Simulation of Nanofluid Flow Through Rectangular Microchannel by Modified Thermal Dispersion Model

In this study, the thermal performance of Al2O3/water nanofluid flows through a rectangular microchannel heat sink with constant heat flux boundary condition is numerically investigated. A modified dispersion model was applied to the energy equation to take into account the effect of nanoparticle presences on the heat transfer rate and the best values of dispersion coefficient which is sensitive to the value Reynolds number were obtained. According to the numerical results, it is possible to predict the thermal performance of nanofluid flows by application of the dispersion model well. Appropriate agreement with experimental data was observed. Also, the effects of Reynolds number ranging from 100 to 300, nanoparticle concentrations and diameters, aspect ratio and heating power on the thermal performance were analyzed. Decreasing the nanoparticles diameter as well as increasing the nanoparticles volume fraction enhance the Nusselt number values. The maximum enhancements of average Nusselt number, around 38%, was observed at Reynolds number of 100 for 1.0% volume concentration of nanofluid flow. For the studied system, the optimum value of aspect ratio was obtained to be 0.526.