Newtonian Nanofluid Research Articles

Flow of non-Newtonian magneto-fluid with gold and alumina nanoparticles through a non-Darcian porous medium

This paper is centered on a numerical solution of non-Newtonian Casson magneto-nanofluid flow underlying an axisymmetric surface through a non-Darcian porous medium with heat generation/absorption. Using similarity transformations, the system of PDEs with the corresponding boundary conditions are reduced to system of nonlinear ODEs. The Chebyshev pseudospectral (CPS) method is used to get a numerical solution for the formulated differential system. Comparisons of the present numerical results with previously published results are made, and fine agreements for some the considered values of parameters were noted. Two cases of nanofluid are considered. The first case is Newtonian nanofluid, water with suspended gold (Au) or alumina (Al2O3) nanoparticles, and representative results are obtained for β → ∞ and Pr = 6.785 (the Prandtl number of water). The second case is non-Newtonian bio-nanofluid, blood with suspended gold (Au) or alumina (Al2O3) nanoparticles, and representative results are obtained for β = 0.1 and Pr = 25 (the Prandtl number of blood). The variation of different physical parameters on non-dimensional velocity and temperature fields as well as the skin friction coefficient and the Nusselt number are discussed. It is demonstrated that the implication of a nanoparticle into bio-fluid can modify the stream design. Also, the nanoparticles with high thermal conductivity (gold) have better enhancement on heat transfer compared to alumina, i.e., the effectiveness of adding gold to the water and blood is higher than adding alumina. One of the most important applications of nanotechnology in the field of medicine is the use of nanoparticles (gold molecules) in chemotherapy to get rid of cancer cells.

Sensitivity analysis of radiative heat transfer in Casson and nano fluids under diffusion-thermo and heat absorption effects

The exact analysis of the magnetohydrodynamic flow of a Newtonian nanofluid past an inclined plate through a porous medium is carried out. The flows of a Newtonian nanofluid and a non-Newtonian Casson fluid are juxtaposed. The heat transport phenomenon is analyzed in the presence of Dufour and heat absorption effects. The Darcy model and Rosseland approximation are employed to simulate the effects of porous media and radiative heat. The exact solutions are obtained by using the Laplace transform method. The effects of different physical parameters on the velocity, temperature and concentration profiles are scrutinized using graphs. Statistical techniques, like the slope of data points, coefficient of correlation, probable error, and multiple linear regression, are employed to analyze the rate of heat transfer and skin friction coefficient. Further, the sensitivity of the skin friction coefficient and Nusselt number are analyzed using the Response Surface Methodology (RSM). The Nusselt number has a positive sensitivity towards thermal radiation, and it is negatively sensitive towards nanoparticle volume fraction and Dufour number.

Heat transfer investigation of combined electroosmotic/pressure driven nanofluid flow in a microchannel: Effect of heterogeneous surface potential and slip boundary condition

Abstract In the present study, electroosmotic and pressure driven Newtonian nanofluid flow in a microchannel with constant temperature boundary condition is studied via Lattice Poisson–Boltzmann method. In order to validate the numerical solution, the computed results are compared with some existing analytical solutions. Then, effects of different parameters such as ratio of pressure velocity to Helmholtz–Smolochowski velocity, slip coefficient, nanoparticles volume fraction and diameter on flow field and heat transfer is examined. The results show that by fixing the electric field and increasing the pressure force, Nusselt number decreases, and it increases by fixing the pressure force and increasing the electric field. Also, increasing the slip coefficient causes the velocity enhancement in the electroosmotic flow. Furthermore, increasing the nanoparticles volume fraction decreases the velocity and increases Nusselt number. Finally heterogeneous surface potential moves the vortices toward the walls and enables controlling the quantity and direction of velocity field.

