Natural Convection Heat Transfer Enhancement of Circular Obstacle within Square Enclosure

The natural convection heat transfer within the enclosure is a classical problem by highlighting the real field applications such as electronic packaging industry, PCR-chips for DNA amplification, energy-efficient design of buildings rooms, operation and safety of nuclear reactors, convective heat transfer within boilers, furnaces and solar systems and thermal energy storage. Hence, the present study numerically investigates the flow and heat transfer characteristics within the square enclosure having the heated circular obstacle at the middle with an air of constant thermophysical properties is considered as working fluid. Also, the study continues after introducing winglets at different angles, i.e. 0 0 , 30 0 , 45 0 , 60 0 , 70 0 and 90 0 . The detailed hydrodynamic and thermal boundary conditions that are required considered and mentioned. The influence of circular obstacle with and without winglets has been reported by comparing velocity and vorticity magnitude also estimating natural convection heat transfer from obstacles. The heat transfer of the enclosure is maximum when the winglet is placed at 45 0 , because of the flow confinement provided and also allowing the fluid to interact more with the hot obstacle and carries more heat. In highest Rayleigh number, the following heat transfer enhancement has been achieved, circle-circle with winglet @ 45 0 = 10.58%.