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ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

NUMERICAL SIMULATION FOR NONLINEAR CHARACTERS OF NATURAL CONVECTION IN AN ANNULUS WITH AN INTERNAL CONCENTRIC SLOTTED CYLINDER

Get access (open in a dialog) DOI: 10.1615/IHTC13.p9.170
9 pages

Resumo

To be presented in this paper are nonlinear characters of natural convection in an annulus with an internal concentric slotted cylinder. The engineering background of this work is natural convection heat transfer in enclosed isolated-phase buses used in power plants. Numerical simulations have been performed using SIMPLE algorithm with QUICK scheme for the nonlinear phenomena of natural convection, and oscillation and bifurcation are studied. For the numerical simulations, an unsteady mathematical model is adopted and the whole annulus with an internal concentric slotted cylinder is taken as the solution domain. It can be found from the numerical results that even though the all boundary conditions are steady and symmetrical about the vertical central line, the flow and heat transfer in the annulus are oscillatory and unsymmetrical when the Rayleigh number is over a critical value Rac2, and when the Rayleigh number is over another critical value Rac1, two different flow patterns can be obtained using different initial conditions, i.e. the numerical solution is not unique. The values of two critical Rayleigh numbers Rac1 and Rac2 are dependent on the slot width S of slotted inner cylinder. Rac1 and Rac2 at different slot widths are given numerically in this paper by gradual approaching method.