In order to improve performances, in terms of higher thermodynamic efficiency and power output for heat exchanging devices like solar air heaters, heat exchangers and machines like gas turbines, the study of heat transfer mechanism and fluid flow play a vital role. Thermal assessment of heat exchanging devices, computational fluid dynamics (CFD) approach has advantages over the cost effecting practical experiments. To understand the complete phenomenon of heat transfer, heat flow as well as fluid flow must be considered in numerical analysis. Hence, accurate numerical method turbulence model and equation solving approach are required to predict heat transfer behaviour.