Forced Convective Heat Transfer of MgO/Water Nanofluid under Constant Heat Flux: Experimental and Statistical Investigation

This paper examines experimentally and statistically the heat transfer of the internal convection of MgO-water nonofluids in a copper tube for a fully turbulent regime under constant heat flux boundary condition. The Nusselt number and convective heat transfer coefficients of nonofluids in different volumetric concentrations (0, 0.05%, and 0.15%) of nonofluids were estimated. Local convective heat transfer coefficient was also observed at different points along the pipe at different Reynolds numbers. The results showed that heat transfer coefficient increased with an increase in the flow rate of nofluids from 6 to 10 l/min and the concentration of nonofluids from 0 to 0.15 vol.%. Conversely, the heat transfer coefficient decreases with increasing the nanofluid inlet temperature from 30 to 40 °C. At concentrations of 0.05 and 0.15% vol.% of MgO nanoparticles, the increase in the Nusselt number compared to pure water is 21.2% and 45.9%, respectively. The Taguchi method was also used to analyze the results statistically. The maximum predicted value for the Nusselt number is 114.165, and the error between the experimental value and the predicted value is 1%. Also, the concentration of nanofluid has 54.362% contribution in the Nusselt number of MgO/water nanofluid