NEW BOUNDED SKEW CENTRAL DIFFERENCE SCHEME .2. APPLICATION TO NATURAL-CONVECTION IN AN ECCENTRIC ANNULUS

The bounded skew central difference scheme (NVF SCDS) [1] is used to s tudy numerically the combined effect of vertical (epsilon(y)) and hori zontal (epsilon(x)) eccentricities on natural convection in an annulus between a heated horizontal cylinder and its square enclosure. Four R ayleigh numbers (Ra = 10(3), 10(4), 10(5), and 10(6)), three aspect ra tios (R/L = 0.1, 0.2 and 0.3), and eccentricity values ranging from -0 .3 to 0.3 are considered. At constant enclosure aspect ratio, the tota l heat transfer increases with increasing Rayleigh number. For constan t Rayleigh-number values, convection contribution to total heat transf er decreases with increasing values of R/L. For conduction-dominated f lows, heat transfer increases with increasing \epsilon(y)\ and/or \eps ilon(x)\. For convection-dominated flows, heat transfer increases with decreasing epsilon(y) for epsilon(y) < 0, decreases with increasing e psilon(y) for epsilon(y) > 0 and decreases with decreasing epsilon(x) for epsilon(x) < 0. For the case when conduction and convection are of equal importance, there is a critical epsilon(x) for which the total heat transfer is minimum.