Experimental Investigation of Heat Transfer Enhancement in a Shell and Tube Heat Exchanger Using Al₂O₃ Nanofluids and Ethylene Glycol Mixtures

Abstract

Improving the thermal performance of shell and tube heat exchangers is a major area of research in thermal engineering, driven by energy efficiency requirements across power generation, chemical processing, HVAC, and automotive cooling applications. This paper presents an experimental investigation of heat transfer characteristics in a 19-tube copper shell and tube heat exchanger using three heat transfer fluids: distilled water (baseline), ethylene glycol-water mixture (30:70 by volume), and aluminium oxide (Al2O3) nanofluid in water at concentrations of 0.5, 1.0, and 1.5 volume percent. Al2O3 nanoparticles of 40 nm average diameter were synthesised by the co-precipitation method and characterised by XRD and TEM. Experiments were conducted at cold fluid flow rates of 0.5 to 2.0 LPM and a fixed hot water shell-side temperature of 70°C. The Nusselt number, overall heat transfer coefficient, heat transfer rate, pressure drop, and thermal enhancement factor were determined for all fluid-flow rate combinations. Results show that Al2O3 nanofluid at 1.0 vol% achieves 21.2 percent higher Nusselt number and 21.6 percent higher overall heat transfer coefficient compared to water at a Reynolds number of 4480, with only 10.9 percent increase in pressure drop, yielding a thermal enhancement factor of 1.28. Ethylene glycol mixture shows inferior heat transfer despite higher viscosity, due to reduced Reynolds number at equivalent flow rate. An empirical Nusselt number correlation for the tested nanofluid in the turbulent regime is developed with R² of 0.974.

Cite as:

Wakurde P B. (2026). Experimental Investigation of Heat Transfer Enhancement in a Shell and Tube Heat Exchanger Using Al₂O₃ Nanofluids and Ethylene Glycol Mixtures. Research and Reviews: Journal of Mechanical Engineering, 2(2), 31–39. https://doi.org/10.5281/zenodo.21849726