Experimental and numerical study of nanofluid flow and heat transfer over microscale forward-facing step

Experimental and numerical investigations are presented to illustrate the nanofluid flow and heat transfer characteristics over microscale forward-facing step (MFFS). The duct inlet and the step height were 400μm and 600μm respectively. All the walls are considered adiabatic except the downstream wall was exposed to a uniform heat flux boundary condition. The distilled water was utilized as a base fluid with two types of nanoparticles Al₂O₃ and SiO₂ suspended in the base fluid. The nanoparticle volume fraction range was from 0 to 0.01 with an average nanoparticle diameter of 30nm. The experiments were conducted at a Reynolds number range from 280 to 480. The experimental and numerical results revealed that the water-SiO₂ nanofluid has the highest Nusselt number, and the Nusselt number increases with the increase of volume fraction. The average friction factor of water-Al₂O₃ was less than of water-SiO₂ mixture and pure water. The experimental results showed 30.6% enhancement in the average Nusselt number using water-SiO₂ nanofluid at 1% volume fraction. The numerical results were in a good agreement with the experimental results.