Turbulent flow and heat transfer of Water/Al2O3 nanofluid inside a rectangular ribbed channel

In present study, the turbulent flow and heat transfer of Water/Al2O3 nanofluid inside a rectangular channel have been numerically simulated. The main purpose of present study is investigating the effect of attack angle of inclined rectangular rib, Reynolds number and volume fraction of nanoparticles on heat transfer enhancement. For this reason, the turbulent flow of nanofluid has been simulated at Reynolds numbers ranging from 15000 to 30000 and volume fractions of nanoparticles from 0 to 4%. The changes attack angle of ribs have been investigated ranging from 0 to 180°. The results show that, the changes of attack angle of ribs, due to the changes of flow pattern and created vortexes inside the channel, have significant effect on fluid mixing. Also, the maximum rate of heat transfer enhancement accomplishes in attack angle of 60°. In Reynolds numbers of 15000, 20000 and 30000 and attack angle of 60°, comparing to the attack angle of 0°, the amount of Nusselt number enhances to 2.37, 1.96 and 2 times, respectively. Also, it can be concluded that, in high Reynolds numbers, by using ribs and nanofluid, the performance evaluation criterion improves.