Numerical study of flow and heat transfer characteristics of CuO/H2O nanofluid within a mini tube

Nanofluids are new heat transfer fluids, which improve thermal performance while reducing the size of systems. In this study, the numerical domain as a three-dimensional copper mini tube was simulated to study the characteristics of flow and heat transfer of CuO/H2O nanofluid, flowed horizontally within it. The selected model for this study was a two-phase mixture model. The results indicated that nanofluids with the platelet nanoparticles have better thermal performance than other shapes of nanoparticles such as cylindrical, Blade, Brick, and spherical nanoparticles, respectively. By studying the flow characteristics, it was found that the pressure drop and friction factor of the nanofluids are dependent on the shape of the nanoparticles so that the nanofluids containing spherical nanoparticles have the lowest reduction in the friction factor and nanofluids containing platelet-shaped nanoparticles have the highest reduction in friction factor. Furthermore, as new formulas, two correlations were suggested to calculate the Nusselt number of nanofluids according to the effect of nanoparticle shape on the laminar and turbulent flow regimes.