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This paper deals with the analysis of the flow and heat transfer performance of ternary nanofluid flowing past a stretching sheet under the influence of quadratic convection. The ternary nanofluid is formed by suspending three different nanoparticles, namely, titanium dioxide (TiO2), silver (Ag) and graphene (Gr) in the base fluid water (H2O). Thus, the ternary nanofluid obtained is Gr–Ag–TiO2/H2O where the hybrid nanofluid Ag–TiO2/H2O forms the base fluid for the resulting ternary nanofluid. The addition of TiO2 nanoparticles enhances the photocatalytic nature of the base fluid and makes it useful in various applications concerning the medicinal field. The presence of Gr helps in intensifying the thermal conductivity of water while the suspension of silver nanoparticles ensures chemical stability. Meanwhile, the thermophysical properties of the ternary nanofluid are mathematically defined and the system of equations that describe the flow of a ternary nanofluid past a stretching sheet is framed using differential equations. The outcomes of this study are interpreted through graphs for velocity and temperature profiles of the ternary nanofluid. It was mainly observed that the thermal conductance of ternary nanofluid was higher than the monophase and hybrid nanofluid. Also, the presence of quadratic convection had a prominent impact on the ternary nanofluid flow. The Nusselt number was found to be greater for spherical nanoparticles and it was found to be least for blade-shaped nanoparticles. [ABSTRACT FROM AUTHOR]

Stagnation point flow defines the fluid motion near the stagnation point of a solid surface and has utilization in the process of polymer extrusion, electronic gadgets cooling, nuclear reactor, etc. Furthermore, the main theme of this work is to analyze the heat transfer characteristics of stagnation point flow of Casson nanofluid over stretching sheet using induced magnetic field and Cattaneo-Christov model. The Casson fluid is a non-Newtonian fluid model; and in the current work the working fluid consists of nanoparticles of Au (Gold) and blood (Casson fluid). In the existing model, temperature of the surface depends on the distance from the stagnation point. Therefore, Darcy-Forchheimer porous model is incorporated. The solution of coupled nonlinear PDEs is obtained by bvp4c. The heat transfer and flow characteristics of Au-blood based Casson nanofluid are discussed graphically. The dual behavior is observed in the profiles of induced magnetic field with increase in the value of reciprocal magnetic Prandtl number, however the velocity outlines of Au-blood nanofluid declined. A comparison is presented with previous article and is found to be in good agreement. [ABSTRACT FROM AUTHOR]

The importance of non-Newtonian fluid (Casson fluid) in industry is increasingly appreciated. However, little is known about the flow rheology of Casson fluid flowing over a Riga plate. Thus, the purpose of this investigation is to examine the nature of entropy generation (EG) and heat transfer (HT) on Casson hybrid nanofluid flow past a Riga plate by considering the influences of magnetic field and thermal radiation. The Hamilton–Crosser (Model 1) and Xue model (Model 2) of thermal conductivity are incorporated for Casson hybrid nanofluid. The governing equations are solved by numerical methods i.e., bvp4c and shooting techniques. In the current framework, the comparative patterns for both models of temperature, velocities, EG and Bejan number are depicted due to the existing parameters. The domain of the pertinent parameters is taken as thermal radiation, 4 ≤ R a ≤ 7 ; stretching parameter, 0. 6 ≤ λ ≤ 1 ; Casson factor, 0. 5 ≤ δ ≤ 2 ; rotation parameter, 1 ≤ ℜ t ≤ 4 and Hartmann number, 2 ≤ H a ≤ 1 1. The outcomes show that the rise in volume fraction and thermal conductivity profile of Xue model (Model 2) is better than Hamilton–Crosser model (Model 1). Moreover, EG profiles are escalated with augmentation in values of Hartmann number and stretching parameter for both models. The results of the study are useful for predicting the rheology of right fluid, while it also assists in safeguarding the boundary layer (BL) separation, along with establishing a parallel force to the surface in assisting the domain of science and technology. Mathematical model addressing the three-dimensional flow of Casson hybrid nanofluid over a Riga plate subject to viscous dissipation and linear thermal radiation was investigated. The solution to the governing equations are obtained through two numerical schemes, (i) shooting method and (ii) bvp4c. Effect of the active parameters on entropy generation is discussed through graphs and it was observed that for increasing value of both Hartmann number and stretching parameter the profiles of entropy generation increases. [ABSTRACT FROM AUTHOR]

