▎ 摘　　要

Recent studies showed that nanofluids are considered as a promising way to enhance the heat transfer properties of coolants. Currently, in a car radiator forced convection heat transfer method is carried out to cool circulating fluid. The mixture of water with either ethylene or propylene-glycol is necessary to lower its freezing point and eliminate ice formation. However, the boiling point of deionized water can be pushed up by mixing it with anti-freezing materials like ethylene glycol (EG). Hence the present research work focuses on the heat transfer characteristics of nano-fluids with different combinations of EG and deionized water (60:40, 30:70, and 20:80) along with graphene oxide (GO) nanoparticles (0.1 % wt). The heat transfer potential of graphene oxide/ deionized water-ethylene glycol nanofluids is experimentally investigated in coolant application for car radiators, in which the coolant flow rate is varied from 180 to 420 (LPH) at a fixed coolant temperature of 90 degrees C. The evaluation of stability is performed using visual inspection and zeta potential test. The density of nanofluid was determined by oscillating U-Tube density meter. The optimized combination of 60% EG, 40% DW and 0.1 wt% GO exhibited higher heat transfer characteristics of the radiator system used. The maximum heat transfer enhancement of 42.77% at 300 LPH, 18.14% at 360 LPH, and 71.1% at 240 LPH for 60:40 EG/DW-based GO nanofluids were obtained. The maximum Nusselt number value of 192 at 420 LPH was observed for 60:40 EG/DW-based GO nanofluid as compared with 20:80, 30:70 EG/DW-based GO nanofluid. It is estimated that by replacing conventional coolant with this nanofluid, reduction in the frontal area of radiator is done which gives more flexibility for industrial design, more eco-friendly vehicle which produces less drag and hence less the fuel cost. (c) 2021 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).