Numerical simulation of nanofluid flow and heat transfer in a microchannel: The effect of changing the injection layout arrangement

This study simulated the forced convective heat transfer of water/alumina nanofluid in a rectangular microchannel. Three techniques were used to enhance heat transfer. First, three top fluid injection points and three bottom ones (six injections in total) were added to the base microchannel. Different fluid injection layouts and their effect on enhancing the thermal performance of the microchannel were then investigated. Results supported the substantial effect of fluid injection layout on heat transfer as the mean Nusselt number was increased by a maximum of 25% (best layout) in high Reynolds numbers. The second technique involved adding of nanofluid to the base fluid. Results showed that adding nanofluid to the base microchannel increased the Nusselt number by a maximum of 3.5%. In the third technique, the fluid injection was added to a microchannel containing nanofluid. Results showed that injection in the presence of a nanofluid improved the Nusselt number by 28%. All three techniques entailed both a positive effect (increased heat transfer) and a negative effect (increased pressure drop). In the most effective technique, the pressure drop was 40% higher than the base microchannel at the point with maximum heat transfer.