Limiting Values for Free-Convection Induced Flow Rates in Vertical Eccentric Annuli with an Isothermal Boundary

Abstract

Fully developed laminar natural convection in vertical eccentric annuli has been investigated under fundamental thermal boundary conditions of the first and third kinds. For conditions of the first kind, numerical solutions are presented showing the effect of eccentricity on the velocity profiles and the local Nusselt number in an annulus of radius ratio 0.5. Limiting values for the induced flow rate and the average Nusselt numbers are presented for a fluid of Pr = 0.7 over wide ranges of eccentricity and annulus radius ratio (0.1-0.9). Closed-form analytical solutions are obtained for fundamental conditions of the third kind and the corresponding variations in the limiting induced flow rates with eccentricity are presented.