MHD flow and heat transfer in a backward-facing step

Abbassi, H.; Nassrallah, Sassi Ben

doi:10.1016/j.icheatmasstransfer.2006.09.010

Cited by 66 publications

(17 citation statements)

References 8 publications

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“…It is observed in Figure 15(a) that Xr/ h is getting smaller when Stuart number N is reaching the value 0.1 containing increasing effect of applied magnetic field. This behavior is in accordance with the one obtained in Abbassi et al [7]. While keeping 0 N 0.1, the length l of the channel is taken as l = 8 to be able to increase Re.…”

Section: Mhd Flow Over a Backward-facing Stepsupporting

confidence: 90%

“…The variation of recirculations in this case depends only on Reynolds number and, the size of recirculations gets larger as Re increases. When the induced magnetic field inside the fluid is neglected, even an external magnetic effect is present, the variations of recirculation lengths are functions of Stuart number (Abbassi et al [7]) depending on Re and also the intensity of applied magnetic field. However, for the MHD flow in which the induced magnetic field inside the channel is also taken into consideration, the recirculation lengths are functions of Stuart number depending on both Re and Ha with the presence of magnetic Reynolds number Re m .…”

Section: Mhd Flow Over a Backward-facing Stepmentioning

confidence: 99%

“…Navarro et al [6] dealt with a stream function-vorticity formulation and presented an extension of the generalized Peaceman and Rachford alternating-direction implicit scheme (ADI) in comparison with ADI scheme for the solution of the MHD flow equations at low magnetic Reynolds numbers. In the paper of Abbassi and Nassrallah [7], the recirculation lengths formed in front of the step face in backward-facing step channel flow are studied by using control volume FEM in terms of primitive variables under an applied external magnetic field. The variation of circulation zones are given with respect to Stuart number, but the induced magnetic field inside the fluid is neglected.…”

Section: Introductionmentioning

confidence: 99%

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The DRBEM solution of incompressible MHD flow equations

Bozkaya

Tezer‐Sezgin

2010

Numerical Methods in Fluids

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SUMMARYThis paper presents a dual reciprocity boundary element method (DRBEM) formulation coupled with an implicit backward difference time integration scheme for the solution of the incompressible magnetohydrodynamic (MHD) flow equations. The governing equations are the coupled system of Navier-Stokes equations and Maxwell's equations of electromagnetics through Ohm's law. We are concerned with a stream function-vorticity-magnetic induction-current density formulation of the full MHD equations in 2D. The stream function and magnetic induction equations which are poisson-type, are solved by using DRBEM with the fundamental solution of Laplace equation. In the DRBEM solution of the time-dependent vorticity and current density equations all the terms apart from the Laplace term are treated as nonhomogeneities. The time derivatives are approximated by an implicit backward difference whereas the convective terms are approximated by radial basis functions. The applications are given for the MHD flow, in a square cavity and in a backward-facing step. The numerical results for the square cavity problem in the presence of a magnetic field are visualized for several values of Reynolds, Hartmann and magnetic Reynolds numbers. The effect of each parameter is analyzed with the graphs presented in terms of stream function, vorticity, current density and magnetic induction contours. Then, we provide the solution of the step flow problem in terms of velocity field, vorticity, current density and magnetic field for increasing values of Hartmann number.

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Section: Mhd Flow Over a Backward-facing Stepsupporting

confidence: 90%

Section: Mhd Flow Over a Backward-facing Stepmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The DRBEM solution of incompressible MHD flow equations

Bozkaya

Tezer‐Sezgin

2010

Numerical Methods in Fluids

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“…For convection in cavities, the magnetic field was found to reduce the heat transfer rate [20][21][22]. However, recent studies showed that the magnetic field effects can be beneficial to enhance the convection for configurations that produce multiple re-circulations as in vented cavities [23] or in separated flows as encountered in sudden area expansion geometries [24,25]. Magnetic field effects are recently used with nanofluids [26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Effects of a Rotating Cone on the Mixed Convection in a Double Lid-Driven 3D Porous Trapezoidal Nanofluid Filled Cavity under the Impact of Magnetic Field

2020

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Effects of a rotating cone in 3D mixed convection of CNT-water nanofluid in a double lid-driven porous trapezoidal cavity is numerically studied considering magnetic field effects. The numerical simulations are performed by using the finite element method. Impacts of Richardson number (between 0.05 and 50), angular rotational velocity of the cone (between −300 and 300), Hartmann number (between 0 and 50), Darcy number (between 10 − 4 and 5 × 10 − 2 ), aspect ratio of the cone (between 0.25 and 2.5), horizontal location of the cone (between 0.35 H and 0.65 H) and solid particle volume fraction (between 0 and 0.004) on the convective heat transfer performance was studied. It was observed that the average Nusselt number rises with higher Richardson numbers for stationary cone while the effect is reverse for when the cone is rotating in clockwise direction at the highest supped. Higher discrepancies between the average Nusselt number is obtained for 2D cylinder and 3D cylinder configuration which is 28.5% at the highest rotational speed. Even though there are very slight variations between the average Nu values for 3D cylinder and 3D cone case, there are significant variations in the local variation of the average Nusselt number. Higher enhancements in the average Nusselt number are achieved with CNT particles even though the magnetic field reduced the convection and the value is 84.3% at the highest strength of magnetic field. Increasing the permeability resulted in higher local and average heat transfer rates for the 3D porous cavity. In this study, the aspect ratio of the cone was found to be an excellent tool for heat transfer enhancement while 95% enhancements in the average Nusselt number were obtained. The horizontal location of the cone was found to have slight effects on the Nusselt number variations.

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“…Borghi et al [4] numerically investigated nonlinear electrodynamics in MHD regimes with magnetic Reynolds number numerically. Abbassi and Nassrallah [5] used finite element method to solve MHD problem. Finite difference method was adopted by Sposito and Icefall [6].…”

Section: Introductionmentioning

confidence: 99%