In this paper, we have investigated the Hall and ion slip effects on the unsteady magnetohydrodynamic (MHD) free convective rotating flow over an exponentially accelerated inclined plate entrenched in a saturated porous medium with the effect of angle of inclination, variable temperature and concentration. The flow induced by the presence of heat source/sink and destructive reaction. The Laplace transform technique has been used to solve the governing equations. The effects of the non-dimensional parameters on the governing flow velocity, temperature and concentration are examined with graphical profiles. Also for engineering interest the shear stress, Nusselt number and Sherwood number are obtained analytically and discussed computationally with reference to foremost flow parameters. It is reported that the presence of magnetic field prevents the flow reversal. Angle of inclination sustains a retarding effect on velocity distribution. The present study has an immediate application in understanding the drag experienced at the heated and inclined surfaces in a seepage flow.

Hall and ion slip effects on unsteady MHD free convective rotating flow through a saturated porous medium over an exponential accelerated plate

Magnetic field effect on the enhancement of nanofluids heat transfer of a confined jet impingement in mini-channel heat sink

A steady laminar two-dimensional magneto-hydrodynamics (MHD) natural convection flow in a square enclosure filled with an electrically conducting fluid is numerically investigated using Lattice Boltzmann Method (LBM). The left and right vertical sidewalls of the square enclosure are maintained at hot and cold temperatures respectively. The horizontal top and bottom walls are considered thermally insulated. An adiabatic square shaped body is located in the center of a square enclosure and an external magnetic field is applied parallel to the horizontal x -axis. In the present work, the following parametric ranges of the non-dimensional groups are utilized: Hartmann number is varied as 0 ⩽ Ha ⩽ 50, Rayleigh number is varied as 10 3  ⩽ Ra ⩽ 10 5 , Prandtl number is varied 0.05 ⩽ Pr ⩽ 5. It is found that the Hartmann number, Rayleigh number, and Prandtl number have an important role on the flow and thermal characteristics. It is found that when the Hartmann number increases the average Nusselt number decreases. The results also explain that the effect of magnetic field on flow field increases by increasing Prandtl number. However, the Prandtl number effect on the average Nusselt number with a magnetic field is less than the case without a magnetic field. Comparisons with previously published numerical works are performed and good agreements between the results are observed.

Modeling of MHD natural convection in a square enclosure having an adiabatic square shaped body using Lattice Boltzmann Method

The knowledge of heat and mass transfer of MHD flows over different geometries is very important for heat exchangers design, transpiration, fiber coating, etc. With this initiation, a mathematical model is proposed to investigate the two-dimensional flow, heat and mass transfer of magnetohydrodynamic flow over three different geometries (vertical cone, vertical wedge, and a vertical plate). Cattaneo-Christov heat flux with external magnetic field, thermophoresis and Brownian movement effect are introduced in the model. Runge-Kutta and Newton’s methods are employed to solve the altered governing nonlinear equations. The influences of the parameters of concern on the common profiles (velocity, temperature, and concentration) are conversed (in three cases). By viewing the same parameters, skin friction coefficient, heat and mass transfer rates are discussed with the assistance of tables. It is discovered that the momentum and thermal boundary layers are non-uniform for the MHD flow over three geometries (vertical cone, wedge, and a plate). Thermal and solutal Grashof numbers regulate the temperature and concentration fields. The heat and mass transfer rates of the flow over a cone are highly influenced by the thermal relaxation parameter.

Free convective MHD Cattaneo-Christov flow over three different geometries with thermophoresis and Brownian motion

Double-diffusive natural convection with entropy generation in a two-dimensional enclosure with partial vertical heating and salting sources for an aspect ratio Ar = 4 is investigated in the current study. A numerical methodology based on the finite volume method and a full multigrid technique is employed. The effects of various parameters; the Rayleigh number (10 3  ⩽ Ra ⩽ 2 x 10 5 ), the buoyancy ratio (−8 ⩽  N  ⩽ 8), the source location (0 ⩽  η  ⩽ 3), the Lewis number (10 ⩽ Le ⩽ 100), and, the source length (0.25 ⩽  d  ⩽ 2) on the flow patterns are analyzed. Correlations of average Nusselt and Sherwood numbers are established as a function of two parameters (Ra, d ) and (Le, d ), respectively. The numerical outcome of the present study shows that, by increasing the Lewis number in the range 10–100, the heat and mass transfer rates are significantly enhanced. In terms of irreversibility phenomena at the steady case, comparison of total entropy profiles with respect to N shows that irreversibility criterion is dominated by entropy generation due to fluid friction. Especial attention is attributed to the periodic flow behavior that appears for N in the range (0.87–0.99) outside of which it remains steady. According to the entropy generation phenomena, total entropy generation S tot and Bejan number Be were observed to oscillate with the same frequency but in opposing phases and with different amplitudes.

Double-diffusive natural convection and entropy generation in an enclosure of aspect ratio 4 with partial vertical heating and salting sources

Double-diffusive convective flow in an inclined rectangular enclosure with the shortest sides being insulated and impermeable is investigated numerically. Constant temperatures and concentration are imposed along the longest sides of the enclosure. In addition, a uniform magnetic field is applied in a horizontal direction. Laminar regime is considered under steady state condition. The transport equations for continuity, momentum, energy and species transfer are solved using the finite volume technique. The validity of the numerical code used is ascertained and good agreement was found with published results. The numerical results are reported for the effect of thermal Rayleigh number on the contours of streamline, temperature, and concentration. In addition, results for the average Nusselt and Sherwood numbers are presented and discussed for various parametric conditions. This study was done for constant Prandtl number, Pr = 0.7, aspect ratio, A = 2, Lewis number, Le = 2, the buoyancy ratio, N = 1, Hartmann number, Ha = 10 and the dimensionless heat generation, Φ = 1. Computations are carried out for RaT ranging from 103 to 5 * 105 and inclination angle range of 0° ⩽ γ ⩽ 180°.

Numerical simulation of double-diffusive natural convective flow in an inclined rectangular enclosure in the presence of magnetic field and heat source, part A: Effect of Rayleigh number and inclination angle

Mahmoud Z. Elfeky

Papers

Numerical simulation of double-diffusive natural convective flow in an inclined rectangular enclosure in the presence of magnetic field and heat source, part A: Effect of Rayleigh number and inclination angle