The stated experiment focused on the study of convective heat transfer and friction loss in a circular flow passage for Graphene oxide based nanofluids which are consist of Graphene Oxide/DW with their different wt.% concentrations. These Graphene oxide/DW based nanofluids were been prepared by using the facile two-step method, while the Graphene oxide nanoparticles were synthesized by the modified hummer method. Four different (0.025, 0.05, 0.075, and 0.1 wt. %) were produced by dispersing exfoliated graphene oxide nanoparticles in distilled water under high probe sonication. The Graphene Oxide/DW based nanofluids flowing in a horizontal circular heat exchanger counter flow under turbulent flow conditions were been investigated for heat transfer, Nusselt numbers, pressure drop, and friction loss studies. The constant heat flux and varying flow rate conditions have been used to analyze the heat transfer improvement in a circular heat exchanger. The results showed that the convective heat transfer coefficient of the nanofluids is slightly higher than the base fluid at the same flow rate and the same inlet temperature. The heat transfer coefficient of the Graphene Oxide/DW based nanofluids increased by almost 9.8%, 15.2%, 18.9%, and 26% for a concentration of 0.025wt%, 0.05wt%, 0.075wt%, 0.1wt% respectively when compared which is more than base fluid to distilled (DW).  However, an increase in the concentration causes an increase in the viscosity of the nanofluid leading to a slight increase in the friction factor. All the wt.% concentrations of Graphene Oxide/DW based nanofluids give improved heat transfer properties as compared to the based fluid without using solid graphene oxide nanoparticles.