MHD boundary layer flow of Carreau fluid over a convectively heated bidirectional sheet with non-fourier heat flux and variable thermal conductivity

© 2019 by the authors. In the present exploration, instead of the more customary parabolic Fourier law, we have adopted the hyperbolic Cattaneo-Christov (C-C) heat flux model to jump over the major hurdle of parabolic energy equation . The more realistic three-dimensional Carreau fluid flow analysis is conducted in attendance of temperature-dependent thermal conductivity. The other salient impacts affecting the considered model are the homogeneous-heterogeneous (h-h) reactions and magnetohydrodynamic (MHD). The boundary conditions supporting the problem are convective heat and of h-h reactions. The considered boundary layer problem is addressed via similarity transformations to obtain the system of coupled differential equations. The numerical solutions are attained by undertaking the MATLAB built-in function bvp4c. To comprehend the consequences of assorted parameters on involved distributions, different graphs are plotted and are accompanied by requisite discussions in the light of their physical significance. To substantiate the presented results, a comparison to the already conducted problem is also given. It is envisaged that there is a close correlation between the two results. This shows that dependable results are being submitted. It is noticed that h-h reactions depict an opposite behavior versus concentration profile. Moreover, the temperature of the fluid augments for higher values of thermal conductivity parameters

3D Magneto Hydrodynamic Slip Flow of Al50Cu50-Water and Cu-Water Nanofluids over a Variable Thickness Stretched Surface

The current paper covers the examination of 3D magneto hydrodynamic nanofluid motion past a slendering (variable thickness) stretching surface under the influence of MHD, Soret and Dufour effects, thermophoresis, Brownian motion and slip impact. For this study, we considered the Cu-water and Al50Cu50-water nanofluids past a non-uniform thickness stretching surface. With the help of similarity transformations, we transformed the derived governed equations as ordinary differential equations. The mathematical outcomes determined by employing Runge-Kutta and Newton’s methods. We reveal and interpretation the graphs for different parameters like magnetic number, volumetric fraction, Soret number, Dufour number, Brownian motion, thermophoresis parameter, stretching parameter, slip parameters h1 and h2. We discussed the skin friction coefficient, reduced Nusselt and reduced Sherwood numbers for the influence of the pertinent parameters with the assistance of tables separately for two nanofluids (Cu-water and Al50Cu50-water nanofluids). Results are validated by comparing with the published results and found a favorable agreement. Keywords: Slip flow, Slendering sheet, Cross diffusion, MHD

Irreversibility minimization analysis of ferromagnetic Oldroyd-B nanofluid flow under the influence of a magnetic dipole

© 2021, The Author(s). Studies highlighting nanoparticles suspensions and flow attributes in the context of their application are the subject of current research. In particular, the utilization of these materials in biomedical rheological models has gained great attention. Magneto nanoparticles have a decisive role in the ferrofluid flows to regulate their viscoelastic physiognomies. Having such substantial interest in the flow of ferrofluids our objective is to elaborate the melting heat transfer impact in a stretched Oldroyd-B flow owing to a magnetic dipole in the presence of entropy generation optimization. Buongiorno nanofluid model expounding thermophoretic and Brownian features are considered. Moreover, activation energy with chemical reaction is also considered. The Cattaneo–Christov heat flux model is affianced instead of conventional Fourier law. The renowned bvp4c function of MATLAB is utilized to handle the nonlinearity of the system. Impacts of miscellaneous parameters are portrayed through graphical fallouts and numeric statistics. Results divulge that the velocity and temperature profiles show the opposite trend for growing estimates of the ferromagnetic parameter. It is also noticed that the temperature ratio parameter diminishes the entropy profile. Moreover, it is seen that the concentration profile displays a dwindling trend for the Brownian motion parameter and the opposite trend is witnessed for the thermophoretic parameter

Impact of nonlinear thermal radiation on stagnation-point flow of a Carreau nanofluid past a nonlinear stretching sheet with binary chemical reaction and activation energy