Magnetic field impact on nanofluid convective flow in a vented trapezoidal cavity using Buongiorno's mathematical model

Numerical study for the effect of an external magnetic field on the mixed convection of Al2O3–water Newtonian nanofluid in a right-angle vented trapezoidal cavity was performed using the finite volume method. The non-homogeneous Buongiorno model is applied for numerical description of the dynamic phenomena inside the cavity. The nanofluid, with low temperature and high concentration, enters the cavity through the upper open border, and is evacuated through opening placed at the right end of the bottom wall. The cavity is heated from the inclined wall, while the remainder walls are adiabatic and impermeable to both the base fluid and nanoparticles. After validation of the model, the analysis was carried out for a wide range of Hartmann number (0 ≼ Ha ≼ 100) and nanoparticles volume fraction (0 ≼ ϕ0 ≼ 0.06). The flow behavior as well as the temperature and nanoparticles distribution shows a particular sensitivity to the variations of both the Hartmann number and the nanofluid concentration. The domination of conduction mechanism at high Hartmann numbers reflects the significant effect of Brownian diffusion which tends to uniform the distribution of nanoparticles in the domain. The average Nusselt number which increases with the nanoparticles addition, depends strongly on the Hartmann number. Finally, a correlation predicting the average Nusselt number within such geometry as a function of the considered parameters is proposed.

Nanofluids as coolant in a shell and tube heat exchanger: ANN modeling and multi-objective optimization

In the present study, an artificial neural network (ANN) was developed to predict the thermal and hydrodynamic behavior of two types of Newtonian nanofluids used as coolants in a shell and tube heat exchanger (STHE). Inputs of the ANN model are nanoparticle volume concentration, Reynolds number, nanoparticle thermal conductivity, and Prandtl number. Results indicate that the ANN model predicts the experimental data with very high accuracy. Values of Nusselt number resulted from experiments and those obtained from the ANN have at most 9% difference, this value is 9.6% for the pressure drop. Multi-objective optimization was implemented with the aim of minimizing the total pressure drop and maximizing the nanofluids Nusselt number in the STHE according to NSGA-II algorithm. In optimization procedure nanofluids pressure drop and the Nusselt number (tube-side) was evaluated by the ANN model. To find the shell-side pressure drop method of Delaware was employed. Nanofluids concentration and Reynolds number were selected as decision parameters. The Pareto front was obtained. The best solution adopted from points on the Pareto front by two well-known decision-making methods LINMAP and TOPSIS. The Nusselt number of optimal solutions are about 30% greater than the base fluid and pressure drop of optimal solutions are about 10% lower than the base fluid.

Analytical solution of Newtonian nanofluid flow in a tapered artery based on a consistent couple stress theory

Reduction of the stenosis in arteries is one of the most important applications of nanoparticles in medicine. Thus, investigating nanoparticles in stenosed arteries is a subject attracting so much attention from the researchers nowadays. However, considering the small size of arteries, it seems that non-classical theories demonstrate better results when compared to the classical Navier-Stokes theory. The present paper aims at investigating the Newtonian nanofluid flow through divergent and convergent, non-tapered and tapered arteries with mild stenosis according to the consistent couple stress theory. Concentration, temperature, and velocity profiles, as well as the impact of various parameters such as the height of the stenosis, the shape of the stenosis curve, Brownian distribution parameter, thermophoresis distribution parameter, Darcy number, and the length scale were calculated for all the three geometries. Results demonstrate that an increase in the height of the stenosis and an increase in the Darcy coefficient, respectively, lead to a decrease and an increase in the axial velocity in all three artery geometries. Moreover, an increase in the impact of the length scale leads to a decrease in the axial velocity. The impact of the length scale on the velocity profile shows the significance of the length parameter on the flow within the geometries with small sizes which is not present in the classical Navier-Stokes theory.

An experimental study on the rheological behavior of hybrid Tungsten oxide (WO3)-MWCNTs/engine oil Newtonian nanofluids

In recent years, numerous studies have been done on the rheological behavior and heat transfer of nanofluids. In this paper, an experimental study on the rheological behavior of hybrid WO3-MWCNTs/Engine Oil hybrid Newtonian nanofluid has been carried out. Tungsten oxide (WO3) nanoparticles have diameter of 23–65 nm and MWCNTs nanoparticles have diameter of 20–30 nm. Experiments were carried out at 6 vol fraction of nanoparticles of φ = 0, 0.05, 0.1, 0.2, 0.4 and 0.6% at the temperatures of 20, 30, 40, 50 and 60 °C. The results show that the relationship between the shear rate and shear stress of the base fluid and the hybrid nanofluid of WO3-MWCNTs/Engine Oil is linear at all temperatures and volume fraction of nanoparticles. So, the base fluid and the hybrid nanofluids are Newtonian. Also, with increasing temperature, the viscosity of nanofluid decreases and with increasing volume fraction of nanoparticles, the viscosity increases. Finally, a mathematical model has been proposed to estimate the nanofluid viscosity. The results obtained from the model show good compatibility with experimental values.

