Heat Transfer Characteristics of Vertical Curved Annular Insulation Layer Numerical Analysis of Three-Dimensional Natural Convection in Porous Medium, (2)

Numerical analysis has been performed on three-dimensional natural convective heat transfer characteristics in a porous medium enclosed with a vertical concentric curved annulus with relation to the thermal insulation layer in the high temperature ducting system of HTGR. The Darcy's law and the Boussinesq's approximation are assumed to be applicable. Governing equations are transformed into the finite difference equations which are numerically solved by means of successive over-relaxation procedure for a range of RaDa (a product of Rayleigh number Ra and Darcy number Da) from 100 to 800. Two typical cases of vertical arrangement A and B were analyzed and compared each other. Results show that the flow field and the temperature profile have both characteristics of those for horizontal and vertical annulli, and the insulation performance in Case B becomes worse compared with Case A for all over the range of RaDa. Available informations were obtained with respect to the thermal insulation design of high temperature ducting system.