Investigate effect of the pitch and helical fins height on the hydrothermal performance of the double‐pipe heat exchanger

This study explores the impact of pitch and helical fin height on the hydrothermal performance of a two‐tube heat exchanger. Both numerical and experimental analyses were employed to investigate how different fin geometries influence pressure drop, heat transfer efficiency, and overall system performance. Six new models, denoted as Models B to G, featuring various helical fin configurations with distinct heights and angles using smooth copper plate fins, were developed alongside the traditional model (Model A), while maintaining the tube specifications of Model A. The findings demonstrate that helical fin angle and height play a significant role in shaping the thermal and hydrodynamic characteristics of the heat exchanger. Optimal fin configurations were identified to enhance heat transfer effectiveness while minimizing pressure losses, offering valuable insights for the design of efficient two‐tube helical fin heat exchangers and underscoring the importance of geometric parameters in enhancing hydrothermal performance. The evaluation of the seven models under consistent conditions revealed notable enhancements. For instance, Model D exhibited a Nusselt number 56.5% higher than the conventional model, while Model F displayed a 51.84% increase. Models D and F achieved variation coefficients in the overall performance factor (OPF) of 1.63 and 1.12, respectively, surpassing the traditional model. Additionally, two equations derived from multiple regression analysis were formulated to establish relationships between the Nusselt number and friction factor with parameters such as the Reynolds number, Prandtl number, and fin pitch/height ratio.