scholarly journals Jeffrey Fluid Flow through Porous Medium in the Presence of Magnetic Field in Narrow Tubes

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Santhosh Nallapu ◽  
G. Radhakrishnamacharya
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Fluid Flow ◽  
Effective Viscosity ◽  
Equations Of Motion ◽  
Flow Characteristics ◽  
Darcy Number ◽  
Jeffrey Fluid ◽  
Tube Radius ◽  
The Core

Jeffrey fluid flow in the presence of magnetic field through porous medium in tubes of small diameters is studied. It is assumed that the core region consists of a Jeffrey fluid and the peripheral region of a Newtonian fluid. Making the assumptions as in the work of Chaturani and Upadhya, the linearised equations of motion have been solved and analytical solution has been obtained. The influence of various pertinent parameters on the flow characteristics such as effective viscosity, core hematocrit, and mean hematocrit has been studied and discussed through graphs. It is found that the effective viscosity and mean hematocrit decrease with Jeffrey parameter and Darcy number but increase with tube hematocrit and tube radius. Also, the core hematocrit decreases with Jeffrey parameter, Darcy number, tube hematocrit, and tube radius. Further, it is noticed that the flow exhibits the anomalous Fahraeus-Lindquist effect.

Natural Convection in a Porous Medium Rectangular Cavity with an Applied Vertical Magnetic Field Using Lattice Boltzmann Method

2011 ◽  
Vol 110-116 ◽  
pp. 839-846 ◽  
Author(s):  
Hamid Reza Ashorynejad ◽  
Mousa Farhadi ◽  
Kurosh Sedighi ◽  
Arman Hasanpour
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Mhd Flow ◽  
Darcy Number ◽  
Hydrodynamic Characteristics ◽  
Boltzmann Method

A numerical study of the magnetohydrodynamic (MHD) flow in a square cavity filled with porous medium is presented by Lattice Boltzmann Method (LBM). The left and right vertical walls of the cavity are kept at constant but different temperatures while both the top and bottom horizontal walls are insulated. The effects of the controlling parameters involved in the heat transfer and hydrodynamic characteristics are studied in detail. The results show that heat and mass transfer mechanisms and the flow characteristics inside the enclosure depend strongly on the strength of the magnetic field and Darcy number. The average Nusselt number decreases with rising values of the Hartmann number while this increases with increasing values of the Darcy number.

scholarly journals Chemical Entropy Generation and MHD Effects on the Unsteady Heat and Fluid Flow through a Porous Medium

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Gamal M. Abdel-Rahman Rashed
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Fluid Flow ◽  
Entropy Generation ◽  
Lewis Number ◽  
Heat Transfer Fluid ◽  
Governing Equations ◽  
Flow Through ◽  
Heat And Fluid Flow ◽  
Chemical Reaction Parameter

Chemical entropy generation and magnetohydrodynamic effects on the unsteady heat and fluid flow through a porous medium have been numerically investigated. The entropy generation due to the use of a magnetic field and porous medium effects on heat transfer, fluid friction, and mass transfer have been analyzed numerically. Using a similarity transformation, the governing equations of continuity, momentum, and energy and concentration equations, of nonlinear system, were reduced to a set of ordinary differential equations and solved numerically. The effects of unsteadiness parameter, magnetic field parameter, porosity parameter, heat generation/absorption parameter, Lewis number, chemical reaction parameter, and Brinkman number parameter on the velocity, the temperature, the concentration, and the entropy generation rates profiles were investigated and the results were presented graphically.

Natural Convection Inside a Bidisperse Porous Medium Enclosure

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Arunn Narasimhan ◽  
B. V. K. Reddy
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Natural Convection ◽  
Volume Fraction ◽  
Solid Phase ◽  
Darcy Number ◽  
The Core ◽  
Side Walls ◽  
Porous Blocks ◽  
Rayleigh Numbers

Bidisperse porous medium (BDPM) consists of a macroporous medium whose solid phase is replaced with a microporous medium. This study investigates using numerical simulations, steady natural convection inside a square BDPM enclosure made from uniformly spaced, disconnected square porous blocks that form the microporous medium. The side walls are subjected to differential heating, while the top and bottom ones are kept adiabatic. The bidispersion effect is generated by varying the number of blocks (N2), macropore volume fraction (ϕE), and internal Darcy number (DaI) for several enclosure Rayleigh numbers (Ra). Their effect on the BDPM heat transfer (Nu) is investigated. When Ra is fixed, the Nu increases with an increase in both DaI and DaE. At low Ra values, Nu is strongly affected by both DaI and ϕE. When N2 is fixed, at high Ra values, the porous blocks in the core region have negligible effect on the Nu. A correlation is proposed to evaluate the heat transfer from the BDPM enclosure, Nu, as a function of Raϕ, DaE, DaI, and N2. It predicts the numerical results of Nu within ±15% and ±9% in two successive ranges of modified Rayleigh number, RaϕDaE.

