A nanofluid is a new heat transfer fluid produced by mixing a base fluid and solid nano sized particles. It has been reported this fluid has great potential in heat transfer applications, because of its increased thermal conductivity and even increased Nusselt number due to higher thermal conductivity, Brownian motion of nanoparticles, and other various effects on heat transfer phenomenon. But its potential in heat transfer applications has not been confirmed yet due to lack of conclusive information to predict the performance in heat transfer equipments. The aim of this thesis work is to predict convective heat transfer of copper in ethylene glycol nanofluids both experimentally and numerically. A locally fabricated convective heat transfer set up and a computational fluid dynamics (CFD) code in ANSYS Fluent 2021 R2 was used to obtain results in a circular pipe with constant wall heat flux boundary conditions in a turbulent flow. The forced convective heat transfer was studied with horizontal circular smooth stainless-steel tube with Reynolds numbers varying in the range of 4000-10000 and volume concentration of 0.1%, 0.5%,1%. In this thesis work, the effect of several parameters such as Reynolds number, volume fraction and inlet temperature on heat transfer and flow characteristics were investigated. Both the experimental and numerical results, in a good agreement to each other (±5.7 % average deviation), show that the nanofluid with all values of particle concentrations achieved higher Nusselt number than pure ethylene glycol where the nanofluid with the highest particle concentration achieved the highest Nusselt number. For all the cases Nusselt number increased with the increase of Reynolds number and distance along the tube. On average scale, for Reynolds number of 10000 and inlet temperature of 303.15K, Nusselt number increases to 1.1 times for nanofluids of 1% particle concentration compared to the base fluid. Friction factor increases with increasing volume fraction and inlet temperature for both the numerical and experimental analyses. Keywords: Copper-ethylene glycol nanofluids, Constant heat flux, Turbulent flow, Circular pipe, Computational Fluid Dynamics (CFD), Heat transfer enhancement