scholarly journals Numerical Investigation for the Modeling of the Magnetic Buoyancy Force during the Natural Convection of Air in a Square Enclosure

2014 ◽  
Vol 6 ◽  
pp. 873260 ◽  
Author(s):  
Kewei Song ◽  
Toshio Tagawa ◽  
Liang-bi Wang ◽  
Hiroyuki Ozoe
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
Buoyancy Force ◽  
Nonuniform Magnetic Field ◽  
Temperature Fields ◽  
Two Dimensional ◽  
Numerical Computations ◽  
Square Enclosure ◽  
Magnetic Buoyancy ◽  
Magnetizing Force

Numerical computations are carried out for natural convection of air in a two-dimensional square enclosure under a nonuniform magnetic field and together with the gravity field. The nonuniform magnetic field is supplied by a cubic permanent magnet placed above the enclosure. Two kinds of the expressions for the magnetizing force are considered and compared in the numerical computations. The flow and temperature fields, the magnetizing force field and the Nusselt number for two kinds of magnetizing force expressions are all presented in this paper. The numerical results reveal that the natural convection inside the enclosure does not depend on the types of the expressions for magnetizing force.

scholarly journals Soret effects due to natural convection between inclined plates with magnetic field

1970 ◽  
Vol 39 (2) ◽  
pp. 65-70 ◽  
Author(s):  
MC Raju ◽  
SVK Varma ◽  
PV Reddy ◽  
Sumon Saha
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
Binary Mixture ◽  
Thermal Diffusion ◽  
Buoyancy Force ◽  
Dimensionless Parameter ◽  
Perturbation Technique ◽  
Flow And Heat Transfer ◽  
Parameter Measuring ◽  
Inclined Plates

The effect of small uniform magnetic field on separation of a binary mixture for the case of a fully developed natural convection between two heated inclined plates has been investigated in this paper. Neglecting the induced electric field the equations governing the motion, temperature and concentration are solved by simple perturbation technique, in terms of dimensionless parameter measuring buoyancy force. The expressions for velocity, temperature and concentration are obtained. The effects of Hartmann number (M), thermal diffusion number (td), the buoyancy force parameter (N) and the inclination angle (ψ) of the plates with the horizontal are studied on the flow and heat transfer quantities. Keywords: Natural convection, thermal diffusion, magnetic field, incompressible fluid, binary mixture. doi:10.3329/jme.v39i2.1848 Journal of Mechanical Engineering, Vol. ME39, No. 2, Dec. 2008 65-70

Numerical Study of Joint Magnetisztion and Gravitational Convection of Air in a Square Enclosure under Quadrupole Magnetic Field

2011 ◽  
Vol 354-355 ◽  
pp. 190-194
Author(s):  
Chang Wei Jiang ◽  
Er Shi ◽  
Xian Feng Zhu ◽  
Zhen Zhou
Keyword(s):  
Magnetic Field ◽  
Magnetic Force ◽  
Numerical Study ◽  
Simple Algorithm ◽  
Potential Method ◽  
Temperature Fields ◽  
Square Enclosure ◽  
Gravitational Fields ◽  
Nusselt Numbers ◽  
Scalar Magnetic Potential

Numerical computations were carried out for theromagnetic convection of air in a square enclosure under both magnetising and gravitational fields. Scalar magnetic potential method was used to calculate magnetic field. The governing equations in primitive variables were discretized by the finite-volume method and solved by the SIMPLE algorithm. The flow and temperature fields for the air natural convection were presented and the local and mean Nusselt numbers on the walls were calculated and compared. The results show that the magnetic force has significant effect on the flow field and heat transfer in a square enclosure, the average Nusselt number respects the trend of decrease first and then increase when the magnetic force number increases.

Three-Dimensional Numerical Analysis for Convection of Air in a Bore Space of a Superconducting Magnet

2003 ◽  
Author(s):  
G. Tomita ◽  
M. Kaneda ◽  
T. Tagawa ◽  
H. Ozoe
Keyword(s):  
Magnetic Field ◽  
Heat Flux ◽  
Natural Convection ◽  
Numerical Analysis ◽  
Strong Magnetic Field ◽  
Three Dimensional ◽  
Superconducting Magnet ◽  
Constant Heat Flux ◽  
Constant Heat ◽  
Magnetizing Force

Three-dimensional numerical computations were carried out for the natural convection of air in a horizontal cylindrical enclosure in a magnetic field, which is modeled for a bore space of a horizontal superconducting magnet. The enclosure was cooled from the circumferential sidewall at the constant heat flux and vertical end walls were thermally insulated. A strong magnetic field was considered by a one-turn electric coil with the concentric and twice diameter of the cylinder. Without a magnetic field, natural convection occurs along the circumferential sidewall. When a magnetic field was applied, magnetizing force induced the additional convection, that is, the cooled air at the circumferential wall was attracted to the location of a coil. Consequently, the temperature around the coil decreased extensively.

Hot-Film Measurement of Natural Convection in Liquid Gallium With and Without Magnetic Fields

Volume 1 ◽  
2004 ◽  
Author(s):  
B. Xu ◽  
B. Q. Li ◽  
D. E. Stock
Keyword(s):  
Magnetic Field ◽  
Temperature Field ◽  
Natural Convection ◽  
External Magnetic Field ◽  
Narrow Range ◽  
Temperature Fields ◽  
Liquid Gallium ◽  
Numerical Predictions ◽  
Velocity And Temperature Fields ◽  
Hot Film

The velocity and temperature fields induced by natural convection in liquid gallium were measured. Measurements were taken with and without an external magnetic field applied to the liquid gallium. The velocity field was measured with a hot-film anemometer and the temperature field with a thermocouple. The hot film was calibrated over a narrow range of temperatures in a rotating turntable filled with liquid gallium. The external magnetic field damped both the velocity and temperature fields compared to similar conditions when no external magnetic field was present. The experimental results compared reasonably well with previous numerical predictions.

An asymptotic model of two-dimensional convection in the limit of low Prandtl number

1981 ◽  
Vol 102 ◽  
pp. 75-83 ◽  
Author(s):  
F. H. Busse ◽  
R. M. Clever
Keyword(s):  
Nusselt Number ◽  
Prandtl Number ◽  
Buoyancy Force ◽  
Close Agreement ◽  
Preceding Paper ◽  
Critical Value ◽  
Temperature Fields ◽  
Asymptotic Model ◽  
Two Dimensional ◽  
Velocity And Temperature Fields

An approximate solution of two-dimensional convection in the limit of low Prandtl number is presented in which the buoyancy force is balanced by the inertial terms. The results indicate that inertial convection becomes possible when the Rayleigh number exceeds a critical value of about 7 × 103. Beyond this value the velocity and temperature fields become independent of the Prandtl number except in thin boundary layers. The convective heat transport approaches the law Nu = 0·175 R¼ for the Nusselt number Nu. These results are in reasonably close agreement with the numerical results described in the preceding paper by Clever & Busse (1980).

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