Experimental study of the heat transfer coefficient of an automobile radiator using alumina & titania based nanofluids as coolants

Better engine cooling capability remains a desperate challenge in automotive heat management, as traditional water-ethylene glycol coolants regularly manifest limited heat transfer potential.This work investigates the improvement of radiator operation using alumina and titania-based nanofluids as a progressive heat-transfer approach.Nanofluids were produced by ultrasonic dispersion of nanoparticles (0.02-0.08 vol%) in water-ethylene glycol mixtures, followed by experimental testing in a customized automobile radiator test rig at an inlet temperature of 65°C and flow rates of 7-14 L min -1 .The specific-heat equation was employed to determine the rate of heat transfer, and differential surface-fluid temperature analyses were used to obtain convective heat-transfer coefficients.The results show that adding alumina and titania nanoparticles notably enhances heat transfer.The hybrid nanofluid (0.06 vol% alumina + 0.02 vol% titania) achieved a highest heat transfer coefficient of nearly 6400 W m -2 K -1 , depicting a 155.6% increase over distilled water and about 60% advancement compared to the base water-ethylene glycol mixture.Radiator efficacy improved by 25-47%, while specific heat capacity was reduced by up to 73%, specifying a faster heating-cooling reaction.The results proposed that nanoparticle-induced micro-convection and improved thermal conduction govern the observed enhancements.The novelty of this work lies in experimentally quantifying the integrated thermal impact of alumina-titania nanofluids under practical automotive conditions, extending existing literature focused primarily on single nanoparticles.These results provide design insights for developing high-efficiency cooling systems in electronic thermal management, automobiles, and renewable-energy heat exchangers.