An integrative approach using axial fins, numerical assessment, and experimental data analysis in helical heat exchangers

In this study, the assessment of heat transfer in a helical coil heat exchanger with double, triple, and quadruple axial fins was conducted numerically. The impact of varying fin heights and thicknesses on heat transfer was analyzed. Experimental measurements of fluid thermal conductivity and dynamic viscosity were conducted and then incorporated into the simulations. Additionally, the effects of using SiO2, CuO, and CeO2 with a volume fraction of 0.5%, as well as a hybrid nanofluid containing CuO and CeO2 nanoparticles mixed with water, were explored. Results indicated a 4.97% improvement in the Nusselt number with quadruple fins compared to the triple fins model at a Reynolds number of 30,000. Axial fins in proposed heat exchanger enhance heat transfer by increasing the surface area and promoting turbulence, which disrupts the thermal boundary layer and improves fluid mixing. Furthermore, at Re = 15,000, a 21.3% increase in the friction factor was observed for the model with a 0.5 mm fin thickness compared to the base model, attributed to the promotion of turbulent flow. Moreover, a 0.39% enhancement in the outlet temperature was illustrated by altering the axial fins' height. Finally, an 8.4% increment in the thermal performance of the proposed helical coil heat exchanger at a Reynolds number of 30,000 was achieved through the utilization of a hybrid nanofluid.