Optimum natural convection from square cylinder in vertical channel

Laminar natural convection from a horizontal isothermal square cylinder inside a vertical adiabatic parallel plate channel is studied using finite difference method. The solution is obtained for the square side length to channel width aspect ratio changed from 0.1 to 0.8. The cylinder is placed at mid-height of the channel at different lateral locations with changeable values for the left to right clearance ratio. The results indicate that the laminar natural convection is significantly affected by the aspect ratio and the lateral position. For any Grashof number, an optimum aspect ratio exists for the maximum heat transfer rate. Central positioning is observed to be the best from the heat transfer point of view. Correlations for the optimum aspect ratio, corresponding Nusselt number and apparent Reynolds number are presented.