This research peruses the characteristics of nanoparticles on stagnation point flow of a generalized Newtonian Carreau fluid past a nonlinear stretching sheet with nonlinear thermal radiation. The process of mass transfer is modeled using activation energy and binary chemical reaction along with the Brownian motion and thermophoresis. For energy activation a modified Arrhenius function is invoked. With regard to the solution of the governing differential equations, suitable transformation variables are used to obtain the system of nonlinear ordinary differential equations before being numerically solved using the shooting method. Graphical results are shown in order to scrutinize the behavior of pertinent parameters on velocity, temperature profiles, and concentration of nanoparticle. Also, the behavior of fluid flow is investigated through the coefficient of the skin friction, Nusselt number, Sherwood number, and streamlines. Results showed that the velocity ratio parameter serves to increase the velocity of fluid and reduces the temperature distribution and nanoparticle concentration. The results were compared with the available studies and were found to be in excellent agreement

Heat and Mass Transfer in Radiative Casson Fluid Flow Caused by a Vertical Plate with Variable Magnetic Field Effect

The aim of the present study is to investigate influence of variable magnetic field, heat and mass transfer in radiative Casson fluid flow past an infinite vertical porous plate. The governing equations of the flow, heat and mass transfer are transformed into a system of nonlinear ordinary differential equations and solved analytically by the perturbation technique with matlab package. The results obtained show that the velocity, temperature and concentration fields are appreciably influenced by the chemical reaction, thermal stratification and magnetic field. It is observed that the thermal radiation and magnetic field decreases the velocity, temperature and concentration profiles. There is also considerable effects of magnetic field and chemical reaction on skin friction coefficient and Nusselt number. Keywords: MHD, Variable magnetic field, Radiative, Casson fluid, dissipative, Heat transfer, Mass transfer

Thermal Conductivity in the Boundary Layer of Non-Newtonian Fluid with Particle Suspension

The present chapter is focused on studies concerned with three-dimensional flow and heat transfer analysis of Carreau fluid with nanoparticle suspension. The heat transfer analysis in the boundary was carried out with the fluid flow over a stretching surface under the influence of nonlinear thermal radiation, mixed convection and convective boundary condition. Suitable similarity transformations are employed to reduce the governing partial differential equations into coupled nonlinear ordinary differential equations. The equations in non-linear form are then solved numerically using Runge-Kutta-Fehlberg fourth fifth-order method with the help of symbolic algebraic software MAPLE. The results so extracted are well tabulated and adequate discussions on the parameters affecting flow and heat transfer analysis were carried out with the help of plotted graphs

Unsteady 3D MHD Carreau and Casson Fluids over a Stretching Sheet with Non-Uniform Heat Source/Sink

In this study, we analyzed the effects of nonlinear thermal radiation and non-uniform heat source/sink on an unsteady three-dimensional flow of Carreau and Casson fluid past a stretching surface. The transformed governing equations are solved numerically using Runge-Kutta based shooting technique. We obtained better accuracy of the present results by comparing with the already published literature. The influence of dimensionless parameters on velocity and temperature profiles along with the friction factors, local Nusselt and Sherwood numbers are discussed with the help of graphs and tables. We presented dual nature solutions for the flow over a Carreau and Casson fluid cases. It is also found that the non-uniform heat source or sink is control the thermal boundary layer for both the Casson and Carreau fluid cases. Keywords: MHD, unsteady, nonlinear thermal radiation, Carreau fluid, Casson fluid, 3D

Heat transfer in MHD flow of Carreau ternary-hybrid nanofluid over a curved surface stretched exponentially

This investigation aims to study Magnetohydrodynamics (MHD)two-dimensional incompressible boundary layer performing non-Newtonian Carreau ternary-hybrid nanofluid flow with heat transfer through an exponential stretching curved surface. The ternary-hybrid nanofluid has been synthesized with titanium oxide, aluminum oxide, and silver dispersionin the base fluid water. TheNavier Stokes equation and Carreau ternary-hybrid nanofluid model govern the partial differential equations (PDEs), and appropriate similarity transformations are utilized to transfer these PDEs into ordinary differential equations (ODEs). The effects of the pertinent parameters on the dimensionless velocity and temperature profiles are analyzed withfigures. This study provides new insights and solutions to previously unsolved problems related to heat transfer in the MHD flow of a Carreau Ternary-Hybrid Nanofluid over a curved surface stretched exponentially, or it could contribute to the existing knowledge and literature by refining existing models or methods. The surface drag force and Nusselt numbers are studied for the different values of the governing parameters throughgraphs. It is demonstrated that the heat transfer rate and skin friction increase from base fluid to mono, hybrid, and ternary nanofluids. Both heat transfer rate and skin friction increase with the addition of nanoparticles

