Fluid visualization and heat-transfer tests in a 180-deg round turned channel with a perforated divider

This study provided a new configuration of the 180-deg round turned channel with a perforated divider, as well as experimentally investigated the effect of perforations on the fluid flow and heat transfer. The flow visualizations and heat-transfer tests indicated that the big diameter of perforation and the positive angle of perforation changed the fluid flow pattern and the local Nusselt-number distribution strongly by comparing those of non-perforation system. The big-diameter perforations decreased the average Nusselt number, especially at the positive angle of perforations; while the number and location of perforations did not result in obvious influence herein. Besides, the average Nusselt number for the system of small perforations was about 3-8% higher than that of non-perforation one. Therefore, this work demonstrated that by adjusting the size and angle of perforations, this new cooling channel could achieve spatial thermal regulation or enhance the total heat transfer.