Micropolar Nanofluid Research Articles

Triple convective flow of micropolar nanofluids in double lid-driven enclosures partially filled with LTNE porous layer under effects of an inclined magnetic field

In this paper, free, forced and Marangoni convective flows within an open enclosure partially filled with a porous medium under impacts of an inclined magnetic field are investigated. The forced convection is due to the movement of the side walls, the free convection induces from the heated part in the bottom wall and the Marangoni convection is a responsible on the thermal interaction at the free surface (top wall). The flow domain is partially heated from below and partially filled by a porous medium. The local thermal non-equilibrium model (LTNEM) is used to represent the thermal field in the porous layer (bottom layer) while the two-phase model is used to simulated the micropolar nanofluid behavior. Two cases based on the direction of the movement of the side walls are considered, namely, assisting flow (downward lid motion) and opposing flow (upward lid motion). Numerical analysis based on the finite volume method is conducted and the obtained are presented in terms of the streamlines, isotherms, angular velocity, and the cup-mixing temperature θcup, the bulk-averaged temperature θave and the average Nusselt numbers. The controlling parameters, in this situation, are the Darcy number Da, the Marangoni number Ma, the Nield number H, the vortex viscosity Δ, the Biot number Bi and the Hartmann number Ha. The results revealed that the increase in the Nield number enhances the cup-mixing temperature θcupand bulk-averaged temperature θave regardless the direction of the side walls motion. Also, the average Nusselt number is boosted as the Marangoni number is grown.

MHD micropolar nanofluid flow through an inclined channel with entropy generation subjected to radiative heat flux, viscous dissipation and multiple slip effects

PurposeMiniaturization with high thermal performance and lower cost is one of the advanced developments in industrial science chemical and engineering fields including microheat exchangers, micro mixers, micropumps, cooling microelectro mechanical devices, etc. In addition to this, the minimization of the entropy is the utilization of the energy of thermal devices. Based on this, in the present investigation, micropolar nanofluid flow through an inclined channel under the impacts of viscous dissipation and mixed convection with velocity slip and temperature jump has been numerically studied. Also the influence of magnetism and radiative heat flux is used.Design/methodology/approachThe nonlinear system of ordinary differential equations are obtained by applying suitable dimensionless variables to the governing equations, and then the Runge–Kutta–Felhberg integration scheme is used to find the solution of velocity and temperature. Entropy generation and Bejan number are calculated via using these solutions.FindingsIt is established to notice that the entropy generation can be improved with the aspects of viscous dissipation, magnetism and radiative heat flux. The roles of angle of inclination , Eckert number , Reynolds number , thermal radiation , material parameter slip parameter , microinertial parameter , magnetic parameter , Grashof number and pressure gradient parameter are demonstrated. It is found that the angle of inclination and Grashof number enhances the entropy production while it is diminished with material parameter and magnetic parameter.Originality/valueElectrically conducting micropolar nanofluid flow through an inclined channel subjected to the friction irreversibility with temperature jump and velocity slip under the influence of radiative heat flux has been numerically investigated.

Finite element analysis of micropolar nanofluid flow through an inclined microchannel with thermal radiation

PurposeIn recent years, microfluidics has turned into a very important region of research because of its wide range of applications such as microheat exchanger, micromixers fuel cells, cooling systems for microelectronic devices, micropumps and microturbines. Therefore, in this paper, micropolar nanofluid flow through an inclined microchannel is numerically investigated in the presence of convective boundary conditions. Heat transport of fluid includes radiative heat, viscous and Joule heating phenomena.Design/methodology/approachGoverning equations are nondimensionalized by using suitable dimensionless variables. The relevant dimensionless ordinary differential systems are solved by using variational finite element method. Detailed computations are done for velocity, microrotation and temperature functions. The influence of various parameters on entropy generation and the Bejan number is displayed and discussed.FindingsIt is established that the entropy generation rate increased with both Grashof number and Eckert number, while it decreased with nanoparticle volume fraction and material parameter. Temperature is decreased by increasing the volume fraction of Ag nanoparticle dispersed in water.Originality/valueAccording to the literature survey and the best of the author’s knowledge, no similar studies have been executed on micropolar nanofluid flow through an inclined microchannel with effect of viscous dissipation, Joule heating and thermal radiation.

