Thermohydraulic performance enhancement for flow through circular geometries using curved pins

Passive techniques for enhancing the thermal performance of existing systems show promise for various thermal applications. This study examines the use of curved pins with a rectangular cross-section mounted on the inner surface of a circular tube. These curved pins enhance the fluid's residence time by creating circulation, improving local and average heat transfer coefficients. The research investigates the average heat transfer and pressure drop in circular tubes equipped with curved pins under fully developed turbulent flow conditions. The Reynolds numbers at the inlet range from 10,000 to 50,000. The results reveal that the convective heat transfer coefficient on the inner tube surface can be up to 200% higher than that of a smooth tube. Additionally, the cost-effectiveness of this heat transfer enhancement method is assessed by considering the associated pressure drop using the thermohydraulic performance parameter (R3), which ranges from 0.75 to 1.40.