Effects of Geometrical Parameters and Physical Properties Variation on Transient Natural. Convection and Conduction of High Prandtl Number Fluid in Enclosures

The transient laminar natural convection and conduction of high Prandtl number (Pr = 1.9 × 104) fluid with variable viscosity in a cavity bounded with massive walls is numerically studied. Initially the fluid in the cavity is considered to be at rest at constant temperature and the temperature of the six walls is set to constant value through the cooling process. The effect of wall thickness (20% and 40% cavity length), aspect ratio (1 and 0.5) and Rayleigh number (1.4 × 106 and 2.7 × 107) is studied. The time evolution of the flow patterns, the temperature contours and Nusselt number correlation are presented and analyzed.