Document Type : Original Research Paper
Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
This paper examines experimentally 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 a larger heat transfer coefficient with nonoﬂuids compared to the base fluid. 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 .Nusselt numbers increased to 45.9% as a result of the implementation of nonoﬂuids at concentration of 0.15 vol.% in comparison with the base ﬂuid. The Taguchi method was also used to analyze the results statistically. The maximum Nusselt number in nonoﬂuids, the effect of each operational parameter on the Nusselt number, as well as the optimal values of each parameter was determined.