This investigation includes a three-dimensional Darcy–Forchheimer flow model and the heat transfer phenomenon of H2O-CNTs nanofluid for a two-way stretchable surface. Xue's proposed thermal conductivity model is employed. The numerical analysis scheme is applied to solve the transformed PDEs. The outline of velocities, temperature, surface drag forces and Nusselt number against relevant variables are portrayed. From this study, it has been noted that with an increase in Eckert numbers along both directions, two patterns were obtained for temperature curves, the initial temperature outlines increased and after that they decreased. Moreover, the width of the thermal boundary layer for H2O-MWCNT nanofluid was more compared to H2O-SWCNT nanofluid. To validate the existing code, numerical outcomes were compared to the earlier published data. [ABSTRACT FROM AUTHOR]

Extensive analysis has recently been presented on the applications of nanofluids in heat transfer developments. The primary concern of this work is to excogitate the flow features of blood flow with the inclusion of gold plated nanoparticles. In this regard, the Casson fluid model was adopted to simulate the transportation of blood flow. The momentum features of flowing fluid are divulged by incorporating magnetization and porosity aspects whereas thermal attributes of concerned flow are anticipated under nonlinearized radiating thermal flux. Formulated governing expressions are transmuted into the system of the nonlinearized ordinary differential structure by implementing appropriate conversion. The solution is headed by implementing an efficient build in routine renowned as bvp4c based on the finite differencing. The impacts of the involved parameters on the resulting dimensionless profiles are discussed thoroughly. The results indicating that the velocity in radial direction declines with augmenting the nanoparticle volume fraction, while the velocity in the azimuthal direction and the temperature upsurge. Besides, the velocities in the radial and azimuthal directions augment due to rotation parameter and the temperature shrinks. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Recent developments in fluid dynamics have been focusing on nanofluids, which preserve significant thermal conductivity properties and magnify heat transport in fluids. Classical nanofluid studies are generally confined to models described by partial differential equations of an integer order, where the memory effect and hereditary properties of materials are neglected. To overcome these downsides, the present work focuses on studying nanofluids with fractional derivatives formed by differential equations with Caputo time derivatives that provide memory effect on nanofluid characteristics. Further, heat transfer enhancement and boundary layer flow of fractional Maxwell nanofluid with single‐ wall and multiple walls carbon nanotubes are investigated. The Maxwell nanofluid saturates the porous medium. Also, buoyancy, magnetic, electric, and heating effects are considered. Governing continuity, momentum, and energy equations involving Caputo time‐fractional derivatives reduced non-dimensional forms using suitable dimensionless quantities. Numerical solutions for arising nonlinear problems are developed using finite difference approximation combined with L1 algorithm. The influence of involved physical parameters on flow and heat transfer characteristics is analyzed and depicted graphically. Our simulations found out that surface drag of Maxwell nanofluid with single‐ walled carbon nanotubes dominates nanofluids with multiple walls carbon nanotubes, but the reverse trend is noticed for larger Grashof number values. [ABSTRACT FROM AUTHOR]

The major focus of the current study was the modeling of 3D Darcy–Forchheimer flow of water–CNTs nanofluid. Impacts of non-uniform heat source/sink and Ohmic heating on 3D magneto hydrodynamic flow of water–CNTs (SWCNT and MWCNT) nanofluid were assessed. The numerical analysis method 'Runge–Kutta–Fehlberg' was applied for existing PDEs. It was noted that the thermal boundary layer was extended for increasing Eckert numbers along x and y direction, when the fluid showed movement away from the surface. Moreover, the gap in thermal boundary layer for H2O-SWCNT was more in comparison with H2O–MWCNT nanofluid. The numerical data of this study were validated with earlier reported outcomes and were observed to have good concord. [ABSTRACT FROM AUTHOR]

A numerical simulation for mixed convective three-dimensional slip flow of water-based nanofluids with temperature jump boundary condition is presented. The flow is caused by nonlinear stretching surface. Conservation of energy equation involves the radiation heat flux term. Applied transverse magnetic effect of variable kind is also incorporated. Suitable nonlinear similarity transformations are used to reduce the governing equations into a set of self-similar equations. The subsequent equations are solved numerically by using shooting method. The solutions for the velocity and temperature distributions are computed for several values of flow pertinent parameters. Further, the numerical values for skin-friction coefficients and Nusselt number in respect of different nanoparticles are tabulated. A comparison between our numerical and already existing results has also been made. It is found that the velocity and thermal slip boundary condition showed a significant effect on momentum and thermal boundary layer thickness at the wall. The presence of nanoparticles stabilizes the thermal boundary layer growth. [ABSTRACT FROM AUTHOR]

