Magneto-convection of water near its maximum density in a cavity with partially thermally active walls

Abstract

The main objective of the present numerical investigation is to understand the effect of partially active thermal zones and density inversion on the buoyancy-driven convection of cold water near its maximum density under the influence of uniform magnetic field inside a square cavity. The partially heated or cooled zones are placed along the vertical sidewalls of the cavity while the other inactive portions of the walls are considered to be adiabatic and thermally insulated. The length of the partially active thermal zones is measured to be equal to half the length of the cavity’s height. When the locations of heating and cooling zones are placed in different positions, it provides a significant effect on flow pattern and the rate of heat transfer. To investigate this location effect, the thermally active zones are placed in a combination of five different relative positions along the vertical sidewalls. The modeled equations are solved using finite volume method with Semi-Implicit Method for Pressure Linked Equation algorithm. The numerical coding is done through the FORTRAN 95 programming for numerical simulation and the results attained are represented graphically in the form of flow field and temperature distribution for various values of density inversion parameter, Hartmann number, and for various positions of thermal zones. The results reveal that the heat transfer rate behaves nonlinearly on increasing the density inversion parameter values. The high transfer rate is perceived for the location middle–middle when $T_m<0.5$ and for top–bottom when $T_m\ge 0.5$ for all values of the Hartmann number.