scholarly journals Non-Darcian effect on double-diffusive natural convection inside aninclined square Dupuit-Darcy porous cavity under a magnetic field

2019 ◽  
pp. 271-271
Author(s):  
Redha Rebhi ◽  
Noureddine Hadidi ◽  
Rachid Bennacer
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
Numerical Study ◽  
Lewis Number ◽  
Boussinesq Approximation ◽  
Buoyant Force ◽  
Porous Cavity ◽  
Effect Parameter ◽  
The Magnetic Field ◽  
Double Diffusive

This paper presents a numerical study of a double diffusive convection in an inclined square porous cavity filled with an electrically conducting binary mixture. The upper and bottom walls are maintained at a constant temperatures and concentrations whereas the left and right walls are assumed to be adiabatic and impermeable. A uniform and tilted magnetic field is applied at an angle, ?, about the horizontal, it is obvious that this is related to the orientation of the magnetic force that can help or oppose the buoyant force. The Dupuit-Darcy flow model, which includes effects of the inertial parameter, with the Boussinesq approximation, energy and species transport equations are solved numerically using the classical finite difference method. Governing parameters of the problem under study are the thermal Rayleigh number, Rt, Hartmann number, Ha, Lewis number, Le, the buoyancy ratio, ?,inclination angle, ? and tilting angle of the magnetic field, ?,. The numerical results are reported on the contours of streamline, temperature, and concentration and for the average Nusselt and Sherwood numbers for various parametric conditions. It is demonstrated that both the inertial effect parameter and the magnetic field, have a strong influence on the strength of the natural convection heat and mass transfer within the porous layer.

scholarly journals Double-Diffusive of Natural Convection in an Inclined Porous Square Domain Generalized Model

2019 ◽  
Vol 12 (3) ◽  
pp. 151-160
Author(s):  
Khaled Al-Farhany ◽  
A. Turan
Keyword(s):  
Natural Convection ◽  
Lewis Number ◽  
Boussinesq Approximation ◽  
Darcy Number ◽  
Governing Equations ◽  
Simpler Algorithm ◽  
Wide Range ◽  
Finite Volume Approach ◽  
Buoyancy Ratio ◽  
Double Diffusive

Numerical investigate of double-diffusive natural convection in an inclined porous square. Two opposing walls of the square cavity are adiabatic; while the other walls are, kept at constant concentrations and temperatures. The Darcy–Forchheimer–Brinkman model is used to solve the governing equations with the Boussinesq approximation. A code written in FORTRAN language developed to solve the governing equations in dimensionless forms using a finite volume approach with a SIMPLER algorithm. The results presented in U-velocity and V-velocity, isotherms, iso-concentration, streamline, the average Nusselt number, and the average Sherwood number for different values of the dimensionless parameters. A wide range of these parameters have been used including; Darcy Number, modified Rayleigh number, Lewis number, buoyancy ratio, and inclination angle.  The results show that for opposite buoyancy ratio (N≤-1), the Nu decreases when the Le increases and the Sh increase when the Le increases. For an (N>0), the Nu increases when the Le increases until Le is equal to 1 and then it decreases, also Sh increases when the Le increases

An Unsteady Double-Diffusive Natural Convection in an Inclined Rectangular Enclosure with Different Angles of Magnetic Field

2016 ◽  
Vol 13 (04) ◽  
pp. 1641015 ◽  
Author(s):  
Sabyasachi Mondal ◽  
Precious Sibanda
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
Staggered Grid ◽  
Convection Flow ◽  
Rectangular Enclosure ◽  
Nusselt Numbers ◽  
Inclination Angles ◽  
The Magnetic Field ◽  
Buoyancy Ratio ◽  
Double Diffusive

An unsteady double-diffusive natural convection flow in an inclined rectangular enclosure subject to an applied magnetic field and heat generation parameter is studied. The enclosure is heated and concentrated from one side and cooled from the adjacent side. The other two sides are adiabatic. The governing equations are solved numerically using a staggered grid finite-difference method to determine the streamline, isotherm and iso-concentration contours. We have further obtained the average Nusselt numbers and average Sherwood numbers for various values of buoyancy ratio and different angles of the magnetic field by considering three different inclination angles of the enclosure while keeping the aspect ratio fixed. The results indicate that the flow pattern, temperature and concentration fields are significantly dependent on the buoyancy ratio and the magnetic field angles. It is found that different angles of the magnetic field suppress the convection flow and its direction influences the flow patterns. This leads to the appearance of inner loop and multiple eddies.

scholarly journals Magnetohydrodynamics, Natural Convection, and Entropy Generation of CuO–Water Nanofluid in an I-Shape Enclosure—A Numerical Study

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
Ali Malekpour ◽  
Nader Karimi ◽  
Amirfarhang Mehdizadeh
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Natural Convection ◽  
Entropy Generation ◽  
Numerical Study ◽  
Heat Transfer Process ◽  
Geometrical Parameters ◽  
Strong Function ◽  
Exact Shape ◽  
The Magnetic Field

Abstract This paper presents a numerical study of the magnetohydrodynamics, natural convection, and thermodynamic irreversibilities in an I-shape enclosure, filled with CuO-water nanofluid and subject to a uniform magnetic field. The lateral walls of the enclosure are maintained at different but constant temperatures, while the top and bottom surfaces are adiabatic. The Brownian motion of the nanoparticles is taken into account and an extensive parametric study is conducted. This involves the variation of Rayleigh and Hartmann numbers, and the concentration of nanoparticles and also the geometrical specifications of the enclosure. Further, the behaviors of streamlines and isotherms under varying parameters are visualized. Unlike that in other configurations, the rate of heat transfer in the I-shaped enclosure appears to be highly location dependent and convection from particular surfaces dominates the heat transfer process. It is shown that interactions between the magnetic field and natural convection currents in the investigated enclosure can lead to some peculiarities in the thermal behavior of the system. The results also demonstrate that different parts of the enclosure may feature significantly different levels of heat transfer sensitivity to the applied magnetic field. Further, the analysis of entropy generation indicates that the irreversibility of the system is a strong function of the geometrical parameters and that the variations in these parameters can minimize the total generation of entropy. This study clearly shows that ignoring the exact shape of the enclosure may result in major errors in the prediction of heat transfer and second law performances of the system.

