Heat transfer and flow characteristics for turbulent flow in a heat exchanger tube with drumet-cut twisted tape inserts: A numerical analysis and correlation development

To improve the transfer of heat in a heat exchanger tube equipped with novel drumet-cut twisted tape (DCTT), this research presents a numerical model. Investigation of Nusselt number (Nu), friction factor (f), and thermal performance (η) in turbulent flow has been reported with the depth of cut (4 mm ≤ b ≤ 13 mm), and width of cut (11 mm ≤ c ≤ 17 mm) of DCTT over Reynolds number (10,000 ≤ Re ≤ 22,000) using ANSYS FLUENT. The reliability of the k −ε RNG turbulence model is established by comparison with all other existing models in the current study. The Nu from Dittus − Boelter and f from Blasius correlation are employed to validate the proposed numerical model. The DCTT-equipped tube produces extra flow and whirling of the flow around the cuts. This generated flow assists in the transfer of heat and pressure drop between the tube’s near-wall area and core. The near-wall fluid’s centrifugal motion and improved mixing caused by the drumet-cut have a significant impact on the fluid region’s friction factor properties and heat transfer. The results indicate that DCTT exhibits improvements of up to 16.06%, 27.73%, and 8.29% in the Nu, f, and η respectively when compared to plain twisted tape (PTT). It is found that b of 13 mm yields the highest η of 1.259 at Re 10,000. It has also been compared to existing works, and the proposed geometry shows excellent performance. In addition, the correlations for Nu, Nu/Nup, f, f/fp, and η are established for DCTT inserts, and it turned out that their deviations are within ±7%, ±5%, ±12%, ±9%, and ±8% respectively. It is anticipated that this numerical analysis would aid academics and engineers in the design of contemporary heat exchangers.