Transient Analysis of Third-Grade Viscoelastic Nanofluid Flow External to a Heated Cylinder with Buoyancy Effects

Nanotechnology is rapidly embracing numerous areas of manufacturing and process engineering. New types of nanomaterials are being exploited to improve, for example, coating integrity, anti-corrosion characteristics and other features of fabricated components. Motivated by these developments, in the current study a mathematical model is developed for unsteady free-convective laminar flow of third-grade viscoelastic fluid (doped with nanoparticles) from a semi-infinite vertical isothermal cylinder, as a model of thermal coating flow of a pipe geometry. Non-Newtonian behavior is simulated with the thermodynamically robust third-grade Reiner–Rivlin model which accurately represents polymer fluids. Nanoscale effects are analyzed with the Buongiorno two-component nanofluid model. The governing equations comprise a set of highly coupled, nonlinear, multi-degree partial differential equations featuring viscoelastic and nanofluid parameters. An implicit Crank–Nicolson numerical scheme is implemented to solve the emerging nonlinear problem with appropriate initial and boundary conditions. Detailed graphical plots for velocity, temperature and nanoparticle volume fraction are presented for a range of different parameters (i.e., third-grade fluid parameter, Brownian motion parameter, thermophoretic parameter, buoyancy ratio parameter, Lewis number). Additionally, distributions of the heat transfer coefficient, skin friction and Sherwood number at the cylinder surface are visualized. Furthermore, streamlines, isotherms and nanoparticle volume fraction contour plots are included for variation of the third-grade parameter. Contour plots for the third-grade nanofluid flow are found to deviate significantly from those corresponding to Newtonian nanofluids. Validation of the numerical solutions with earlier studies is also included.

MHD fluid flow with the effect of mixed convection passing on a magnetic sphere in newtonian nano fluid

This paper considers magneto-hydrodynamics (MHD) fluid flow with the effect of mixed convection passing on a magnetic sphere in nano fluid. Titanium dioxide (TiO2) is chosen as solid particle in nano fluid. The dimensional governing equations are developed from continuity equation, momentum equation, and energy equation. Furthermore, the dimensional governing equations are transformed into the non-dimensional governing equation by using non-dimensional parameters and variables. Then, the non-dimensional governing equations are transformed into similarity equations using stream function and then solved numerically using implicit finite difference method. The results of numerical solution are obtained using variation of non-dimensional parameters which consist of magnetic parameter, mixed convective parameter, and volume fraction. The numerical results show that the velocity and temperature decrease when magnetic parameter increases. The velocity and temperature increase when mixed convective parameter also increases. Finally, the velocity decreases and temperature increases when volume fraction parameters increase.

Functionalized multi-walled carbon nanotubes based Newtonian Nano fluids for medium temperature heat transfer applications

Functionalized multi-walled carbon nanotubes (f-MWCNTs) were synthesized and dispersed in the organic heat transfer fluids (OHTFs) to improve the thermo-physical properties of the medium temperature stable Nano thermic fluids (MNTFs). The prepared MNTFs showed an enhancement in thermal conductivity especially at high temperatures compared to the base OHTFs with addition of low quantities of f-MWCNTs. Based on the rheological studies, the Newtonian behaviour of the synthesized MNTFs have been demonstrated over a wide range of shear rates at various temperatures. The present study thus confirms the potential of developed MNTFs with desired rheological properties, high thermal and mechanical stability, high flash point, high specific heat capacity and high thermal conductivity for medium temperature heat transfer applications. The developed MNTFs were found to exhibit high and stable dispersion even after centrifugation with a speed of 5000 rpm for 30 min.