scholarly journals Soret effects due to natural convection in a non-Newtonian fluid flow in porous medium with heat and mass transfer

2014 ◽  
Vol 11 (2) ◽  
pp. 147-156 ◽  
Author(s):  
M.C Raju ◽  
S.V.K Varma
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Fluid Flow ◽  
Newtonian Fluid ◽  
Porous Plate ◽  
Sink Strength ◽  
Suction Parameter ◽  
Electrically Conducting ◽  
Highly Nonlinear ◽  
Constant Suction

The problem of unsteady MHD free convective, incompressible electrically conducting, non-Newtonian fluid through porous medium bounded by an infinite porous plate in the presence of constant suction has been studied. A magnetic field of uniform strength is assumed to be applied normal to the plate. The equations governing the fluid flow which are highly nonlinear are reduced to linear by using perturbation method and have been solved subject to the relevant boundary conditions. It is noted that the velocity of the fluid is increased as Soret number and suction parameter increase, whereas reverse phenomenon is observed in case of magnetic field strength and sink strength. DOI: http://dx.doi.org/10.3329/jname.v11i2.17563

A nonlinear stability analysis in a double-diffusive magnetized ferrofluid with magnetic-field-dependent viscosity saturating a porous medium

2009 ◽  
Vol 87 (6) ◽  
pp. 659-673 ◽  
Author(s):  
Sunil ◽  
Amit Mahajan
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Nonlinear Stability ◽  
Stability Result ◽  
Darcy Number ◽  
Linear Instability ◽  
Nonlinear Stability Analysis ◽  
Field Dependent ◽  
Magnetized Ferrofluid ◽  
Mfd Viscosity

A rigorous nonlinear stability result is derived by introducing a suitable generalized energy functional for a magnetized ferrofluid layer heated and soluted from below with magnetic-field-dependent (MFD) viscosity saturating a porous medium, in the stress-free boundary case. The mathematical emphasis is on how to control the nonlinear terms caused by the magnetic-body and inertia forces. For ferrofluids, we find that there is possibility of existence of subcritical instabilities, however, it is noted that, in case of a non-ferrofluid, the global nonlinear stability Rayleigh number is exactly the same as that for linear instability. For lower values of magnetic parameters, this coincidence is immediately lost. The effect of the magnetic parameter, M3; solute gradient, Sf; Darcy number, Da; and MFD viscosity parameter, δ; on the subcritical instability region has also been analyzed.

Investigation of the Fluid Flow in a Rotor-Stator Cavity With Inward Through-Flow

2009 ◽  
Author(s):  
Bjo¨rn-Christian Will ◽  
Friedrich-Karl Benra
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Flow Model ◽  
Equations Of Motion ◽  
Tangential Velocity ◽  
Layer Model ◽  
Practical Applications ◽  
The Core ◽  
Through Flow ◽  
Core Rotation

The present paper covers fluid flow in rotor-stator cavities with inward through-flow. First, a general introduction into the physics of the cavity boundary layer flow is given. The structure of the flow is very complex and depends on different dimensionless parameters. For practical applications, simple and robust calculation procedures are crucial for design purposes. Two basic modelling approaches are compared (3 layer model of Kurokawa [14] and “one layer” approach of Mo¨hring [17]) with experimental data from the literature. The flow models are classified in context of the simplified equations of motion by emphasizing the main assumptions and simplifications in their derivation. Further on, for the one layer model, the use of the logarithmic law for the velocity distribution close to the wall is proposed instead of the classic 1/7 power law. The modified flow model is validated against experimental data for different parameter combinations, yielding better agreement for moderate inlet rotation. Finally numerical simulations have been performed in order to investigate the discrepancies between measured and calculated core rotation distributions for strong inlet swirl. It is supposed that the assumption of radial equilibrium in the core region is not necessarily appropriate for evaluation of the core rotation. Further on, it is clarified in which situations the tangential velocity component of the absolute velocity at the impeller outlet can be used as a boundary condition for the flow model.

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