P. Kandaswamy

Natural convection in a square cavity due to thermally active plates for different boundary conditions

Abstract This work deals with the study of natural convection cooling of thermally active plates placed inside an air filled cavity at the center, with two different boundary conditions imposed on the cavity walls. By an active plate we mean one that is hotter due to isothermal heating or inherent heat generation. The walls of the cavity are subjected to either an isothermal temperature or a uniform outward heat flux. The finite difference method using the alternating direction implicit method coupled with the successive over-relaxation technique is employed to solve the governing nonlinear coupled equations. The results are presented and discussed in terms of a steady state isotherm and streamline plot, and over all Nusselt numbers. This study will provide qualitative suggestions that may improve the thermal design of sealed modern electronic packages which are encountered frequently in the electronics industry.

Natural Convection in a Cavity with Mutually Orthogonal Thermally Active Baffles

Natural convective cooling of two mutually orthogonal thermally active baffles placed inside an air filled square cavity is studied numerically. The active baffles may be either isothermal or heat generating. The flow is assumed to be two-dimensional. The finite difference method using alternating direction implicit method together with successive over relaxation technique is employed to solve the governing coupled nonlinear equations. Computations have been carried out for fixed values of Grashof number and Prandtl number. The effects of different locations of the baffles on the heat transfer characteristics are discussed in terms of steady state isotherm, streamline plots and overall Nusselt number. It is found that a better overall heat transfer can be achieved by placing one of the plates far away from the core region of the cavity in the case of isothermally heated baffles, whereas, no significant change occurs in the case of discretely heat-generating one.