Computational study of unsteady couple stress magnetic nanofluid flow from a stretching sheet with Ohmic dissipation

To provide a deeper insight of the transport phenomena inherent to the manufacturing of magnetic nano-polymer materials, in the present work a mathematical model is developed for time-dependent hydromagnetic rheological nano-polymer boundary layer flow and heat transfer over a stretching sheet in the presence of a transverse static magnetic field. Joule heating (Ohmic dissipation) and viscous heating effects are included since these phenomena arise frequently in magnetic materials processing. Stokes’ couple stress model is deployed to simulate non-Newtonian microstructural characteristics. The Tiwari–Das nanoscale model is adopted which permits different nanoparticles to be simulated (in this article, both copper–water and aluminium oxide–water nanofluids are considered). Similarity transformations are utilized to convert the governing partial differential conservation equations into a system of coupled, non-linear ordinary differential equations with appropriate wall and free stream boundary conditions. The shooting technique is used to solve the reduced non-linear coupled ordinary differential boundary value problem via MATLAB symbolic software. Validation with published results from the literature is included for the special cases of non-dissipative and Newtonian nanofluid flows. Fluid velocity and temperature profiles for both copper and aluminium oxide (Al2O3) nanofluids are observed to be enhanced with greater non-Newtonian couple stress parameter and magnetic parameter, whereas the opposite trend is computed with greater values of unsteadiness parameter. The boundary layer flow is accelerated with increasing buoyancy parameter, elastic sheet stretching parameter and convection parameter. Temperatures are generally increased with greater couple stress rheological parameter and are consistently higher for the aluminium oxide nanoparticle case. Temperatures are also boosted with magnetic parameter and exhibit an overshoot near the wall when magnetic parameter exceeds unity (magnetic force exceeds viscous force). A decrease in temperatures is induced with increasing sheet stretching parameter. Increasing Eckert number elevates temperatures considerably. With greater nanoparticle volume fraction, both skin friction and Nusselt number are elevated, and copper nanoparticles achieve higher magnitudes than aluminium oxide.

Statistical investigation for developing a new model for rheological behavior of ZnO–Ag (50%–50%)/Water hybrid Newtonian nanofluid using experimental data

In this paper, the test results, along with the results of data analysis, are presented by graphs and tables. The effect of volume fraction and temperature on viscosity of a hybrid nanofluid, i.e. ZnO–Ag (50%–50%)-Water, is presented. Finally, a model for calculating nanofluid’s viscosity is based on available data was proposed. The results show that the dynamic viscosity decreases with increasing temperature and increases with increasing volume fraction of nanoparticles. Also, an increase in volume fraction at all temperatures is associated with an increase in relative viscosity. This increase was reported modest and linear in very low volume fractions. The margin of deviation between laboratory results and extracted experimental equations is equal to 1.8%.

Statistical investigation for developing a new model for rheological behavior of Silica–ethylene glycol/Water hybrid Newtonian nanofluid using experimental data

In this experimental investigation, we developed a new model for rheological behavior of Silica–Ethylene glycol/Water (30: 70 vol. %) hybrid Newtonian nanofluid. The tests were carried out in volume fractions of 0.1%, 0.25%, 0.5%, 0.75%, and 1.5%, the temperature range from 25 °C to 50 °C, and in the shear rate range 24.48 s−1 to 73.44 s−1. It can be deduced that the obtained correlation is a suitable model for estimating the desired nanofluid viscosity. Also, as the volume fraction increases, the relative viscosity increases due to the greater dispersion of the nanoparticles in the base fluid. The maximum marginal deviation values in this graph are shown to be equal to 1.37%. This value is acceptable for an experimental correlation. We find that the relationship between shear stress and shear rate is linear; then the desired fluid is Newtonian. At the maximum volume fraction, the percentage of loss of viscosity from the minimum temperature to the maximum temperature is 89%. In addition, at maximum operating temperature, the percentage increase in relative viscosity in the maximum volume fraction relative to the minimum fraction is 48%.

Comparative analysis on non-linear radiative heat transfer on MHD Casson nanofluid past a thin needle

The aim of this work is scrutinizing the consequences of non-linear radiation on MHD Casson nanofluid along thin needle. The situation has been mathematically modelled taking into account the thermo-diffuso and diffuso-thermo effects. Here two types of surfaces are dealt; one is fixed needle and other is moving needle. The Prandtl boundary layer equations are enclosed and solved numerically using similarity variables. Impact of different material parameters on the momentum, temperature and species concentration along with the quantities related engineering aspects like skin friction coefficient, rate of energy transfer and Sherwood number are obtained and illustrated through graphs. A comparison examination is made between studied Casson nanoflow usage makes the environment cool, reduces the friction at the surface. But Newtonian nanofluid is good for species diffusion. Numerical obtained solutions are contrasted with the published literature and found to be in nice agreement. The present exploration exhibits the prominent features in hybrid solar magneto-hydrodynamic nanofluid systems and aircraft technology.

