Mechanics of heat transfer through twisted tape fitted in heat exchanger tube in turbulent regime

A heat exchanger (HE) is one of the essential thermal devices for transferring heat energy, which is frequently employed in many thermal applications such as chemical, petrochemical, steel, glass, and coal industry. ANSYS Fluent 19.2 was utilized to investigate the Nusselt number (Nu), friction factor (f), and thermo-hydraulic performance index (eta) in a turbulent flow tube with plain twisted tape (PTT). The effect of twist ratios (3 <= p/w <= 5) is examined for 10,000 <= Re <= 22,000 in a tube of diameter 20 mm. In this article, all known turbulence models are compared, and the RNG (k - epsilon) turbulence model is determined to be accurate. Regarding heat transfer and thermo-hydraulic performance, plain twisted tape outperforms plain tube (PT). The twisted tape design, which causes swirl flow, intensifies this effect by disrupting thermal boundaries and enhancing fluid mixing. The optimum thermo-hydraulic performance of 1.09 is achieved for p/w = 3 at Re = 10,000. Moreover, the performance of PTT is further compared with existing literature, and it was found that PTT performs better for all the values of the Reynolds number.