Experimental study of free single jet impingement utilizing high concentration SiO2 nanoparticles water base nanofluid

An experimental investigation was conducted in order to study heat transfer between a vertical free surface jet and a horizontal stainless steel heated plate. The jet was composed of water-SiO2 nanofluid with an average particle size of 8 nm delivered from a fixed nozzle diameter of 6 mm. The results covered a wide range of jet Reynolds number up to 40000, ten nanoparticle volume fractions (0% <= phi <= 8.5%), five jet aspect ratios (z/d = 0.5, 1, 2, 4 and 8) and plate radius to jet diameter ratio (r/d) up to 12.5. The experimental results illustrated that the enhancement of the average Nusselt number increases with the volume fraction and Reynolds number. Therefore, the volume fraction can significantly provide a heat transfer enhancement of the average Nusselt number up to 80% for a volume fraction of 8.5% compared to pure water. Conversely, the effect of nozzle to plate aspect ratio (z/d) is not significant. Finally, a new heat transfer correlation has been proposed for the average Nusselt number as a function of Peclet number, a nanoparticle volume fraction, a plate to jet diameter ratio and a nozzle to plate aspect ratio.