scholarly journals Effect of magnetic field on heat transfer from a channel: Nanofluid flow and porous layer arrangement

Author(s):  
Somayeh Davoodabadi Farahani ◽  
Mohammad Amiri ◽  
Behnam Kazemi Majd ◽  
Amir Mosavi
2017 ◽  
Vol 21 (6 Part B) ◽  
pp. 3062-3062
Author(s):  
E Editorial

Due to error of the Editorial staff, unrevised manuscript has been published instead of the REVISED MANUSCRIPT sent by authors after peer review process. The corrected version of this article is printed in this issue on pages pp. 3063-3073<br><br><font color="red"><b> Link to the corrected article <u><a href="http://dx.doi.org/10.2298/TSCI160524180R">10.2298/TSCI160524180R</a></b></u>


2016 ◽  
Vol 26 (5) ◽  
pp. 1416-1432 ◽  
Author(s):  
Saman Rashidi ◽  
Javad Abolfazli Esfahani ◽  
Mohammad Sadegh Valipour ◽  
Masoud Bovand ◽  
Ioan Pop

Purpose – The analysis of the flow field and heat transfer around a tube row or tube banks wrapped with porous layer have many related engineering applications. Examples include the reactor safety analysis, combustion, compact heat exchangers, solar power collectors, high-performance insulation for buildings and many another applications. The purpose of this paper is to perform a numerical study on flows passing through two circular cylinders in side-by-side arrangement wrapped with a porous layer under the influence of a magnetic field. The authors focus the attention to the effects of magnetic field, Darcy number and pitch ratio on the mechanism of convection heat transfer and flow structures. Design/methodology/approach – The Darcy-Brinkman-Forchheimer model for simulating the flow in porous medium along with the Maxwell equations for providing the coupling between the flow field and the magnetic field have been used. Equations with the relevant boundary conditions are numerically solved using a finite volume approach. In this study, Stuart and Darcy numbers are varied within the range of 0 < N < 3 and 1e-6 < Da < 1e-2, respectively, and Reynolds and Prandtl numbers are equal to Re=100 and Pr=0.71, respectively. Findings – The results show that the drag coefficient decreases for N < 0.6 and increases for N > 0.6. Also, the effect of magnetic field is negligible in the gap between two cylinders because the magnetic field for two cylinders counteracts each other in these regions. Originality/value – To the authors knowledge, in the open literature, flow passing over two circular cylinders in side-by-side arrangement wrapped with a porous layer has been rarely investigated especially under the influence of a magnetic field.


2020 ◽  
Vol 82 (2) ◽  
Author(s):  
P. H. Tan ◽  
K. S. Fong ◽  
A. Y. Mohd Yassin ◽  
M. Latheef

Magnetic heating of crude oil mixed with nanoparticle for heat transfer mechanism enhancement has received much attention in enhanced oil recovery (EOR). In the present work, the heat transfer of Fe3O4, Al2O3, CuO, Cu nanoparticles mixed in crude oil is theoretically investigated. The mathematical model of magnetic field heating in reservoir is represented by the channel flow of crude oil-nanofluid subjected to a longitudinal spatially varying magnetic field. The viscous incompressible flow is bounded by nonisothermal walls. The coupled nonlinear partial differential equations (PDEs) are solved numerically using an unconditionally stable time integration and finite element method. The numerical results are validated against data available in literature. The physical aspects of the crude oil-nanofluid flow and heat transfer are discussed in terms of several pertinent parameters such as solid nano fraction, skin friction, magnetic, Hartmann and Nusselt numbers. It is found that the enhancement of heat transfer increases with the magnetic number and solid nano fraction while decreases with the increase in Hartmann number. It is shown that, the addition of nanoparticle and increment of magnetic number is effective in the localised heating. In addition, the heat transfer of Fe3O4, Al2O3, CuO, Cu nanoparticles in crude oil mixed are investigated and assessed against each other. It is observed that, the heating mechanism would not be as effective for high electrically conducting nanoparticles. The results also indicate that nanoparticle with high thermal conductivity and low electrical conductivity is preferable in obtaining susceptible thermal heating for the EOR.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Qingkai Zhao ◽  
Hang Xu ◽  
Longbin Tao

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.


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