Numerical study of the laminar natural convection heat transfer from three attached horizontal isothermal cylinders

Abstract

Based on the model by Bejan et al., natural convection heat transfer, from three attached horizontal isothermal cylinders immersed in quiescent air in an inverted triangular array, has been numerically investigated over 10 ? Ra ? 106. The representative results made up of streamlines and isothermal contours, local and average Nusselt number have been showed. It can be seen there exist several vortexes in the wake region of the downstream cylinders because of the strong interaction of two merging plumes. Additionally, with the effect of the vortex and the preheating among three attached cylinders, the average heat transfer rate for the whole configuration has been reduced by about 38.7~58.5% compared with single cylinder. Finally, average Nusselt number for this configuration has been correlated with Rayleigh number, which provides a valid prediction for engineering calculation including this kind of fundamental configuration