Dufour and Soret effects on Darcy-Forchheimer flow of second-grade fluid with the variable magnetic field and thermal conductivity

2020 ◽  
Vol 30 (9) ◽  
pp. 4331-4347 ◽  
Author(s):  
Ambreen A. Khan ◽  
S. Naeem ◽  
R. Ellahi ◽  
Sadiq M. Sait ◽  
K. Vafai

Purpose This study aims to investigate the effect of two-dimensional Darcy-Forchheimer flow over second-grade fluid with linear stretching. Heat transfer through convective boundary conditions is taken into account. Design/methodology/approach Nonlinear coupled governing equations are tackled with a homotopy algorithm, while for numerical computation the computer software package BVPh 2.0 is used. The convergence analysis is also presented for the validation of analytical and numerical results. Findings Valuation for the impact of key parameters such as variable thermal conductivity, Dufour and Soret effects and variable magnetic field in an electrically conducted fluid on the velocity, concentration and temperature profiles are graphically illustrated. It is observed from the results that temperature distribution rises by Dufour number whereas concentration distribution rises by Soret number. The Forchheimer number and porosity parameter raise the skin friction coefficient. The permeable medium has a vital impact and can help in reining the rate of heat transfer. Practical implications The permeable medium has a vital impact and can help in reining the rate of heat transfer. Originality/value To the best of the authors’ knowledge, this study is reported for the first time.

2019 ◽  
Vol 29 (8) ◽  
pp. 2948-2963 ◽  
Author(s):  
Muhammad Waqas ◽  
Muhammad Mudassar Gulzar ◽  
Zeeshan Asghar ◽  
Z. Ali ◽  
Waqar Azeem Khan ◽  
...  

Purpose The purpose of this study is to elaborate mixed convection impact in stratified nanofluid flow by convectively heated moving surface. Rheological relations of second-grade fluid are used for formulation. Magnetic field, heat absorption/generation and convective conditions are considered for modeling. Design/methodology/approach Convergent solutions are achieved using homotopy procedure. Findings The authors found opposing behavior for radiation and thermal stratification variables against thermal field. Originality/value No such analysis has yet been reported.


Author(s):  
Maryam Momeni ◽  
Naghmeh Jamshidi ◽  
Amin Barari ◽  
Ganji Domairry

PurposeThe purpose of this paper is to study the flow and heat transfer of an incompressible homogeneous second‐grade fluid past a stretching sheet channel and employ the homotopy analysis method (HAM) to compute an approximation to the solution of the system of nonlinear differential equations governing on the problem.Design/methodology/approachIn this paper, a study of the flow and heat transfer of an incompressible homogeneous second‐grade fluid past a stretching sheet channel is presented and the HAM is employed to compute an approximation to the solution of the system of nonlinear differential equations governing on the problem. It has been attempted to show the capabilities and wide‐range applications of the HAM in comparison with the numerical method in solving this problem.FindingsThe obtained solutions, in comparison with the exact solutions admit a remarkable accuracy.Originality/valueIn this paper, a study of the flow and heat transfer of an incompressible homogeneous second‐grade fluid past a stretching sheet channel is presented and the HAM is employed to compute an approximation to the solution of the system of nonlinear differential equations governing on the problem. The paper shows the capabilities and wide‐range applications of the HAM in comparison with the numerical method in solving this problem. The obtained solutions, in comparison with the exact solutions admit a remarkable accuracy.


2019 ◽  
Vol 29 (4) ◽  
pp. 1466-1489 ◽  
Author(s):  
Mohammadhossein Hajiyan ◽  
Shohel Mahmud ◽  
Mohammad Biglarbegian ◽  
Hussein A. Abdullah ◽  
A. Chamkha

Purpose The purpose of this paper is to investigate the convective heat transfer of magnetic nanofluid (MNF) inside a square enclosure under uniform magnetic fields considering nonlinearity of magnetic field-dependent thermal conductivity. Design/methodology/approach The properties of the MNF (Fe3O4+kerosene) were described by polynomial functions of magnetic field-dependent thermal conductivity. The effect of the transverse magnetic field (0 < H < 105), Hartmann Number (0 < Ha < 60), Rayleigh number (10 <Ra <105) and the solid volume fraction (0 < φ < 4.7%) on the heat transfer performance inside the enclosed space was examined. Continuity, momentum and energy equations were solved using the finite element method. Findings The results show that the Nusselt number increases when the Rayleigh number increases. In contrast, the convective heat transfer rate decreases when the Hartmann number increases due to the strong magnetic field which suppresses the buoyancy force. Also, a significant improvement in the heat transfer rate is observed when the magnetic field is applied and φ = 4.7% (I = 11.90%, I = 16.73%, I = 10.07% and I = 12.70%). Research limitations/implications The present numerical study was carried out for a steady, laminar and two-dimensional flow inside the square enclosure. Also, properties of the MNF are assumed to be constant (except thermal conductivity) under magnetic field. Practical implications The results can be used in thermal storage and cooling of electronic devices such as lithium-ion batteries during charging and discharging processes. Originality/value The accuracy of results and heat transfer enhancement having magnetic field-field-dependent thermal conductivity are noticeable. The results can be used for different applications to improve the heat transfer rate and enhance the efficiency of a system.


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