Effect of Ultra-Low Concentrated Reduced Graphene Oxide Nanofluid on Radiator Performance

Abstract

Abstract Nano-coolants are engineered colloidal suspensions of nanoparticles in the conventional coolant (water-ethylene glycol). Use of metals and metallic oxide nanofluids at concentrations greater than 0.01 vol. % have been studied in greater detail compared to functionalized graphene nanofluids. In the present work, an experimental investigation is carried out on an automobile radiator by changing the conventional coolant to reduced graphene oxide nano-coolant. The present study focuses on the effect of ultra-low nanoparticle concentration (0.002-0.006 vol. %), Reynolds number of hot coolant (80 - 170), Reynolds number of air (210 - 270), and inlet temperature of hot coolant (40 ºC and 60 ºC). The effect of these parameters on the performance of the radiator is measured in terms of convective heat transfer coefficient (CHTC), Nusselt number, friction factor and effectiveness. Results show that at 0.006 vol. % concentration, a maximum increase of 100.5 % and 111% respectively, in CHTC and effectiveness with a reduction in friction factor. Reduced graphene oxide nano-coolant offers great scope for reducing the radiator size and increasing its performance.