Effects of delta winglets on performance of wavy plate-fin in PFHEs: Nanofluid as heat transfer media

In the current experimental study, the use of delta winglets to enhance heat transfer in wavy plate-fins (WPFs) is proposed in presence of Al 2 O 3 /water nanofluid. Impacts of the most effective parameters, including waviness aspect ratio ( γ = 0.33, 0.42, and 0.51), winglets height ( h = 2, 4, and 6 mm), nanoparticles mass fraction (0–0.4%), and Reynolds number (4500–11,500), are examined. In order to prepare the nanofluids, a two-step method is adopted, alpha aluminum oxide nanoparticles as additive and deionized water as base fluid. The results depict that the use of proposed geometries leads to a considerable heat transfer enhancement in plate-fin heat exchangers, especially at the highest values of waviness aspect ratio and winglets height. However, optimum thermal–hydraulic performance is detected for a specific geometry of WPF with γ = 0.42 and h = 6 mm. To evaluate the performance of WPFs with prepared nanofluids, variations of heat transfer coefficient and pressure drop are reported regarding to the based fluid. The maximum heat transfer enhancement of 11.3% is observed for 0.4% nanofluid flow over the WPF with γ = 0.51 and h = 6 mm.