Numerical investigation of fluid flow and heat transfer of nanofluids in microchannel with longitudinal fins

Thermal and hydraulic characteristics of laminar nanofluid flow in square microchannel with longitudinal inner fins are numerically investigated. The external walls of microchannel are heated at constant heat flux and four rectangular fins are fixed on the internal walls. Four different types of nanofluid are used as working fluids which are SiO₂, Al₂O₃, CuO and ZnO dispersed in pure water base fluid. Different volume fractions of 1–2% and different nanoparticle diameters of 30–60 nm are employed. The results show that the SiO₂ nanofluid has the highest heat transfer rate among all of four tested nanofluids. The increase in nanoparticle volume fraction and the decrease in the nanoparticle diameter would increase the Nusselt number value. The friction factor does not change significantly by using nanofluid with different volume fractions and different nanoparticle diameters. Moreover, the results indicate that nanofluid can enhance the performance of microchannel with longitudinal fins.