Numerical Study of Heat Transfer and Pressure Drop in Forced-convection Nanofluid flow through an internally ribbed pipe

Heat transfer and pressure drop in Al2O3-water nanofluid flow through an internally ribbed pipe is studied numerically. The governing conservation equations in cylindrical coordinates for laminar incompressible flow are solved using well-known SIMPLE algorithm based on finite-volume method. The effects of flow parameters, the distance between the pipe ribs, and the volume fraction of nanoparticles, on heat transfer and friction coefficient are investigated. The obtained results illustrate that increasing nanoparticles volume fraction makes the thermal entrance length decrease, and consequently, the heat transfer gets increased. It also reveals that 5% of increment in nanoparticles volume fraction may lead to 28-percent rise in local Nusselt number and about 11-percent rise in average Nusselt number. In this case, the friction factor will also increase about 1.5 times in comparison with the pure fluid ones. The results also show that increasing the pipe ribs distance by five times in Re=100, will make the average Nusselt number increase by 2.45 times.