LAMINAR NATURAL-CONVECTION HEAT-TRANSFER IN AN ECCENTRIC RHOMBIC ANNULUS

The effect of vertical eccentricity on natural convection in a rhombic annulus is studied numerically for enclosure gap values (E(g)) of 0.5 and 0.75, eccentricity (is-an-element-of) values from -0.25 to 0.25, and Rayleigh numbers (Ra) from 10(4) to 10(8). Negative values of is-an-element-of (inner rhombus displaced downward) lead to an increase in heat transfer. At low Ra there is a critical positive is-an-element-of for which the flow strength is a maximum. At high Ra, increasing positive is-an-element-of results in a decrease in the flow strength and heat transfer. For any is-an-element-of > 0 there is a critical Ra, beyond which there is a decrease in the total heat transfer. This critical Ra increases with decreasing E(g) values.