Article

1998 ◽  
Vol 76 (5) ◽  
pp. 391-401
Author(s):  
MES Ahmed ◽  
H A Attia
Keyword(s):  
Magnetic Field ◽  
Outer Cylinder ◽  
Constant Heat Flux ◽  
Constant Heat ◽  
Eccentric Annulus ◽  
Electrically Conducting ◽  
Flow And Heat Transfer ◽  
The Magnetic Field ◽  
External Uniform Magnetic Field ◽  
Steady Laminar

The steady laminar flow and heat transfer of an incompressible, electrically conducting, non-Newtonian fluid in an eccentric annulus are studied in the presence of an external uniform magnetic field. The inner cylinder is subject to a constant heat flux while the outer cylinder is adiabatic and the viscous and Joule dissipations are taken into consideration. A numerical solution for the governing partial differential equations is developed and the influence of the magnetic field on both the velocity and temperature distributions are discussed.PACS Nos.: 47.65, 47.50, 47.15C

Hiemenz magnetic flow of a non-Newtonian fluid of second grade with heat transfer

2000 ◽  
Vol 78 (9) ◽  
pp. 875-882 ◽  
Author(s):  
H A Attia
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Newtonian Fluid ◽  
Second Grade ◽  
Magnetic Flow ◽  
Electrically Conducting ◽  
Flow And Heat Transfer ◽  
Energy Equations ◽  
The Magnetic Field ◽  
Steady Laminar

The steady laminar flow of an incompressible viscous electrically conducting non-Newtonian fluid of second grade impinging normal to a plane wall with heat transfer is investigated. An externally applied uniform magnetic field is applied normal to the wall, which is maintained at a constant temperature. A numerical solution for the governing momentum and energy equations is obtained. The effect of the characteristics of the non-Newtonian fluid and the magnetic field on both the flow and heat transfer is outlined. PACS Nos.: 47.50 and 47.15

Stability of Taylor–Couette Magnetoconvection With Radial Temperature Gradient and Constant Heat Flux at the Outer Cylinder

2006 ◽  
Vol 129 (3) ◽  
pp. 302-310 ◽  
Author(s):  
R. K. Deka ◽  
A. S. Gupta
Keyword(s):  
Magnetic Field ◽  
Heat Flux ◽  
Outer Cylinder ◽  
Constant Heat Flux ◽  
Taylor Number ◽  
Wave Number ◽  
Constant Heat ◽  
Radial Temperature ◽  
Electrically Conducting ◽  
Wide Gap

An analysis is made of the linear stability of wide-gap hydromagnetic (MHD) dissipative Couette flow of an incompressible electrically conducting fluid between two rotating concentric circular cylinders in the presence of a uniform axial magnetic field. A constant heat flux is applied at the outer cylinder and the inner cylinder is kept at a constant temperature. Both types of boundary conditions viz; perfectly electrically conducting and electrically nonconducting walls are examined. The three cases of μ<0 (counter-rotating), μ>0 (co-rotating), and μ=0 (stationary outer cylinder) are considered. Assuming very small magnetic Prandtl number Pm, the wide-gap perturbation equations are derived and solved by a direct numerical procedure. It is found that for given values of the radius ratio η and the heat flux parameter N, the critical Taylor number Tc at the onset of instability increases with increase in Hartmann number Q for both conducting and nonconducting walls thus establishing the stabilizing influence of the magnetic field. Further it is found that insulating walls are more destabilizing than the conducting walls. It is observed that for given values of η and Q, the critical Taylor number Tc decreases with increase in N. The analysis further reveals that for μ=0 and perfectly conducting walls, the critical wave number ac is not a monotonic function of Q but first increases, reaches a maximum and then decreases with further increase in Q. It is also observed that while ac is a monotonic decreasing function of μ for N=0, in the presence of heat flux (N=1), ac has a maximum at a negative value of μ (counter-rotating cylinders).

Magnetohydrodynamic transient-free convection flow past a semi-infinite vertical plate with constant heat flux

1991 ◽  
Vol 69 (12) ◽  
pp. 1451-1453 ◽  
Author(s):  
M. Y. Gokhale ◽  
V. M. Soundalgekar
Keyword(s):  
Magnetic Field ◽  
Average Nusselt Number ◽  
Vertical Plate ◽  
Constant Heat Flux ◽  
Convection Flow ◽  
Free Convection Flow ◽  
Constant Heat ◽  
Average Skin ◽  
The Magnetic Field ◽  
Infinite Vertical Plate

A. magnetohydrodynamic transient-free convection flow of air past a semi-infinite vertical plate with a constant heat flux and a transversely applied uniform magnetic field is studied using the finite-difference method. The equations are solved by a computer using the Thomas algorithm. The transient temperature, transient velocity, average skin friction, and average Nusselt number are shown graphically. It is observed that the average skin friction and the average Nusselt number decrease owing to the application of the magnetic field. It also takes more time to reach a steady state when the magnetic field is present.

scholarly journals Free convection between vertical concentric annuli with induced magnetic field when inner cylinder is electrically conducting

2014 ◽  
Vol 13 (10) ◽  
pp. 5063-5074 ◽  
Author(s):  
SARVESHA NAND ◽  
Ashok Kumar Singh
Keyword(s):  
Magnetic Field ◽  
Radiation Heat Transfer ◽  
Outer Cylinder ◽  
Boussinesq Approximation ◽  
Constant Heat Flux ◽  
Physical Parameters ◽  
Induced Current ◽  
Induced Magnetic Field ◽  
Radial Magnetic Field ◽  
Electrically Conducting

