Numerical Simulation of Natural Convection in Horizontal Hexagonal Honeycomb.

The numerical study on natural convection in a horizontal hexagonal honeycomb enclosure was performed, the results of flow and heat transfer were obtained on adiabatic side wall thermal boundary condition for Rayleigh numbers in the range of 500 to 10⁵. The finite volume method with SIMPLEC algorithm was used in the numerical calculation, and the temperature dependency of the fluid properties was considered. The numerical results show that the air in a closed cavity becomes unsteady at Ra = 1 000. The second order upwind scheme and QUICK scheme give almost the same results of flow and heat transfer in the honeycomb, while one order upwind scheme will result in some error. The numerical results also show that the Boussinesq approximation will bring large error for big wall temperature difference. [ABSTRACT FROM AUTHOR]