Influence of nanofluid on turbulent forced convective flow in a channel with detached rib-arrays

In this paper forced convection turbulent nanofluid flow is numerically investigated to analyze the effects of different types of nanoparticles with different nanoparticle parameters in a fully detached ribbed channel. The bottom wall of the channel is kept at a constant temperature while the upper wall is thermally insulated. The continuity, momentum and energy equations were discretized and solved by the Finite Volume Method (FVM). The influence of different types of nanoparticles (Al2O3, CuO, SiO2, and ZnO) with nanoparticle concentration (1% to 4%) and nanoparticle diameter (20 nm to 50 nm) suspended in a water as a base fluid is studied on the heat transfer enhancement, friction factor and pressure drop. The Reynolds number was in the range of 10,000 to 50,000 in a rectangular channel having mounted rectangular ribs on its bottom wall with clearance ratio of 0.1. The results indicate that the highest heat transfer enhancement is achieved with SiO2 nanofluid and the friction factor did not considerably change with using different types of nanoparticles in the base fluid. Furthermore, increment of nanoparticle concentration or Reynolds number has a positive impact on heat transfer enhancement due to the increment of the velocity and thermal conductivity of the mixture. However, a rise of nanoparticle diameter decreases the heat transfer enhancement due to stronger Brownian motion even at lower nanoparticle diameter. (c) 2013 Elsevier Ltd. All rights reserved.