Enhanced heat transfer performance of an automobile radiator with graphene based suspensions

We report the convective heat transfer coefficient and pressure drop of graphene nanoplatelets seeded in water-ethylene glycol mixture flowing through an automobile radiator. The volume concentrations of graphene nanoplatelets were varied from 0.1% to 0.5%. Thermophysical properties such as thermal conductivity, viscosity, density and specific heat capacity of nanofluids were measured experimentally. Mass flow rate of nanofluids were varied from 10 g/s to 100 g/s. Nanofluid inlet temperature was considered as 35 degrees C and 45 degrees C while the ambient air velocity was fixed as 3 m/s for the convective heat transfer experiments. The convective heat transfer coefficient of nanofluids increases with increasing loading of graphene nanoplatelets, nanofluid inlet temperature and mass flow rate. The enhancement of convective heat transfer coefficient for the highest concentration (0.5 vol%) and highest mass flow rate (100 g/s) was found to be 20% and 51% when the nanofluid inlet temperature was 35 degrees C and 45 degrees C respectively. The pressure drop of nanofluid increases with respect to graphene nanoplatelets loading and mass flow rate. As the loading of nanoplatelets increases from 0 to 0.5 vol% the pressure drop increases from 3.07 to 4.88 kPa at 35 degrees C while it increases from 3.02 to 4.04 kPa at 45 degrees C for 100 g/s. The present nanofluid has a potential to replace the conventional heat transfer fluids leading to compact thermal systems. (C) 2017 Elsevier Ltd. All rights reserved.