Combined convective heat transfer of nano fluids flow over triple backward facing step having baffle on its upper wall

Abstract

Numerical simulation of turbulent combined convective heat transfer of nanofluid flow over a two-dimensional horizontal backward-facing step (BFS) with baffle on its upper wall are carried out. The Reynolds number used in this study ranged from 7500 to 10000. The heating process corresponds to a channel heated from below at constant temperature keeping all other channel walls insulated. The momentum and energy equations were discretized by means of a finite volume technique. The SIMPLE algorithm scheme was applied to link the pressure and velocity fields inside the domain for four different types of nanoparticles, TiO2, Al2O3, CuO, and SiO2, with 3 % volume fraction and particle diameter of 20nm in a base fluid (water). In this thesis, several parameters such as Reynolds number, types of nanoparticle with different shapes( spherical, cylindrical, and plate)are investigated to identify their effects on the flow and thermal fields over BFS geometries. The numerical results indicate that nanofluids with low density nanoparticles such as SiO2withplate shape of nanoparticles has higher velocity than those with high density nanoparticles such as CuO. The two types of nanofluid achieved higher Nusselt number than other nanofluids. The result of Nusselt number shows that with using nanofluid the Nusselt number increases 16% and subsequently heat transfer increases