Abstract
A finite volume model is developed for analyzing transient natural convection in vertical annuli, which are assumed to be isothermally heated (or cooled) from the inner surface and insulated from horizontal and outer surfaces. Based on the numerical results, the dependence of transient heat transfer on governing dimensionless parameters is investigated. It is found that the dimensionless accumulated heat transfer as a function of dimensionless time can be satisfactorily approximated by a simple correlation, which explicitly includes the effects of the Rayleigh and Prandtl numbers as well as the enclosure aspect ratio and height-inner radius ratio.
Acknowledgments
This work was supported by a grant from the U. S. Department of Energy (DE-FG36-08GO18146).