MULTIGRID COMPUTATION OF NATURAL-CONVECTION IN ENCLOSURES WITH A CONDUCTIVE BAFFLE

Conjugate heat transfer has been investigated in a two-dimensional squ are enclosure with a conducting vertical baffle of finite thickness an d varying height. The horizontal end walls are assumed to be adiabatic , and the vertical walls are at constant but different temperatures. C alculations are made by a staggered, finite volume multigrid procedure . The performance of the multigrid method in accelerating the converge nce rate is remarkable by comparison with the usual iterative method. The influence of inserting a baffle into the buoyancy-driven square ca vity on the heat transfer, as well as on the temperature distribution and velocity field, has been obtained for various Rayleigh numbers Ra, solid / fluid conductivity ratio k, dimensionless baffle height H, a nd baffle location L. Predicted flow patterns and isotherms indicate t hat the effect of inserting baffles of varying height upon the overall heat transfer and local temperature profiles in the cavity is limited , except when the height of baffle is large (H > 0.5). The effect of c onductivity is also found to be marginal. However, both the height and the conductivity become very important when the baffle is located ver y near the hot wall or cold walls.