Investigation of various hybrid nanofluids to enhance the performance of a shell and tube heat exchanger

In this study, we aim to investigate the heat transfer and flow characteristics of diverse hybrid nanofluids (CuO-ZnO-Water, EG-Water, CuO-EG-Water, SiO2-EG-Water, and Al2O3-EG-Water) as coolants across eight discrete inlet velocities in a shell and tube heat exchanger. Various materials (copper, stainless steel, titanium, and carbon steel) have been employed for the tubing to optimize system performance. The impact of Reynolds number concerning hybrid nanofluids on Nusselt number and friction factor was assessed in this research. The results of the numerical simulations are found to agree well with experimental results within an average deviation of 1.8%. The results indicated the superior heat transfer capabilities of the hybrid nanofluid compared to the base fluid across all conditions. The outcomes revealed the superior heat transfer capabilities of the CuO-ZnO-Water hybrid nanofluid under all tested conditions. When employing CuO-ZnO-Water as a coolant, a substantial increase of over 9% in temperature reduction was observed, as opposed to the approximately 6% attained by other hybrid nanofluids at a lower velocity of 0.5 m/s. Notably, higher Reynolds numbers corresponded to increased Nusselt numbers and decreased friction factors. The decline percentage of the friction factor was 43% at Reynolds number ranging between 10,000 to 40,000. We emphasize the imperative need to optimize nanoparticle types for crafting hybrid nanofluids to enhance the performance of industrial heat exchangers and their coolant efficiency. Ultimately, the utilization of hybrid nanofluids in conjunction with shell and tube heat exchanger systems has yielded a notable enhancement in the overall thermal efficiency of these systems.