Heat Transfer and Pressure Drop Augmentation of a Helically Coiled Tube with Using Graphene Nanoplatelet-Water Nanofluid

In the present study, to investigate the effect of GnP-water nanofluid mass fraction on heat transfer and fluid friction characteristics in a helically coiled heat exchanger tube a numerical study is carried out. The impact of various mass fraction (0.5, 0.75, 1.00 %) of GnP-water nanofluid on Nusselt number and friction factor is studied for Reynolds number ranging from 7000 to 13000. The numerical solution procedure includes the investigation of heat transfer and pressure drop characteristics with using finite volume method with the Transition SST model is based on the coupling of the SST k-ω transport equations to solve the continuity, momentum, energy and turbulence equations in three-dimensional domain. The use of GnP-water nanofluids with in the coiled heat exchanger tubes leads to increase in heat transfer and pressure drop over the smooth tube. The Nusselt number increases with the increment of the nanofluid concentrations and Reynolds number.  In conclusion, to enhance heat transfer, Graphene nanoplatelet-water nanofluids can be widely applied wherever helically coiled heat exchangers are used.