Experimental Investigation on Enhancement of Heat Transfer using γ-Al2O3–Water as a Nanofluid in a Finned Tube Heat Exchanger

Abstract

This research discusses the literature on experimental investigations of heat transfer improvement with the help of nanofluids in heat exchangers. The research does show that the performance of the compound is better in terms of heat transfer than the base fluids in the horizontal shell and tube heat exchangers. Nevertheless, the viscosity increases with the nanoparticle concentration, and this influences the friction factor. This study reveals that the application of nanofluids increases the performance of heat exchangers in the cross-flow low integral finned tubes. The experimental studies reveal that there is an enhancement in thermal conductivity and heat transfer coefficients in Al₂O₃/distilled water nanofluid that makes them suitable for improving the heat exchanger efficiency. The experiments were performed at concentrations of γ-Al₂O₃ of 0.0%, 0.1%, and 0.5%, at the temperatures of 45 °C, 55 °C, and 65 °C, and at the γ-Al₂O₃/water flow rates of 2, 4, and 6 LPM. Experiments reveal that finned tubes increase the heat transfer coefficients, which is useful for understanding the performance of heat exchangers under various operating conditions. For instance, the addition of 0.5% Al₂O₃ resulted in an increase of heat transfer rate by 30% and heat transfer coefficient by 22% when the flow rate was 4 LPM and the temperature was 65°C. The Nusselt number also rose by 8% for Al₂O₃ nanofluid compared to distilled water under the same conditions. This research supports that under optimized concentrations of nanofluids, thermal management in heat exchangers is enhanced with the thermal efficiency increasing with the Re to a point of optimum at Re=7000. This work improves heat transfer in finned tube heat exchangers with nanomaterial-water mixtures and presents correlations, recommendations, and directions for further work.