scholarly journals The effect of an external magnetic field on the entropy generation in three-dimensional natural convection

2010 ◽  
Vol 14 (2) ◽  
pp. 341-352 ◽  
Author(s):  
Lioua Kolsi ◽  
Awatef Abidi ◽  
Naceur Borjini ◽  
Ben Aïssia
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
External Magnetic Field ◽  
Liquid Metal ◽  
Entropy Generation ◽  
Numerical Study ◽  
Three Dimensional ◽  
Laminar Natural Convection ◽  
The Magnetic Field

A 3-D original numerical study of entropy generation in the case of liquid metal laminar natural convection in a differentially heated cubic cavity and in the presence of an external magnetic field orthogonal to the isothermal walls is carried out. The effect of this field on the various types of irreversibilities is analyzed. It was observed that in the presence of a magnetic field the generated entropy is distributed on the entire cavity and that the magnetic field limits the 3-D character of the distribution of the generated entropy.

scholarly journals Numerical Study of the Magnetic Field Effect on Ferromagnetic Fluid Flow and Heat Transfer in a Square Porous Cavity

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3235 ◽  
Author(s):  
Mohamed El-Amin ◽  
Usama Khaled ◽  
Abderrahmane Beroual
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Fluid Flow ◽  
Numerical Study ◽  
Mass Transfer Rate ◽  
Porous Cavity ◽  
Flow And Heat Transfer ◽  
Magnetization Density ◽  
Ferromagnetic Fluid ◽  
The Magnetic Field

A numerical study of ferromagnetic-fluid flow and heat transfer in a square porous cavity under the effect of a magnetic field is presented. The water-magnetic particle suspension is treated as a miscible mixture and, thus, the magnetization, density and viscosity of the ferrofluid are obtained. The governing partial-differential equations were solved numerically using the cell-centered finite-difference method for the spatial discretization, while the multiscale time-splitting implicit method was developed to treat the temporal discretization. The Courant–Friedrichs–Lewy stability condition (CFL < 1) was used to make the scheme adaptive by dividing time steps as needed. Two cases corresponding to Dirichlet and Neumann boundary conditions were considered. The efficiency of the developed algorithm as well as some physical results such as temperature, concentration, and pressure; and the local Nusselt and Sherwood numbers at the cavity walls are presented and discussed. It was noticed that the particle concentration and local heat/mass transfer rate are related to the magnetic field strength, and both pressure and velocity increase as the strength of the magnetic was increased.

Natural convection with volumetric heat generation and external magnetic field in differentially heated enclosure

2014 ◽  
Vol 228 (15) ◽  
pp. 2711-2727 ◽  
Author(s):  
Farid Berrahil ◽  
Smail Benissaad ◽  
Abid Chérifa ◽  
Marc Médale
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
External Magnetic Field ◽  
Prandtl Number ◽  
Heat Generation ◽  
Numerical Study ◽  
Internal Heat ◽  
Internal Heat Generation ◽  
Simpler Algorithm ◽  
The Magnetic Field

Abstract This work presents a numerical study of natural convection in a laterally heated cavity filled with an electrically conductive fluid ([Formula: see text]) in the presence of an external magnetic field and an internal heat source. The finite volume method with the SIMPLER algorithm is used to solve the system of equations governing the magnetohydrodynamics flow. The influence of volumetric heating SQ on the flow structure and on the heat transfer within the cavity for Gr = 104, 105, and 106 was examined. The effects of aspect ratio ( A = 1, 0.5, and 2), Prandtl number (low Prandtl number fluids), and magnetic field ([Formula: see text] to [Formula: see text]) were determined in the steady state with internal heat generation. Two orientations of the magnetic field were considered in order to have better control of the flow. The strongest stabilization of the flow field with internal heat generation is found when the magnetic field is oriented horizontally.

The Model for Calculation the Hall Effect Parameter

2004 ◽  
Vol 9 (2) ◽  
pp. 129-138
Author(s):  
J. Kleiza ◽  
V. Kleiza
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Mapping Method ◽  
Sample Thickness ◽  
System Of Nonlinear Equations ◽  
Specific Resistivity ◽  
Conformal Mapping Method ◽  
Effect Parameter ◽  
The Magnetic Field

A method for calculating the values of specific resistivity ρ as well as the product µHB of the Hall mobility and magnetic induction on a conductive sample of an arbitrary geometric configuration with two arbitrary fitted current electrodes of nonzero length and has been proposed an grounded. During the experiment, under the constant value U of voltage and in the absence of the magnetic field effect (B = 0) on the sample, the current intensities I(0), IE(0) are measured as well as the mentioned parameters under the effect of magnetic fields B1, B2 (B1 ≠ B2), i.e.: IE(β(i)), I(β(i)), i = 1, 2. It has been proved that under the constant difference of potentials U and sample thickness d, the parameters I(0), IE(0) and IE(β(i)), I(β(i)), i = 1, 2 uniquely determines the values of the product µHB and specific resistivity ρ of the sample. Basing on the conformal mapping method and Hall’s tensor properties, a relation (a system of nonlinear equations) between the above mentioned quantities has been found.

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