The present study examines the effect of slip and convective boundary condition on magnetohydrodynamic (MHD) stagnation point flow and heat transfer due to Casson nanofluid past a stretching sheet. Similarity transformation is used to convert the nonlinear governing equations and their associated boundary conditions into dimensionless form. The resulting system of ordinary differential equations is then solved numerically using the Runge-Kutta-Fehlberg method along with shooting technique. Numerical results are obtained for velocity, temperature, and concentration distribution as well as for the skin friction coefficient, the local Nusselt number, and Sherwood number. It is found that the local Nusselt number and Sherwood number decrease with an increase in Casson parameter γ. However, the skin friction coefficient -f"(0) increases with an increase in Casson parameter γ and decreases with an increase in velocity ratio parameter A. The results are displayed both in graphical and tabular form to illustrate the effect of the governing parameters on the dimensionless velocity, temperature, and concentration. Then, comparison has been made and found to be in good agreement with a previous published result on special cases of the problem. [ABSTRACT FROM AUTHOR]

This paper investigates numerically the effects of variable viscosity on unsteady generalized Couette flow of a water base nanofluid with convective cooling at the moving surface. The Buongiorno model utilized for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The nonlinear governing equations of continuity, momentum, energy and nanoparticles concentration are tackled numerically using a semi discretization finite difference method together with Runge-Kutta Fehlberg integration scheme. Numerical results for velocity, temperature, and nanoparticles concentration profiles together with skin friction and Nusselt number are obtained graphically and discussed quantitatively. [ABSTRACT FROM AUTHOR]

An investigation of the magnetohydrodynamics (MHD) boundary layer slip flow over a vertical stretching sheet in nanofluid with non-uniform heat generation/absorbtion in the presence of a uniform transverse magnetic field has been carried out. The governing non-linear partial differential equations are transformed into a system of coupled non-linear ordinary differential equations using similarity transformations and then solved numerically using the Runge-Kutta fourth order method with shooting technique. Numerical results are obtained for the fluid velocity, temperature as well as the shear stress and the rate of heat transfer at the surface of the sheet. The results show that there are significant effects of various pertinent parameters on velocity and temperature profiles. [ABSTRACT FROM AUTHOR]

Heat transfer characteristics of a Berman flow of water based nanofluids containing copper (Cu) and alumina (Al2O3) as nanoparticles in a porous channel with Navier slip, viscous dissipation, and convective cooling are investigated. It is assumed that the exchange of heat with the ambient surrounding takes place at the channel walls following Newton's law of cooling. The governing partial differential equations and boundary conditions are converted into a set of nonlinear ordinary differential equations using appropriate similarity transformations. These equations are solved analytically by regular perturbation methods with series improvement technique and numerically using an efficient Runge-Kutta Fehlberg integration technique coupled with shooting scheme. The effects of the governing parameters on the dimensionless velocity, temperature, skin friction, pressure drop, and Nusselt numbers are presented graphically and discussed quantitatively. [ABSTRACT FROM AUTHOR]

The photocatalytic nature of TiO2 finds applications in medicinal field to kill cancer cells, bacteria, and viruses under mild ultraviolet illumination and the antibacterial characteristic of Ag makes the composition Ag-TiO2 applicable for various purposes. It can also be used in other engineering appliances and industries such as humidity sensor, coolants, and in footwear industry. Hence, this study deals with the analysis of the effects of magnetic field, thermal radiation, and quartic autocatalysis of heterogeneous-homogeneous reaction in an electrically conducting Ag-TiO2-H2O hybrid nanofluid. Furthermore, the gyrotactic microorganisms are used as active mixers to prevent agglomeration and sedimentation of TiO2 that occurs due to its hydrophobic nature. The mathematical model takes the form of partial differential equations with viscosity and thermal conductivity being the functions of volume fraction. These equations are converted to ordinary differential equations by using similarity transformation and are solved by RKF-45 method with the aid of shooting method. It is observed that the increase in the size of the needle enhances the overall performance of the hybrid nanofluid. Furthermore, the temperature of the hybrid nanofluid increases with the increase in volume fraction. It is observed that the friction produced by the Lorentz force increases the temperature of the nanofluid. It is further observed that the heterogeneous reaction parameter has more significant effect on the concentration of bulk fluid than the homogeneous reaction parameter. [ABSTRACT FROM AUTHOR]