An analysis is made for the fully developed laminar free convective flow in an open ended vertical concentric annuli with constant heat flux and constant temperature on the inner and outer walls, in the presence of a radial magnetic field. The length of the cylinder is assumed to be infinite and radiation heat transfer from the hot surface is assumed to be negligible. The inner cylinder is taken to be magnetic conducting while the outer cylinder is non-conducting. Buoyancy effect is also considered along with Boussinesq approximation. The induced magnetic field is taken into account arising due to the motion of an electrically conducting fluid. The governing linear simultaneous ordinary differential equations are first obtained in the non dimensional form and solved analytically for the velocity, induced magnetic field, temperature field and  then skin-friction and induced current density are obtained. The expressions for the fluid flux and induced current flux in non-dimensional form have been also obtained. The effects of governing physical parameters occurring in the model are shown on the graphs and tables.

scholarly journals Stability of narrow-gap MHD Taylor-Couette flow with radial heating and constant heat flux at the outer cylinder

2005 ◽  
Vol 32 (4) ◽  
pp. 359-384 ◽  
Author(s):  
R.K. Deka
Keyword(s):  
Magnetic Field ◽  
Heat Flux ◽  
Couette Flow ◽  
Axial Magnetic Field ◽  
Outer Cylinder ◽  
Constant Heat Flux ◽  
Wave Number ◽  
Narrow Gap ◽  
Critical Wave Number ◽  
Constant Heat

A linear stability analysis has been presented for hydromagnetic dissipative Couette flow, a viscous electrically conducting fluid between rotating concentric cylinders in the presence of a uniform axial magnetic field and constant heat flux at the outer cylinder. The narrow-gap equations with respect to axisymmetric disturbances are derived and solved by a direct numerical procedure. Both types of boundary conditions, conducting and non-conducting walls are considered. A parametric study covering on the basis of ?, the ratio of the angular velocity of the outer cylinder to that of inner cylinder, Q, the Hartmann number which represents the strength of the axial magnetic field, and N, the ratio of the Rayleigh number and Taylor number representing the supply of heat to the outer cylinder at constant rate is presented. The three cases of ? < 0 (counter rotating), ? > 0 (co-rotating) and ? = 0 (stationary outer cylinder) are considered wherein the magnetic Prandtl number is assumed to be small. Results show that the stability characteristics depend mainly on the conductivity on the cylinders and not on the heat supplied to the outer cylinder. As a departure from earlier results corresponding to isothermal as well as hydromagnetic flow, it is found that the critical wave number is strictly a monotonic decreasing function of Q for conducting walls. Also, the presence of constant heat flux leads to a fall in the critical wave number for counter rotating cylinders, which states that for large values of -?, there occur transition from axisymmetric to non-axisymmetric disturbance whether the flow is hydrodynamic or hydromagnetic and this transition from axisymmetric to non-axisymmetric disturbance occur earlier as the strength of the magnetic field increases.

Homann magnetic flow and heat transfer with uniform suction or injection

2003 ◽  
Vol 81 (10) ◽  
pp. 1223-1230 ◽  
Author(s):  
H A Attia
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Numerical Solutions ◽  
Axisymmetric Flow ◽  
Electrically Conducting ◽  
Uniform Suction ◽  
Flow And Heat Transfer ◽  
Suction Or Injection ◽  
Energy Equations ◽  
The Magnetic Field

The steady axisymmetric flow of an incompressible viscous electrically conducting fluid impinging on a permeable flat plate with heat transfer is investigated. An external uniform magnetic field as well as a uniform suction or injection are applied normal to the plate, which is maintained at a constant temperature. Numerical solutions for the governing momentum and energy equations are obtained. The effect of the magnetic field and the uniform suction or injection on both the flow and heat transfer is presented and discussed.PACS Nos.: 47.50, 47.15

scholarly journals Homotopy Analysis Solution of Hydromagnetic Mixed Convection Flow Past an Exponentially Stretching Sheet with Hall Current

2012 ◽  
Vol 2012 ◽  
pp. 1-26 ◽  
Author(s):  
Mohamed Abd El-Aziz ◽  
Tamer Nabil
Keyword(s):  
Magnetic Field ◽  
Mixed Convection ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Electrically Conducting ◽  
Hall Parameter ◽  
Homotopy Analysis ◽  
Continuous Sheet ◽  
Exponentially Stretching ◽  
The Magnetic Field

The effect of thermal radiation on steady hydromagnetic heat transfer by mixed convection flow of a viscous incompressible and electrically conducting fluid past an exponentially stretching continuous sheet is examined. Wall temperature and stretching velocity are assumed to vary according to specific exponential forms. An external strong uniform magnetic field is applied perpendicular to the sheet and the Hall effect is taken into consideration. The resulting governing equations are transformed into a system of nonlinear ordinary differential equations using appropriate transformations and then solved analytically by the homotopy analysis method (HAM). The solution is found to be dependent on six governing parameters including the magnetic field parameterM, Hall parameterm, the buoyancy parameterξ, the radiation parameterR, the parameter of temperature distributiona, and Prandtl number Pr. A systematic study is carried out to illustrate the effects of these major parameters on the velocity and temperature distributions in the boundary layer, the skin-friction coefficients, and the local Nusselt number.

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