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Numerical Heat Transfer, Part A: Applications
An International Journal of Computation and Methodology
Volume 71, 2017 - Issue 10
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Original Articles

Numerical study of MHD natural convection in a rectangular enclosure with an insulated block

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Pages 1004-1022 | Received 23 Jan 2017, Accepted 27 Apr 2017, Published online: 16 Jun 2017
 

ABSTRACT

The present study numerically investigates the two-dimensional laminar natural convection in a differently heated rectangular enclosure with an insulated square block, in the presence of a uniform magnetic field applied in the horizontal direction. Numerical simulations were performed for the conditions of different Rayleigh and Hartmann numbers with a fixed Prandtl number. The heat transfer rate decreases with the increase in the intensity of the magnetic field. It was found that the insertion of an insulated block contributes to the enhancement of the heat transfer rate in certain ranges of the block size and the Hartmann number.

Nomenclature

AR=

area ratio of block and enclosure

B=

magnitude of the magnetic field flux (kg/s2 A)

Cp=

specific heat at constant pressure (J/kg K)

g=

gravitational acceleration (m/s2)

Ha=

Hartmann number

k=

thermal conductivity (W/m K)

L=

length of enclosure (m)

p=

dimensionless pressure

P=

pressure (N/m2)

Pr=

Prandtl number

Ra=

Rayleigh number

t=

time (s)

T=

temperature (K)

u, v=

velocity components in the x-direction and the y-direction (m/s)

U, V=

dimensionless velocity components in the X-direction and the Y-direction

x, y=

Cartesian coordinates (m)

X, Y=

dimensionless Cartesian coordinates

α=

thermal diffusivity (m2/s)

β=

thermal expansion coefficient (1/K)

θ=

dimensionless temperature

µ=

dynamic viscosity (kg/m s)

ν=

kinematic viscosity (m2/s)

ρ=

density of fluid (kg/m3)

σ=

electrical conductivity of fluid (S/m)

τ=

dimensionless time scale

Subscripts=
C=

cold

H=

hot

Nomenclature

AR=

area ratio of block and enclosure

B=

magnitude of the magnetic field flux (kg/s2 A)

Cp=

specific heat at constant pressure (J/kg K)

g=

gravitational acceleration (m/s2)

Ha=

Hartmann number

k=

thermal conductivity (W/m K)

L=

length of enclosure (m)

p=

dimensionless pressure

P=

pressure (N/m2)

Pr=

Prandtl number

Ra=

Rayleigh number

t=

time (s)

T=

temperature (K)

u, v=

velocity components in the x-direction and the y-direction (m/s)

U, V=

dimensionless velocity components in the X-direction and the Y-direction

x, y=

Cartesian coordinates (m)

X, Y=

dimensionless Cartesian coordinates

α=

thermal diffusivity (m2/s)

β=

thermal expansion coefficient (1/K)

θ=

dimensionless temperature

µ=

dynamic viscosity (kg/m s)

ν=

kinematic viscosity (m2/s)

ρ=

density of fluid (kg/m3)

σ=

electrical conductivity of fluid (S/m)

τ=

dimensionless time scale

Subscripts=
C=

cold

H=

hot

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