Background: Automotive radiators rely on the thermophysical properties of the circulating coolant to reject engine heat to the surrounding air, and conventional water-ethylene glycol mixtures possess comparatively low thermal conductivity, motivating research into nanoparticle-enhanced coolants, or nanofluids, as a means of improving heat rejection without increasing radiator size or weight.

Objective: This study evaluates the effect of dispersing Al2O3 and CuO nanoparticles, at volume concentrations of 0.1%, 0.3%, 0.5%, 1.0%, 1.5%, and 2.0%, in a 50:50 water-ethylene glycol base fluid on the overall heat transfer coefficient, heat transfer enhancement, and pumping power penalty of a simulated automotive radiator test loop.

Method: A simulated dataset, modelled on patterns reported in published experimental research on Al2O3 and CuO automotive radiator nanofluids, was used to evaluate overall heat transfer coefficient, Nusselt number, heat transfer enhancement, and pumping power penalty across thirty-six simulated test runs (six concentration levels, two nanoparticle types, three replicates). Data were analysed using descriptive statistics and one-way analysis of variance (ANOVA) in SPSS (version 27).

Key Results: Both nanofluids increased the overall heat transfer coefficient relative to the base fluid, with CuO/water-ethylene glycol nanofluid outperforming Al2O3/water-ethylene glycol at every tested concentration, achieving a maximum enhancement of approximately 30.4% at 1.5% volume concentration before performance plateaued at 2.0%. Pumping power penalty increased monotonically with concentration, reaching approximately 42.6% at 2.0% concentration for the CuO nanofluid, exceeding the corresponding heat transfer gain beyond approximately 1.5% concentration.