Enhanced heat transfer characteristics of water based hybrid nanofluids with graphene nanoplatelets and multi walled carbon nanotubes

Abstract A detailed experimental work on the convective heat transfer characteristics of water based hybrid nanofluids with Graphene Nanoplatelets and Multi Walled Carbon Nanotubes in the ratio 1:1 has been performed. Volume concentrations viz., 0.01%, 0.05%, 0.1%, 0.15% and 0.2% were considered. The hybrid nanofluid was passed through the micro channel heat sink which was electrically heated to simulate the heat load. The heat load was varied from 50 W to 200 W while the flow rate of nanofluid was varied from 5 g/s to 30 g/s. The thermal conductivity of the 0.2 vol% nanofluid was 25% higher than the base fluid while the convective heat transfer coefficient was enhanced by 85% leading to a reduction of heat sink temperature by 12 °C. Variations of friction factor during nanofluid flow were nearly constant with respect to Reynolds number and volume concentration of the nanomaterials. This shows the absence of any penalty in the pressure drop with the addition of nanomaterials. The results showed the hybrid nanofluid (Graphene Nanoplatelets /Multi Walled Carbon Nanotubes-water) as an effective coolant for the replacement of the conventional coolant for electronic cooling applications.