3D flow and heat transfer of micropolar fluid suspended with mixture of nanoparticles (Ag-CuO/H2O) driven by an exponentially stretching surface

PurposeThe purpose of this paper is to discuss the 3D micropolar hybrid (Ag-CuO/H2O) nanofluid past rapid moving surface, where porous medium has been considered.Design/methodology/approachThe model of problem was represented by highly partial differential equations which were deduced by using suitable approximations (boundary layer). Then, the governing model was converted into five combined ordinary differential equations applying proper similarity transformations. Therefore, the eminent iterative Runge–Kutta–Fehlberg method (RKF45) has been applied to solve the resulting equations.FindingsHigher values of vortex viscosity, spin gradient viscosity and micro-inertia density parameters are reduced in horizontal direction, whereas opposite behaviour is noticed for vertical direction.Originality/valueThe work has not been done in the area of hybrid micropolar nanofluid. Hence, this article culminates to probe how to improve the thermal conduction and fluid flow in 3D boundary layer flow of micropolar mixture of nanoparticles driven by rapidly moving plate with convective boundary condition.

Numerical simulation of double diffusive convection and electroosmosis during peristaltic transport of a micropolar nanofluid on an asymmetric microchannel

A numerical computation is performed to analyze the double diffusive convection in micropolar nanofluids flow governed by peristaltic pumping in an asymmetric microchannel, in the presence of thermal radiation and an external magnetic field. The highly nonlinear governing equations are diluted by using desirable physical assumptions such as lubrication approximation and low zeta potential. Convective boundary conditions are employed. This enables us to determine numerical estimates of various physical flow variables such as velocity, pressure gradient, spin velocity, temperature of the nanofluid, concentration of solute, and volume fraction of nanoparticles for sundry parameters like micropolar parameter, coupling parameter, solutal Grashof number, thermophoretic diffusion coefficient, Grashof number, thermal radiation parameter and Helmholtz–Smoluchowski velocity with the aid of bvp4c function built-in command of MATLAB 2012b. Influence of each relevant parameter on flow, thermal and species characteristics are computed in this study. Influence of Soret and Dufour parameters are also simulated. This model is applicable to the study of chemical fraternization/separation procedures and various thermal management systems like of heat sinks, thermoelectric coolers, forced air systems and fans, heat pipes, and many more.

Heat Transfer Enhancement of Magneto-Micropolar Nanofluid Over a Wedge

Current investigation characterizes the flow and heat transmission of magneto-micropolar nanofluid through a non-isothermal wedge. The base-fluid as water and micropolar nanofluid as Copper or Alumina-nanoparticles are considered. Applying the similarity transformations along with non-dimensional quantities the formulated equations of the investigation are transmuted into a system of non-linear ODEs with a collection of convenient boundary conditions. The fourth-order finite difference method (FFDM) is then applied to determine the solution of a collection of resultant equations. The outcomes obtained by FFDM have also compared with cited works. Illustrations describing influences of prominent parameters which provide physical interpretations of temperature, micro rotation and velocity fields are examined in detail with the help of graphical representations. Both the skin friction coefficient and Nusselt number are computed and exhibited through tabular forms. This investigation determined that the skin-friction coefficient and heat transport rate improved along with augmentation in the magnetic force. micropolar parameter and the nanoparticle volume fraction augmented the Both skin friction coefficient and Nusselt number.

Three-Dimensional Numerical Analysis on Performance Enhancement of Micropolar Hybrid Nanofluid in Comparison with Simple Nanofluid

The objectives of the present research work are the three-dimensional computational analysis and predictions on double-diffusive natural convection in a cubic cavity filled with Cu–Al2O3/water micropolar hybrid nanofluid. The governing equations are carefully modified employing vorticity–vector potential formulation and are solved by the finite volume method. Performance enhancement of Cu–Al2O3/water micropolar hybrid nanofluid is judiciously compared with the Cu/water simple nanofluid. Besides, the influences of concentration of nanoparticles, Rayleigh number, buoyancy ratio, and micropolar vortex parameter on the flow field and heat transfer are critically analyzed. The results show that heat and mass transfer rates are lower for a micropolar nanofluid model when compared to the pure nanofluid model. The hybrid micropolar nanofluid displays more heat and mass transfer rates for thermal buoyancy-dominated zones when compared with traditional nanofluid. Conversely, the heat and mass transfer rates are decreased when using micropolar hybrid nanofluid for the solutal-dominated regime. The enhancement of micropolar viscosity parameter results in a decrease of average Nusselt and Sherwood numbers which are more perceptible in the thermal buoyancy-dominated flow.

