Mixed convective of hybrid nanofluids flow in a backward-facing step

Abstract

Convective of hybrid nanofluids heat transfer flow over backward facing step in a heated rectangular duct under laminar flow is performed experimentally. It is used mixing of Al2O3 and TiO2 solid nanoparticles suspended in pure water. The preparation process of hybrid nanofluid for 1%, 2% and 3% mass fraction has been conducted. The test rig of this experimental study has been fabricated then both temperature and pressure drop along the duct have been measured. The duct is heated from the bottom by using an electrical heater and the other walls are being insulated. Results of heat transfer enhancement and pressure drop are indicated. It was observed that Nusselt number increases with increase of Reynolds number and mass fraction while, friction factor decreases as decrease of Reynolds number and increase of mass fraction. It is concluded that significant using the hybrid nanofluid through facing step. The enhancement of heat transfer and pressure drop are approximately 14% and 4% respectively.