Experimental investigation on turbulent convection heat transfer of SiC/W and MgO/W nanofluids in a circular tube under constant heat flux boundary condition

The main purpose of this research is to investigate the effect of using SiC/water and MgO/water nanofluids on convection heat transfer in a circular tube with constant heat flux boundary condition. Thermophysical properties of these nanofluids, such as viscosity, density, and thermal conductivity, have also been measured and reported. SiC nanoparticles with 50 nm diameters at 0.04–0.2% volume concentrations and MgO nanoparticles with a size of 40 nm and volume concentration ranging from 0.02 to 0.12% are used to make the nanofluids. This study is done in a vertically oriented straight stainless steel tube under turbulent flow condition. Results of heat analysis showed that both Gnielinski and Hausen correlations underpredict the experimental data. Two models have been developed to predict heat parameters of nanofluids based on Gnielinski and Hausen correlations using experimental data. Modified correlations can precisely estimate Nusselt number and heat transfer coefficient of nanofluids in the range of nanoparticles studied with maximum errors of less than 1%. The average increase in Nusselt number for SiC/water and MgO/water nanofluids in the entire range of Reynolds number and volume percent used in this work is 8.88 and 5.71%, respectively, compared to distilled water under similar conditions.