Performance Analysis of Compact Heat Exchanger Using Reduced Graphene Oxide Nanofluid

A radiator is a heat exchanger which uses convection to transfer heat from hot fluid to cold fluid. Staggered fin cross flow heat exchangers use atmospheric air as a cold fluid which is used in automobiles to cool internal combustion engines. A wind tunnel is provided with the rig which is used to produce similar conditions as present in an automobile radiator. A conventional coolant comprises a mixture of ethylene glycol and water in varying combining ratios. The preparation of reduced graphene oxide nanofluid in this study is done using the two-step method, which involves preparing base fluid and separately adding nanoparticles into it in the desired concentration. Reduced Graphene Oxide was suspended in the base fluid using a probe and ultra sonicator using sonication. This solution was then used to analyze heat transfer properties in a compact heat exchanger. This study involves analyzing (0.03 vol%—0.05%) vol. concentration of nanoparticles in the nanofluid by varying the Reynolds number of hot coolants from 80 to 140 and varying the Reynolds number of air from 210 to 250 at inlet temperatures of 50 and 60 °C. The results obtained indicate how effective nanofluids are over base fluids which are water + ethylene glycol. The effectiveness of the nanofluids is studied using factors such as friction factor, the Nusselt number, and effectiveness. The results obtained from the experiment show (i) a reduction in the friction factor as the flow rate increases, (ii) an increase in the Nusselt number at higher concentrations, and (iii) a maximum increase in the effectiveness of 74% from the base fluid at 0.05 vol% concentrations of nanoparticles.