Enhancing convective heat transfer in circular tubes is essential for improving energy efficiency in industrial systems, particularly under low-flow conditions. This study employs computational fluid dynamics to systematically analyze the effects of twisted tape inserts with varying lengths and segment numbers on flow and heat transfer performance of water flowing through tubes under uniform wall heat flux. The results demonstrate that twisted tapes generate swirling flow, disrupt the thermal boundary layer, and promote fluid mixing, leading to heat transfer enhancement. While shorter tapes reduce flow resistance, they also decrease the Nusselt number; however, increasing the number of tape segments from one to four raises the average Nusselt number from approximately 14.6 at a Reynolds number of 400 to 24.2 at a Reynolds number of 1800, representing an increase of over 60%, with the four-segment design achieving the highest overall performance evaluation criterion. This work presents a systematic quantification of the effects of tape length and segment number on heat transfer and pressure drop under low Reynolds number conditions, revealing that segmented designs offer a superior balance between heat transfer enhancement and pressure drop penalty compared to continuous twisted tapes, rendering them a practical solution for low-velocity, compact heat exchangers.
Luo et al. (Mon,) studied this question.