MHD free convection flow of power-law nanofluid film along an inclined surface with viscous dissipation and joule heating

Purpose The purpose of this study is to present the magnetohydrodynamic (MHD) flow and heat transfer in an accelerating film of a non-Newtonian pseudo-plastic nanofluid along an inclined surface with viscous dissipation and Joule heating. Design/methodology/approach An incompressible and inelastic fluid is assumed to obey the Ostwald-de-Waele power law model and the action of viscous stresses is confined to the developing momentum boundary layer adjacent to the solid surface. Viscous dissipation and Joule heating on the flow of electrically conducting film in the presence of uniform transverse magnetic field is considered for the Carboxyl Methyl Cellulose (CMC) water-based nanofluid. The fluid is the CMC-water-based with concentration (0.1-0.4 per cent) containing three types of nano-solid particles Cu, Al2O3 and TiO2. The modeled boundary layer conservation equations are transformed to dimensionless, coupled and highly non-linear system of differential equations, and then solved numerically by means of a local non-similarity approach with shooting technique. To validate the numerical results, a comparison of the present results is made with the earlier published results and is found to be in good agreement. Findings The effects of magnetic parameter, Prandtl number, Eckert number and Biot numbers on the velocity and temperature fields are presented graphically and discussed for various values of thermo-physical parameters. It has been found that magnetic field decelerates the fluid velocity for both cases of Newtonian nanofluid and pseudo-plastic nanofluid because of the generated drag-like Lorentz force. This is of great benefit in magnetic materials processing operations, utilizing static transverse uniform magnetic field, as it allows a strong regulation of the flow field. Research limitations/implications The numerical study is valid for two-dimensional, steady, laminar film flow of Ostwald-de-Waele power law non-Newtonian nanofluid along an inclined plate. A uniform transverse magnetic field of strength B0 is applied perpendicular to the wall. Assume that the base fluid and the nano-solid particles are in thermal equilibrium with no slip effects. The interaction of magnetic field with nanofluid has several potential implications and may be used to deal with the problems such as cooling nuclear reactors by liquid sodium and inducting the flow meter which depends on the potential difference in the fluid along the direction perpendicular to the motion and to the magnetic field. Practical implications The study has significant applications in magnetic field control of materials processing systems. Originality/value The results of the present study may be attentiveness to the engineers and applied mathematicians who are interested in hydrodynamics and heat transfer enhancement associated with film flows.

Numerical investigation on fluid dynamic and thermal behavior of a non-Newtonian Al2O3–water nanofluid flow in a confined impinging slot jet

A numerical investigation of hydrodynamic and heat transfer behaviors for Al2O3–water nanofluids for laminar confined slot jet impingement is presented. This study has been conducted by considering the nanofluid as Newtonian as well as non-Newtonian for a wide range of solid volume fraction (0 ≤ φ ≤ 5%) and Reynolds number range of (25–300). A single-phase fluid approach was used to model the nanofluid and the Ostwald–de Waele model described the non-Newtonian shear thinning nanofluid behavior has been adopted. A comparison with Newtonian and non-Newtonian nanofluid in terms of heat transfer coefficient, Nusselt number, streamlines and isotherms contours has been performed for the same Reynolds number, jet inlet velocity and the same aspect ratio H/W. It has been observed that the rate of heat transfer increases with Reynolds number and solid volume fraction of the nanofluid. Noting that the local Nusselt number is much higher for non-Newtonian nanofluid than Newtonian flow in the entire target surface with a particular enhancement located at the jet axis where a relative increase of 9.8% is evaluated for φ = 5% and Re = 300. However, the pumping power results showed a steep increase with the volume fraction for a Newtonian nanofluid case. In fact, the required PP is 1.32, 1.53, 1.99, 2.11 and 4 times greater than the values calculated in case of pure water at φ = 1, 2, 3, 4 and 5 respectively. At the same value of volume fraction φ, it is noted that the pumping power for a non-Newtonian nanofluid is many times higher than PP required in Newtonian nanofluid case, especially at Re ≤ 200. Lastly, the correlations for stagnation point and average Nusselt number are provided for Newtonian and non-Newtonian nanofluid.

