Development of improved heat transfer of double helical pipe heat exchangers using nano-fluids and perforated curved tabulators

作者：Lotfi Ben Said, Ali B.M. Ali, As’ad Alizadeh, Kuwar Mausam, Saurav Dixit, Rifaqat Ali, Mohammed A. Tashkandi, Lioua Kolsi · 发表于：Case Studies in Thermal Engineering · 年份：2025 · DOI：10.1016/j.csite.2025.106106 · 被引用次数：16 · 研究领域：Heat Transfer and Optimization、Nanofluid Flow and Heat Transfer、Heat Transfer Mechanisms

This study examines a helical double-pipe heat exchanger's thermal and fluid flow performance incorporating a curved perforated turbulator and hybrid nanofluids. Two nanofluids, Al 2 O 3 -TiO 2 /water, and Ag-HEG/water, were compared with pure water and a baseline case without a turbulator to evaluate heat transfer enhancement. The research is divided into two phases. In the first phase, the thermal and hydrothermal behavior of two hybrid nanofluids—Al 2 O 3 -TiO 2 /water and Ag-HEG/water—was evaluated and compared to pure water and a baseline case without turbulators to assess their effectiveness. In the second phase, the influence of nanoparticle volume concentration (φ 1 = φ 2 ) of the selected hybrid nanofluid according to the results obtained from the first section, Al 2 O 3 -TiO 2 /water, was analyzed over a range of 0.1–0.5. The curved turbulator, featuring inner ribs and perforations, was designed to induce swirl flows, enhance fluid mixing, and disrupt thermal boundary layers to improve heat transfer. The numerical analysis was performed using the finite volume method in a commercial code. The findings of the first section show that Al 2 O 3 -TiO 2 /water achieves the highest heat transfer rate; its heat transfer coefficient is about 1.04 %, 2.63 %, and 18.19 % greater than cases with Ag-HEG/water, pure water, and without turbulator, respectively at Re = 14,000. However, the thermal performance factor of the case without a turbulator is more significant than that of ...