Numerical simulation of conjugate forced turbulent heat convection with induced natural laminar convection in a 2D inner cavity

Unsteady natural convection process of a fluid inside an inner walled vessel caused by an external forced turbulent convective flow of air in a rectangular duct has been analyzed numerically for Re = 5000; Re = 22,000. Fluid mechanics and conjugate convective heat transfer, for both inner fluid (water) and outer fluid (air), described in terms of continuity, linear momentum, k-ε turbulence model and energy equations were predicted by using the finite-volume method (FVM). Results for the streamlines, isotherms, local Nusselt numbers along the cavity walls and the average friction factor are presented. A comparison between obtained results for both Reynolds number is made. In general, it was found that the cooling process is improved up to 79% when Re number is increased from 5000 to 22,000; and the fluid mechanics characteristics inside the vessel is not considerable affected by the velocity inlet of the cooling air.