Hybrid nanocoolant for enhanced heat transfer performance in vehicle cooling system

Abstract

An enormous amount of heat generated from a vehicle engine could be removed fractionally by using a radiator. The struggle to maintain efficient heat exchange in a vehicle cooling system is arduous as both active and passive methods require time to catch up with high-power engine technologies. This study reported the heat transfer performance of a novel hybrid nanocoolant with various mixing ratios. The hybrid nanocoolant consisted of carboxyl-functionalised graphene nanoplatelets (CGnP) and titanium dioxide (TiO2) nanoparticles in a mixture of distilled water and ethylene glycol. The thermal performance of the hybrid nanocoolant was conducted using a test rig equipped with a crossflow type radiator. The effect of different hybrid mixing ratios, Reynolds number, and air inlet velocity on heat transfer performance was studied. The Nusselt number obtained with distilled water and base coolant was close to the Dehghandokht's and Shah-London's correlations. When CGnP-TiO2 (70:30) with 0.1 wt% concentration was mixed into the base coolant, 4.94%, 35.87%, and 20.48% of maximum increments were observed for Nusselt number, overall heat transfer coefficient, and effectiveness of radiator, respectively. The maximum error in estimating heat transfer performance using proposed correlations was less than 8%. It can be concluded that hybrid nanocoolant with different mixing ratios significantly affects heat transfer performance. This characteristic is vital for determining the best possible attributes in various nanocomposite combinations.