Numerical investigation of heat transfer and laminar Water-Al2O3 ‎nanofluid flow in a rectangular Rib-Microchannel

This paper numerically examines the laminar forced convection of a water–Al2O3 nanofluid flowing through a horizontal rib-microchannel. The middle section of the down wall microchannel is Affected by cold temperatures with a constant and uniform tempreture Tc. The middle section is also influenced by a transverse rib array. The effects of height rib in a two dimensional rib-microchannel on flow and heat transfer parameters of laminar water-Al2O3 nanofluid are investigated. The characteristics of this research are numerically investigated by the commercial software Fluent 6.3 in a Reynolds number as Re=10 and Re=100. Four different states of hight rib are analyzed. Higher conventional internal ribs or increasing the turbulators can significantly improve the performances of the convective heat transfer within a microchannel. It is seen that larger height rib and volume fraction of nanoparticles corresponds more heat transfer rate; however the added high ribs can cause a larger friction factor than that in the corresponding microchannel by constant height rib. At present article the effect of height rib on the fluid flow parameters are also studied for all different states of it. The results show that the microchannel performs better heat transfers at higher values of the Reynolds numbers. For all values of the Reynolds numbers and volume fraction of nanoparticles considered in this study, the average Nusselt number on the middle section surface of the microchannel increases as the solid volume fraction increases.