Numerical Investigation of Hydrothermal Performance Enhancement Using Modified Twisted Tape Having a Curved and Concave Cross-section Inserted in a Horizontal Tube

The present study investigated the enhancement of convective heat transfer in horizontal tubes using twisted tape inserts, particularly emphasizing the influence of modifications to their geometrical configurations. Three twisted tape models were designed using SolidWorks: a plain tape, a tape with curved edges, and a tape with curved edges and holes. Two twist ratios were considered, namely TR۱ = ۶.۶۶۶ and TR۲ = ۵. Computational Fluid Dynamics (CFD) simulations were performed to evaluate the velocity and temperature fields, Nusselt number, and friction factor over a Reynolds number range of ۱۵,۰۰۰–۲۵,۰۰۰. The results indicate that employing twisted tape with curved edges and perforations leads to the greatest enhancement in heat transfer. Specifically, the Nusselt number increases from ۴۱۰ for curved edges without perforations to ۴۶۰, whereas the plain tape achieves ۳۸۰ at Re = ۲۵,۰۰۰ and TR۲. The tape with curved edges (without holes) demonstrated the most favorable improvement in friction factor, attaining a value of ۰.۰۲۴ versus ۰.۰۲۹ for the plain tape, corresponding to a ۲۰.۸% reduction. As a result, the performance evaluation factor achieved a peak value of ۱.۲۴, indicating a ۳۰.۵% improvement. These findings demonstrated that optimized twisted tape geometries significantly enhanced heat transfer performance while maintaining reasonable pressure drop penalties. This highlights their potential applicability in thermal system design, particularly in compact and energy-efficient heat exchangers.

کلیدواژه ها:

Twisted tape ، Hydrothermal performance ، Curved and concave edges ، Horizontal tube ، Heat exchangers