Shahrood University of Technology Journal of Solid and Fluid Mechanics 2251-9475 16 1 2026 03 21 Thermo-Hydraulic Performance of Shell-and-Tube Heat Exchangers with Twisted Oval Tubes Thermo-Hydraulic Performance of Shell-and-Tube Heat Exchangers with Twisted Oval Tubes 81 90 3792 10.22044/jsfm.2026.16155.3970 FA Mansour Talebi Nuclear Science and Technology Research Institute SIna Poultangari Islamic Azad University, Isfahan, Iran Mohammad Amin Borhani Shahid Beheshti University Journal Article 2025 05 08 A twisted tube heat exchanger is a type of heat exchanger with an elliptical cross-section. This study aims to evaluate the effects of tube geometry on heat transfer performance and pressure drop. Using computational fluid dynamics (CFD), the thermohydraulic behavior of these heat exchangers was analyzed through three-dimensional modeling. Simulations were carried out for various elliptical aspect ratios and fluid velocities. The analyses were performed in ANSYS Fluent using the k-ε turbulence model.<br /><br />The simulation results show that wall heat flux increases by approximately 25% at a Reynolds number of 1350 as the aspect ratio increases from 1 (circular) to 2, indicating improved heat transfer with more elongated ellipses up to that point. However, increasing the aspect ratio beyond 2 (up to 4) results in minimal changes in heat flux. At lower velocities, the impact of the aspect ratio on heat transfer becomes more pronounced. Furthermore, the pressure drop increases by about 17% at a Reynolds number of 2000 when the aspect ratio rises from 1 to 2. These findings can be applied to the design of more efficient oval tube heat exchangers A twisted tube heat exchanger is a type of heat exchanger with an elliptical cross-section. This study aims to evaluate the effects of tube geometry on heat transfer performance and pressure drop. Using computational fluid dynamics (CFD), the thermohydraulic behavior of these heat exchangers was analyzed through three-dimensional modeling. Simulations were carried out for various elliptical aspect ratios and fluid velocities. The analyses were performed in ANSYS Fluent using the k-ε turbulence model.<br /><br />The simulation results show that wall heat flux increases by approximately 25% at a Reynolds number of 1350 as the aspect ratio increases from 1 (circular) to 2, indicating improved heat transfer with more elongated ellipses up to that point. However, increasing the aspect ratio beyond 2 (up to 4) results in minimal changes in heat flux. At lower velocities, the impact of the aspect ratio on heat transfer becomes more pronounced. Furthermore, the pressure drop increases by about 17% at a Reynolds number of 2000 when the aspect ratio rises from 1 to 2. These findings can be applied to the design of more efficient oval tube heat exchangers https://jsfm.shahroodut.ac.ir/article_3792_d740c0aad12563c68fc04df28c3818fe.pdf