Rayleigh-Benard Convection in a Dusty Newtonian Nanofluid With and Without Coriolis Force

Rayleigh-Benard Convection in a Dusty Newtonian Nanofluid With and Without Coriolis Force

Nanofluid flow in a catheterized tapered artery

This study was conducted with the aim of investigating the Newtonian nanofluid flow in a catheterized tapered artery through using a completely consistent couple stress theory. In the process of carrying out this study, the slip condition at the arterial wall and the catheter, as well as, the permeability was taken into account. Further, the velocity, temperature, and concentration profiles were analytically modeled and the effect of the length scale on these profiles was well presented through the way it influences small-scale flows. The effect of the slip condition at the artery and catheter walls on the velocity was also investigated and revealed that any increase in the velocity leads to an increase in the slip velocity. Furthermore, the effect of other parameters such as the catheter diameter, shape, and height of the stenosis on these profiles was explored for all three artery geometries, i.e., diverging tapered artery, converging tapered artery, and non-tapered artery, respectively. The findings suggested that any increase in the catheter diameter and stenosis height can decrease the velocity and nanoparticle concentration profiles, while the temperature profile increases. It was also found that by increasing the stenosis shape parameter the velocity and concentration profiles increase and temperature decreases.

Entropy generation analysis of different nanofluid flows in the space between two concentric horizontal pipes in the presence of magnetic field: Single-phase and two-phase approaches

In this paper, entropy generation analysis of different nanofluid flows in the space between two concentric horizontal pipes in the presence of magnetic field by using of single-phase and two-phase approaches was carried out. Single-phase model and two-phase model (mixture) are utilized to model the flow and heat transfer for Newtonian nanofluids in the space between two concentric horizontal tubes subjected to the magnetic field. The Reynolds and Hartman numbers ranges are 500 ≤Re≤ 1500 and 0 ≤Ha≤ 20, respectively. In this study, heat transfer of various nanofluids (Al2O3, TiO2, ZnO and SiO2) and their entropy generation have been investigated. The effect of diameter of particles (water-Al2O3 nanofluid) on heat transfer and entropy generation has also been studied. Average Nusselt number in terms of Hartman number and Reynolds number for different nanofluids for single-phase and two-phase models in various volume fractions, entropy generation due to friction, magnet and heat transfer in terms of radial direction for different Hartman numbers, Reynolds number and different nanofluids with different diameter of particles were obtained. We found that in all states, the Nusselt number is higher in two-phase model than in single-phase model. The maximum pressure difference for single- and two-phase models occurs at maximum volume fractions and Hartman number. Also, as the diameter of the nanoparticle increases, the result will be an increase in the temperature of the walls, leading to an increase in entropy generation. Also, as the Hartman number increases, the amount of entropy generation increases.

MODELING AND SIMULATION OF THE NANOFLUID TRANSPORT VIA ELASTIC SHEETS

The field of nanofluidics research has spanned over the past decade with a variety of promising applications. We investigate the “laminar boundary layer flow” of a Newtonian nanofluid past a moving extendable/contractable horizontal plate with surface velocity and thermal slip effects. The passively controlled nanofluid model (PCM) is considered. Such models are physically more realistic as compared to the “actively controlled models” (ACM). Using Lie symmetry group method, the governing equations are reduced by a set of highly coupled nonlinear ODE’s with thermo-solutal coupled boundary conditions. The reduced equations are solved numerically by a generalized collocation method. The influences of the emerging parameters on the local skin friction factor and the local Nusselt number are depicted numerically. The skin friction is decreased as the thermophoresis and buoyancy ratio parameters are decreased. The heat transfer rates reduce with thermophoresis and buoyancy ratio parameters. Velocity slip also leads to a rise in wall temperature gradient. This study is relevant to near-wall flows in nanofluid fuel cells, nano-materials processing, etc.