Mixed Magnetoconvection of Nanofluids in a Long Vertical Porous Channel

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Alessandra Borrelli ◽  
Giulia Giantesio ◽  
Maria Cristina Patria
Keyword(s):  
Magnetic Field ◽  
Uniform Magnetic Field ◽  
Volume Fraction ◽  
Reverse Flow ◽  
Boussinesq Approximation ◽  
Porous Channel ◽  
Nanoparticle Volume Fraction ◽  
Induced Magnetic Field ◽  
Two Phase ◽  
External Uniform Magnetic Field

Abstract This paper aimed to study the flow of a nanofluid in a long vertical porous channel when an external uniform magnetic field is impressed. The Buongiorno two-phase model of nanofluid is supposed to be slightly compressible in order to assume the Oberbeck–Boussinesq approximation. The velocity, the induced magnetic field, the temperature, and the nanoparticle volume fraction are analytically obtained. Detailed considerations are drawn for the occurrence of the reverse flow phenomenon. Moreover, a selected set of plots illustrating the influence of various parameters involved in the problem is presented and discussed.

scholarly journals Magnetohydrodynamic Flow of a Bingham Fluid in a Vertical Channel: Mixed Convection

Fluids ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 154
Author(s):  
Alessandra Borrelli ◽  
Giulia Giantesio ◽  
Maria Cristina Patria
Keyword(s):  
Magnetic Field ◽  
Mixed Convection ◽  
Uniform Magnetic Field ◽  
Hartmann Number ◽  
Reverse Flow ◽  
Vertical Channel ◽  
Bingham Fluid ◽  
Induced Magnetic Field ◽  
Bingham Number ◽  
External Uniform Magnetic Field

In this paper, we describe our study of the mixed convection of a Boussinesquian Bingham fluid in a vertical channel in the absence and presence of an external uniform magnetic field normal to the walls. The velocity, the induced magnetic field, and the temperature are analytically obtained. A detailed analysis is conducted to determine the plug regions in relation to the values of the Bingham number, the buoyancy parameter, and the Hartmann number. In particular, the velocity decreases as the Bingham number increases. Detailed considerations are drawn for the occurrence of the reverse flow phenomenon. Moreover, a selected set of diagrams illustrating the influence of various parameters involved in the problem is presented and discussed.

Reverse Flow in Magnetoconvection of Two Immiscible Fluids in a Vertical Channel

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Alessandra Borrelli ◽  
Giulia Giantesio ◽  
Maria Cristina Patria
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Mixed Convection ◽  
Newtonian Fluid ◽  
Hartmann Number ◽  
Reverse Flow ◽  
Vertical Channel ◽  
Boussinesq Approximation ◽  
Immiscible Fluids ◽  
Induced Magnetic Field

This paper concerns the study of the influence of an external magnetic field on the reverse flow occurring in the steady mixed convection of two Newtonian immiscible fluids filling a vertical channel under the Oberbeck–Boussinesq approximation. The two isothermal boundaries are kept either at different or at equal temperatures. The velocity, the temperature, and the induced magnetic field are obtained analytically. The results are presented graphically and discussed for various values of the parameters involved in the problem (in particular, the Hartmann number and the buoyancy coefficient) and are compared with those for a single Newtonian fluid. The occurrence of the reverse flow is explained and carefully studied.

Heat transfer of water–graphene oxide nanofluid magnetohydrodynamic flow through a channel in the presence of the induced magnetic field

2020 ◽  
pp. 095440622094890
Author(s):  
Nematollah Askari ◽  
Hossein Salmani ◽  
Mohammad Hasan Taheri ◽  
Mojtaba Masoumnezhad ◽  
Mohammad Ali Kazemi
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Nanoparticle Volume Fraction ◽  
Induced Current ◽  
Induced Magnetic Field ◽  
Magnetic Prandtl Number ◽  
Injection Parameter ◽  
Flow Through

In the present study, the heat transfer of nanofluid magnetohydrodynamic (MHD) fluid flow through a channel with radiation and viscous dissipation effect is considered. Also, the induced magnetic field is considered. The main aim of the study is to obtain the impact of the induced magnetic field, nanoparticle volume fraction, non-electrically conducting, and conducting walls on the MHD nanofluid flow and heat transfer. Hence, the governing equations include momentum, energy, and induced magnetic field equations that are transformed into non-dimensional forms. The analytical least square method (LSM) and numerical finite element method (FEM) effectively conducted for solving the problem. The results of LSM and FEM are compared, and it is observed that there is an excellent agreement. The effect of several parameters such as Hartmann number, suction/injection parameter, magnetic Prandtl number, radiation parameter, Eckert number, and nanoparticle volume fraction are demonstrated and discussed. It can be concluded that the augmentation of the Hartmann number reduces the value of velocity by up to 50%, and the magnetic Prandtl number augmentation reduces the non-dimensional velocity value of about 10% but increases the induced current density value more than twice. Moreover, the increase of radiation parameter, Eckert number, and nanoparticle volume fraction enhance the heat transfer by 20–50%. Besides, the absolute value of the induced magnetic field increases when the Hartmann number rises. Further, the injection parameter decreases the value of velocity and induced magnetic field by 40–50%; whereas, the value of temperature increases by about 40%, and the induced current density increases by 5–7 times. The suction parameter has the contrary effect.