Heat convection in micropolar nanofluid through porous medium-filled rectangular open enclosure: effect of an embedded heated object with different geometries

A numerical investigation has been performed to analyze heat convection through a micropolar nanofluid in an open rectangular enclosure filled with a porous medium. The enclosure is embedded with a heated object and having a heated non-planar bottom wall. Three different shapes of the embedded heated object, diamond-shaped, L-shaped, and triangular-shaped, are considered, and their effects are compared numerically. Successive over-relaxation method coupled with Gauss–Seidel iteration technique are employed in order to numerically tackle the nonlinear model momentum and energy equations. The outcomes are discussed in terms of streamlines, isotherms, and isolines of microrotation, averaged Nusselt number on the heated wall for different values of intricated parameters. The calibrated parameters Darcy number, vortex viscosity, Rayleigh number, and volume fraction of nanoparticles, respectively, are taken in the range 0.0001 ≤ Da ≤ 0.1, 0.5 ≤ K ≤ 5.0, 104 ≤ Ra ≤ 106, and 0 ≤ φ ≤ 0.04. It reveals that in the absence of heated object, the non-planarity of the wall lessens the heat transfer rate by 12.95% (when compared to the planar wall). The impact of the shape of the embedded heated object on the heat transfer rate is estimated and found an enhancement of 15.34%, 11.63%, 13.51% for diamond-shaped, L-shaped, and triangular-shaped objects, respectively. Increasing the Darcy number boosts the heat transfer rate while an upsurge in the vortex viscosity parameter lessens the heat transfer rate. The Nusselt number in the enclosure with and without a heated object (depending on the volume fraction of nanoparticles) is also computed numerically.

MHD nonlinear natural convection flow of a micropolar nanofluid past a nonisothermal rotating disk

AbstractThe aim of this analysis is to examine the steady, laminar boundary layer flow of a micropolar nanofluid owing to a rotating disk in the presence of a magnetic field and thermal and solutal nonlinear convection and nonisothermal parameters. The governing joined partial differential equations are converted into nonlinear ordinary differential equations by means of available transformations. The equations are calculated using the method bvp4c from Matlab software. The convergence test has been maintained; for the number of spots greater than the appropriate mesh number of points, the precision is not influenced, but the set time is boosted. Moreover, various quantities of the main parameters on skin friction coefficients, wall couple stress coefficients, Nusselt number, Sherwood number, velocities, temperature, and concentration of nanofluid are analyzed by means of tables and graphs. The results indicate that the presence of the nonisothermal parameter boosts the radial skin friction, temperature, and Sherwood number but causes decaying concentration distributions, the azimuthal skin friction coefficient, and Nusselt number that indicate the diffusion of momentum occurs more around the surface of the rotating disk.

Thermal analysis of Casson micropolar nanofluid flow over a permeable curved stretching surface under the stagnation region

We consider a curved surface upon which the Casson micropolar nanofluid flow is discharged to understand the behavior of such flow and heat progression. The non-Newtonian fluid flow is controlled with the introduction of a magnetic force which is directed against the flow to alter the moment of flow. An increase in the numerical value of modified Hartmann number slows down the flow by adding discharge against the flow. Lorentz force produced by increasing the curve of the channel suppresses the flow velocity. The micropolar parameter reduces the drag and helps in increasing the fluid flow. Mathematical modeling of the problem is done by taking into account the conventional assumptions taken in fluid flow theories. The modeled equations are simplified by considering similar transformation variables used in the contemporary literature. Numerical result is obtained by using bvp4c solver used in MATLAB by allowing the acceptable tolerance level at 1e−4. Various tests are carried out to choose the best match of the parametric values which help in achieving the defined boundary conditions. The output of the various solutions is plotted under varying values of different parameters, and henceforth the changes occurred are noted and discussed. The behavior of velocity, microrotational, temperature and concentration profiles is observed by comparing the graphical and tabular values. The role of different physical quantities under different parametric assumptions for stretching/shrinking channel is also taken into account and highlighted.

Theoretical aspects of micropolar nanofluid flow past a deformable rotating cone

The intension of this investigation is to analyze the laminar boundary layer flow of micropolar nanofluid inside a deformable rotating cone. A comparison is carried out between three types of nanofluids with nanoparticles, that is, metal (Cu), metallic oxide (Al2O3), and a semiconductor (TiO2) with water as base fluid. Brinkman and Maxwell's model of effective dynamic viscosity and thermal conductivity is considered. Using suitable similarity transformations, the governing coupled non‐linear boundary layer partial differential equations are reduced to non‐linear ordinary differential equations, which are further solved numerically by bvp4c technique. The results obtained reveal interesting effects of important pertinent parameters, that is, rotation parameter ω, nanoparticle concentration parameter φ, and micropolar parameter Δ on velocity, microrotation, and temperature profiles, which are analyzed graphically. A comparative analysis of the results of numerically calculated skin friction coefficients and Nusselt number for these parameters are also presented. The problem throughout the whole study is analyzed for both the strong and weak concentration of micro‐elements. It is found that the ω and Δ enhance the flow and ω, φ, and Δ boosts the rate of heat transfer in all cases of stretching/shrinking rotating cone except for the case of shrinking rotating cone in which the growth of Δ declines the rate of heat transfer for strong/weak concentration of microelements. Moreover, Cu–water has the highest skin friction and Nusselt number.

