Convective cooling of tandem heated squares in a channel

Abstract

This article elaborates on the numerical simulation of forced convective incompressi-ble flow in a horizontal plane channel and heat transfer over two isothermal tandem square cylinders. Finite-volume method was applied to discretize the momentum and energy equations. This study details the effects of S/H (gap between two squares), Reynolds number, and blockage ratio on the characteristics of flow field and heat transfer. The blockage ratios and Reynolds numbers were chosen between 12.5 to 50 per cent and 100≤Re≤300, respectively. Results are presented in the form of time-averaged streamlines, instantaneous contours of temperature and vorticity, and some characteristics of fluid flow and heat transfer such as time-averaged of the local and total Nusselt number, drag coefficient, and Strouhal number. The present results show that the gap spacing between squares at high blockage ratios does not have an obvious effect on heat transfer. On the other hand, this parameter plays a main role on the drag coefficient at a high value (S/H=4), which is because of the formation of the vortex cores in gap spacing and downstream of the second square. The heat transfer rate of the second square increases with the increase of S/H. Increasing the blockage ratio has a negative effect on convective heat transfer of the second square. With the vortex shedding in the gap spacing, the drag coefficient and the Nusselt number both increase in the second square in comparison to the first square.