MHD flow and heat transfer of a magnetite–water nanofluid in porous medium under the effects of chemical reaction

2017 ◽  
Vol 14 (3) ◽  
pp. 193-199 ◽  
Author(s):  
Meysam Amini ◽  
Esmaeil GhasemiKafrudi ◽  
Mohammad Reza Habibi ◽  
Azin Ahmadi ◽  
Akram HosseinNia
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Chemical Reaction ◽  
Fluid Velocity ◽  
Mhd Flow ◽  
Industrial Applications ◽  
Temperature Fields ◽  
Stagnation Flow ◽  
Content Type ◽  
Flow And Heat Transfer

Purpose Due to the extensive industrial applications of stagnation flow problems, the present work aims to investigate the magnetohydrodynamics (MHD) flow and heat transfer of a magnetite nanofluid (here Fe3O4–water nanofluid) impinging a flat porous plate under the effects of a non-uniform magnetic field and chemical reaction with variable reaction rate. Design/methodology/approach Similarity transformations are applied to reduce the governing partial differential equations with boundary conditions into a system of ordinary differential equations over a semi-infinite domain. The modified fourth-order Runge–Kutta method with the shooting technique which is developed for unbounded domains is conducted to give approximate solutions of the problem, which are then verified by results of other researchers, showing very good agreements. Findings The effects of the volume fraction of nanoparticles, permeability, magnetic field, chemical reaction and Schmidt number on velocity, temperature and concentration fields are examined and graphically illustrated. It was found that fluid velocity and temperature fields are affected strongly by the types of nanoparticles. Moreover, magnetic field and radiation have strong effects on velocity and temperature fields, fluid velocity increases and thickness of the velocity boundary layer decreases as magnetic parameter M increases. The results also showed that the thickness of the concentration boundary layer decreases with an increase in the Schmidt number, as well as an increase in the chemical reaction coefficient. Research limitations/implications The thermophysical properties of the magnetite nanofluid (Fe3O4–water nanofluid) in different conditions should be checked. Practical implications Stagnation flow of viscous fluid is important due to its vast industrial applications, such as the flows over the tips of rockets, aircrafts, submarines and oil ships. Moreover, nanofluid, a liquid containing a dispersion of sub-micronic solid particles (nanoparticles) with typical length of the order of 1-50 nm, showed abnormal convective heat transfer enhancement, which is remarkable. Originality/value The major novelty of the present work corresponds to utilization of a magnetite nanofluid (Fe3O4–water nanofluid) in a stagnation flow influenced by chemical reaction and magnetic field. It should be noted that in addition to a variable chemical reaction, the permeability is non-uniform, while the imposed magnetic field also varies along the sheet. These, all, make the present work rather original.

Numerical study of unsteady MHD Couette flow and heat transfer of nanofluids in a rotating system with convective cooling

2016 ◽  
Vol 26 (5) ◽  
pp. 1567-1579 ◽  
Author(s):  
Ahmada Omar Ali ◽  
Oluwole Daniel Makinde ◽  
Yaw Nkansah-Gyekye
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Couette Flow ◽  
Numerical Study ◽  
Integration Scheme ◽  
Parallel Plates ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Mhd Couette Flow ◽  
Rotating Channel

Purpose – The purpose of this paper is to investigate numerically the unsteady MHD Couette flow and heat transfer of viscous, incompressible and electrically conducting nanofluids between two parallel plates in a rotating channel. Design/methodology/approach – The nanofluid is set in motion by the combined action of moving upper plate, Coriolis force and the constant pressure gradient. The channel rotates in unison about an axis normal to the plates. The nonlinear governing equations for velocity and heat transfer are obtained and solved numerically using semi-discretization, shooting and collocation (bvp4c) techniques together with Runge-Kutta Fehlberg integration scheme. Findings – Results show that both magnetic field and rotation rate demonstrate significant effect on velocity and heat transfer profiles in the system with Cu-water nanofluid demonstrating the highest velocity and heat transfer efficiency. These numerical results are in excellent agreements with the results obtained by other methods. Practical implications – This paper provides a very useful source of information for researchers on the subject of hydromagnetic nanofluid flow in rotating systems. Originality/value – Couette flow of nanofluid in the presence of applied magnetic field in a rotating channel is investigated.

scholarly journals Effect of Velocity Slip Boundary Condition on the Flow and Heat Transfer of Cu-Water and TiO2-Water Nanofluids in the Presence of a Magnetic Field

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Abdelhalim Ebaid ◽  
Fahd Al Mutairi ◽  
S. M. Khaled
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Fluid Velocity ◽  
Velocity Slip ◽  
Slip Boundary Condition ◽  
Dual Solutions ◽  
Slip Condition ◽  
Shrinking Sheet ◽  
Physical Parameters ◽  
Flow And Heat Transfer

In nanofluid mechanics, it has been proven recently that the no slip condition at the boundary is no longer valid which is the reason that we consider the effect of such slip condition on the flow and heat transfer of two types of nanofluids. The present paper considers the effect of the velocity slip condition on the flow and heat transfer of the Cu-water and the TiO2-water nanofluids over stretching/shrinking sheets in the presence of a magnetic field. The exact expression for the fluid velocity is obtained in terms of the exponential function, while an effective analytical procedure is suggested and successfully applied to obtain the exact temperature in terms of the generalized incomplete gamma function. It is found in this paper that the Cu-water nanofluid is slower than the TiO2-water nanofluid for both cases of the stretching/shrinking sheets. However, the temperature of the Cu-water nanofluid is always higher than the temperature of the TiO2-water nanofluid. In the case of shrinking sheet the dual solutions have been obtained at particular values of the physical parameters. In addition, the effect of various physical parameters on such dual solutions is discussed through the graphs.

