Magnetohydrodynamic Effect on Flow Structures Between Coaxial Cylinders Heated from Below

Mahfoud, Brahim; Benhacine, H.; Laouari, A.; Bendjaghlouli, A.

doi:10.2514/1.t5805

Cited by 15 publications

(7 citation statements)

References 21 publications

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“…First, the used numerical model has been validated by comparing the present numerical results with the numerical results of Mahfoud et al (2020) and Kakarantzas et al (2017) who investigated the flow and heat transfer of liquid metal, which rotates in the annular of concentric cylinders under a magnetic field effect. Figure 2 shows the reproduction of the radial distribution of axial velocity in the middle of the domain (z=1 plane), for Ha= 100 and the aspect ratio H⁄Ro= 2.0 when the annular gap is R=0.4 and the Rayleigh number Ra=10 5 .…”

Section: Resultsmentioning

confidence: 99%

“…The literature review on convection problems confirmed that a magnetic field is used to stabilize the perturbation in the fluid motion and control the velocity field (Mahfoud and Bessaїh 2012b;Mahfoud et al2016Mahfoud et al , 2019Mahfoud et al , 2020. After that, Bendjaghlouli et al (2019a,b) have discussed the influence of the geometry and the thermal gradient to generated small vortices with and without an applied magnetic field.…”

Section: Introductionmentioning

confidence: 97%

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Stability of an Electrically Conducting Fluid Flow between Coaxial Cylinders under Magnetic field

Benhacine

Mahfoud

Salmi

2022

JAFM

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This research aims to investigate the vortex breakdown zone, the stability margin, and the fluid layers of the rotating flow between two vertical coaxial cylinders under the effect of thermal gradient and an axial magnetic field. The governing Navier-Stokes, temperature, and potential equations are solved using the finitevolume method. Three combinations of aspect ratios (γ) and Reynolds numbers (Re) are compared. The pumping action sets up a secondary circulation along the meridional plane of the annular gap. For certain combinations, the vortex breakdown bubble occurred near the inner wall. Bifurcation in form of multiple fluid layers becomes apparent when the temperature difference exceeds a critical value. These fluid layers play the role of thermal insulation and limit the heat transfer between the hot top and cold bottom of the coaxial cylinders. Both the vortex breakdown and fluid layers could be suppressed by the magnetic field; the increasing of Hartmann number (Ha) would reduce the number of fluid layers. Diagrams represent the effect of increasing Richardson number (Ri) on fluid layers are established. Then stability diagrams corresponding to the transition from the multiple fluid layers zone to the one fluid layer zone for increasing Prandtl number (Pr) are obtained.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Stability of an Electrically Conducting Fluid Flow between Coaxial Cylinders under Magnetic field

Benhacine

Mahfoud

Salmi

2022

JAFM

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“…This force decreases or increases the axial velocity and therefore affects the rotating flow field. In this case, the Hartmann layer replaces the Ekman layer and the Ekman boundary layer forms in the vicinity of the rotating disc [14]. The challenges of the stability of mixed flow in an enclosed container are discussed in reference [15], which verified that the uniform magnetic field may be employed to control and stabilize fluid motion.…”

Section: Introductionmentioning

confidence: 98%

Buoyancy force and magnetic field effects on laminar vortex breakdown and fluid layers

MAHFOUD

Moussaoui

2023

Journal of Thermal Engineering

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In this study, the Generalized Integral Transformation Technique (GITT) is used to describe the effect of buoyancy force and magnetic field on the vortex breakdown process generated by the rotation of an electrically conductive fluid. A magnetic field is positioned vertically to stabilize the swirling flow caused by the rotation of the bottom disc of a cylindrical recipient. Three fluids were compared in this study where the range of Richardson number is 0 ≤Ri ≤2.0. When the temperature difference is greater than Ri = 0.1, many layers become visible. These stratified flu id layers act as thermal insulators. In the case of stratification, the increased magnetic field reduces the total number of layers formed in the fluid. The influence of gradient temperature on the distribution of the layers generated is discussed. The limitations between the multilayer structure and the monolayer structure for three fluids are calculated as a function of the flow parameters.

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“…The investigation showed that the heat transport strength was found to reduce with magnetic field improvement. The work of Mahfoud et al 18 analyzed the impacts of MHD on the thermal and flow profiles within coaxial cylinders that have been heated from the bottom. Hu 19 used the lattice Boltzmann approach to study the impact of the movement of an elliptical particle in a square enclosure propelled by the lid.…”

Section: Introductionmentioning

confidence: 99%

Magnetoconvection around an elliptic cylinder placed in a lid‐driven square enclosure subjected to internal heat generation or absorption

Olayemi

Al‐Farhany

Obalalu³

et al. 2022

Heat Trans

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The impacts of MHD and heat generation/absorption on lid‐driven convective fluid flow occasioned by a lid‐driven square enclosure housing an elliptic cylinder have been investigated numerically. The elliptic cylinder and the horizontal enclosure boundaries were insulated and the left vertical lid‐driven wall was experienced at a fixed hot temperature, and the right wall was exposed to a fixed cold temperature. COMSOL Multiphysics 5.6 software was used to resolve the nondimensional equations governing flow physics. A set of parameters, such as Hartmann number (0 ≤ italicHa ≤ 50 $0\le {Ha}\le 50$), Reynolds number (1 0 2 ≤ italicRe ≤ 1 0 3 $1{0}^{2}\le {Re}\le 1{0}^{3}$), Grashof number (1 0 2 ≤ italicGr ≤ 1 0 5 $1{0}^{2}\le {Gr}\le 1{0}^{5}$), heat generation‐absorption parameter (− 3 ≤ J ≤ 3 $-3\le J\le 3$), and elliptical cylinder aspect ratio (AR) (1.0 ≤ italicAR ≤ 3.0 $1.0\le {AR}\le 3.0$) have been investigated. The current study discovered that for low Reynolds number, the adiabatic cylinder AR of 2.0 provided the optimum heat transfer enhancement for the model investigated, also the impact of cylinder size diminishes beyond Gr = 104. But for high Reynolds (Re = 1000), the size of the cylinder with AR = 3.0 offered the highest heat transfer augmentation. The clockwise flow circulation reduces because of an increase in AR, which hinders the flow circulation. In addition, heat absorption supports heat transfer augmentation while heat generation can suppress heat transfer improvement.

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Magnetohydrodynamic Effect on Flow Structures Between Coaxial Cylinders Heated from Below

Cited by 15 publications

References 21 publications

Stability of an Electrically Conducting Fluid Flow between Coaxial Cylinders under Magnetic field

Stability of an Electrically Conducting Fluid Flow between Coaxial Cylinders under Magnetic field

Buoyancy force and magnetic field effects on laminar vortex breakdown and fluid layers

Magnetoconvection around an elliptic cylinder placed in a lid‐driven square enclosure subjected to internal heat generation or absorption

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