Effect of Nanoparticle Diameter on Nanofluid Turbulent Forced Convective Heat Transfer in a Square Cross-Sectioned Horizontal Channel
Mutlu TEKİR Recep EKİCİLER Kamil ARSLAN
AbstractThis study investigates the heat transfer enhancements of CuO nanofluid according to nanoparticle size. For maximum heat transfer enhancement, optimum nanoparticle diameter is going to be found. In this numerical study, forced convection nanofluid flow in a 0.01-m x 0.01-m cross-sectioned and 3-m long square duct under turbulent flow regime was investigated. Constant heat flux of 20 kW/m2 was applied to the surfaces of the duct. CuO/water nanofluid was used in analyses to enhance the convective heat transfer of the base fluid. Thermo-physical properties of nanofluid are constant. Analyses were performed for Reynolds numbers between 104 and 105, also for volume concentrations between 0% and 4%. The finite volume discretization method was used to solve the governing equations. Single phase model was considered. Thermophysical properties of the nanofluid were found thanks to the single phase correlations which depended on nanoparticle diameter. The effects of nanoparticle diameter on velocity distribution, average Nusselt number, and average Darcy friction factor were investigated in detail. The results indicate that higher volume concentrations of CuO/water nanofluid offers more average convective heat transfer enhancement. Higher nanoparticle size nanofluids offer lower enhancement