NUMERICAL INVESTIGATION ON LAMINAR FORCED CONVECTION IN TRIANGULAR CROSS SECTION MINI DUCTS WITH NANOFLUIDS AND RECTANGULAR RIBS

In this paper a numerical investigation on laminar forced convection flow of a nanofluid, water–alumina nanoparticles, in a mini duct with triangular cross section is accomplished with the lower heated surface with transversal ribs. A constant and uniform heat flux on the bottom surface of the heat sink is applied and a mixture model approach is employed to simulate the nanofluid flow. The analysis is performed for a three-dimensional combined conductive-convective heat transfer in a square section with triangular duct, at steady state regime. The CFD commercial code Fluent is employed to solve the three-dimensional numerical model by means of a finite volume technique. The investigation is carried out for Reynolds number in the range from 100 to 2000, volumetric concentration of nanoparticles equal to 0% 4% and 6%. Results are presented in terms of temperature and velocity distributions, surface shear stress and heat transfer convective coefficient, Nusselt number and required pumping power profiles for different nanoparticle volume fractions. Comparison with results related to the fluid dynamic and thermal behaviors highlights the enhancement in heat transfer, with respect to the base fluid, due to the presence of nanoparticles.