Effect of Local Magnetic Fields on Electrically Conducting Fluid Flow and Heat Transfer

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Xidong Zhang ◽  
Hulin Huang

The prediction of electrically conducting fluid past a localized zone of applied magnetic field is the key for many practical applications. In this paper, the characteristics of flow and heat transfer (HI) for a liquid metal in a rectangular duct under a local magnetic field are investigated numerically using a three-dimensional model and the impact of some parameters, such as constrainment factor, κ, interaction parameter, N, and Reynolds number, Re, is also discussed. It is found that, in the range of Reynolds number 100 ≤ Re ≤ 900, the flow structures can be classified into the following four typical categories: no vortices, one pair of magnetic vortices, three pairs of vortices and vortex shedding. The simulation results indicate that the local heterogeneous magnetic field can enhance the wall-heat transfer and the maximum value of the overall increment of HI is about 13.6%. Moreover, the pressure drop penalty (ΔPpenalty) does not increasingly depend on the N for constant κ and Re. Thus, the high overall increment of HI can be obtained when the vortex shedding occurs.

2009 ◽  
Vol 419-420 ◽  
pp. 353-356 ◽  
Author(s):  
Chien Hsin Chen

The problem of flow and heat transfer over a continuously stretching surface finds applications in many manufacturing processes, such as polymer extrusion, wire drawing, continuous casting, glass fiber production, and metallurgical processes. It is known that the properties of the final product depend considerably on the rate of cooling during the manufacturing processes. The rate of cooling can be controlled by drawing the strips in an electrically conducting fluid subject to a magnetic field, so that a final product of desired characteristics can be achieved. In this study, the problem of magneto-hydrodynamic (MHD) mixed convective flow and heat transfer of an electrically conducting fluid past a stretching surface under the influence of an applied magnetic field is analyzed. After transforming the governing equations with suitable dimensionless variables, numerical solutions are generated by an implicit finite-difference technique for the non-similar, coupled flow. To reveal the tendency of the solutions, typical results for the velocity and temperature profiles, the skin-friction coefficient, and the local Nusselt number are presented for different parameters.


2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Ali Shakiba ◽  
Asghar B. Rahimi

The steady, viscous flow and mixed convection heat transfer of an incompressible electrically conducting fluid within a vertical cylindrical annulus with moving walls are investigated. This annulus is under the influence of a radial magnetic field and the fluid is suctioned/injected through the cylinders' walls. An exact solution of the Navier–Stokes equations and energy equation is derived in this problem where heat is transferred from the hot cylinder walls with constant temperature to the cooler moving fluid. The role of the movement of the annulus walls is studied on the flow and heat transfer of the fluid within the annulus, for the first time. The effects of other parameters, including Prandtl number, Hartman number, mixed convection parameter, suction/injection parameter and ratio of the radius, on the behavior of the flow and heat transfer of the fluid is also considered. The results indicate that if, for example, the internal cylinder wall moves in the direction of z-axis and the external cylinder is stationary, the maximum and minimum heat transfer occur on the walls of internal and external cylinders, respectively. Moreover, the augmentation of the radius ratio between the two cylinders increases the rate of heat transfer and decreases the shear stress on the wall of the internal and external cylinders, however, the results on the wall of external cylinder are exactly the reverse. Consequently, by changing the effective parameters used in this paper, the flow of the fluid can be controlled and the heat transfer of the fluid can be improved.


2004 ◽  
Vol 46 (2) ◽  
pp. 237-248 ◽  
Author(s):  
Hazem A. Attia ◽  
Mohamed E. S. Ahmed

AbstractThe steady flow of an incompressible viscous non-Newtonian electrically conducting fluid and heat transfer due to the rotation of an infinite disk are studied considering the Hall effect. The effects of an externally applied uniform magnetic field, the Hall current, and the non-Newtonian fluid characteristics on the velocity and temperature distributions as well as the heat transfer are considered. Numerical solutions of the nonlinear equations which govern the magnetohydrodynamics (MHD) and energy transfer are obtained over the entire range of the physical parameters.


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