Effect of aspect ratio and arrangement of surface-mounted circular cylinders on heat transfer characteristics

The flow and heat transfer characteristics over three rows of circular cylinders mounted on a flat plate have been studied numerically using the commercial software ANSYS Fluent version 15.0. The present three-dimensional investigations aim to determine the effect of the aspect ratio of surface-mounted circular cylinders on heat transfer enhancement and fluid flow characteristics. Both inline and staggered arrangements of cylinders have been considered for Reynolds numbers ranging from 1000 to 4000. The flow field and heat transfer characteristics are studied using streamline plots and temperature contours in various planes. Enhancement in heat transfer is quantified in terms of span-averaged and overall Nusselt number (Nu). Variations in the perimeter-averaged Nu along the height of a cylinder and of height-averaged Nu around the cylinders are presented. The combined effects of heat transfer and pressure drop are expressed in terms of the thermal performance factor (JF) and are evaluated for different cylinder heights and inflow velocities.