Investigation of Hydrothermal Behavior of Fe3O4-H2O Nanofluid Natural Convection in a Novel Shape of Porous Cavity Subjected to Magnetic Field Dependent (MFD) Viscosity

2020 ◽  
Vol 30 ◽  
pp. 101395 ◽  
Author(s):  
M. Molana ◽  
A.S. Dogonchi ◽  
T. Armaghani ◽  
Ali J. Chamkha ◽  
D.D. Ganji ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
Porous Cavity ◽  
Field Dependent ◽  
Mfd Viscosity

Simulation of natural convection of Fe3O4-water ferrofluid in a circular porous cavity in the presence of a magnetic field

2019 ◽  
Vol 134 (2) ◽  
Author(s):  
Zhixiong Li ◽  
Ahmad Shafee ◽  
M. Ramzan ◽  
H. B. Rokni ◽  
Qasem M. Al-Mdallal
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
Porous Cavity

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.

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 The Effect of Magnetic Field Dependent Viscosity on Ferromagnetic Convection in a Rotating Sparsely Distributed Porous Medium - Revisited

2020 ◽  
Vol 25 (1) ◽  
pp. 142-158
Author(s):  
J. Prakash ◽  
P. Kumar ◽  
S. Manan ◽  
K.R. Sharma
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Critical Rayleigh Number ◽  
Wave Number ◽  
Stationary Mode ◽  
Free Boundaries ◽  
Field Dependent ◽  
Mfd Viscosity ◽  
Magnetic Field Dependent Viscosity ◽  
Dependent Viscosity

AbstractThe effect of magnetic field dependent (MFD) viscosity on the thermal convection in a ferrofluid layer saturating a sparsely distributed porous medium has been investigated by using the Darcy-Brinkman model in the simultaneous presence of a uniform vertical magnetic field and a uniform vertical rotation. A correction is applied to the study of Vaidyanathan et al. [11] which is very important in order to predict the correct behavior of MFD viscosity. A linear stability analysis has been carried out for stationary modes and oscillatory modes separately. The critical wave number and critical Rayleigh number for the onset of instability, for the case of free boundaries, are determined numerically for sufficiently large values of the magnetic parameter M1. Numerical results are obtained and are illustrated graphically. It is shown that magnetic field dependent viscosity has a destabilizing effect on the system for the case of stationary mode and a stabilizing effect for the case of oscillatory mode, whereas magnetization has a destabilizing effect.

MHD natural convection in a square porous cavity filled with a water-based magnetic fluid in the presence of geothermal viscosity

2018 ◽  
Vol 28 (9) ◽  
pp. 2111-2131 ◽  
Author(s):  
Mikhail A. Sheremet ◽  
Marina S. Astanina ◽  
Ioan Pop
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Natural Convection ◽  
Magnetic Fluid ◽  
Convective Flow ◽  
Uniform Magnetic Field ◽  
Vertical Wall ◽  
Content Type ◽  
Porous Cavity ◽  
Water Based

Purpose The purpose of this paper is a numerical analysis of natural convection in a square porous cavity filled with a water-based magnetic fluid of geothermal viscosity under the effect of inclined uniform magnetic field. Design/methodology/approach The domain of interest includes the square porous cavity filled with a water-based magnetic fluid (W40). Horizontal walls are supposed to be adiabatic, while right vertical wall is kept at constant low temperature and left vertical wall is kept at constant high temperature. An inclined uniform magnetic field affects the fluid flow and heat transfer inside the cavity. The viscosity of the working fluid is proportional to the linearly decreasing function of depth (vertical coordinate) and inversely proportional to the linear function of temperature. It is assumed in the analysis that the flow is laminar. The fluid is Newtonian and the Boussinesq approximation is valid. The governing equations have been discretized using the finite difference method with the uniform grid. Simulations have been carried out for different values of the Rayleigh number, Hartmann number, Darcy number, magnetic field inclination angle and viscosity variation parameters. Findings It has been revealed that an increase in the viscosity parameters leads to the heat transfer enhancement and convective flow intensification. At the same time, this intensification is more essential for high values of the Rayleigh number. Originality/value The originality of this work is to analyze MHD natural convection in a square porous cavity filled with a water-based magnetic fluid of geothermal viscosity. The results would benefit scientists and engineers to become familiar with the analysis of convective heat and mass transfer in nanofluids, and the way to predict the properties of nanofluid convective flow in advanced technical systems, in industrial sectors including transportation, power generation, chemical sectors and electronics.

scholarly journals Parametric analysis of magnetic field-dependent viscosity and advection–diffusion between rotating discs

2020 ◽  
Vol 29 ◽  
pp. 2633366X1989637
Author(s):  
Rehan Ali Shah ◽  
Aamir Khan ◽  
Amjad Ali
Keyword(s):  
Magnetic Field ◽  
Reynolds Number ◽  
Flow Behavior ◽  
Mathematical Formulation ◽  
Magnetic Reynolds Number ◽  
Fluid Temperature ◽  
Advection Diffusion ◽  
Field Dependent ◽  
Number Formula ◽  
Mfd Viscosity

The constitutive expressions of unsteady Newtonian fluid are employed in the mathematical formulation to model the flow between the circular space of porous and contracting discs. The flow behavior is investigated for magnetic field-dependent (MFD) viscosity and heat/mass transfers under the influence of a variable magnetic field. The equation for conservation of mass, modified Navier–Stokes, Maxwell, advection diffusion and transport equations are coupled as a system of ordinary differential equations. The expressions for torques and magnetohydrodynamic pressure gradient equation are derived. The MFD viscosity [Formula: see text], magnetic Reynolds number [Formula: see text], squeezing Reynolds number [Formula: see text], rotational Reynolds number [Formula: see text], magnetic field components [Formula: see text], [Formula: see text], pressure [Formula: see text] and the torques [Formula: see text], [Formula: see text] which the fluid exerts on discs are discussed through numerical results and graphical aids. It is concluded that magnetic Reynolds number causes an increase in magnetic field distributions and decrease in tangential velocity of flow field, also the fluid temperature is decreasing with increase in magnetic Reynolds number. The azimuthal and axial components of magnetic field have opposite behavior with increase in MFD viscosity.

Sign in / Sign up

Export Citation Format

Share Document