Numerical Simulation of MHD Stagnation Point Flow of Micropolar Heat Generating and Dissipative Nanofluid : SLM Approach

In the present paper, we study the magnetohydrodynamic stagnation point flow dealing with heat and mass transfer of a micropolar nanofluid influenced with heat generation and viscous dissipation. Nonlinear ordinary differential equations are obtained by applying suitable similarity transformation on the governing partial differential equations. These differential equations have been solved by successive linearization method (SLM). The effects of various dimensionless parameters, such as heat generation parameter, thermophoretic parameter and stagnation parameter on the flow field, are discussed through tables and graphs by accumulating sufficient data using SLM. Results show many important facts, including temperature distribution gradual increment with the increase of heat generation and microrotation parameters. Quadratic multiple regression analysis has been performed for skin friction coefficient, local Sherwood number and local Nusselt number. When free stream velocity and stretching velocity are equal, variation in microrotation and magnetic field leads to very low perturbation in skin friction, local Sherwood number and local Nusselt number, whereas when free stream velocity is dominant over stretching velocity, there occurs reverse heat flow at the surface of the sheet.

Exact solutions of micropolar SWCNTs nanofluid with heat transfer

AbstractThe present study is aimed to analyze the unsteady micropolar nanofluid flow passing over an oscillating infinite vertical plate. The flow is affected by thermal radiation and Newtonian heating. Single‐walled carbon nanotubes (SWCNTs) are added to enrich the thermal properties of the micropolar fluid. Kerosene is taken as the base liquid to enhance heat transfer. By using dimensional analysis, the governing equations for temperature, velocity, and microrotation are reduced to dimensionless form and after that, these equations have been solved by applying Laplace transform method to get the exact solutions. Finally, we have presented the effects of material and flow parameters and illustrated graphically by the Mathcad software. We found that microrotation, temperature, and velocity are decreasing functions of Prandtl number but have shown increasing behavior for Grashof number. Furthermore, we found that SWCNTs‐water‐based nanofluid has a comparatively higher heat transfer rate than SWCNTs‐kerosene and SWCNTs‐engine oil‐based nanofluids.

Inclined Lorentz force impact on convective-radiative heat exchange of micropolar nanofluid inside a porous enclosure with tilted elliptical heater

The combined impacts of inclined Lorentz force and thermal radiation on natural convection inside a porous chamber having micropolar nanoliquid and elliptical tilted heater are examined numerically. Micropolar fluid containing nanoparticles of copper oxide of low concentration circulates within the domain affected by the buoyancy and Lorentz forces. KKL approach is applied to define dependency of the nanofluid heat conductivity and viscosity on the nano-sized particles concentration and temperature, simultaneously. Governing equations with relevant boundary conditions written in non-dimensional stream function were solved by the Galerkin finite element method. An impact of important control parameters on micropolar nanofluid flow and heat exchange was analyzed. It was shown that change of the elliptical heater orientation reflects a significant modification of considered isolines and heat exchange rate. At the same time, average Nusselt number has maximum values for α = 0 and α = π and minimum value at α = π/2.

Thermal conductivity and Heat generation parameter analysis on microploar nanofluid flows

In this paper, it deals that the numerical study of variable thermal conductivity and radiation on the flow and heat transfer of an electrically conducting micropolar nanofluid over a continuously stretching surface with varying temperature in the presence of a magnetic field and heat source/sink.

Numerical Computing Paradigm for Investigation of Micropolar Nanofluid Flow Between Parallel Plates System with Impact of Electrical MHD and Hall Current

The current study develops a novel application of numerical computing paradigm to inspect the cumulative effects of both electric and magnetic field on a micropolar nanofluid bounded by two parallel plates in a rotating system by using Adams and Explicit Runge–Kutta (RK) solvers. The steady state micropolar nanofluidics flow has been considered between parallel plates under the Hall current effect. The conventional expressions for the governing flow in terms of system of ODEs are engaged. Adams and Explicit RK-based numerical solvers have been exploited for approximate solution of the system dynamics. Accuracy, convergence and stability analyses of both numerical schemes established their correctness. The impact of the Sherwood number on the concentration profile, Nusselt number and coefficient of skin friction on temperature and velocity profiles, respectively, have been analyzed numerically along with thermophoresis investigation, rotation, Hall current and Brownian motion of micropolar nanofluid. The effect of physical quantities including viscosity, magnetic, rotating, coupling, Brownian motion, thermophoretic and micropolar fluid parameters as well as Prandtl and Schmidt numbers has been presented.

