Forced convective heat transfer of non-Newtonian CMC-based CuO nanofluid in a tube

In the present study, the thermal and rheological characteristics of power-law non-Newtonian CMC-based CuO nanofluid in a tube is studied using ANSYS FLUENT software. The tube is under a constant heat flux and nanofluid’s viscosity is a function of shear rate and temperature. Two inlet velocity distributions of fully developed and uniform flow are employed. The volume fractions in the range of 0% to 4% and the Reynolds numbers in the range of 600 to 1500 are considered in the simulations. For both velocity profiles, the temperature and shear rate have considerable influences on the viscosity. Local heat transfer coefficient in the axial direction is enhanced by increasing the volume fraction. It was shown that the volume fractions less than 1.5% have an effect on local heat transfer slightly. It is revealed that as the Reynolds number increases, the local heat transfer and the average Nusselt number decrease. In conflict with the previous investigations, the present results show that the average Nusselt number is reduced by increasing the volume fraction of nanoparticles.