scholarly journals Effect of magnetic field on nanofluid free convection in Conical Partially Annular Space

2020 ◽  
Vol 330 ◽  
pp. 01005
Author(s):  
Abderrahmane AISSA ◽  
Mohamed Amine MEDEBBER ◽  
Khaled Al-Farhany ◽  
Mohammed SAHNOUN ◽  
Ali Khaleel Kareem ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Boussinesq Approximation ◽  
Simulation Software ◽  
Comsol Multiphysics ◽  
Governing Equations ◽  
Element Analysis ◽  
Vertical Side ◽  
Side Walls

Natural convection of a magneto hydrodynamic nanofluid in a porous cavity in the presence of a magnetic field is investigated. The two vertical side walls are held isothermally at temperatures Th and Tc, while the horizontal walls of the outer cone are adiabatic. The governing equations obtained with the Boussinesq approximation are solved using Comsol Multiphysics finite element analysis and simulation software. Impact of Rayleigh number (Ra), Hartmann number (Ha) and nanofluid volume fraction (ϕ) are depicted. Results indicated that temperature gradient increases considerably with enhance of Ra and ϕ but it reduces with increases of Ha.

MHD natural convection of Cu/H2O nanofluid in a horizontal semi-cylinder with a local triangular heater

2018 ◽  
Vol 28 (12) ◽  
pp. 2979-2996 ◽  
Author(s):  
A.S. Dogonchi ◽  
Mikhail A. Sheremet ◽  
Ioan Pop ◽  
D.D. Ganji
Keyword(s):  
Magnetic Field ◽  
Rayleigh Number ◽  
Free Convection ◽  
Shape Factor ◽  
Uniform Magnetic Field ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Horizontal Cylinder ◽  
Content Type ◽  
Nanoparticles Volume Fraction

Purpose The purpose of this study is to investigate free convection of copper-water nanofluid in an upper half of circular horizontal cylinder with a local triangular heater under the effects of uniform magnetic field and cold cylinder shell using control volume finite element method (CVFEM). Design/methodology/approach Governing equations formulated in dimensionless stream function, vorticity and temperature variables using the single-phase nanofluid model with Brinkman correlation for the effective dynamic viscosity and Hamilton and Crosser model for the effective thermal conductivity have been solved numerically by CVFEM. Findings The impacts of control parameters such as the Rayleigh number, Hartmann number, nanoparticles volume fraction, local triangular heater size, shape factor on streamlines and isotherms as well as local and average Nusselt numbers have been examined. The outcomes indicate that the average Nusselt number is an increasing function of the Rayleigh number, shape factor and nanoparticles volume fraction, while it is a decreasing function of the Hartmann number. Originality/value A complete study of the free convection of copper-water nanofluid in an upper half of circular horizontal cylinder with a local triangular heater under the effects of uniform magnetic field and cold cylinder shell using CVFEM is addressed.

Influence of an inclined magnetic field on the Poiseuille flow of immiscible micropolar–Newtonian fluids in a porous medium

2018 ◽  
Vol 96 (9) ◽  
pp. 1016-1028 ◽  
Author(s):  
Pramod Kumar Yadav ◽  
Sneha Jaiswal
Keyword(s):  
Magnetic Field ◽  
Rotational Velocity ◽  
Immiscible Fluids ◽  
Newtonian Fluids ◽  
Porous Channel ◽  
Physical Parameters ◽  
Inclined Magnetic Field ◽  
Two Phase ◽  
Flow Through ◽  
Newtonian Viscous Fluid

The present problem is concerned with two-phase fluid flow through a horizontal porous channel in the presence of uniform inclined magnetic field. The micropolar fluid or Eringen fluid and Newtonian viscous fluid are flowing in the upper and lower regions of the horizontal porous channel, respectively. In this paper, the permeability of each region of the horizontal porous channel has been taken to be different. The effects of various physical parameters like angles of inclination of magnetic field, viscosity ratio, micropolarity parameter, etc., on the velocities, micro-rotational velocity of two immiscible fluids in horizontal porous channel, wall-shear stress, and flow rate have been discussed. The result obtained for immiscible micropolar–Newtonian fluids are compared with the results of two immiscible Newtonian fluids. The obtained result may be used in production of oil from oil reservoirs, purification of contaminated ground water, etc.

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