NATURAL CONVECTION OF VISCOPLASTIC FLUIDS IN AN ENCLOSURE WITH LOCALIZED HEATING AND SYMMETRICAL COOLING

In this study a computational investigation of two-dimensional, steady-state, natural convection of viscoplastic fluid in a square enclosure has been presented. The enclosure has been locally heated from the bottom wall using a constant heat flux source and symmetrically cooled from both the side walls. The other walls are maintained as insulated surfaces. Finite volume based code has been used in the simulation and Bingham model has been used to model the rheology of the enclosed viscoplastic fluids. Simulations have been made for three different heating lengths of the bottom wall. The flow phenomenon and heat transfer inside the enclosure have been investigated for different properties of viscoplastic fluid, heating conditions and heated length. It has been observed that for a particular thermal condition the heat transfer coefficient or the Nusselt number decrease with the increase in yield stress value of the fluid due to weakening of convective circulation.