Investigation of heat transfer enhancement of Cu-water nanofluid by different configurations of double rotating cylinders in a vented cavity with different inlet and outlet ports

In this study, four novel configurations of rotating cylinders in cavity with multiple ports in the presence Cu water nanofluid are proposed. A set of case studies are conducted to analyze the effect of the main contributing factors; Reynolds numbers, Rotational Reynolds numbers, the nanofluid volume fraction, position of inlet and outlet ports, and cylinders configurations (A, B, C, and D) on the flow and heat transfer characteristics. The mean Nusselt number and Performance Evaluation Criteria (PEC) are implemented to achieve the most suitable system for various situations, as well as finding the efficiency of these configurations. The results show that increasing the nanofluid volume fraction and the rotational Reynolds number cause the mean Nusselt number and PEC to increase. Also, the results indicate that there is an optimum point, at Re = 600, which the mean Nusselt number and PEC are maximized for configuration A. Results indicate that configuration C with inlet port I1 and outlet port O1 has the highest heat transfer enhancement, while configuration C with inlet port I1 and outlet port O2 is much beneficial than the other configurations in terms of the overall PEC criteria of both cylinders.