoparticle adsorption, which in its turn dramatically depends on nanoparticle concentration, has to be taken into account. The latter circumstance strongly (via the RC characteristic of the circuit) affects the results of conductivity measurements. We propose the new algorithm of the impedance measurement data analysis for the particles’ concentration dependence of conductivity σ(ϕ) (where ϕ is the volume fraction of nanoparticles in suspension) for the suspensions of the diamante nanoparticles in alcohol which demonstrates the adequate correspondence of the Maxwell’s theory to the available experimental findings.