On the Effectiveness of Ion Slip on Steady MHD Flow and Heat Transfer Above a Rotating Disk With Ohmic Heating

2006 ◽  
Vol 128 (6) ◽  
pp. 1236-1239 ◽  
Author(s):  
Hazem Ali Attia
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Steady Flow ◽  
Finite Differences ◽  
Ohmic Heating ◽  
Mhd Flow ◽  
Rotating Disk ◽  
Flow And Heat Transfer ◽  
Ion Slip ◽  
Steady Magnetic Field

The steady flow and heat transfer of a conducting fluid due to the rotation of an infinite, nonconducting disk in the presence of an axial uniform steady magnetic field are studied considering the ion slip and the Ohmic heating. The relevant equations are solved numerically using finite differences and the solution shows that the inclusion of the ion slip gives some interesting results.

scholarly journals Two-layer nanofluid flow and heat transfer in a horizontal microchannel with electric double layer effects and magnetic field

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Qingkai Zhao ◽  
Hang Xu ◽  
Longbin Tao
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Double Layer ◽  
Electric Double Layer ◽  
Lower Layer ◽  
Fluid Velocity ◽  
Heat Transfer Process ◽  
The Body ◽  
Nanofluid Flow ◽  
Content Type

Purpose The purpose of this paper is to investigate the immiscible two-layer heat fluid flows in the presence of the electric double layer (EDL) and magnetic field. The effects of EDL, magnetic field and the viscous dissipative term on fluid velocity and temperature, as well as the important physical quantities, are examined and discussed. Design/methodology/approach The upper and lower regions in a horizontal microchannel with one layer being filled with a nanofluid and the other with a viscous Newtonian fluid. The nanofluid flow in the lower layer is described by the Buongiorno’s nanofluid model with passively controlled model at the boundaries. An appropriate set of non-dimensional quantities are used to simplify the nonlinear systems. The resulting coupled nonlinear equations are solved by using homotopy analysis method. Findings The present work demonstrates that increasing the EDL thickness and Hartmann number can restrain the fluid flow. The Brinkmann number has a significant role in the enhancement of heat transfer. It is also identified that the influence of EDL effects on microflow cannot be ignored. Originality/value The effects of viscous dissipation involved in the heat transfer process and the body force because of the EDL and the magnetic field are considered in the thermal energy and momentum equations for both regions. The detailed derivation procedure of the analytical solution for electrostatic potential is provided. The analytical solutions can lead to improved understanding of the complex microfluidic systems.

A comprehensive review on natural convection flow and heat transfer

2019 ◽  
Vol 29 (3) ◽  
pp. 834-877 ◽  
Author(s):  
Alireza Rahimi ◽  
Ali Dehghan Saee ◽  
Abbas Kasaeipoor ◽  
Emad Hasani Malekshah
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Industrial Applications ◽  
Convection Flow ◽  
Heat Sources ◽  
Comprehensive Review ◽  
Content Type ◽  
Thermal Boundary Conditions ◽  
Flow And Heat Transfer ◽  
Different Types

PurposeThe purpose of this paper is to carry out a comprehensive review of some latest studies devoted to natural convection phenomenon in the enclosures because of its significant industrial applications.Design/methodology/approachGeometries of the enclosures have considerable influences on the heat transfer which will be important in energy consumption. The most useful geometries in engineering fields are treated in this literature, and their effects on the fluid flow and heat transfer are presented.FindingsA great variety of geometries included with different physical and thermal boundary conditions, heat sources and fluid/nanofluid media are analyzed. Moreover, the results of different types of methods including experimental, analytical and numerical are obtained. Different natures of natural convection phenomenon including laminar, steady-state and transient, turbulent are covered. Overall, the present review enhances the insight of researchers into choosing the best geometry for thermal process.Originality/valueA comprehensive review on the most practical geometries in the industrial application is performed.

Hall effect on MHD flow and heat transfer of nanofluids over a stretching wedge in the presence of velocity slip and Joule heating

Open Physics ◽  
2013 ◽  
Vol 11 (12) ◽  
Author(s):  
Xiaohong Su ◽  
Liancun Zheng
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Hall Effect ◽  
Joule Heating ◽  
Volume Fraction ◽  
Wedge Angle ◽  
Mhd Flow ◽  
Velocity Slip ◽  
Temperature Fields ◽  
Flow And Heat Transfer

AbstractThis paper deals with the boundary layer flow and heat transfer of nanofluids over a stretching wedge with velocity-slip boundary conditions. In this analysis, Hall effect and Joule heating are taken into consideration. Four different types of water-base nanofluids containing copper (Cu), silver (Ag), alumina (Al2O3), and titania (TiO2) nanoparticles are analyzed. The partial differential equations governing the flow and temperature fields are converted into a system of nonlinear ordinary differential equations using a similarity transformation. The resulting similarity equations are then solved by using the shooting technique along with the fourth order Runge-Kutta method. The effects of types of nanoparticles, the volume fraction of nanoparticles, the magnetic parameter, the Hall parameter, the wedge angle parameter, and the velocityslip parameter on the velocity and temperature fields are discussed and presented graphically, respectively.

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