Soret, Dufour, and activation energy effects on double diffusive convective couple stress micropolar nanofluid flow in a Hall MHD generator system

In this paper, the effect of activation energy, Soret, and Dufour on non-isothermal heat transfer via the non-linear wall of the steady convective flow of micropolar nanofluid magnetohydrodynamics is investigated. Variations in thermophoresis, Brownian motion, couple stress, and Hall current are also considered. Transformations are used to simplify and then solve the governing equations using the optimal homotopy analysis method and are numerically visualized for results. The behavior was examined and explained in all profile graphs. Tables are presented to illustrate the effect of dimensionless parameters on skin friction coefficients, Nusselt and Sherwood numbers. The concentration reduces via the chemical reaction rate, a temperature relative parameter, and increases with an increase in the activation energy and Soret number. It was found that the local skin-friction coefficient at the generator increases with an increase in the Hall current parameter, solutal Grashof number, and couple stress parameter on the x-axis, the local heat rate decreases through the Dufour number and Brownian motion parameter, and the mass transfer rate increases with an increase in the activation energy parameter and Schmitz and Reynolds numbers.

Onset of gyrotactic microorganisms in MHD Micropolar nanofluid flow with partial slip and double stratification

The study of nanofluid dynamics under the influence of bioconvection has valuable applications as the nanofluids possess tremendous heat transfer capabilities in comparison to the ordinary fluids. Having such amazing characteristics of nanofluids in mind, the objective of the present study is to analyze the influence of bioconvective Micropolar nanofluid flow comprising gyrotactic microorganisms with the thermal and solutal stratifications at the boundary surface. The novelty of the present study is enhanced by adding the contribution of nonlinear thermal radiation with partial slip boundary condition. The Homotopy Analysis Method (HAM) is employed to address the highly nonlinear system of differential equations. This system of differential equations is an outcome of suitable transformations applied to the mathematical model described by the system of partial differential equations. Illustrations depicting influences of prominent parameters are supported by requisite discussions keeping in view their physical significance. It is comprehended that the local density number is deteriorated for Peclet and bio-convection Lewis numbers. It is also observed that fluid velocity is declined for growing estimates of bioconvection Rayleigh number.

Energy and mass transport of micropolar nanofluid flow over an inclined surface with Keller‐Box simulation

AbstractIn this article, micropolar nanofluid boundary layer flow over a slanted stretching surface with Soret and Dufour effect is studied. The inclined stretching surface in this study is considered permeable and linear. In this problem, the Buongiorno model is considered for thermal efficiencies of fluid flow in the existence of Brownian movement and thermophoresis properties. The nonlinear problem for Micropolar Nanofluid flow over the slanted channel is developed to think about the heat and mass exchange phenomenon by incorporating portent flow factors to strengthened boundary layers. In this study, nonlinear partial differential equations are converted to nonlinear ordinary differential equations by utilizing appropriate similarity transformations then elucidated the numerical outcomes by the Keller‐Box technique. An examination of the set‐up results is performed with accessible outcomes and perceived in a good settlement without involved impacts. Numerical and graphical outcomes are additionally displayed in tables and charts.

Nonlinear Convection Flow of Micropolar Nanofluid due to a Rotating Disk with Multiple Slip Flow

In this analysis, steady, laminar, and two-dimensional boundary layer flow of nonlinear convection micropolar nanofluid due to a rotating disk is considered. The mathematical formulation for the flow problem has been made. By means of appropriate similarity transformation and dimensionless variables, the governing nonlinear boundary value problems were reduced into coupled high-order nonlinear ordinary differential equations with numerically solved. The equations were calculated using method bvp4c from matlab software for various quantities of main parameters. The influences of different parameters on skin friction coefficients f″0 and G′0, wall duo stress coefficients H1′0, -H2′0, and -H3′0, the Nusselt number -θ′0, and Sherwood number Ω′0, as well as the velocities, temperature, and concentration are analysed and discussed through tables and plotted graphs. The findings indicate that an increase in the values of thermal and solutal nonlinear convection parameters allow to increase the value of velocities f′η and Gη near surface of the disk and reduce at far away from the disk as well as thermal and solutal Grashof numbers tolerate to increase in the value of radial velocity f′η near surface of the disk.