Steady forced convection flow and heat transfer in a nanofluid with passive control model

The study of convective heat transfer and fluid flow has important engineering and industrial applications, for instance in the cooling of engine vehicles. Fluid such as water is commonly used as a heat transfer fluid because of its high heat capacity. Nevertheless, the limitation of water and the low thermal conductivity of other conventional heat transfer fluids could affect the efficiency of heat exchange. Therefore, a type of fluid with suspension of solid particles into base fluid, namely nanofluid was considered due to the property of nanofluid that enhances heat transfer. Mathematical models of nanofluid normally include a boundary condition that assumed nanoparticle volume fraction at the surface is constant. This boundary condition however might not be able to describe adequately the condition of nanofluid volume fraction at the boundary. Hence, a different boundary condition that considers nanoparticle mass flux at the boundary to be zero and adjusted accordingly is applied in this thesis. Recently, the use of micropolar fluid as a base fluid to nanofluid was applied in many studies. The local influence of intrinsic motion and microstructure of the fluid elements that are essential to this model of fluid can be advantageous as it can appropriately describe the types of fluid such as polymeric suspension and animal blood. Motivated by these reasons, numerical analysis of nanofluid and micropolar nanofluid flow with zero nanoparticle mass flux along with three different effects and geometries for each problem were deliberated in this thesis. The effects are viscous dissipation, Soret and Dufour, and chemical reaction, and the geometry that was investigated are moving plate, stretching plate, and wedge. In order to reduce the governing equations, series of transformation variables are used to transform the dimensional governing equations into dimensionless differential equations. The non-dimensional equations in ordinary differential equations were then solved numerically using Runge-Kutta Fehlberg. The results obtained were then compared with the limiting cases from previous study. This is done to determine the accuracy of the results published. Several parameters were examined in this thesis, namely Eckert number, Soret number, Dufour number, magnetic field, Brownian motion, thermophoresis, Lewis number, and Prandtl number. The results of reduced Nusselt number, skin friction coefficient, velocity profile, angular velocity profile, temperature profile, and concentration profile for each parameter were presented in tables and graph. It was found that the temperature and concentration profile shown a consistent result when there is an effect of viscous dissipation and chemical reaction. Temperature profile increases when thermophoresis parameter increases. In thermophoresis, the particle from the heated region is transferred to the cold region. Thus, this causes the nanofluid temperature to be increasing due to huge number of nanoparticles shifted from the hot region, which enhance the fluid temperature. Concentration profile was found to increase then decrease for both of the problems when the thermophoresis parameter and Brownian motion parameter increase. However, in the presence of Soret and Dufour, the temperature profile was found to increase when Brownian motion parameter increases, and concentration decreases then increases when the thermophoresis parameter increases. In comparison to the previous study, the difference is the temperature profile increases following an increase of Brownian motion parameter and concentration profile increase when thermophoresis increases

Convective-radiative magnetized dissipative nanofluid (CNTs-water) transport in porous media, using Darcy–Brinkman–Forchheimer model

The main objective of this investigation is to deliberate the novel analysis of buoyancy-driven nanofluid flow across a vertical stretching surface embedded in a porous medium with the consideration of an inclined magnetic field and heating effects caused by viscosity, thermal radiations, and heat source factor. A material made of glass ball is applied as the porous medium. Water is regarded as a base fluid, while carbon nanotubes are termed as the nanoparticles. The governing equations are formulated by employing fundamental laws. With the application of appropriate non-similar transformations, the emerging flow system is translated into dimensionless differential form. The obtained coupled, non-similar system of nonlinear partial differential equations (PDEs) is tackled by employing local non-similarity technique up to second level of iterations in conjunction with the Lobatto III technique in MATLAB. According to the findings, increasing the Hartmann number diminishes fluid velocity while augmentation in radiation parameter and nanoparticle volume fraction raises the temperature profile. Moreover, nanofluids contain MWCNTs as such nanoparticles exhibit larger estimations of Nusselt number than SWCNTs-water nanofluid. Authors introduced appropriate transformations for considered problem and argued the local non-similarity approach for simulating the dimensionless structure. To the best of authors' observations, no such study is yet published in literature